diff options
Diffstat (limited to 'pkg/sentry')
414 files changed, 15783 insertions, 4465 deletions
diff --git a/pkg/sentry/arch/arch_aarch64.go b/pkg/sentry/arch/arch_aarch64.go index 343f81f59..0f433ee79 100644 --- a/pkg/sentry/arch/arch_aarch64.go +++ b/pkg/sentry/arch/arch_aarch64.go @@ -17,7 +17,6 @@ package arch import ( - "encoding/binary" "fmt" "io" @@ -29,7 +28,14 @@ import ( ) // Registers represents the CPU registers for this architecture. -type Registers = linux.PtraceRegs +// +// +stateify savable +type Registers struct { + linux.PtraceRegs + + // TPIDR_EL0 is the EL0 Read/Write Software Thread ID Register. + TPIDR_EL0 uint64 +} const ( // SyscallWidth is the width of insturctions. @@ -49,9 +55,14 @@ const ARMTrapFlag = uint64(1) << 21 type aarch64FPState []byte // initAarch64FPState sets up initial state. +// +// Related code in Linux kernel: fpsimd_flush_thread(). +// FPCR = FPCR_RM_RN (0x0 << 22). +// +// Currently, aarch64FPState is only a space of 0x210 length for fpstate. +// The fp head is useless in sentry/ptrace/kvm. +// func initAarch64FPState(data aarch64FPState) { - binary.LittleEndian.PutUint32(data, fpsimdMagic) - binary.LittleEndian.PutUint32(data[4:], fpsimdContextSize) } func newAarch64FPStateSlice() []byte { @@ -90,6 +101,8 @@ func NewFloatingPointData() *FloatingPointData { // State contains the common architecture bits for aarch64 (the build tag of this // file ensures it's only built on aarch64). +// +// +stateify savable type State struct { // The system registers. Regs Registers @@ -97,9 +110,6 @@ type State struct { // Our floating point state. aarch64FPState `state:"wait"` - // TLS pointer - TPValue uint64 - // FeatureSet is a pointer to the currently active feature set. FeatureSet *cpuid.FeatureSet @@ -153,7 +163,6 @@ func (s *State) Fork() State { return State{ Regs: s.Regs, aarch64FPState: s.aarch64FPState.fork(), - TPValue: s.TPValue, FeatureSet: s.FeatureSet, OrigR0: s.OrigR0, } @@ -237,18 +246,18 @@ func (s *State) ptraceGetRegs() Registers { return s.Regs } -var registersSize = (*Registers)(nil).SizeBytes() +var ptraceRegistersSize = (*linux.PtraceRegs)(nil).SizeBytes() // PtraceSetRegs implements Context.PtraceSetRegs. func (s *State) PtraceSetRegs(src io.Reader) (int, error) { var regs Registers - buf := make([]byte, registersSize) + buf := make([]byte, ptraceRegistersSize) if _, err := io.ReadFull(src, buf); err != nil { return 0, err } regs.UnmarshalUnsafe(buf) s.Regs = regs - return registersSize, nil + return ptraceRegistersSize, nil } // PtraceGetFPRegs implements Context.PtraceGetFPRegs. @@ -274,7 +283,7 @@ const ( func (s *State) PtraceGetRegSet(regset uintptr, dst io.Writer, maxlen int) (int, error) { switch regset { case _NT_PRSTATUS: - if maxlen < registersSize { + if maxlen < ptraceRegistersSize { return 0, syserror.EFAULT } return s.PtraceGetRegs(dst) @@ -287,7 +296,7 @@ func (s *State) PtraceGetRegSet(regset uintptr, dst io.Writer, maxlen int) (int, func (s *State) PtraceSetRegSet(regset uintptr, src io.Reader, maxlen int) (int, error) { switch regset { case _NT_PRSTATUS: - if maxlen < registersSize { + if maxlen < ptraceRegistersSize { return 0, syserror.EFAULT } return s.PtraceSetRegs(src) diff --git a/pkg/sentry/arch/arch_amd64.go b/pkg/sentry/arch/arch_amd64.go index 3b3a0a272..1c3e3c14c 100644 --- a/pkg/sentry/arch/arch_amd64.go +++ b/pkg/sentry/arch/arch_amd64.go @@ -300,7 +300,7 @@ func (c *context64) PtracePeekUser(addr uintptr) (interface{}, error) { // PTRACE_PEEKUSER and PTRACE_POKEUSER are only effective on regs and // u_debugreg, returning 0 or silently no-oping for other fields // respectively. - if addr < uintptr(registersSize) { + if addr < uintptr(ptraceRegistersSize) { regs := c.ptraceGetRegs() buf := make([]byte, regs.SizeBytes()) regs.MarshalUnsafe(buf) @@ -315,7 +315,7 @@ func (c *context64) PtracePokeUser(addr, data uintptr) error { if addr&7 != 0 || addr >= userStructSize { return syscall.EIO } - if addr < uintptr(registersSize) { + if addr < uintptr(ptraceRegistersSize) { regs := c.ptraceGetRegs() buf := make([]byte, regs.SizeBytes()) regs.MarshalUnsafe(buf) diff --git a/pkg/sentry/arch/arch_arm64.go b/pkg/sentry/arch/arch_arm64.go index ada7ac7b8..550741d8c 100644 --- a/pkg/sentry/arch/arch_arm64.go +++ b/pkg/sentry/arch/arch_arm64.go @@ -73,6 +73,8 @@ const ( ) // context64 represents an ARM64 context. +// +// +stateify savable type context64 struct { State sigFPState []aarch64FPState // fpstate to be restored on sigreturn. @@ -142,7 +144,7 @@ func (c *context64) SetStack(value uintptr) { // TLS returns the current TLS pointer. func (c *context64) TLS() uintptr { - return uintptr(c.TPValue) + return uintptr(c.Regs.TPIDR_EL0) } // SetTLS sets the current TLS pointer. Returns false if value is invalid. @@ -151,7 +153,7 @@ func (c *context64) SetTLS(value uintptr) bool { return false } - c.TPValue = uint64(value) + c.Regs.TPIDR_EL0 = uint64(value) return true } diff --git a/pkg/sentry/arch/arch_x86.go b/pkg/sentry/arch/arch_x86.go index dc458b37f..b9405b320 100644 --- a/pkg/sentry/arch/arch_x86.go +++ b/pkg/sentry/arch/arch_x86.go @@ -31,7 +31,11 @@ import ( ) // Registers represents the CPU registers for this architecture. -type Registers = linux.PtraceRegs +// +// +stateify savable +type Registers struct { + linux.PtraceRegs +} // System-related constants for x86. const ( @@ -311,12 +315,12 @@ func (s *State) ptraceGetRegs() Registers { return regs } -var registersSize = (*Registers)(nil).SizeBytes() +var ptraceRegistersSize = (*linux.PtraceRegs)(nil).SizeBytes() // PtraceSetRegs implements Context.PtraceSetRegs. func (s *State) PtraceSetRegs(src io.Reader) (int, error) { var regs Registers - buf := make([]byte, registersSize) + buf := make([]byte, ptraceRegistersSize) if _, err := io.ReadFull(src, buf); err != nil { return 0, err } @@ -374,7 +378,7 @@ func (s *State) PtraceSetRegs(src io.Reader) (int, error) { } regs.Eflags = (s.Regs.Eflags &^ eflagsPtraceMutable) | (regs.Eflags & eflagsPtraceMutable) s.Regs = regs - return registersSize, nil + return ptraceRegistersSize, nil } // isUserSegmentSelector returns true if the given segment selector specifies a @@ -543,7 +547,7 @@ const ( func (s *State) PtraceGetRegSet(regset uintptr, dst io.Writer, maxlen int) (int, error) { switch regset { case _NT_PRSTATUS: - if maxlen < registersSize { + if maxlen < ptraceRegistersSize { return 0, syserror.EFAULT } return s.PtraceGetRegs(dst) @@ -563,7 +567,7 @@ func (s *State) PtraceGetRegSet(regset uintptr, dst io.Writer, maxlen int) (int, func (s *State) PtraceSetRegSet(regset uintptr, src io.Reader, maxlen int) (int, error) { switch regset { case _NT_PRSTATUS: - if maxlen < registersSize { + if maxlen < ptraceRegistersSize { return 0, syserror.EFAULT } return s.PtraceSetRegs(src) diff --git a/pkg/sentry/control/BUILD b/pkg/sentry/control/BUILD index e74275d2d..2c5d14be5 100644 --- a/pkg/sentry/control/BUILD +++ b/pkg/sentry/control/BUILD @@ -16,14 +16,12 @@ go_library( ], deps = [ "//pkg/abi/linux", - "//pkg/context", "//pkg/fd", - "//pkg/fspath", "//pkg/log", "//pkg/sentry/fdimport", "//pkg/sentry/fs", "//pkg/sentry/fs/host", - "//pkg/sentry/fsbridge", + "//pkg/sentry/fs/user", "//pkg/sentry/fsimpl/host", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", @@ -35,7 +33,6 @@ go_library( "//pkg/sentry/vfs", "//pkg/sentry/watchdog", "//pkg/sync", - "//pkg/syserror", "//pkg/tcpip/link/sniffer", "//pkg/urpc", "@org_golang_x_sys//unix:go_default_library", diff --git a/pkg/sentry/control/logging.go b/pkg/sentry/control/logging.go index 811f24324..8a500a515 100644 --- a/pkg/sentry/control/logging.go +++ b/pkg/sentry/control/logging.go @@ -70,8 +70,8 @@ type LoggingArgs struct { type Logging struct{} // Change will change the log level and strace arguments. Although -// this functions signature requires an error it never acctually -// return san error. It's required by the URPC interface. +// this functions signature requires an error it never actually +// returns an error. It's required by the URPC interface. // Additionally, it may look odd that this is the only method // attached to an empty struct but this is also part of how // URPC dispatches. diff --git a/pkg/sentry/control/pprof.go b/pkg/sentry/control/pprof.go index 663e51989..2bf3c45e1 100644 --- a/pkg/sentry/control/pprof.go +++ b/pkg/sentry/control/pprof.go @@ -49,6 +49,9 @@ type ProfileOpts struct { // - dump out the stack trace of current go routines. // sentryctl -pid <pid> pprof-goroutine type Profile struct { + // Kernel is the kernel under profile. It's immutable. + Kernel *kernel.Kernel + // mu protects the fields below. mu sync.Mutex @@ -57,9 +60,6 @@ type Profile struct { // traceFile is the current execution trace output file. traceFile *fd.FD - - // Kernel is the kernel under profile. - Kernel *kernel.Kernel } // StartCPUProfile is an RPC stub which starts recording the CPU profile in a diff --git a/pkg/sentry/control/proc.go b/pkg/sentry/control/proc.go index 2ed17ee09..dfa936563 100644 --- a/pkg/sentry/control/proc.go +++ b/pkg/sentry/control/proc.go @@ -18,7 +18,6 @@ import ( "bytes" "encoding/json" "fmt" - "path" "sort" "strings" "text/tabwriter" @@ -26,13 +25,10 @@ import ( "golang.org/x/sys/unix" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/fspath" - "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/fdimport" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/host" - "gvisor.dev/gvisor/pkg/sentry/fsbridge" + "gvisor.dev/gvisor/pkg/sentry/fs/user" hostvfs2 "gvisor.dev/gvisor/pkg/sentry/fsimpl/host" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" @@ -40,7 +36,6 @@ import ( "gvisor.dev/gvisor/pkg/sentry/limits" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/sentry/vfs" - "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/urpc" ) @@ -108,6 +103,9 @@ type ExecArgs struct { // String prints the arguments as a string. func (args ExecArgs) String() string { + if len(args.Argv) == 0 { + return args.Filename + } a := make([]string, len(args.Argv)) copy(a, args.Argv) if args.Filename != "" { @@ -141,7 +139,6 @@ func ExecAsync(proc *Proc, args *ExecArgs) (*kernel.ThreadGroup, kernel.ThreadID func (proc *Proc) execAsync(args *ExecArgs) (*kernel.ThreadGroup, kernel.ThreadID, *host.TTYFileOperations, *hostvfs2.TTYFileDescription, error) { // Import file descriptors. fdTable := proc.Kernel.NewFDTable() - defer fdTable.DecRef() creds := auth.NewUserCredentials( args.KUID, @@ -179,43 +176,32 @@ func (proc *Proc) execAsync(args *ExecArgs) (*kernel.ThreadGroup, kernel.ThreadI initArgs.MountNamespaceVFS2.IncRef() } ctx := initArgs.NewContext(proc.Kernel) + defer fdTable.DecRef(ctx) + + if kernel.VFS2Enabled { + // Get the full path to the filename from the PATH env variable. + if initArgs.MountNamespaceVFS2 == nil { + // Set initArgs so that 'ctx' returns the namespace. + // + // MountNamespaceVFS2 adds a reference to the namespace, which is + // transferred to the new process. + initArgs.MountNamespaceVFS2 = proc.Kernel.GlobalInit().Leader().MountNamespaceVFS2() + } + } else { + if initArgs.MountNamespace == nil { + // Set initArgs so that 'ctx' returns the namespace. + initArgs.MountNamespace = proc.Kernel.GlobalInit().Leader().MountNamespace() - if initArgs.Filename == "" { - if kernel.VFS2Enabled { - // Get the full path to the filename from the PATH env variable. - if initArgs.MountNamespaceVFS2 == nil { - // Set initArgs so that 'ctx' returns the namespace. - // - // MountNamespaceVFS2 adds a reference to the namespace, which is - // transferred to the new process. - initArgs.MountNamespaceVFS2 = proc.Kernel.GlobalInit().Leader().MountNamespaceVFS2() - } - - paths := fs.GetPath(initArgs.Envv) - vfsObj := proc.Kernel.VFS() - file, err := ResolveExecutablePath(ctx, vfsObj, initArgs.WorkingDirectory, initArgs.Argv[0], paths) - if err != nil { - return nil, 0, nil, nil, fmt.Errorf("error finding executable %q in PATH %v: %v", initArgs.Argv[0], paths, err) - } - initArgs.File = fsbridge.NewVFSFile(file) - } else { - // Get the full path to the filename from the PATH env variable. - paths := fs.GetPath(initArgs.Envv) - if initArgs.MountNamespace == nil { - // Set initArgs so that 'ctx' returns the namespace. - initArgs.MountNamespace = proc.Kernel.GlobalInit().Leader().MountNamespace() - - // initArgs must hold a reference on MountNamespace, which will - // be donated to the new process in CreateProcess. - initArgs.MountNamespace.IncRef() - } - f, err := initArgs.MountNamespace.ResolveExecutablePath(ctx, initArgs.WorkingDirectory, initArgs.Argv[0], paths) - if err != nil { - return nil, 0, nil, nil, fmt.Errorf("error finding executable %q in PATH %v: %v", initArgs.Argv[0], paths, err) - } - initArgs.Filename = f + // initArgs must hold a reference on MountNamespace, which will + // be donated to the new process in CreateProcess. + initArgs.MountNamespace.IncRef() } } + resolved, err := user.ResolveExecutablePath(ctx, &initArgs) + if err != nil { + return nil, 0, nil, nil, err + } + initArgs.Filename = resolved fds := make([]int, len(args.FilePayload.Files)) for i, file := range args.FilePayload.Files { @@ -428,67 +414,3 @@ func ttyName(tty *kernel.TTY) string { } return fmt.Sprintf("pts/%d", tty.Index) } - -// ResolveExecutablePath resolves the given executable name given a set of -// paths that might contain it. -func ResolveExecutablePath(ctx context.Context, vfsObj *vfs.VirtualFilesystem, wd, name string, paths []string) (*vfs.FileDescription, error) { - root := vfs.RootFromContext(ctx) - defer root.DecRef() - creds := auth.CredentialsFromContext(ctx) - - // Absolute paths can be used directly. - if path.IsAbs(name) { - return openExecutable(ctx, vfsObj, creds, root, name) - } - - // Paths with '/' in them should be joined to the working directory, or - // to the root if working directory is not set. - if strings.IndexByte(name, '/') > 0 { - if len(wd) == 0 { - wd = "/" - } - if !path.IsAbs(wd) { - return nil, fmt.Errorf("working directory %q must be absolute", wd) - } - return openExecutable(ctx, vfsObj, creds, root, path.Join(wd, name)) - } - - // Otherwise, we must lookup the name in the paths, starting from the - // calling context's root directory. - for _, p := range paths { - if !path.IsAbs(p) { - // Relative paths aren't safe, no one should be using them. - log.Warningf("Skipping relative path %q in $PATH", p) - continue - } - - binPath := path.Join(p, name) - f, err := openExecutable(ctx, vfsObj, creds, root, binPath) - if err != nil { - return nil, err - } - if f == nil { - continue // Not found/no access. - } - return f, nil - } - return nil, syserror.ENOENT -} - -func openExecutable(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, root vfs.VirtualDentry, path string) (*vfs.FileDescription, error) { - pop := vfs.PathOperation{ - Root: root, - Start: root, // binPath is absolute, Start can be anything. - Path: fspath.Parse(path), - FollowFinalSymlink: true, - } - opts := &vfs.OpenOptions{ - Flags: linux.O_RDONLY, - FileExec: true, - } - f, err := vfsObj.OpenAt(ctx, creds, &pop, opts) - if err == syserror.ENOENT || err == syserror.EACCES { - return nil, nil - } - return f, err -} diff --git a/pkg/sentry/device/device.go b/pkg/sentry/device/device.go index 69e71e322..f45b2bd2b 100644 --- a/pkg/sentry/device/device.go +++ b/pkg/sentry/device/device.go @@ -188,6 +188,9 @@ type MultiDevice struct { // String stringifies MultiDevice. func (m *MultiDevice) String() string { + m.mu.Lock() + defer m.mu.Unlock() + buf := bytes.NewBuffer(nil) buf.WriteString("cache{") for k, v := range m.cache { diff --git a/pkg/sentry/devices/memdev/full.go b/pkg/sentry/devices/memdev/full.go index c7e197691..511179e31 100644 --- a/pkg/sentry/devices/memdev/full.go +++ b/pkg/sentry/devices/memdev/full.go @@ -42,10 +42,11 @@ type fullFD struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *fullFD) Release() { +func (fd *fullFD) Release(context.Context) { // noop } diff --git a/pkg/sentry/devices/memdev/null.go b/pkg/sentry/devices/memdev/null.go index 33d060d02..4918dbeeb 100644 --- a/pkg/sentry/devices/memdev/null.go +++ b/pkg/sentry/devices/memdev/null.go @@ -43,10 +43,11 @@ type nullFD struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *nullFD) Release() { +func (fd *nullFD) Release(context.Context) { // noop } diff --git a/pkg/sentry/devices/memdev/random.go b/pkg/sentry/devices/memdev/random.go index acfa23149..5e7fe0280 100644 --- a/pkg/sentry/devices/memdev/random.go +++ b/pkg/sentry/devices/memdev/random.go @@ -48,6 +48,7 @@ type randomFD struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD // off is the "file offset". off is accessed using atomic memory // operations. @@ -55,7 +56,7 @@ type randomFD struct { } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *randomFD) Release() { +func (fd *randomFD) Release(context.Context) { // noop } diff --git a/pkg/sentry/devices/memdev/zero.go b/pkg/sentry/devices/memdev/zero.go index 3b1372b9e..2e631a252 100644 --- a/pkg/sentry/devices/memdev/zero.go +++ b/pkg/sentry/devices/memdev/zero.go @@ -44,10 +44,11 @@ type zeroFD struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *zeroFD) Release() { +func (fd *zeroFD) Release(context.Context) { // noop } diff --git a/pkg/sentry/devices/ttydev/BUILD b/pkg/sentry/devices/ttydev/BUILD new file mode 100644 index 000000000..12e49b58a --- /dev/null +++ b/pkg/sentry/devices/ttydev/BUILD @@ -0,0 +1,16 @@ +load("//tools:defs.bzl", "go_library") + +licenses(["notice"]) + +go_library( + name = "ttydev", + srcs = ["ttydev.go"], + visibility = ["//pkg/sentry:internal"], + deps = [ + "//pkg/abi/linux", + "//pkg/context", + "//pkg/sentry/fsimpl/devtmpfs", + "//pkg/sentry/vfs", + "//pkg/usermem", + ], +) diff --git a/pkg/sentry/devices/ttydev/ttydev.go b/pkg/sentry/devices/ttydev/ttydev.go new file mode 100644 index 000000000..fd4b79c46 --- /dev/null +++ b/pkg/sentry/devices/ttydev/ttydev.go @@ -0,0 +1,91 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package ttydev implements devices for /dev/tty and (eventually) +// /dev/console. +// +// TODO(b/159623826): Support /dev/console. +package ttydev + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/devtmpfs" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/usermem" +) + +const ( + // See drivers/tty/tty_io.c:tty_init(). + ttyDevMinor = 0 + consoleDevMinor = 1 +) + +// ttyDevice implements vfs.Device for /dev/tty. +type ttyDevice struct{} + +// Open implements vfs.Device.Open. +func (ttyDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { + fd := &ttyFD{} + if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{ + UseDentryMetadata: true, + }); err != nil { + return nil, err + } + return &fd.vfsfd, nil +} + +// ttyFD implements vfs.FileDescriptionImpl for /dev/tty. +type ttyFD struct { + vfsfd vfs.FileDescription + vfs.FileDescriptionDefaultImpl + vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD +} + +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *ttyFD) Release(context.Context) {} + +// PRead implements vfs.FileDescriptionImpl.PRead. +func (fd *ttyFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { + return 0, nil +} + +// Read implements vfs.FileDescriptionImpl.Read. +func (fd *ttyFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + return 0, nil +} + +// PWrite implements vfs.FileDescriptionImpl.PWrite. +func (fd *ttyFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + return src.NumBytes(), nil +} + +// Write implements vfs.FileDescriptionImpl.Write. +func (fd *ttyFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { + return src.NumBytes(), nil +} + +// Register registers all devices implemented by this package in vfsObj. +func Register(vfsObj *vfs.VirtualFilesystem) error { + return vfsObj.RegisterDevice(vfs.CharDevice, linux.TTYAUX_MAJOR, ttyDevMinor, ttyDevice{}, &vfs.RegisterDeviceOptions{ + GroupName: "tty", + }) +} + +// CreateDevtmpfsFiles creates device special files in dev representing all +// devices implemented by this package. +func CreateDevtmpfsFiles(ctx context.Context, dev *devtmpfs.Accessor) error { + return dev.CreateDeviceFile(ctx, "tty", vfs.CharDevice, linux.TTYAUX_MAJOR, ttyDevMinor, 0666 /* mode */) +} diff --git a/pkg/sentry/devices/tundev/BUILD b/pkg/sentry/devices/tundev/BUILD new file mode 100644 index 000000000..71c59287c --- /dev/null +++ b/pkg/sentry/devices/tundev/BUILD @@ -0,0 +1,23 @@ +load("//tools:defs.bzl", "go_library") + +licenses(["notice"]) + +go_library( + name = "tundev", + srcs = ["tundev.go"], + visibility = ["//pkg/sentry:internal"], + deps = [ + "//pkg/abi/linux", + "//pkg/context", + "//pkg/sentry/arch", + "//pkg/sentry/fsimpl/devtmpfs", + "//pkg/sentry/inet", + "//pkg/sentry/kernel", + "//pkg/sentry/socket/netstack", + "//pkg/sentry/vfs", + "//pkg/syserror", + "//pkg/tcpip/link/tun", + "//pkg/usermem", + "//pkg/waiter", + ], +) diff --git a/pkg/sentry/devices/tundev/tundev.go b/pkg/sentry/devices/tundev/tundev.go new file mode 100644 index 000000000..a40625e19 --- /dev/null +++ b/pkg/sentry/devices/tundev/tundev.go @@ -0,0 +1,178 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package tundev implements the /dev/net/tun device. +package tundev + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/devtmpfs" + "gvisor.dev/gvisor/pkg/sentry/inet" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/socket/netstack" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/tcpip/link/tun" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +const ( + netTunDevMajor = 10 + netTunDevMinor = 200 +) + +// tunDevice implements vfs.Device for /dev/net/tun. +type tunDevice struct{} + +// Open implements vfs.Device.Open. +func (tunDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { + fd := &tunFD{} + if err := fd.vfsfd.Init(fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{ + UseDentryMetadata: true, + }); err != nil { + return nil, err + } + return &fd.vfsfd, nil +} + +// tunFD implements vfs.FileDescriptionImpl for /dev/net/tun. +type tunFD struct { + vfsfd vfs.FileDescription + vfs.FileDescriptionDefaultImpl + vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD + + device tun.Device +} + +// Ioctl implements vfs.FileDescriptionImpl.Ioctl. +func (fd *tunFD) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) { + request := args[1].Uint() + data := args[2].Pointer() + + switch request { + case linux.TUNSETIFF: + t := kernel.TaskFromContext(ctx) + if t == nil { + panic("Ioctl should be called from a task context") + } + if !t.HasCapability(linux.CAP_NET_ADMIN) { + return 0, syserror.EPERM + } + stack, ok := t.NetworkContext().(*netstack.Stack) + if !ok { + return 0, syserror.EINVAL + } + + var req linux.IFReq + if _, err := usermem.CopyObjectIn(ctx, uio, data, &req, usermem.IOOpts{ + AddressSpaceActive: true, + }); err != nil { + return 0, err + } + flags := usermem.ByteOrder.Uint16(req.Data[:]) + return 0, fd.device.SetIff(stack.Stack, req.Name(), flags) + + case linux.TUNGETIFF: + var req linux.IFReq + + copy(req.IFName[:], fd.device.Name()) + + // Linux adds IFF_NOFILTER (the same value as IFF_NO_PI unfortunately) when + // there is no sk_filter. See __tun_chr_ioctl() in net/drivers/tun.c. + flags := fd.device.Flags() | linux.IFF_NOFILTER + usermem.ByteOrder.PutUint16(req.Data[:], flags) + + _, err := usermem.CopyObjectOut(ctx, uio, data, &req, usermem.IOOpts{ + AddressSpaceActive: true, + }) + return 0, err + + default: + return 0, syserror.ENOTTY + } +} + +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *tunFD) Release(ctx context.Context) { + fd.device.Release(ctx) +} + +// PRead implements vfs.FileDescriptionImpl.PRead. +func (fd *tunFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { + return fd.Read(ctx, dst, opts) +} + +// Read implements vfs.FileDescriptionImpl.Read. +func (fd *tunFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + data, err := fd.device.Read() + if err != nil { + return 0, err + } + n, err := dst.CopyOut(ctx, data) + if n > 0 && n < len(data) { + // Not an error for partial copying. Packet truncated. + err = nil + } + return int64(n), err +} + +// PWrite implements vfs.FileDescriptionImpl.PWrite. +func (fd *tunFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + return fd.Write(ctx, src, opts) +} + +// Write implements vfs.FileDescriptionImpl.Write. +func (fd *tunFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { + data := make([]byte, src.NumBytes()) + if _, err := src.CopyIn(ctx, data); err != nil { + return 0, err + } + return fd.device.Write(data) +} + +// Readiness implements watier.Waitable.Readiness. +func (fd *tunFD) Readiness(mask waiter.EventMask) waiter.EventMask { + return fd.device.Readiness(mask) +} + +// EventRegister implements watier.Waitable.EventRegister. +func (fd *tunFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + fd.device.EventRegister(e, mask) +} + +// EventUnregister implements watier.Waitable.EventUnregister. +func (fd *tunFD) EventUnregister(e *waiter.Entry) { + fd.device.EventUnregister(e) +} + +// IsNetTunSupported returns whether /dev/net/tun device is supported for s. +func IsNetTunSupported(s inet.Stack) bool { + _, ok := s.(*netstack.Stack) + return ok +} + +// Register registers all devices implemented by this package in vfsObj. +func Register(vfsObj *vfs.VirtualFilesystem) error { + return vfsObj.RegisterDevice(vfs.CharDevice, netTunDevMajor, netTunDevMinor, tunDevice{}, &vfs.RegisterDeviceOptions{}) +} + +// CreateDevtmpfsFiles creates device special files in dev representing all +// devices implemented by this package. +func CreateDevtmpfsFiles(ctx context.Context, dev *devtmpfs.Accessor) error { + return dev.CreateDeviceFile(ctx, "net/tun", vfs.CharDevice, netTunDevMajor, netTunDevMinor, 0666 /* mode */) +} diff --git a/pkg/sentry/fdimport/fdimport.go b/pkg/sentry/fdimport/fdimport.go index a4199f9e9..1b7cb94c0 100644 --- a/pkg/sentry/fdimport/fdimport.go +++ b/pkg/sentry/fdimport/fdimport.go @@ -15,6 +15,8 @@ package fdimport import ( + "fmt" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/host" @@ -48,7 +50,7 @@ func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds [] if err != nil { return nil, err } - defer appFile.DecRef() + defer appFile.DecRef(ctx) // Remember this in the TTY file, as we will // use it for the other stdio FDs. @@ -67,7 +69,7 @@ func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds [] if err != nil { return nil, err } - defer appFile.DecRef() + defer appFile.DecRef(ctx) } // Add the file to the FD map. @@ -84,6 +86,9 @@ func importFS(ctx context.Context, fdTable *kernel.FDTable, console bool, fds [] func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdioFDs []int) (*hostvfs2.TTYFileDescription, error) { k := kernel.KernelFromContext(ctx) + if k == nil { + return nil, fmt.Errorf("cannot find kernel from context") + } var ttyFile *vfs.FileDescription for appFD, hostFD := range stdioFDs { @@ -97,7 +102,7 @@ func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdi if err != nil { return nil, err } - defer appFile.DecRef() + defer appFile.DecRef(ctx) // Remember this in the TTY file, as we will use it for the other stdio // FDs. @@ -114,7 +119,7 @@ func importVFS2(ctx context.Context, fdTable *kernel.FDTable, console bool, stdi if err != nil { return nil, err } - defer appFile.DecRef() + defer appFile.DecRef(ctx) } if err := fdTable.NewFDAtVFS2(ctx, int32(appFD), appFile, kernel.FDFlags{}); err != nil { diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go index ab1424c95..735452b07 100644 --- a/pkg/sentry/fs/copy_up.go +++ b/pkg/sentry/fs/copy_up.go @@ -201,7 +201,7 @@ func copyUpLocked(ctx context.Context, parent *Dirent, next *Dirent) error { parentUpper := parent.Inode.overlay.upper root := RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } // Create the file in the upper filesystem and get an Inode for it. @@ -212,7 +212,7 @@ func copyUpLocked(ctx context.Context, parent *Dirent, next *Dirent) error { log.Warningf("copy up failed to create file: %v", err) return syserror.EIO } - defer childFile.DecRef() + defer childFile.DecRef(ctx) childUpperInode = childFile.Dirent.Inode case Directory: @@ -226,7 +226,7 @@ func copyUpLocked(ctx context.Context, parent *Dirent, next *Dirent) error { cleanupUpper(ctx, parentUpper, next.name, werr) return syserror.EIO } - defer childUpper.DecRef() + defer childUpper.DecRef(ctx) childUpperInode = childUpper.Inode case Symlink: @@ -246,7 +246,7 @@ func copyUpLocked(ctx context.Context, parent *Dirent, next *Dirent) error { cleanupUpper(ctx, parentUpper, next.name, werr) return syserror.EIO } - defer childUpper.DecRef() + defer childUpper.DecRef(ctx) childUpperInode = childUpper.Inode default: @@ -352,14 +352,14 @@ func copyContentsLocked(ctx context.Context, upper *Inode, lower *Inode, size in if err != nil { return err } - defer upperFile.DecRef() + defer upperFile.DecRef(ctx) // Get a handle to the lower filesystem, which we will read from. lowerFile, err := overlayFile(ctx, lower, FileFlags{Read: true}) if err != nil { return err } - defer lowerFile.DecRef() + defer lowerFile.DecRef(ctx) // Use a buffer pool to minimize allocations. buf := copyUpBuffers.Get().([]byte) diff --git a/pkg/sentry/fs/copy_up_test.go b/pkg/sentry/fs/copy_up_test.go index 91792d9fe..c7a11eec1 100644 --- a/pkg/sentry/fs/copy_up_test.go +++ b/pkg/sentry/fs/copy_up_test.go @@ -126,7 +126,7 @@ func makeOverlayTestFiles(t *testing.T) []*overlayTestFile { if err != nil { t.Fatalf("failed to create file %q: %v", name, err) } - defer f.DecRef() + defer f.DecRef(ctx) relname, _ := f.Dirent.FullName(lowerRoot) @@ -171,7 +171,7 @@ func makeOverlayTestFiles(t *testing.T) []*overlayTestFile { if err != nil { t.Fatalf("failed to find %q: %v", f.name, err) } - defer d.DecRef() + defer d.DecRef(ctx) f.File, err = d.Inode.GetFile(ctx, d, fs.FileFlags{Read: true}) if err != nil { diff --git a/pkg/sentry/fs/dev/net_tun.go b/pkg/sentry/fs/dev/net_tun.go index dc7ad075a..ec474e554 100644 --- a/pkg/sentry/fs/dev/net_tun.go +++ b/pkg/sentry/fs/dev/net_tun.go @@ -80,8 +80,8 @@ type netTunFileOperations struct { var _ fs.FileOperations = (*netTunFileOperations)(nil) // Release implements fs.FileOperations.Release. -func (fops *netTunFileOperations) Release() { - fops.device.Release() +func (fops *netTunFileOperations) Release(ctx context.Context) { + fops.device.Release(ctx) } // Ioctl implements fs.FileOperations.Ioctl. diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go index 65be12175..a2f751068 100644 --- a/pkg/sentry/fs/dirent.go +++ b/pkg/sentry/fs/dirent.go @@ -325,7 +325,7 @@ func (d *Dirent) SyncAll(ctx context.Context) { for _, w := range d.children { if child := w.Get(); child != nil { child.(*Dirent).SyncAll(ctx) - child.DecRef() + child.DecRef(ctx) } } } @@ -451,7 +451,7 @@ func (d *Dirent) walk(ctx context.Context, root *Dirent, name string, walkMayUnl // which don't hold a hard reference on their parent (their parent holds a // hard reference on them, and they contain virtually no state). But this is // good house-keeping. - child.DecRef() + child.DecRef(ctx) return nil, syscall.ENOENT } @@ -468,20 +468,20 @@ func (d *Dirent) walk(ctx context.Context, root *Dirent, name string, walkMayUnl // their pins on the child. Inotify doesn't properly support filesystems that // revalidate dirents (since watches are lost on revalidation), but if we fail // to unpin the watches child will never be GCed. - cd.Inode.Watches.Unpin(cd) + cd.Inode.Watches.Unpin(ctx, cd) // This child needs to be revalidated, fallthrough to unhash it. Make sure // to not leak a reference from Get(). // // Note that previous lookups may still have a reference to this stale child; // this can't be helped, but we can ensure that *new* lookups are up-to-date. - child.DecRef() + child.DecRef(ctx) } // Either our weak reference expired or we need to revalidate it. Unhash child first, we're // about to replace it. delete(d.children, name) - w.Drop() + w.Drop(ctx) } // Slow path: load the InodeOperations into memory. Since this is a hot path and the lookup may be @@ -512,12 +512,12 @@ func (d *Dirent) walk(ctx context.Context, root *Dirent, name string, walkMayUnl // There are active references to the existing child, prefer it to the one we // retrieved from Lookup. Likely the Lookup happened very close to the insertion // of child, so considering one stale over the other is fairly arbitrary. - c.DecRef() + c.DecRef(ctx) // The child that was installed could be negative. if cd.IsNegative() { // If so, don't leak a reference and short circuit. - child.DecRef() + child.DecRef(ctx) return nil, syscall.ENOENT } @@ -531,7 +531,7 @@ func (d *Dirent) walk(ctx context.Context, root *Dirent, name string, walkMayUnl // we did the Inode.Lookup. Fully drop the weak reference and fallback to using the child // we looked up. delete(d.children, name) - w.Drop() + w.Drop(ctx) } // Give the looked up child a parent. We cannot kick out entries, since we just checked above @@ -587,7 +587,7 @@ func (d *Dirent) exists(ctx context.Context, root *Dirent, name string) bool { return false } // Child exists. - child.DecRef() + child.DecRef(ctx) return true } @@ -622,7 +622,7 @@ func (d *Dirent) Create(ctx context.Context, root *Dirent, name string, flags Fi } child := file.Dirent - d.finishCreate(child, name) + d.finishCreate(ctx, child, name) // Return the reference and the new file. When the last reference to // the file is dropped, file.Dirent may no longer be cached. @@ -631,7 +631,7 @@ func (d *Dirent) Create(ctx context.Context, root *Dirent, name string, flags Fi // finishCreate validates the created file, adds it as a child of this dirent, // and notifies any watchers. -func (d *Dirent) finishCreate(child *Dirent, name string) { +func (d *Dirent) finishCreate(ctx context.Context, child *Dirent, name string) { // Sanity check c, its name must be consistent. if child.name != name { panic(fmt.Sprintf("create from %q to %q returned unexpected name %q", d.name, name, child.name)) @@ -650,14 +650,14 @@ func (d *Dirent) finishCreate(child *Dirent, name string) { panic(fmt.Sprintf("hashed child %q over a positive child", child.name)) } // Don't leak a reference. - old.DecRef() + old.DecRef(ctx) // Drop d's reference. - old.DecRef() + old.DecRef(ctx) } // Finally drop the useless weak reference on the floor. - w.Drop() + w.Drop(ctx) } d.Inode.Watches.Notify(name, linux.IN_CREATE, 0) @@ -686,17 +686,17 @@ func (d *Dirent) genericCreate(ctx context.Context, root *Dirent, name string, c panic(fmt.Sprintf("hashed over a positive child %q", old.(*Dirent).name)) } // Don't leak a reference. - old.DecRef() + old.DecRef(ctx) // Drop d's reference. - old.DecRef() + old.DecRef(ctx) } // Unhash the negative Dirent, name needs to exist now. delete(d.children, name) // Finally drop the useless weak reference on the floor. - w.Drop() + w.Drop(ctx) } // Execute the create operation. @@ -756,7 +756,7 @@ func (d *Dirent) Bind(ctx context.Context, root *Dirent, name string, data trans if e != nil { return e } - d.finishCreate(childDir, name) + d.finishCreate(ctx, childDir, name) return nil }) if err == syscall.EEXIST { @@ -901,7 +901,7 @@ func direntReaddir(ctx context.Context, d *Dirent, it DirIterator, root *Dirent, // references to children. // // Preconditions: d.mu must be held. -func (d *Dirent) flush() { +func (d *Dirent) flush(ctx context.Context) { expired := make(map[string]*refs.WeakRef) for n, w := range d.children { // Call flush recursively on each child before removing our @@ -912,7 +912,7 @@ func (d *Dirent) flush() { if !cd.IsNegative() { // Flush the child. cd.mu.Lock() - cd.flush() + cd.flush(ctx) cd.mu.Unlock() // Allow the file system to drop extra references on child. @@ -920,13 +920,13 @@ func (d *Dirent) flush() { } // Don't leak a reference. - child.DecRef() + child.DecRef(ctx) } // Check if the child dirent is closed, and mark it as expired if it is. // We must call w.Get() again here, since the child could have been closed // by the calls to flush() and cache.Remove() in the above if-block. if child := w.Get(); child != nil { - child.DecRef() + child.DecRef(ctx) } else { expired[n] = w } @@ -935,7 +935,7 @@ func (d *Dirent) flush() { // Remove expired entries. for n, w := range expired { delete(d.children, n) - w.Drop() + w.Drop(ctx) } } @@ -977,7 +977,7 @@ func (d *Dirent) mount(ctx context.Context, inode *Inode) (newChild *Dirent, err if !ok { panic("mount must mount over an existing dirent") } - weakRef.Drop() + weakRef.Drop(ctx) // Note that even though `d` is now hidden, it still holds a reference // to its parent. @@ -1002,13 +1002,13 @@ func (d *Dirent) unmount(ctx context.Context, replacement *Dirent) error { if !ok { panic("mount must mount over an existing dirent") } - weakRef.Drop() + weakRef.Drop(ctx) // d is not reachable anymore, and hence not mounted anymore. d.mounted = false // Drop mount reference. - d.DecRef() + d.DecRef(ctx) return nil } @@ -1029,7 +1029,7 @@ func (d *Dirent) Remove(ctx context.Context, root *Dirent, name string, dirPath // Child does not exist. return err } - defer child.DecRef() + defer child.DecRef(ctx) // Remove cannot remove directories. if IsDir(child.Inode.StableAttr) { @@ -1055,7 +1055,7 @@ func (d *Dirent) Remove(ctx context.Context, root *Dirent, name string, dirPath atomic.StoreInt32(&child.deleted, 1) if w, ok := d.children[name]; ok { delete(d.children, name) - w.Drop() + w.Drop(ctx) } // Allow the file system to drop extra references on child. @@ -1067,7 +1067,7 @@ func (d *Dirent) Remove(ctx context.Context, root *Dirent, name string, dirPath // inode may have other links. If this was the last link, the events for the // watch removal will be queued by the inode destructor. child.Inode.Watches.MarkUnlinked() - child.Inode.Watches.Unpin(child) + child.Inode.Watches.Unpin(ctx, child) d.Inode.Watches.Notify(name, linux.IN_DELETE, 0) return nil @@ -1100,7 +1100,7 @@ func (d *Dirent) RemoveDirectory(ctx context.Context, root *Dirent, name string) // Child does not exist. return err } - defer child.DecRef() + defer child.DecRef(ctx) // RemoveDirectory can only remove directories. if !IsDir(child.Inode.StableAttr) { @@ -1121,7 +1121,7 @@ func (d *Dirent) RemoveDirectory(ctx context.Context, root *Dirent, name string) atomic.StoreInt32(&child.deleted, 1) if w, ok := d.children[name]; ok { delete(d.children, name) - w.Drop() + w.Drop(ctx) } // Allow the file system to drop extra references on child. @@ -1130,14 +1130,14 @@ func (d *Dirent) RemoveDirectory(ctx context.Context, root *Dirent, name string) // Finally, let inotify know the child is being unlinked. Drop any extra // refs from inotify to this child dirent. child.Inode.Watches.MarkUnlinked() - child.Inode.Watches.Unpin(child) + child.Inode.Watches.Unpin(ctx, child) d.Inode.Watches.Notify(name, linux.IN_ISDIR|linux.IN_DELETE, 0) return nil } // destroy closes this node and all children. -func (d *Dirent) destroy() { +func (d *Dirent) destroy(ctx context.Context) { if d.IsNegative() { // Nothing to tear-down and no parent references to drop, since a negative // Dirent does not take a references on its parent, has no Inode and no children. @@ -1153,19 +1153,19 @@ func (d *Dirent) destroy() { if c.(*Dirent).IsNegative() { // The parent holds both weak and strong refs in the case of // negative dirents. - c.DecRef() + c.DecRef(ctx) } // Drop the reference we just acquired in WeakRef.Get. - c.DecRef() + c.DecRef(ctx) } - w.Drop() + w.Drop(ctx) } d.children = nil allDirents.remove(d) // Drop our reference to the Inode. - d.Inode.DecRef() + d.Inode.DecRef(ctx) // Allow the Dirent to be GC'ed after this point, since the Inode may still // be referenced after the Dirent is destroyed (for instance by filesystem @@ -1175,7 +1175,7 @@ func (d *Dirent) destroy() { // Drop the reference we have on our parent if we took one. renameMu doesn't need to be // held because d can't be reparented without any references to it left. if d.parent != nil { - d.parent.DecRef() + d.parent.DecRef(ctx) } } @@ -1201,14 +1201,14 @@ func (d *Dirent) TryIncRef() bool { // DecRef decreases the Dirent's refcount and drops its reference on its mount. // // DecRef implements RefCounter.DecRef with destructor d.destroy. -func (d *Dirent) DecRef() { +func (d *Dirent) DecRef(ctx context.Context) { if d.Inode != nil { // Keep mount around, since DecRef may destroy d.Inode. msrc := d.Inode.MountSource - d.DecRefWithDestructor(d.destroy) + d.DecRefWithDestructor(ctx, d.destroy) msrc.DecDirentRefs() } else { - d.DecRefWithDestructor(d.destroy) + d.DecRefWithDestructor(ctx, d.destroy) } } @@ -1359,7 +1359,7 @@ func (d *Dirent) MayDelete(ctx context.Context, root *Dirent, name string) error if err != nil { return err } - defer victim.DecRef() + defer victim.DecRef(ctx) return d.mayDelete(ctx, victim) } @@ -1411,7 +1411,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string if err != nil { return err } - defer renamed.DecRef() + defer renamed.DecRef(ctx) // Check that the renamed dirent is deletable. if err := oldParent.mayDelete(ctx, renamed); err != nil { @@ -1453,13 +1453,13 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string // Check that we can delete replaced. if err := newParent.mayDelete(ctx, replaced); err != nil { - replaced.DecRef() + replaced.DecRef(ctx) return err } // Target should not be an ancestor of source. if oldParent.descendantOf(replaced) { - replaced.DecRef() + replaced.DecRef(ctx) // Note that Linux returns EINVAL if the source is an // ancestor of target, but ENOTEMPTY if the target is @@ -1470,7 +1470,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string // Check that replaced is not a mount point. if replaced.isMountPointLocked() { - replaced.DecRef() + replaced.DecRef(ctx) return syscall.EBUSY } @@ -1478,11 +1478,11 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string oldIsDir := IsDir(renamed.Inode.StableAttr) newIsDir := IsDir(replaced.Inode.StableAttr) if !newIsDir && oldIsDir { - replaced.DecRef() + replaced.DecRef(ctx) return syscall.ENOTDIR } if !oldIsDir && newIsDir { - replaced.DecRef() + replaced.DecRef(ctx) return syscall.EISDIR } @@ -1493,13 +1493,13 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string // open across renames is currently broken for multiple // reasons, so we flush all references on the replaced node and // its children. - replaced.Inode.Watches.Unpin(replaced) + replaced.Inode.Watches.Unpin(ctx, replaced) replaced.mu.Lock() - replaced.flush() + replaced.flush(ctx) replaced.mu.Unlock() // Done with replaced. - replaced.DecRef() + replaced.DecRef(ctx) } if err := renamed.Inode.Rename(ctx, oldParent, renamed, newParent, newName, replaced != nil); err != nil { @@ -1513,14 +1513,14 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string // can't destroy oldParent (and try to retake its lock) because // Rename's caller must be holding a reference. newParent.IncRef() - oldParent.DecRef() + oldParent.DecRef(ctx) } if w, ok := newParent.children[newName]; ok { - w.Drop() + w.Drop(ctx) delete(newParent.children, newName) } if w, ok := oldParent.children[oldName]; ok { - w.Drop() + w.Drop(ctx) delete(oldParent.children, oldName) } @@ -1551,7 +1551,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string // Same as replaced.flush above. renamed.mu.Lock() - renamed.flush() + renamed.flush(ctx) renamed.mu.Unlock() return nil diff --git a/pkg/sentry/fs/dirent_cache.go b/pkg/sentry/fs/dirent_cache.go index 33de32c69..7d9dd717e 100644 --- a/pkg/sentry/fs/dirent_cache.go +++ b/pkg/sentry/fs/dirent_cache.go @@ -17,6 +17,7 @@ package fs import ( "fmt" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sync" ) @@ -101,7 +102,7 @@ func (c *DirentCache) remove(d *Dirent) { panic(fmt.Sprintf("trying to remove %v, which is not in the dirent cache", d)) } c.list.Remove(d) - d.DecRef() + d.DecRef(context.Background()) c.currentSize-- if c.limit != nil { c.limit.dec() diff --git a/pkg/sentry/fs/dirent_refs_test.go b/pkg/sentry/fs/dirent_refs_test.go index 98d69c6f2..176b894ba 100644 --- a/pkg/sentry/fs/dirent_refs_test.go +++ b/pkg/sentry/fs/dirent_refs_test.go @@ -51,7 +51,7 @@ func TestWalkPositive(t *testing.T) { t.Fatalf("child name = %q has a ref count of %d, want %d", d.name, got, 1) } - d.DecRef() + d.DecRef(ctx) if got := root.ReadRefs(); got != 1 { t.Fatalf("root has a ref count of %d, want %d", got, 1) @@ -61,7 +61,7 @@ func TestWalkPositive(t *testing.T) { t.Fatalf("child name = %q has a ref count of %d, want %d", d.name, got, 0) } - root.flush() + root.flush(ctx) if got := len(root.children); got != 0 { t.Fatalf("root has %d children, want %d", got, 0) @@ -114,7 +114,7 @@ func TestWalkNegative(t *testing.T) { t.Fatalf("child has a ref count of %d, want %d", got, 2) } - child.DecRef() + child.DecRef(ctx) if got := child.(*Dirent).ReadRefs(); got != 1 { t.Fatalf("child has a ref count of %d, want %d", got, 1) @@ -124,7 +124,7 @@ func TestWalkNegative(t *testing.T) { t.Fatalf("root has %d children, want %d", got, 1) } - root.DecRef() + root.DecRef(ctx) if got := root.ReadRefs(); got != 0 { t.Fatalf("root has a ref count of %d, want %d", got, 0) @@ -351,9 +351,9 @@ func TestRemoveExtraRefs(t *testing.T) { t.Fatalf("dirent has a ref count of %d, want %d", got, 1) } - d.DecRef() + d.DecRef(ctx) - test.root.flush() + test.root.flush(ctx) if got := len(test.root.children); got != 0 { t.Errorf("root has %d children, want %d", got, 0) @@ -403,8 +403,8 @@ func TestRenameExtraRefs(t *testing.T) { t.Fatalf("Rename got error %v, want nil", err) } - oldParent.flush() - newParent.flush() + oldParent.flush(ctx) + newParent.flush(ctx) // Expect to have only active references. if got := renamed.ReadRefs(); got != 1 { diff --git a/pkg/sentry/fs/dirent_state.go b/pkg/sentry/fs/dirent_state.go index f623d6c0e..67a35f0b2 100644 --- a/pkg/sentry/fs/dirent_state.go +++ b/pkg/sentry/fs/dirent_state.go @@ -18,6 +18,7 @@ import ( "fmt" "sync/atomic" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/refs" ) @@ -48,7 +49,7 @@ func (d *Dirent) saveChildren() map[string]*Dirent { for name, w := range d.children { if rc := w.Get(); rc != nil { // Drop the reference count obtain in w.Get() - rc.DecRef() + rc.DecRef(context.Background()) cd := rc.(*Dirent) if cd.IsNegative() { diff --git a/pkg/sentry/fs/fdpipe/pipe.go b/pkg/sentry/fs/fdpipe/pipe.go index 9fce177ad..b99199798 100644 --- a/pkg/sentry/fs/fdpipe/pipe.go +++ b/pkg/sentry/fs/fdpipe/pipe.go @@ -115,7 +115,7 @@ func (p *pipeOperations) Readiness(mask waiter.EventMask) (eventMask waiter.Even } // Release implements fs.FileOperations.Release. -func (p *pipeOperations) Release() { +func (p *pipeOperations) Release(context.Context) { fdnotifier.RemoveFD(int32(p.file.FD())) p.file.Close() p.file = nil diff --git a/pkg/sentry/fs/fdpipe/pipe_opener_test.go b/pkg/sentry/fs/fdpipe/pipe_opener_test.go index e556da48a..b9cec4b13 100644 --- a/pkg/sentry/fs/fdpipe/pipe_opener_test.go +++ b/pkg/sentry/fs/fdpipe/pipe_opener_test.go @@ -182,7 +182,7 @@ func TestTryOpen(t *testing.T) { // Cleanup the state of the pipe, and remove the fd from the // fdnotifier. Sadly this needed to maintain the correctness // of other tests because the fdnotifier is global. - pipeOps.Release() + pipeOps.Release(ctx) } continue } @@ -191,7 +191,7 @@ func TestTryOpen(t *testing.T) { } if pipeOps != nil { // Same as above. - pipeOps.Release() + pipeOps.Release(ctx) } } } @@ -279,7 +279,7 @@ func TestPipeOpenUnblocksEventually(t *testing.T) { pipeOps, err := Open(ctx, opener, flags) if pipeOps != nil { // Same as TestTryOpen. - pipeOps.Release() + pipeOps.Release(ctx) } // Check that the partner opened the file successfully. @@ -325,7 +325,7 @@ func TestCopiedReadAheadBuffer(t *testing.T) { ctx := contexttest.Context(t) pipeOps, err := pipeOpenState.TryOpen(ctx, opener, fs.FileFlags{Read: true}) if pipeOps != nil { - pipeOps.Release() + pipeOps.Release(ctx) t.Fatalf("open(%s, %o) got file, want nil", name, syscall.O_RDONLY) } if err != syserror.ErrWouldBlock { @@ -351,7 +351,7 @@ func TestCopiedReadAheadBuffer(t *testing.T) { if pipeOps == nil { t.Fatalf("open(%s, %o) got nil file, want not nil", name, syscall.O_RDONLY) } - defer pipeOps.Release() + defer pipeOps.Release(ctx) if err != nil { t.Fatalf("open(%s, %o) got error %v, want nil", name, syscall.O_RDONLY, err) @@ -471,14 +471,14 @@ func TestPipeHangup(t *testing.T) { f := <-fdchan if f < 0 { t.Errorf("%s: partner routine got fd %d, want > 0", test.desc, f) - pipeOps.Release() + pipeOps.Release(ctx) continue } if test.hangupSelf { // Hangup self and assert that our partner got the expected hangup // error. - pipeOps.Release() + pipeOps.Release(ctx) if test.flags.Read { // Partner is writer. @@ -490,7 +490,7 @@ func TestPipeHangup(t *testing.T) { } else { // Hangup our partner and expect us to get the hangup error. syscall.Close(f) - defer pipeOps.Release() + defer pipeOps.Release(ctx) if test.flags.Read { assertReaderHungup(t, test.desc, pipeOps.(*pipeOperations).file) diff --git a/pkg/sentry/fs/fdpipe/pipe_test.go b/pkg/sentry/fs/fdpipe/pipe_test.go index a0082ecca..1c9e82562 100644 --- a/pkg/sentry/fs/fdpipe/pipe_test.go +++ b/pkg/sentry/fs/fdpipe/pipe_test.go @@ -98,10 +98,11 @@ func TestNewPipe(t *testing.T) { } f := fd.New(gfd) - p, err := newPipeOperations(contexttest.Context(t), nil, test.flags, f, test.readAheadBuffer) + ctx := contexttest.Context(t) + p, err := newPipeOperations(ctx, nil, test.flags, f, test.readAheadBuffer) if p != nil { // This is necessary to remove the fd from the global fd notifier. - defer p.Release() + defer p.Release(ctx) } else { // If there is no p to DecRef on, because newPipeOperations failed, then the // file still needs to be closed. @@ -153,13 +154,14 @@ func TestPipeDestruction(t *testing.T) { syscall.Close(fds[1]) // Test the read end, but it doesn't really matter which. - p, err := newPipeOperations(contexttest.Context(t), nil, fs.FileFlags{Read: true}, f, nil) + ctx := contexttest.Context(t) + p, err := newPipeOperations(ctx, nil, fs.FileFlags{Read: true}, f, nil) if err != nil { f.Close() t.Fatalf("newPipeOperations got error %v, want nil", err) } // Drop our only reference, which should trigger the destructor. - p.Release() + p.Release(ctx) if fdnotifier.HasFD(int32(fds[0])) { t.Fatalf("after DecRef fdnotifier has fd %d, want no longer registered", fds[0]) @@ -282,7 +284,7 @@ func TestPipeRequest(t *testing.T) { if err != nil { t.Fatalf("%s: newPipeOperations got error %v, want nil", test.desc, err) } - defer p.Release() + defer p.Release(ctx) inode := fs.NewMockInode(ctx, fs.NewMockMountSource(nil), fs.StableAttr{Type: fs.Pipe}) file := fs.NewFile(ctx, fs.NewDirent(ctx, inode, "pipe"), fs.FileFlags{Read: true}, p) @@ -334,7 +336,7 @@ func TestPipeReadAheadBuffer(t *testing.T) { rfile.Close() t.Fatalf("newPipeOperations got error %v, want nil", err) } - defer p.Release() + defer p.Release(ctx) inode := fs.NewMockInode(ctx, fs.NewMockMountSource(nil), fs.StableAttr{ Type: fs.Pipe, @@ -380,7 +382,7 @@ func TestPipeReadsAccumulate(t *testing.T) { } // Don't forget to remove the fd from the fd notifier. Otherwise other tests will // likely be borked, because it's global :( - defer p.Release() + defer p.Release(ctx) inode := fs.NewMockInode(ctx, fs.NewMockMountSource(nil), fs.StableAttr{ Type: fs.Pipe, @@ -448,7 +450,7 @@ func TestPipeWritesAccumulate(t *testing.T) { } // Don't forget to remove the fd from the fd notifier. Otherwise other tests // will likely be borked, because it's global :( - defer p.Release() + defer p.Release(ctx) inode := fs.NewMockInode(ctx, fs.NewMockMountSource(nil), fs.StableAttr{ Type: fs.Pipe, diff --git a/pkg/sentry/fs/file.go b/pkg/sentry/fs/file.go index 846252c89..72ea70fcf 100644 --- a/pkg/sentry/fs/file.go +++ b/pkg/sentry/fs/file.go @@ -142,17 +142,17 @@ func NewFile(ctx context.Context, dirent *Dirent, flags FileFlags, fops FileOper } // DecRef destroys the File when it is no longer referenced. -func (f *File) DecRef() { - f.DecRefWithDestructor(func() { +func (f *File) DecRef(ctx context.Context) { + f.DecRefWithDestructor(ctx, func(context.Context) { // Drop BSD style locks. lockRng := lock.LockRange{Start: 0, End: lock.LockEOF} - f.Dirent.Inode.LockCtx.BSD.UnlockRegion(lock.UniqueID(f.UniqueID), lockRng) + f.Dirent.Inode.LockCtx.BSD.UnlockRegion(f, lockRng) // Release resources held by the FileOperations. - f.FileOperations.Release() + f.FileOperations.Release(ctx) // Release a reference on the Dirent. - f.Dirent.DecRef() + f.Dirent.DecRef(ctx) // Only unregister if we are currently registered. There is nothing // to register if f.async is nil (this happens when async mode is @@ -310,7 +310,6 @@ func (f *File) Writev(ctx context.Context, src usermem.IOSequence) (int64, error if !f.mu.Lock(ctx) { return 0, syserror.ErrInterrupted } - unlockAppendMu := f.Dirent.Inode.lockAppendMu(f.Flags().Append) // Handle append mode. if f.Flags().Append { @@ -355,7 +354,6 @@ func (f *File) Pwritev(ctx context.Context, src usermem.IOSequence, offset int64 // offset." unlockAppendMu := f.Dirent.Inode.lockAppendMu(f.Flags().Append) defer unlockAppendMu() - if f.Flags().Append { if err := f.offsetForAppend(ctx, &offset); err != nil { return 0, err @@ -374,9 +372,10 @@ func (f *File) Pwritev(ctx context.Context, src usermem.IOSequence, offset int64 return f.FileOperations.Write(ctx, f, src, offset) } -// offsetForAppend sets the given offset to the end of the file. +// offsetForAppend atomically sets the given offset to the end of the file. // -// Precondition: the file.Dirent.Inode.appendMu mutex should be held for writing. +// Precondition: the file.Dirent.Inode.appendMu mutex should be held for +// writing. func (f *File) offsetForAppend(ctx context.Context, offset *int64) error { uattr, err := f.Dirent.Inode.UnstableAttr(ctx) if err != nil { @@ -386,7 +385,7 @@ func (f *File) offsetForAppend(ctx context.Context, offset *int64) error { } // Update the offset. - *offset = uattr.Size + atomic.StoreInt64(offset, uattr.Size) return nil } @@ -461,7 +460,7 @@ func (f *File) UnstableAttr(ctx context.Context) (UnstableAttr, error) { func (f *File) MappedName(ctx context.Context) string { root := RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } name, _ := f.Dirent.FullName(root) return name diff --git a/pkg/sentry/fs/file_operations.go b/pkg/sentry/fs/file_operations.go index beba0f771..305c0f840 100644 --- a/pkg/sentry/fs/file_operations.go +++ b/pkg/sentry/fs/file_operations.go @@ -67,7 +67,7 @@ type SpliceOpts struct { // - File.Flags(): This value may change during the operation. type FileOperations interface { // Release release resources held by FileOperations. - Release() + Release(ctx context.Context) // Waitable defines how this File can be waited on for read and // write readiness. @@ -160,6 +160,7 @@ type FileOperations interface { // refer. // // Preconditions: The AddressSpace (if any) that io refers to is activated. + // Must only be called from a task goroutine. Ioctl(ctx context.Context, file *File, io usermem.IO, args arch.SyscallArguments) (uintptr, error) } diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go index dcc1df38f..9dc58d5ff 100644 --- a/pkg/sentry/fs/file_overlay.go +++ b/pkg/sentry/fs/file_overlay.go @@ -54,7 +54,7 @@ func overlayFile(ctx context.Context, inode *Inode, flags FileFlags) (*File, err // Drop the extra reference on the Dirent. Now there's only one reference // on the dirent, either owned by f (if non-nil), or the Dirent is about // to be destroyed (if GetFile failed). - dirent.DecRef() + dirent.DecRef(ctx) return f, err } @@ -89,12 +89,12 @@ type overlayFileOperations struct { } // Release implements FileOperations.Release. -func (f *overlayFileOperations) Release() { +func (f *overlayFileOperations) Release(ctx context.Context) { if f.upper != nil { - f.upper.DecRef() + f.upper.DecRef(ctx) } if f.lower != nil { - f.lower.DecRef() + f.lower.DecRef(ctx) } } @@ -164,7 +164,7 @@ func (f *overlayFileOperations) Seek(ctx context.Context, file *File, whence See func (f *overlayFileOperations) Readdir(ctx context.Context, file *File, serializer DentrySerializer) (int64, error) { root := RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dirCtx := &DirCtx{ @@ -497,7 +497,7 @@ func readdirOne(ctx context.Context, d *Dirent) (map[string]DentAttr, error) { if err != nil { return nil, err } - defer dir.DecRef() + defer dir.DecRef(ctx) // Use a stub serializer to read the entries into memory. stubSerializer := &CollectEntriesSerializer{} @@ -521,10 +521,10 @@ type overlayMappingIdentity struct { } // DecRef implements AtomicRefCount.DecRef. -func (omi *overlayMappingIdentity) DecRef() { - omi.AtomicRefCount.DecRefWithDestructor(func() { - omi.overlayFile.DecRef() - omi.id.DecRef() +func (omi *overlayMappingIdentity) DecRef(ctx context.Context) { + omi.AtomicRefCount.DecRefWithDestructor(ctx, func(context.Context) { + omi.overlayFile.DecRef(ctx) + omi.id.DecRef(ctx) }) } @@ -544,7 +544,7 @@ func (omi *overlayMappingIdentity) InodeID() uint64 { func (omi *overlayMappingIdentity) MappedName(ctx context.Context) string { root := RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } name, _ := omi.overlayFile.Dirent.FullName(root) return name diff --git a/pkg/sentry/fs/filesystems.go b/pkg/sentry/fs/filesystems.go index 084da2a8d..d41f30bbb 100644 --- a/pkg/sentry/fs/filesystems.go +++ b/pkg/sentry/fs/filesystems.go @@ -87,20 +87,6 @@ func RegisterFilesystem(f Filesystem) { filesystems.registered[f.Name()] = f } -// UnregisterFilesystem removes a file system from the global set. To keep the -// file system set compatible with save/restore, UnregisterFilesystem must be -// called before save/restore methods. -// -// For instance, packages may unregister their file system after it is mounted. -// This makes sense for pseudo file systems that should not be visible or -// mountable. See whitelistfs in fs/host/fs.go for one example. -func UnregisterFilesystem(name string) { - filesystems.mu.Lock() - defer filesystems.mu.Unlock() - - delete(filesystems.registered, name) -} - // FindFilesystem returns a Filesystem registered at name or (nil, false) if name // is not a file system type that can be found in /proc/filesystems. func FindFilesystem(name string) (Filesystem, bool) { diff --git a/pkg/sentry/fs/fs.go b/pkg/sentry/fs/fs.go index bdba6efe5..d2dbff268 100644 --- a/pkg/sentry/fs/fs.go +++ b/pkg/sentry/fs/fs.go @@ -42,9 +42,10 @@ // Dirent.dirMu // Dirent.mu // DirentCache.mu -// Locks in InodeOperations implementations or overlayEntry // Inode.Watches.mu (see `Inotify` for other lock ordering) // MountSource.mu +// Inode.appendMu +// Locks in InodeOperations implementations or overlayEntry // // If multiple Dirent or MountSource locks must be taken, locks in the parent must be // taken before locks in their children. diff --git a/pkg/sentry/fs/fsutil/BUILD b/pkg/sentry/fs/fsutil/BUILD index 789369220..5fb419bcd 100644 --- a/pkg/sentry/fs/fsutil/BUILD +++ b/pkg/sentry/fs/fsutil/BUILD @@ -8,7 +8,6 @@ go_template_instance( out = "dirty_set_impl.go", imports = { "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap", - "platform": "gvisor.dev/gvisor/pkg/sentry/platform", }, package = "fsutil", prefix = "Dirty", @@ -25,14 +24,14 @@ go_template_instance( name = "frame_ref_set_impl", out = "frame_ref_set_impl.go", imports = { - "platform": "gvisor.dev/gvisor/pkg/sentry/platform", + "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap", }, package = "fsutil", prefix = "FrameRef", template = "//pkg/segment:generic_set", types = { "Key": "uint64", - "Range": "platform.FileRange", + "Range": "memmap.FileRange", "Value": "uint64", "Functions": "FrameRefSetFunctions", }, @@ -43,7 +42,6 @@ go_template_instance( out = "file_range_set_impl.go", imports = { "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap", - "platform": "gvisor.dev/gvisor/pkg/sentry/platform", }, package = "fsutil", prefix = "FileRange", @@ -86,7 +84,6 @@ go_library( "//pkg/sentry/kernel/time", "//pkg/sentry/memmap", "//pkg/sentry/pgalloc", - "//pkg/sentry/platform", "//pkg/sentry/socket/unix/transport", "//pkg/sentry/usage", "//pkg/state", diff --git a/pkg/sentry/fs/fsutil/dirty_set.go b/pkg/sentry/fs/fsutil/dirty_set.go index c6cd45087..2c9446c1d 100644 --- a/pkg/sentry/fs/fsutil/dirty_set.go +++ b/pkg/sentry/fs/fsutil/dirty_set.go @@ -20,7 +20,6 @@ import ( "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/memmap" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/usermem" ) @@ -159,7 +158,7 @@ func (ds *DirtySet) AllowClean(mr memmap.MappableRange) { // repeatedly until all bytes have been written. max is the true size of the // cached object; offsets beyond max will not be passed to writeAt, even if // they are marked dirty. -func SyncDirty(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, dirty *DirtySet, max uint64, mem platform.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error { +func SyncDirty(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, dirty *DirtySet, max uint64, mem memmap.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error { var changedDirty bool defer func() { if changedDirty { @@ -194,7 +193,7 @@ func SyncDirty(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet // successful partial write, SyncDirtyAll will call it repeatedly until all // bytes have been written. max is the true size of the cached object; offsets // beyond max will not be passed to writeAt, even if they are marked dirty. -func SyncDirtyAll(ctx context.Context, cache *FileRangeSet, dirty *DirtySet, max uint64, mem platform.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error { +func SyncDirtyAll(ctx context.Context, cache *FileRangeSet, dirty *DirtySet, max uint64, mem memmap.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error { dseg := dirty.FirstSegment() for dseg.Ok() { if err := syncDirtyRange(ctx, dseg.Range(), cache, max, mem, writeAt); err != nil { @@ -210,7 +209,7 @@ func SyncDirtyAll(ctx context.Context, cache *FileRangeSet, dirty *DirtySet, max } // Preconditions: mr must be page-aligned. -func syncDirtyRange(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, max uint64, mem platform.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error { +func syncDirtyRange(ctx context.Context, mr memmap.MappableRange, cache *FileRangeSet, max uint64, mem memmap.File, writeAt func(ctx context.Context, srcs safemem.BlockSeq, offset uint64) (uint64, error)) error { for cseg := cache.LowerBoundSegment(mr.Start); cseg.Ok() && cseg.Start() < mr.End; cseg = cseg.NextSegment() { wbr := cseg.Range().Intersect(mr) if max < wbr.Start { diff --git a/pkg/sentry/fs/fsutil/file.go b/pkg/sentry/fs/fsutil/file.go index 08695391c..dc9efa5df 100644 --- a/pkg/sentry/fs/fsutil/file.go +++ b/pkg/sentry/fs/fsutil/file.go @@ -31,7 +31,7 @@ import ( type FileNoopRelease struct{} // Release is a no-op. -func (FileNoopRelease) Release() {} +func (FileNoopRelease) Release(context.Context) {} // SeekWithDirCursor is used to implement fs.FileOperations.Seek. If dirCursor // is not nil and the seek was on a directory, the cursor will be updated. @@ -296,7 +296,7 @@ func (sdfo *StaticDirFileOperations) IterateDir(ctx context.Context, d *fs.Diren func (sdfo *StaticDirFileOperations) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) { root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dirCtx := &fs.DirCtx{ Serializer: serializer, diff --git a/pkg/sentry/fs/fsutil/file_range_set.go b/pkg/sentry/fs/fsutil/file_range_set.go index 5643cdac9..bbafebf03 100644 --- a/pkg/sentry/fs/fsutil/file_range_set.go +++ b/pkg/sentry/fs/fsutil/file_range_set.go @@ -23,13 +23,12 @@ import ( "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/usermem" ) // FileRangeSet maps offsets into a memmap.Mappable to offsets into a -// platform.File. It is used to implement Mappables that store data in +// memmap.File. It is used to implement Mappables that store data in // sparsely-allocated memory. // // type FileRangeSet <generated by go_generics> @@ -65,20 +64,20 @@ func (FileRangeSetFunctions) Split(mr memmap.MappableRange, frstart uint64, spli } // FileRange returns the FileRange mapped by seg. -func (seg FileRangeIterator) FileRange() platform.FileRange { +func (seg FileRangeIterator) FileRange() memmap.FileRange { return seg.FileRangeOf(seg.Range()) } // FileRangeOf returns the FileRange mapped by mr. // // Preconditions: seg.Range().IsSupersetOf(mr). mr.Length() != 0. -func (seg FileRangeIterator) FileRangeOf(mr memmap.MappableRange) platform.FileRange { +func (seg FileRangeIterator) FileRangeOf(mr memmap.MappableRange) memmap.FileRange { frstart := seg.Value() + (mr.Start - seg.Start()) - return platform.FileRange{frstart, frstart + mr.Length()} + return memmap.FileRange{frstart, frstart + mr.Length()} } // Fill attempts to ensure that all memmap.Mappable offsets in required are -// mapped to a platform.File offset, by allocating from mf with the given +// mapped to a memmap.File offset, by allocating from mf with the given // memory usage kind and invoking readAt to store data into memory. (If readAt // returns a successful partial read, Fill will call it repeatedly until all // bytes have been read.) EOF is handled consistently with the requirements of @@ -141,7 +140,7 @@ func (frs *FileRangeSet) Fill(ctx context.Context, required, optional memmap.Map } // Drop removes segments for memmap.Mappable offsets in mr, freeing the -// corresponding platform.FileRanges. +// corresponding memmap.FileRanges. // // Preconditions: mr must be page-aligned. func (frs *FileRangeSet) Drop(mr memmap.MappableRange, mf *pgalloc.MemoryFile) { @@ -154,7 +153,7 @@ func (frs *FileRangeSet) Drop(mr memmap.MappableRange, mf *pgalloc.MemoryFile) { } // DropAll removes all segments in mr, freeing the corresponding -// platform.FileRanges. +// memmap.FileRanges. func (frs *FileRangeSet) DropAll(mf *pgalloc.MemoryFile) { for seg := frs.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { mf.DecRef(seg.FileRange()) diff --git a/pkg/sentry/fs/fsutil/frame_ref_set.go b/pkg/sentry/fs/fsutil/frame_ref_set.go index dd6f5aba6..a808894df 100644 --- a/pkg/sentry/fs/fsutil/frame_ref_set.go +++ b/pkg/sentry/fs/fsutil/frame_ref_set.go @@ -17,7 +17,7 @@ package fsutil import ( "math" - "gvisor.dev/gvisor/pkg/sentry/platform" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/usage" ) @@ -39,7 +39,7 @@ func (FrameRefSetFunctions) ClearValue(val *uint64) { } // Merge implements segment.Functions.Merge. -func (FrameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform.FileRange, val2 uint64) (uint64, bool) { +func (FrameRefSetFunctions) Merge(_ memmap.FileRange, val1 uint64, _ memmap.FileRange, val2 uint64) (uint64, bool) { if val1 != val2 { return 0, false } @@ -47,13 +47,13 @@ func (FrameRefSetFunctions) Merge(_ platform.FileRange, val1 uint64, _ platform. } // Split implements segment.Functions.Split. -func (FrameRefSetFunctions) Split(_ platform.FileRange, val uint64, _ uint64) (uint64, uint64) { +func (FrameRefSetFunctions) Split(_ memmap.FileRange, val uint64, _ uint64) (uint64, uint64) { return val, val } // IncRefAndAccount adds a reference on the range fr. All newly inserted segments // are accounted as host page cache memory mappings. -func (refs *FrameRefSet) IncRefAndAccount(fr platform.FileRange) { +func (refs *FrameRefSet) IncRefAndAccount(fr memmap.FileRange) { seg, gap := refs.Find(fr.Start) for { switch { @@ -74,7 +74,7 @@ func (refs *FrameRefSet) IncRefAndAccount(fr platform.FileRange) { // DecRefAndAccount removes a reference on the range fr and untracks segments // that are removed from memory accounting. -func (refs *FrameRefSet) DecRefAndAccount(fr platform.FileRange) { +func (refs *FrameRefSet) DecRefAndAccount(fr memmap.FileRange) { seg := refs.FindSegment(fr.Start) for seg.Ok() && seg.Start() < fr.End { diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go index e82afd112..ef0113b52 100644 --- a/pkg/sentry/fs/fsutil/host_file_mapper.go +++ b/pkg/sentry/fs/fsutil/host_file_mapper.go @@ -21,7 +21,6 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/memmap" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/usermem" ) @@ -126,7 +125,7 @@ func (f *HostFileMapper) DecRefOn(mr memmap.MappableRange) { // offsets in fr or until the next call to UnmapAll. // // Preconditions: The caller must hold a reference on all offsets in fr. -func (f *HostFileMapper) MapInternal(fr platform.FileRange, fd int, write bool) (safemem.BlockSeq, error) { +func (f *HostFileMapper) MapInternal(fr memmap.FileRange, fd int, write bool) (safemem.BlockSeq, error) { chunks := ((fr.End + chunkMask) >> chunkShift) - (fr.Start >> chunkShift) f.mapsMu.Lock() defer f.mapsMu.Unlock() @@ -146,7 +145,7 @@ func (f *HostFileMapper) MapInternal(fr platform.FileRange, fd int, write bool) } // Preconditions: f.mapsMu must be locked. -func (f *HostFileMapper) forEachMappingBlockLocked(fr platform.FileRange, fd int, write bool, fn func(safemem.Block)) error { +func (f *HostFileMapper) forEachMappingBlockLocked(fr memmap.FileRange, fd int, write bool, fn func(safemem.Block)) error { prot := syscall.PROT_READ if write { prot |= syscall.PROT_WRITE diff --git a/pkg/sentry/fs/fsutil/host_mappable.go b/pkg/sentry/fs/fsutil/host_mappable.go index 78fec553e..c15d8a946 100644 --- a/pkg/sentry/fs/fsutil/host_mappable.go +++ b/pkg/sentry/fs/fsutil/host_mappable.go @@ -21,18 +21,17 @@ import ( "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/memmap" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/usermem" ) -// HostMappable implements memmap.Mappable and platform.File over a +// HostMappable implements memmap.Mappable and memmap.File over a // CachedFileObject. // // Lock order (compare the lock order model in mm/mm.go): // truncateMu ("fs locks") // mu ("memmap.Mappable locks not taken by Translate") -// ("platform.File locks") +// ("memmap.File locks") // backingFile ("CachedFileObject locks") // // +stateify savable @@ -124,24 +123,24 @@ func (h *HostMappable) NotifyChangeFD() error { return nil } -// MapInternal implements platform.File.MapInternal. -func (h *HostMappable) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { +// MapInternal implements memmap.File.MapInternal. +func (h *HostMappable) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { return h.hostFileMapper.MapInternal(fr, h.backingFile.FD(), at.Write) } -// FD implements platform.File.FD. +// FD implements memmap.File.FD. func (h *HostMappable) FD() int { return h.backingFile.FD() } -// IncRef implements platform.File.IncRef. -func (h *HostMappable) IncRef(fr platform.FileRange) { +// IncRef implements memmap.File.IncRef. +func (h *HostMappable) IncRef(fr memmap.FileRange) { mr := memmap.MappableRange{Start: fr.Start, End: fr.End} h.hostFileMapper.IncRefOn(mr) } -// DecRef implements platform.File.DecRef. -func (h *HostMappable) DecRef(fr platform.FileRange) { +// DecRef implements memmap.File.DecRef. +func (h *HostMappable) DecRef(fr memmap.FileRange) { mr := memmap.MappableRange{Start: fr.Start, End: fr.End} h.hostFileMapper.DecRefOn(mr) } diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go index 800c8b4e1..fe8b0b6ac 100644 --- a/pkg/sentry/fs/fsutil/inode_cached.go +++ b/pkg/sentry/fs/fsutil/inode_cached.go @@ -26,7 +26,6 @@ import ( ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/usermem" @@ -934,7 +933,7 @@ func maxFillRange(required, optional memmap.MappableRange) memmap.MappableRange // InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable. func (c *CachingInodeOperations) InvalidateUnsavable(ctx context.Context) error { - // Whether we have a host fd (and consequently what platform.File is + // Whether we have a host fd (and consequently what memmap.File is // mapped) can change across save/restore, so invalidate all translations // unconditionally. c.mapsMu.Lock() @@ -999,10 +998,10 @@ func (c *CachingInodeOperations) Evict(ctx context.Context, er pgalloc.Evictable } } -// IncRef implements platform.File.IncRef. This is used when we directly map an -// underlying host fd and CachingInodeOperations is used as the platform.File +// IncRef implements memmap.File.IncRef. This is used when we directly map an +// underlying host fd and CachingInodeOperations is used as the memmap.File // during translation. -func (c *CachingInodeOperations) IncRef(fr platform.FileRange) { +func (c *CachingInodeOperations) IncRef(fr memmap.FileRange) { // Hot path. Avoid defers. c.dataMu.Lock() seg, gap := c.refs.Find(fr.Start) @@ -1024,10 +1023,10 @@ func (c *CachingInodeOperations) IncRef(fr platform.FileRange) { } } -// DecRef implements platform.File.DecRef. This is used when we directly map an -// underlying host fd and CachingInodeOperations is used as the platform.File +// DecRef implements memmap.File.DecRef. This is used when we directly map an +// underlying host fd and CachingInodeOperations is used as the memmap.File // during translation. -func (c *CachingInodeOperations) DecRef(fr platform.FileRange) { +func (c *CachingInodeOperations) DecRef(fr memmap.FileRange) { // Hot path. Avoid defers. c.dataMu.Lock() seg := c.refs.FindSegment(fr.Start) @@ -1046,15 +1045,15 @@ func (c *CachingInodeOperations) DecRef(fr platform.FileRange) { c.dataMu.Unlock() } -// MapInternal implements platform.File.MapInternal. This is used when we +// MapInternal implements memmap.File.MapInternal. This is used when we // directly map an underlying host fd and CachingInodeOperations is used as the -// platform.File during translation. -func (c *CachingInodeOperations) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { +// memmap.File during translation. +func (c *CachingInodeOperations) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { return c.hostFileMapper.MapInternal(fr, c.backingFile.FD(), at.Write) } -// FD implements platform.File.FD. This is used when we directly map an -// underlying host fd and CachingInodeOperations is used as the platform.File +// FD implements memmap.File.FD. This is used when we directly map an +// underlying host fd and CachingInodeOperations is used as the memmap.File // during translation. func (c *CachingInodeOperations) FD() int { return c.backingFile.FD() diff --git a/pkg/sentry/fs/g3doc/.gitignore b/pkg/sentry/fs/g3doc/.gitignore new file mode 100644 index 000000000..2d19fc766 --- /dev/null +++ b/pkg/sentry/fs/g3doc/.gitignore @@ -0,0 +1 @@ +*.html diff --git a/pkg/sentry/fs/g3doc/fuse.md b/pkg/sentry/fs/g3doc/fuse.md new file mode 100644 index 000000000..2ca84dd74 --- /dev/null +++ b/pkg/sentry/fs/g3doc/fuse.md @@ -0,0 +1,263 @@ +# Foreword + +This document describes an on-going project to support FUSE filesystems within +the sentry. This is intended to become the final documentation for this +subsystem, and is therefore written in the past tense. However FUSE support is +currently incomplete and the document will be updated as things progress. + +# FUSE: Filesystem in Userspace + +The sentry supports dispatching filesystem operations to a FUSE server, allowing +FUSE filesystem to be used with a sandbox. + +## Overview + +FUSE has two main components: + +1. A client kernel driver (canonically `fuse.ko` in Linux), which forwards + filesystem operations (usually initiated by syscalls) to the server. + +2. A server, which is a userspace daemon that implements the actual filesystem. + +The sentry implements the client component, which allows a server daemon running +within the sandbox to implement a filesystem within the sandbox. + +A FUSE filesystem is initialized with `mount(2)`, typically with the help of a +utility like `fusermount(1)`. Various mount options exist for establishing +ownership and access permissions on the filesystem, but the most important mount +option is a file descriptor used to establish communication between the client +and server. + +The FUSE device FD is obtained by opening `/dev/fuse`. During regular operation, +the client and server use the FUSE protocol described in `fuse(4)` to service +filesystem operations. See the "Protocol" section below for more information +about this protocol. The core of the sentry support for FUSE is the client-side +implementation of this protocol. + +## FUSE in the Sentry + +The sentry's FUSE client targets VFS2 and has the following components: + +- An implementation of `/dev/fuse`. + +- A VFS2 filesystem for mapping syscalls to FUSE ops. Since we're targeting + VFS2, one point of contention may be the lack of inodes in VFS2. We can + tentatively implement a kernfs-based filesystem to bridge the gap in APIs. + The kernfs base functionality can serve the role of the Linux inode cache + and, the filesystem can map VFS2 syscalls to kernfs inode operations; see + the `kernfs.Inode` interface. + +The FUSE protocol lends itself well to marshaling with `go_marshal`. The various +request and response packets can be defined in the ABI package and converted to +and from the wire format using `go_marshal`. + +### Design Goals + +- While filesystem performance is always important, the sentry's FUSE support + is primarily concerned with compatibility, with performance as a secondary + concern. + +- Avoiding deadlocks from a hung server daemon. + +- Consider the potential for denial of service from a malicious server daemon. + Protecting itself from userspace is already a design goal for the sentry, + but needs additional consideration for FUSE. Normally, an operating system + doesn't rely on userspace to make progress with filesystem operations. Since + this changes with FUSE, it opens up the possibility of creating a chain of + dependencies controlled by userspace, which could affect an entire sandbox. + For example: a FUSE op can block a syscall, which could be holding a + subsystem lock, which can then block another task goroutine. + +### Milestones + +Below are some broad goals to aim for while implementing FUSE in the sentry. +Many FUSE ops can be grouped into broad categories of functionality, and most +ops can be implemented in parallel. + +#### Minimal client that can mount a trivial FUSE filesystem. + +- Implement `/dev/fuse` - a character device used to establish an FD for + communication between the sentry and the server daemon. + +- Implement basic FUSE ops like `FUSE_INIT`, `FUSE_DESTROY`. + +#### Read-only mount with basic file operations + +- Implement the majority of file, directory and file descriptor FUSE ops. For + this milestone, we can skip uncommon or complex operations like mmap, mknod, + file locking, poll, and extended attributes. We can stub these out along + with any ops that modify the filesystem. The exact list of required ops are + to be determined, but the goal is to mount a real filesystem as read-only, + and be able to read contents from the filesystem in the sentry. + +#### Full read-write support + +- Implement the remaining FUSE ops and decide if we can omit rarely used + operations like ioctl. + +# Appendix + +## FUSE Protocol + +The FUSE protocol is a request-response protocol. All requests are initiated by +the client. The wire-format for the protocol is raw C structs serialized to +memory. + +All FUSE requests begin with the following request header: + +```c +struct fuse_in_header { + uint32_t len; // Length of the request, including this header. + uint32_t opcode; // Requested operation. + uint64_t unique; // A unique identifier for this request. + uint64_t nodeid; // ID of the filesystem object being operated on. + uint32_t uid; // UID of the requesting process. + uint32_t gid; // GID of the requesting process. + uint32_t pid; // PID of the requesting process. + uint32_t padding; +}; +``` + +The request is then followed by a payload specific to the `opcode`. + +All responses begin with this response header: + +```c +struct fuse_out_header { + uint32_t len; // Length of the response, including this header. + int32_t error; // Status of the request, 0 if success. + uint64_t unique; // The unique identifier from the corresponding request. +}; +``` + +The response payload also depends on the request `opcode`. If `error != 0`, the +response payload must be empty. + +### Operations + +The following is a list of all FUSE operations used in `fuse_in_header.opcode` +as of Linux v4.4, and a brief description of their purpose. These are defined in +`uapi/linux/fuse.h`. Many of these have a corresponding request and response +payload struct; `fuse(4)` has details for some of these. We also note how these +operations map to the sentry virtual filesystem. + +#### FUSE meta-operations + +These operations are specific to FUSE and don't have a corresponding action in a +generic filesystem. + +- `FUSE_INIT`: This operation initializes a new FUSE filesystem, and is the + first message sent by the client after mount. This is used for version and + feature negotiation. This is related to `mount(2)`. +- `FUSE_DESTROY`: Teardown a FUSE filesystem, related to `unmount(2)`. +- `FUSE_INTERRUPT`: Interrupts an in-flight operation, specified by the + `fuse_in_header.unique` value provided in the corresponding request header. + The client can send at most one of these per request, and will enter an + uninterruptible wait for a reply. The server is expected to reply promptly. +- `FUSE_FORGET`: A hint to the server that server should evict the indicate + node from any caches. This is wired up to `(struct + super_operations).evict_inode` in Linux, which is in turned hooked as the + inode cache shrinker which is typically triggered by system memory pressure. +- `FUSE_BATCH_FORGET`: Batch version of `FUSE_FORGET`. + +#### Filesystem Syscalls + +These FUSE ops map directly to an equivalent filesystem syscall, or family of +syscalls. The relevant syscalls have a similar name to the operation, unless +otherwise noted. + +Node creation: + +- `FUSE_MKNOD` +- `FUSE_MKDIR` +- `FUSE_CREATE`: This is equivalent to `open(2)` and `creat(2)`, which + atomically creates and opens a node. + +Node attributes and extended attributes: + +- `FUSE_GETATTR` +- `FUSE_SETATTR` +- `FUSE_SETXATTR` +- `FUSE_GETXATTR` +- `FUSE_LISTXATTR` +- `FUSE_REMOVEXATTR` + +Node link manipulation: + +- `FUSE_READLINK` +- `FUSE_LINK` +- `FUSE_SYMLINK` +- `FUSE_UNLINK` + +Directory operations: + +- `FUSE_RMDIR` +- `FUSE_RENAME` +- `FUSE_RENAME2` +- `FUSE_OPENDIR`: `open(2)` for directories. +- `FUSE_RELEASEDIR`: `close(2)` for directories. +- `FUSE_READDIR` +- `FUSE_READDIRPLUS` +- `FUSE_FSYNCDIR`: `fsync(2)` for directories. +- `FUSE_LOOKUP`: Establishes a unique identifier for a FS node. This is + reminiscent of `VirtualFilesystem.GetDentryAt` in that it resolves a path + component to a node. However the returned identifier is opaque to the + client. The server must remember this mapping, as this is how the client + will reference the node in the future. + +File operations: + +- `FUSE_OPEN`: `open(2)` for files. +- `FUSE_RELEASE`: `close(2)` for files. +- `FUSE_FSYNC` +- `FUSE_FALLOCATE` +- `FUSE_SETUPMAPPING`: Creates a memory map on a file for `mmap(2)`. +- `FUSE_REMOVEMAPPING`: Removes a memory map for `munmap(2)`. + +File locking: + +- `FUSE_GETLK` +- `FUSE_SETLK` +- `FUSE_SETLKW` +- `FUSE_COPY_FILE_RANGE` + +File descriptor operations: + +- `FUSE_IOCTL` +- `FUSE_POLL` +- `FUSE_LSEEK` + +Filesystem operations: + +- `FUSE_STATFS` + +#### Permissions + +- `FUSE_ACCESS` is used to check if a node is accessible, as part of many + syscall implementations. Maps to `vfs.FilesystemImpl.AccessAt` in the + sentry. + +#### I/O Operations + +These ops are used to read and write file pages. They're used to implement both +I/O syscalls like `read(2)`, `write(2)` and `mmap(2)`. + +- `FUSE_READ` +- `FUSE_WRITE` + +#### Miscellaneous + +- `FUSE_FLUSH`: Used by the client to indicate when a file descriptor is + closed. Distinct from `FUSE_FSYNC`, which corresponds to an `fsync(2)` + syscall from the user. Maps to `vfs.FileDescriptorImpl.Release` in the + sentry. +- `FUSE_BMAP`: Old address space API for block defrag. Probably not needed. +- `FUSE_NOTIFY_REPLY`: [TODO: what does this do?] + +# References + +- [fuse(4) Linux manual page](https://www.man7.org/linux/man-pages/man4/fuse.4.html) +- [Linux kernel FUSE documentation](https://www.kernel.org/doc/html/latest/filesystems/fuse.html) +- [The reference implementation of the Linux FUSE (Filesystem in Userspace) + interface](https://github.com/libfuse/libfuse) +- [The kernel interface of FUSE](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/fuse.h) diff --git a/pkg/sentry/fs/gofer/file.go b/pkg/sentry/fs/gofer/file.go index b2fcab127..c0bc63a32 100644 --- a/pkg/sentry/fs/gofer/file.go +++ b/pkg/sentry/fs/gofer/file.go @@ -114,7 +114,7 @@ func NewFile(ctx context.Context, dirent *fs.Dirent, name string, flags fs.FileF } // Release implements fs.FileOpeations.Release. -func (f *fileOperations) Release() { +func (f *fileOperations) Release(context.Context) { f.handles.DecRef() } @@ -122,7 +122,7 @@ func (f *fileOperations) Release() { func (f *fileOperations) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) { root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dirCtx := &fs.DirCtx{ diff --git a/pkg/sentry/fs/gofer/gofer_test.go b/pkg/sentry/fs/gofer/gofer_test.go index 2df2fe889..326fed954 100644 --- a/pkg/sentry/fs/gofer/gofer_test.go +++ b/pkg/sentry/fs/gofer/gofer_test.go @@ -232,7 +232,7 @@ func TestRevalidation(t *testing.T) { // We must release the dirent, of the test will fail // with a reference leak. This is tracked by p9test. - defer dirent.DecRef() + defer dirent.DecRef(ctx) // Walk again. Depending on the cache policy, we may // get a new dirent. @@ -246,7 +246,7 @@ func TestRevalidation(t *testing.T) { if !test.preModificationWantReload && dirent != newDirent { t.Errorf("Lookup with cachePolicy=%s got new dirent %+v, wanted old dirent %+v", test.cachePolicy, newDirent, dirent) } - newDirent.DecRef() // See above. + newDirent.DecRef(ctx) // See above. // Modify the underlying mocked file's modification // time for the next walk that occurs. @@ -287,7 +287,7 @@ func TestRevalidation(t *testing.T) { if test.postModificationWantUpdatedAttrs && gotModTimeSeconds != nowSeconds { t.Fatalf("Lookup with cachePolicy=%s got new modification time %v, wanted %v", test.cachePolicy, gotModTimeSeconds, nowSeconds) } - newDirent.DecRef() // See above. + newDirent.DecRef(ctx) // See above. // Remove the file from the remote fs, subsequent walks // should now fail to find anything. @@ -303,7 +303,7 @@ func TestRevalidation(t *testing.T) { t.Errorf("Lookup with cachePolicy=%s got new dirent and error %v, wanted old dirent and nil error", test.cachePolicy, err) } if err == nil { - newDirent.DecRef() // See above. + newDirent.DecRef(ctx) // See above. } }) } diff --git a/pkg/sentry/fs/gofer/handles.go b/pkg/sentry/fs/gofer/handles.go index fc14249be..f324dbf26 100644 --- a/pkg/sentry/fs/gofer/handles.go +++ b/pkg/sentry/fs/gofer/handles.go @@ -47,7 +47,8 @@ type handles struct { // DecRef drops a reference on handles. func (h *handles) DecRef() { - h.DecRefWithDestructor(func() { + ctx := context.Background() + h.DecRefWithDestructor(ctx, func(context.Context) { if h.Host != nil { if h.isHostBorrowed { h.Host.Release() @@ -57,7 +58,7 @@ func (h *handles) DecRef() { } } } - if err := h.File.close(context.Background()); err != nil { + if err := h.File.close(ctx); err != nil { log.Warningf("error closing p9 file: %v", err) } }) diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go index a016c896e..3a225fd39 100644 --- a/pkg/sentry/fs/gofer/inode.go +++ b/pkg/sentry/fs/gofer/inode.go @@ -441,8 +441,9 @@ func (i *inodeOperations) Release(ctx context.Context) { // asynchronously. // // We use AsyncWithContext to avoid needing to allocate an extra - // anonymous function on the heap. - fs.AsyncWithContext(ctx, i.fileState.Release) + // anonymous function on the heap. We must use background context + // because the async work cannot happen on the task context. + fs.AsyncWithContext(context.Background(), i.fileState.Release) } // Mappable implements fs.InodeOperations.Mappable. @@ -640,7 +641,7 @@ func (i *inodeOperations) Allocate(ctx context.Context, inode *fs.Inode, offset, // WriteOut implements fs.InodeOperations.WriteOut. func (i *inodeOperations) WriteOut(ctx context.Context, inode *fs.Inode) error { - if !i.session().cachePolicy.cacheUAttrs(inode) { + if inode.MountSource.Flags.ReadOnly || !i.session().cachePolicy.cacheUAttrs(inode) { return nil } diff --git a/pkg/sentry/fs/gofer/path.go b/pkg/sentry/fs/gofer/path.go index cf9800100..3c66dc3c2 100644 --- a/pkg/sentry/fs/gofer/path.go +++ b/pkg/sentry/fs/gofer/path.go @@ -168,7 +168,7 @@ func (i *inodeOperations) Create(ctx context.Context, dir *fs.Inode, name string // Construct the positive Dirent. d := fs.NewDirent(ctx, fs.NewInode(ctx, iops, dir.MountSource, sattr), name) - defer d.DecRef() + defer d.DecRef(ctx) // Construct the new file, caching the handles if allowed. h := handles{ @@ -371,7 +371,7 @@ func (i *inodeOperations) Remove(ctx context.Context, dir *fs.Inode, name string // Find out if file being deleted is a socket or pipe that needs to be // removed from endpoint map. if d, err := i.Lookup(ctx, dir, name); err == nil { - defer d.DecRef() + defer d.DecRef(ctx) if fs.IsSocket(d.Inode.StableAttr) || fs.IsPipe(d.Inode.StableAttr) { switch iops := d.Inode.InodeOperations.(type) { @@ -392,7 +392,7 @@ func (i *inodeOperations) Remove(ctx context.Context, dir *fs.Inode, name string return err } if key != nil { - i.session().overrides.remove(*key) + i.session().overrides.remove(ctx, *key) } i.touchModificationAndStatusChangeTime(ctx, dir) diff --git a/pkg/sentry/fs/gofer/session.go b/pkg/sentry/fs/gofer/session.go index b5efc86f2..7cf3522ff 100644 --- a/pkg/sentry/fs/gofer/session.go +++ b/pkg/sentry/fs/gofer/session.go @@ -89,10 +89,10 @@ func (e *overrideMaps) addPipe(key device.MultiDeviceKey, d *fs.Dirent, inode *f // remove deletes the key from the maps. // // Precondition: maps must have been locked with 'lock'. -func (e *overrideMaps) remove(key device.MultiDeviceKey) { +func (e *overrideMaps) remove(ctx context.Context, key device.MultiDeviceKey) { endpoint := e.keyMap[key] delete(e.keyMap, key) - endpoint.dirent.DecRef() + endpoint.dirent.DecRef(ctx) } // lock blocks other addition and removal operations from happening while @@ -197,7 +197,7 @@ type session struct { } // Destroy tears down the session. -func (s *session) Destroy() { +func (s *session) Destroy(ctx context.Context) { s.client.Close() } @@ -329,7 +329,7 @@ func Root(ctx context.Context, dev string, filesystem fs.Filesystem, superBlockF s.client, err = p9.NewClient(conn, s.msize, s.version) if err != nil { // Drop our reference on the session, it needs to be torn down. - s.DecRef() + s.DecRef(ctx) return nil, err } @@ -340,7 +340,7 @@ func Root(ctx context.Context, dev string, filesystem fs.Filesystem, superBlockF ctx.UninterruptibleSleepFinish(false) if err != nil { // Same as above. - s.DecRef() + s.DecRef(ctx) return nil, err } @@ -348,7 +348,7 @@ func Root(ctx context.Context, dev string, filesystem fs.Filesystem, superBlockF if err != nil { s.attach.close(ctx) // Same as above, but after we execute the Close request. - s.DecRef() + s.DecRef(ctx) return nil, err } @@ -393,13 +393,13 @@ func (s *session) fillKeyMap(ctx context.Context) error { // fillPathMap populates paths for overrides from dirents in direntMap // before save. -func (s *session) fillPathMap() error { +func (s *session) fillPathMap(ctx context.Context) error { unlock := s.overrides.lock() defer unlock() for _, endpoint := range s.overrides.keyMap { mountRoot := endpoint.dirent.MountRoot() - defer mountRoot.DecRef() + defer mountRoot.DecRef(ctx) dirPath, _ := endpoint.dirent.FullName(mountRoot) if dirPath == "" { return fmt.Errorf("error getting path from dirent") diff --git a/pkg/sentry/fs/gofer/session_state.go b/pkg/sentry/fs/gofer/session_state.go index 2d398b753..48b423dd8 100644 --- a/pkg/sentry/fs/gofer/session_state.go +++ b/pkg/sentry/fs/gofer/session_state.go @@ -26,7 +26,8 @@ import ( // beforeSave is invoked by stateify. func (s *session) beforeSave() { if s.overrides != nil { - if err := s.fillPathMap(); err != nil { + ctx := &dummyClockContext{context.Background()} + if err := s.fillPathMap(ctx); err != nil { panic("failed to save paths to override map before saving" + err.Error()) } } diff --git a/pkg/sentry/fs/gofer/socket.go b/pkg/sentry/fs/gofer/socket.go index 40f2c1cad..8a1c69ac2 100644 --- a/pkg/sentry/fs/gofer/socket.go +++ b/pkg/sentry/fs/gofer/socket.go @@ -134,14 +134,14 @@ func (e *endpoint) UnidirectionalConnect(ctx context.Context) (transport.Connect // We don't need the receiver. c.CloseRecv() - c.Release() + c.Release(ctx) return c, nil } // Release implements transport.BoundEndpoint.Release. -func (e *endpoint) Release() { - e.inode.DecRef() +func (e *endpoint) Release(ctx context.Context) { + e.inode.DecRef(ctx) } // Passcred implements transport.BoundEndpoint.Passcred. diff --git a/pkg/sentry/fs/host/BUILD b/pkg/sentry/fs/host/BUILD index aabce6cc9..d41d23a43 100644 --- a/pkg/sentry/fs/host/BUILD +++ b/pkg/sentry/fs/host/BUILD @@ -30,6 +30,7 @@ go_library( "//pkg/context", "//pkg/fd", "//pkg/fdnotifier", + "//pkg/iovec", "//pkg/log", "//pkg/refs", "//pkg/safemem", diff --git a/pkg/sentry/fs/host/control.go b/pkg/sentry/fs/host/control.go index 39299b7e4..0d8d36afa 100644 --- a/pkg/sentry/fs/host/control.go +++ b/pkg/sentry/fs/host/control.go @@ -57,7 +57,7 @@ func (c *scmRights) Clone() transport.RightsControlMessage { } // Release implements transport.RightsControlMessage.Release. -func (c *scmRights) Release() { +func (c *scmRights) Release(ctx context.Context) { for _, fd := range c.fds { syscall.Close(fd) } diff --git a/pkg/sentry/fs/host/file.go b/pkg/sentry/fs/host/file.go index 3e48b8b2c..86d1a87f0 100644 --- a/pkg/sentry/fs/host/file.go +++ b/pkg/sentry/fs/host/file.go @@ -110,7 +110,7 @@ func newFileFromDonatedFD(ctx context.Context, donated int, saveable, isTTY bool name := fmt.Sprintf("host:[%d]", inode.StableAttr.InodeID) dirent := fs.NewDirent(ctx, inode, name) - defer dirent.DecRef() + defer dirent.DecRef(ctx) if isTTY { return newTTYFile(ctx, dirent, flags, iops), nil @@ -169,7 +169,7 @@ func (f *fileOperations) Readiness(mask waiter.EventMask) waiter.EventMask { func (f *fileOperations) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) { root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dirCtx := &fs.DirCtx{ Serializer: serializer, diff --git a/pkg/sentry/fs/host/inode.go b/pkg/sentry/fs/host/inode.go index 62f1246aa..fbfba1b58 100644 --- a/pkg/sentry/fs/host/inode.go +++ b/pkg/sentry/fs/host/inode.go @@ -368,6 +368,9 @@ func (i *inodeOperations) Allocate(ctx context.Context, inode *fs.Inode, offset, // WriteOut implements fs.InodeOperations.WriteOut. func (i *inodeOperations) WriteOut(ctx context.Context, inode *fs.Inode) error { + if inode.MountSource.Flags.ReadOnly { + return nil + } // Have we been using host kernel metadata caches? if !inode.MountSource.Flags.ForcePageCache || !canMap(inode) { // Then the metadata is already up to date on the host. diff --git a/pkg/sentry/fs/host/inode_test.go b/pkg/sentry/fs/host/inode_test.go index c507f57eb..41a23b5da 100644 --- a/pkg/sentry/fs/host/inode_test.go +++ b/pkg/sentry/fs/host/inode_test.go @@ -36,7 +36,7 @@ func TestCloseFD(t *testing.T) { if err != nil { t.Fatalf("Failed to create File: %v", err) } - file.DecRef() + file.DecRef(ctx) s := make([]byte, 10) if c, err := syscall.Read(p[0], s); c != 0 || err != nil { diff --git a/pkg/sentry/fs/host/socket.go b/pkg/sentry/fs/host/socket.go index b6e94583e..a2f3d5918 100644 --- a/pkg/sentry/fs/host/socket.go +++ b/pkg/sentry/fs/host/socket.go @@ -22,7 +22,6 @@ import ( "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/fd" "gvisor.dev/gvisor/pkg/fdnotifier" - "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/socket/control" @@ -39,11 +38,6 @@ import ( // LINT.IfChange -// maxSendBufferSize is the maximum host send buffer size allowed for endpoint. -// -// N.B. 8MB is the default maximum on Linux (2 * sysctl_wmem_max). -const maxSendBufferSize = 8 << 20 - // ConnectedEndpoint is a host FD backed implementation of // transport.ConnectedEndpoint and transport.Receiver. // @@ -103,10 +97,6 @@ func (c *ConnectedEndpoint) init() *syserr.Error { if err != nil { return syserr.FromError(err) } - if sndbuf > maxSendBufferSize { - log.Warningf("Socket send buffer too large: %d", sndbuf) - return syserr.ErrInvalidEndpointState - } c.stype = linux.SockType(stype) c.sndbuf = int64(sndbuf) @@ -204,7 +194,7 @@ func newSocket(ctx context.Context, orgfd int, saveable bool) (*fs.File, error) } // Send implements transport.ConnectedEndpoint.Send. -func (c *ConnectedEndpoint) Send(data [][]byte, controlMessages transport.ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { +func (c *ConnectedEndpoint) Send(ctx context.Context, data [][]byte, controlMessages transport.ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { c.mu.RLock() defer c.mu.RUnlock() @@ -281,7 +271,7 @@ func (c *ConnectedEndpoint) EventUpdate() { } // Recv implements transport.Receiver.Recv. -func (c *ConnectedEndpoint) Recv(data [][]byte, creds bool, numRights int, peek bool) (int64, int64, transport.ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { +func (c *ConnectedEndpoint) Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (int64, int64, transport.ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { c.mu.RLock() defer c.mu.RUnlock() @@ -328,7 +318,7 @@ func (c *ConnectedEndpoint) Recv(data [][]byte, creds bool, numRights int, peek } // close releases all resources related to the endpoint. -func (c *ConnectedEndpoint) close() { +func (c *ConnectedEndpoint) close(context.Context) { fdnotifier.RemoveFD(int32(c.file.FD())) c.file.Close() c.file = nil @@ -384,8 +374,8 @@ func (c *ConnectedEndpoint) RecvMaxQueueSize() int64 { } // Release implements transport.ConnectedEndpoint.Release and transport.Receiver.Release. -func (c *ConnectedEndpoint) Release() { - c.ref.DecRefWithDestructor(c.close) +func (c *ConnectedEndpoint) Release(ctx context.Context) { + c.ref.DecRefWithDestructor(ctx, c.close) } // CloseUnread implements transport.ConnectedEndpoint.CloseUnread. diff --git a/pkg/sentry/fs/host/socket_iovec.go b/pkg/sentry/fs/host/socket_iovec.go index 5c18dbd5e..905afb50d 100644 --- a/pkg/sentry/fs/host/socket_iovec.go +++ b/pkg/sentry/fs/host/socket_iovec.go @@ -17,15 +17,12 @@ package host import ( "syscall" - "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/iovec" "gvisor.dev/gvisor/pkg/syserror" ) // LINT.IfChange -// maxIovs is the maximum number of iovecs to pass to the host. -var maxIovs = linux.UIO_MAXIOV - // copyToMulti copies as many bytes from src to dst as possible. func copyToMulti(dst [][]byte, src []byte) { for _, d := range dst { @@ -76,7 +73,7 @@ func buildIovec(bufs [][]byte, maxlen int64, truncate bool) (length int64, iovec } } - if iovsRequired > maxIovs { + if iovsRequired > iovec.MaxIovs { // The kernel will reject our call if we pass this many iovs. // Use a single intermediate buffer instead. b := make([]byte, stopLen) diff --git a/pkg/sentry/fs/host/socket_test.go b/pkg/sentry/fs/host/socket_test.go index affdbcacb..9d58ea448 100644 --- a/pkg/sentry/fs/host/socket_test.go +++ b/pkg/sentry/fs/host/socket_test.go @@ -67,11 +67,12 @@ func TestSocketIsBlocking(t *testing.T) { if fl&syscall.O_NONBLOCK == syscall.O_NONBLOCK { t.Fatalf("Expected socket %v to be blocking", pair[1]) } - sock, err := newSocket(contexttest.Context(t), pair[0], false) + ctx := contexttest.Context(t) + sock, err := newSocket(ctx, pair[0], false) if err != nil { t.Fatalf("newSocket(%v) failed => %v", pair[0], err) } - defer sock.DecRef() + defer sock.DecRef(ctx) // Test that the socket now is non-blocking. if fl, err = getFl(pair[0]); err != nil { t.Fatalf("getFl: fcntl(%v, GETFL) => %v", pair[0], err) @@ -93,11 +94,12 @@ func TestSocketWritev(t *testing.T) { if err != nil { t.Fatalf("host socket creation failed: %v", err) } - socket, err := newSocket(contexttest.Context(t), pair[0], false) + ctx := contexttest.Context(t) + socket, err := newSocket(ctx, pair[0], false) if err != nil { t.Fatalf("newSocket(%v) => %v", pair[0], err) } - defer socket.DecRef() + defer socket.DecRef(ctx) buf := []byte("hello world\n") n, err := socket.Writev(contexttest.Context(t), usermem.BytesIOSequence(buf)) if err != nil { @@ -115,11 +117,12 @@ func TestSocketWritevLen0(t *testing.T) { if err != nil { t.Fatalf("host socket creation failed: %v", err) } - socket, err := newSocket(contexttest.Context(t), pair[0], false) + ctx := contexttest.Context(t) + socket, err := newSocket(ctx, pair[0], false) if err != nil { t.Fatalf("newSocket(%v) => %v", pair[0], err) } - defer socket.DecRef() + defer socket.DecRef(ctx) n, err := socket.Writev(contexttest.Context(t), usermem.BytesIOSequence(nil)) if err != nil { t.Fatalf("socket writev failed: %v", err) @@ -136,11 +139,12 @@ func TestSocketSendMsgLen0(t *testing.T) { if err != nil { t.Fatalf("host socket creation failed: %v", err) } - sfile, err := newSocket(contexttest.Context(t), pair[0], false) + ctx := contexttest.Context(t) + sfile, err := newSocket(ctx, pair[0], false) if err != nil { t.Fatalf("newSocket(%v) => %v", pair[0], err) } - defer sfile.DecRef() + defer sfile.DecRef(ctx) s := sfile.FileOperations.(socket.Socket) n, terr := s.SendMsg(nil, usermem.BytesIOSequence(nil), []byte{}, 0, false, ktime.Time{}, socket.ControlMessages{}) @@ -158,18 +162,19 @@ func TestListen(t *testing.T) { if err != nil { t.Fatalf("syscall.Socket(syscall.AF_UNIX, syscall.SOCK_STREAM, 0) => %v", err) } - sfile1, err := newSocket(contexttest.Context(t), pair[0], false) + ctx := contexttest.Context(t) + sfile1, err := newSocket(ctx, pair[0], false) if err != nil { t.Fatalf("newSocket(%v) => %v", pair[0], err) } - defer sfile1.DecRef() + defer sfile1.DecRef(ctx) socket1 := sfile1.FileOperations.(socket.Socket) - sfile2, err := newSocket(contexttest.Context(t), pair[1], false) + sfile2, err := newSocket(ctx, pair[1], false) if err != nil { t.Fatalf("newSocket(%v) => %v", pair[1], err) } - defer sfile2.DecRef() + defer sfile2.DecRef(ctx) socket2 := sfile2.FileOperations.(socket.Socket) // Socketpairs can not be listened to. @@ -185,11 +190,11 @@ func TestListen(t *testing.T) { if err != nil { t.Fatalf("syscall.Socket(syscall.AF_UNIX, syscall.SOCK_STREAM, 0) => %v", err) } - sfile3, err := newSocket(contexttest.Context(t), sock, false) + sfile3, err := newSocket(ctx, sock, false) if err != nil { t.Fatalf("newSocket(%v) => %v", sock, err) } - defer sfile3.DecRef() + defer sfile3.DecRef(ctx) socket3 := sfile3.FileOperations.(socket.Socket) // This socket is not bound so we can't listen on it. @@ -237,9 +242,10 @@ func TestRelease(t *testing.T) { } c := &ConnectedEndpoint{queue: &waiter.Queue{}, file: fd.New(f)} want := &ConnectedEndpoint{queue: c.queue} - want.ref.DecRef() + ctx := contexttest.Context(t) + want.ref.DecRef(ctx) fdnotifier.AddFD(int32(c.file.FD()), nil) - c.Release() + c.Release(ctx) if !reflect.DeepEqual(c, want) { t.Errorf("got = %#v, want = %#v", c, want) } diff --git a/pkg/sentry/fs/host/tty.go b/pkg/sentry/fs/host/tty.go index cb91355ab..b5229098c 100644 --- a/pkg/sentry/fs/host/tty.go +++ b/pkg/sentry/fs/host/tty.go @@ -113,12 +113,12 @@ func (t *TTYFileOperations) Write(ctx context.Context, file *fs.File, src userme } // Release implements fs.FileOperations.Release. -func (t *TTYFileOperations) Release() { +func (t *TTYFileOperations) Release(ctx context.Context) { t.mu.Lock() t.fgProcessGroup = nil t.mu.Unlock() - t.fileOperations.Release() + t.fileOperations.Release(ctx) } // Ioctl implements fs.FileOperations.Ioctl. @@ -308,9 +308,9 @@ func (t *TTYFileOperations) checkChange(ctx context.Context, sig linux.Signal) e task := kernel.TaskFromContext(ctx) if task == nil { // No task? Linux does not have an analog for this case, but - // tty_check_change is more of a blacklist of cases than a - // whitelist, and is surprisingly permissive. Allowing the - // change seems most appropriate. + // tty_check_change only blocks specific cases and is + // surprisingly permissive. Allowing the change seems + // appropriate. return nil } diff --git a/pkg/sentry/fs/host/wait_test.go b/pkg/sentry/fs/host/wait_test.go index ce397a5e3..c143f4ce2 100644 --- a/pkg/sentry/fs/host/wait_test.go +++ b/pkg/sentry/fs/host/wait_test.go @@ -39,7 +39,7 @@ func TestWait(t *testing.T) { t.Fatalf("NewFile failed: %v", err) } - defer file.DecRef() + defer file.DecRef(ctx) r := file.Readiness(waiter.EventIn) if r != 0 { diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go index a34fbc946..b79cd9877 100644 --- a/pkg/sentry/fs/inode.go +++ b/pkg/sentry/fs/inode.go @@ -96,13 +96,12 @@ func NewInode(ctx context.Context, iops InodeOperations, msrc *MountSource, satt } // DecRef drops a reference on the Inode. -func (i *Inode) DecRef() { - i.DecRefWithDestructor(i.destroy) +func (i *Inode) DecRef(ctx context.Context) { + i.DecRefWithDestructor(ctx, i.destroy) } // destroy releases the Inode and releases the msrc reference taken. -func (i *Inode) destroy() { - ctx := context.Background() +func (i *Inode) destroy(ctx context.Context) { if err := i.WriteOut(ctx); err != nil { // FIXME(b/65209558): Mark as warning again once noatime is // properly supported. @@ -122,12 +121,12 @@ func (i *Inode) destroy() { i.Watches.targetDestroyed() if i.overlay != nil { - i.overlay.release() + i.overlay.release(ctx) } else { i.InodeOperations.Release(ctx) } - i.MountSource.DecRef() + i.MountSource.DecRef(ctx) } // Mappable calls i.InodeOperations.Mappable. diff --git a/pkg/sentry/fs/inode_inotify.go b/pkg/sentry/fs/inode_inotify.go index efd3c962b..9911a00c2 100644 --- a/pkg/sentry/fs/inode_inotify.go +++ b/pkg/sentry/fs/inode_inotify.go @@ -17,6 +17,7 @@ package fs import ( "fmt" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sync" ) @@ -136,11 +137,11 @@ func (w *Watches) Notify(name string, events, cookie uint32) { } // Unpin unpins dirent from all watches in this set. -func (w *Watches) Unpin(d *Dirent) { +func (w *Watches) Unpin(ctx context.Context, d *Dirent) { w.mu.RLock() defer w.mu.RUnlock() for _, watch := range w.ws { - watch.Unpin(d) + watch.Unpin(ctx, d) } } diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go index 537c8d257..dc2e353d9 100644 --- a/pkg/sentry/fs/inode_overlay.go +++ b/pkg/sentry/fs/inode_overlay.go @@ -85,7 +85,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name upperInode = child.Inode upperInode.IncRef() } - child.DecRef() + child.DecRef(ctx) } // Are we done? @@ -108,7 +108,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name entry, err := newOverlayEntry(ctx, upperInode, nil, false) if err != nil { // Don't leak resources. - upperInode.DecRef() + upperInode.DecRef(ctx) parent.copyMu.RUnlock() return nil, false, err } @@ -129,7 +129,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name if err != nil && err != syserror.ENOENT { // Don't leak resources. if upperInode != nil { - upperInode.DecRef() + upperInode.DecRef(ctx) } parent.copyMu.RUnlock() return nil, false, err @@ -152,7 +152,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name } } } - child.DecRef() + child.DecRef(ctx) } } @@ -183,7 +183,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name // unnecessary because we don't need to copy-up and we will always // operate (e.g. read/write) on the upper Inode. if !IsDir(upperInode.StableAttr) { - lowerInode.DecRef() + lowerInode.DecRef(ctx) lowerInode = nil } } @@ -194,10 +194,10 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name // Well, not quite, we failed at the last moment, how depressing. // Be sure not to leak resources. if upperInode != nil { - upperInode.DecRef() + upperInode.DecRef(ctx) } if lowerInode != nil { - lowerInode.DecRef() + lowerInode.DecRef(ctx) } parent.copyMu.RUnlock() return nil, false, err @@ -248,7 +248,7 @@ func overlayCreate(ctx context.Context, o *overlayEntry, parent *Dirent, name st // user) will clobber the real path for the underlying Inode. upperFile.Dirent.Inode.IncRef() upperDirent := NewTransientDirent(upperFile.Dirent.Inode) - upperFile.Dirent.DecRef() + upperFile.Dirent.DecRef(ctx) upperFile.Dirent = upperDirent // Create the overlay inode and dirent. We need this to construct the @@ -259,7 +259,7 @@ func overlayCreate(ctx context.Context, o *overlayEntry, parent *Dirent, name st // The overlay file created below with NewFile will take a reference on // the overlayDirent, and it should be the only thing holding a // reference at the time of creation, so we must drop this reference. - defer overlayDirent.DecRef() + defer overlayDirent.DecRef(ctx) // Create a new overlay file that wraps the upper file. flags.Pread = upperFile.Flags().Pread @@ -399,7 +399,7 @@ func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, rena if !replaced.IsNegative() && IsDir(replaced.Inode.StableAttr) { children, err := readdirOne(ctx, replaced) if err != nil { - replaced.DecRef() + replaced.DecRef(ctx) return err } @@ -407,12 +407,12 @@ func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, rena // included among the returned children, so we don't // need to bother checking for them. if len(children) > 0 { - replaced.DecRef() + replaced.DecRef(ctx) return syserror.ENOTEMPTY } } - replaced.DecRef() + replaced.DecRef(ctx) } } @@ -455,12 +455,12 @@ func overlayBind(ctx context.Context, o *overlayEntry, parent *Dirent, name stri // Grab the inode and drop the dirent, we don't need it. inode := d.Inode inode.IncRef() - d.DecRef() + d.DecRef(ctx) // Create a new overlay entry and dirent for the socket. entry, err := newOverlayEntry(ctx, inode, nil, false) if err != nil { - inode.DecRef() + inode.DecRef(ctx) return nil, err } // Use the parent's MountSource, since that corresponds to the overlay, @@ -672,7 +672,7 @@ func overlayGetlink(ctx context.Context, o *overlayEntry) (*Dirent, error) { // ground and claim that jumping around the filesystem like this // is not supported. name, _ := dirent.FullName(nil) - dirent.DecRef() + dirent.DecRef(ctx) // Claim that the path is not accessible. err = syserror.EACCES diff --git a/pkg/sentry/fs/inode_overlay_test.go b/pkg/sentry/fs/inode_overlay_test.go index 389c219d6..aa9851b26 100644 --- a/pkg/sentry/fs/inode_overlay_test.go +++ b/pkg/sentry/fs/inode_overlay_test.go @@ -316,7 +316,7 @@ func TestCacheFlush(t *testing.T) { t.Fatalf("NewMountNamespace failed: %v", err) } root := mns.Root() - defer root.DecRef() + defer root.DecRef(ctx) ctx = &rootContext{ Context: ctx, @@ -345,7 +345,7 @@ func TestCacheFlush(t *testing.T) { } // Drop the file reference. - file.DecRef() + file.DecRef(ctx) // Dirent should have 2 refs left. if got, want := dirent.ReadRefs(), 2; int(got) != want { @@ -361,7 +361,7 @@ func TestCacheFlush(t *testing.T) { } // Drop our ref. - dirent.DecRef() + dirent.DecRef(ctx) // We should be back to zero refs. if got, want := dirent.ReadRefs(), 0; int(got) != want { @@ -398,7 +398,7 @@ func (d *dir) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags if err != nil { return nil, err } - defer file.DecRef() + defer file.DecRef(ctx) // Wrap the file's FileOperations in a dirFile. fops := &dirFile{ FileOperations: file.FileOperations, diff --git a/pkg/sentry/fs/inotify.go b/pkg/sentry/fs/inotify.go index e3a715c1f..c5c07d564 100644 --- a/pkg/sentry/fs/inotify.go +++ b/pkg/sentry/fs/inotify.go @@ -80,7 +80,7 @@ func NewInotify(ctx context.Context) *Inotify { // Release implements FileOperations.Release. Release removes all watches and // frees all resources for an inotify instance. -func (i *Inotify) Release() { +func (i *Inotify) Release(ctx context.Context) { // We need to hold i.mu to avoid a race with concurrent calls to // Inotify.targetDestroyed from Watches. There's no risk of Watches // accessing this Inotify after the destructor ends, because we remove all @@ -93,7 +93,7 @@ func (i *Inotify) Release() { // the owner's destructor. w.target.Watches.Remove(w.ID()) // Don't leak any references to the target, held by pins in the watch. - w.destroy() + w.destroy(ctx) } } @@ -321,7 +321,7 @@ func (i *Inotify) AddWatch(target *Dirent, mask uint32) int32 { // // RmWatch looks up an inotify watch for the given 'wd' and configures the // target dirent to stop sending events to this inotify instance. -func (i *Inotify) RmWatch(wd int32) error { +func (i *Inotify) RmWatch(ctx context.Context, wd int32) error { i.mu.Lock() // Find the watch we were asked to removed. @@ -346,7 +346,7 @@ func (i *Inotify) RmWatch(wd int32) error { i.queueEvent(newEvent(watch.wd, "", linux.IN_IGNORED, 0)) // Remove all pins. - watch.destroy() + watch.destroy(ctx) return nil } diff --git a/pkg/sentry/fs/inotify_watch.go b/pkg/sentry/fs/inotify_watch.go index 900cba3ca..605423d22 100644 --- a/pkg/sentry/fs/inotify_watch.go +++ b/pkg/sentry/fs/inotify_watch.go @@ -18,6 +18,7 @@ import ( "sync/atomic" "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sync" ) @@ -105,12 +106,12 @@ func (w *Watch) Pin(d *Dirent) { // Unpin drops any extra refs held on dirent due to a previous Pin // call. Calling Unpin multiple times for the same dirent, or on a dirent // without a corresponding Pin call is a no-op. -func (w *Watch) Unpin(d *Dirent) { +func (w *Watch) Unpin(ctx context.Context, d *Dirent) { w.mu.Lock() defer w.mu.Unlock() if w.pins[d] { delete(w.pins, d) - d.DecRef() + d.DecRef(ctx) } } @@ -125,11 +126,11 @@ func (w *Watch) TargetDestroyed() { // this watch. Destroy does not cause any new events to be generated. The caller // is responsible for ensuring there are no outstanding references to this // watch. -func (w *Watch) destroy() { +func (w *Watch) destroy(ctx context.Context) { w.mu.Lock() defer w.mu.Unlock() for d := range w.pins { - d.DecRef() + d.DecRef(ctx) } w.pins = nil } diff --git a/pkg/sentry/fs/lock/lock.go b/pkg/sentry/fs/lock/lock.go index 926538d90..8a5d9c7eb 100644 --- a/pkg/sentry/fs/lock/lock.go +++ b/pkg/sentry/fs/lock/lock.go @@ -62,7 +62,7 @@ import ( type LockType int // UniqueID is a unique identifier of the holder of a regional file lock. -type UniqueID uint64 +type UniqueID interface{} const ( // ReadLock describes a POSIX regional file lock to be taken @@ -98,12 +98,7 @@ type Lock struct { // If len(Readers) > 0 then HasWriter must be false. Readers map[UniqueID]bool - // HasWriter indicates that this is a write lock held by a single - // UniqueID. - HasWriter bool - - // Writer is only valid if HasWriter is true. It identifies a - // single write lock holder. + // Writer holds the writer unique ID. It's nil if there are no writers. Writer UniqueID } @@ -186,7 +181,6 @@ func makeLock(uid UniqueID, t LockType) Lock { case ReadLock: value.Readers[uid] = true case WriteLock: - value.HasWriter = true value.Writer = uid default: panic(fmt.Sprintf("makeLock: invalid lock type %d", t)) @@ -196,10 +190,7 @@ func makeLock(uid UniqueID, t LockType) Lock { // isHeld returns true if uid is a holder of Lock. func (l Lock) isHeld(uid UniqueID) bool { - if l.HasWriter && l.Writer == uid { - return true - } - return l.Readers[uid] + return l.Writer == uid || l.Readers[uid] } // lock sets uid as a holder of a typed lock on Lock. @@ -214,20 +205,20 @@ func (l *Lock) lock(uid UniqueID, t LockType) { } // We cannot downgrade a write lock to a read lock unless the // uid is the same. - if l.HasWriter { + if l.Writer != nil { if l.Writer != uid { panic(fmt.Sprintf("lock: cannot downgrade write lock to read lock for uid %d, writer is %d", uid, l.Writer)) } // Ensure that there is only one reader if upgrading. l.Readers = make(map[UniqueID]bool) // Ensure that there is no longer a writer. - l.HasWriter = false + l.Writer = nil } l.Readers[uid] = true return case WriteLock: // If we are already the writer, then this is a no-op. - if l.HasWriter && l.Writer == uid { + if l.Writer == uid { return } // We can only upgrade a read lock to a write lock if there @@ -243,7 +234,6 @@ func (l *Lock) lock(uid UniqueID, t LockType) { } // Ensure that there is only a writer. l.Readers = make(map[UniqueID]bool) - l.HasWriter = true l.Writer = uid default: panic(fmt.Sprintf("lock: invalid lock type %d", t)) @@ -277,9 +267,8 @@ func (l LockSet) canLock(uid UniqueID, t LockType, r LockRange) bool { switch t { case ReadLock: return l.lockable(r, func(value Lock) bool { - // If there is no writer, there's no problem adding - // another reader. - if !value.HasWriter { + // If there is no writer, there's no problem adding another reader. + if value.Writer == nil { return true } // If there is a writer, then it must be the same uid @@ -289,10 +278,9 @@ func (l LockSet) canLock(uid UniqueID, t LockType, r LockRange) bool { case WriteLock: return l.lockable(r, func(value Lock) bool { // If there are only readers. - if !value.HasWriter { - // Then this uid can only take a write lock if - // this is a private upgrade, meaning that the - // only reader is uid. + if value.Writer == nil { + // Then this uid can only take a write lock if this is a private + // upgrade, meaning that the only reader is uid. return len(value.Readers) == 1 && value.Readers[uid] } // If the uid is already a writer on this region, then @@ -304,7 +292,8 @@ func (l LockSet) canLock(uid UniqueID, t LockType, r LockRange) bool { } } -// lock returns true if uid took a lock of type t on the entire range of LockRange. +// lock returns true if uid took a lock of type t on the entire range of +// LockRange. // // Preconditions: r.Start <= r.End (will panic otherwise). func (l *LockSet) lock(uid UniqueID, t LockType, r LockRange) bool { @@ -339,7 +328,7 @@ func (l *LockSet) lock(uid UniqueID, t LockType, r LockRange) bool { seg, _ = l.SplitUnchecked(seg, r.End) } - // Set the lock on the segment. This is guaranteed to + // Set the lock on the segment. This is guaranteed to // always be safe, given canLock above. value := seg.ValuePtr() value.lock(uid, t) @@ -386,7 +375,7 @@ func (l *LockSet) unlock(uid UniqueID, r LockRange) { value := seg.Value() var remove bool - if value.HasWriter && value.Writer == uid { + if value.Writer == uid { // If we are unlocking a writer, then since there can // only ever be one writer and no readers, then this // lock should always be removed from the set. diff --git a/pkg/sentry/fs/lock/lock_set_functions.go b/pkg/sentry/fs/lock/lock_set_functions.go index 8a3ace0c1..50a16e662 100644 --- a/pkg/sentry/fs/lock/lock_set_functions.go +++ b/pkg/sentry/fs/lock/lock_set_functions.go @@ -44,14 +44,9 @@ func (lockSetFunctions) Merge(r1 LockRange, val1 Lock, r2 LockRange, val2 Lock) return Lock{}, false } } - if val1.HasWriter != val2.HasWriter { + if val1.Writer != val2.Writer { return Lock{}, false } - if val1.HasWriter { - if val1.Writer != val2.Writer { - return Lock{}, false - } - } return val1, true } @@ -62,7 +57,6 @@ func (lockSetFunctions) Split(r LockRange, val Lock, split uint64) (Lock, Lock) for k, v := range val.Readers { val0.Readers[k] = v } - val0.HasWriter = val.HasWriter val0.Writer = val.Writer return val, val0 diff --git a/pkg/sentry/fs/lock/lock_test.go b/pkg/sentry/fs/lock/lock_test.go index ba002aeb7..fad90984b 100644 --- a/pkg/sentry/fs/lock/lock_test.go +++ b/pkg/sentry/fs/lock/lock_test.go @@ -42,9 +42,6 @@ func equals(e0, e1 []entry) bool { if !reflect.DeepEqual(e0[i].LockRange, e1[i].LockRange) { return false } - if e0[i].Lock.HasWriter != e1[i].Lock.HasWriter { - return false - } if e0[i].Lock.Writer != e1[i].Lock.Writer { return false } @@ -105,7 +102,7 @@ func TestCanLock(t *testing.T) { LockRange: LockRange{2048, 3072}, }, { - Lock: Lock{HasWriter: true, Writer: 1}, + Lock: Lock{Writer: 1}, LockRange: LockRange{3072, 4096}, }, }) @@ -241,7 +238,7 @@ func TestSetLock(t *testing.T) { // 0 max uint64 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, LockEOF}, }, }, @@ -254,7 +251,7 @@ func TestSetLock(t *testing.T) { // 0 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, LockEOF}, }, }, @@ -273,7 +270,7 @@ func TestSetLock(t *testing.T) { LockRange: LockRange{0, 4096}, }, { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{4096, LockEOF}, }, }, @@ -301,7 +298,7 @@ func TestSetLock(t *testing.T) { // 0 4096 max uint64 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 4096}, }, { @@ -318,7 +315,7 @@ func TestSetLock(t *testing.T) { // 0 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, LockEOF}, }, }, @@ -550,7 +547,7 @@ func TestSetLock(t *testing.T) { LockRange: LockRange{0, 1024}, }, { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{1024, 4096}, }, { @@ -594,7 +591,7 @@ func TestSetLock(t *testing.T) { LockRange: LockRange{0, 1024}, }, { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{1024, 3072}, }, { @@ -633,7 +630,7 @@ func TestSetLock(t *testing.T) { // 0 1024 2048 4096 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 1024}, }, { @@ -663,11 +660,11 @@ func TestSetLock(t *testing.T) { // 0 1024 max uint64 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 1024}, }, { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{1024, LockEOF}, }, }, @@ -675,28 +672,30 @@ func TestSetLock(t *testing.T) { } for _, test := range tests { - l := fill(test.before) + t.Run(test.name, func(t *testing.T) { + l := fill(test.before) - r := LockRange{Start: test.start, End: test.end} - success := l.lock(test.uid, test.lockType, r) - var got []entry - for seg := l.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { - got = append(got, entry{ - Lock: seg.Value(), - LockRange: seg.Range(), - }) - } + r := LockRange{Start: test.start, End: test.end} + success := l.lock(test.uid, test.lockType, r) + var got []entry + for seg := l.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { + got = append(got, entry{ + Lock: seg.Value(), + LockRange: seg.Range(), + }) + } - if success != test.success { - t.Errorf("%s: setlock(%v, %+v, %d, %d) got success %v, want %v", test.name, test.before, r, test.uid, test.lockType, success, test.success) - continue - } + if success != test.success { + t.Errorf("setlock(%v, %+v, %d, %d) got success %v, want %v", test.before, r, test.uid, test.lockType, success, test.success) + return + } - if success { - if !equals(got, test.after) { - t.Errorf("%s: got set %+v, want %+v", test.name, got, test.after) + if success { + if !equals(got, test.after) { + t.Errorf("got set %+v, want %+v", got, test.after) + } } - } + }) } } @@ -782,7 +781,7 @@ func TestUnlock(t *testing.T) { // 0 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, LockEOF}, }, }, @@ -824,7 +823,7 @@ func TestUnlock(t *testing.T) { // 0 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, LockEOF}, }, }, @@ -837,7 +836,7 @@ func TestUnlock(t *testing.T) { // 0 4096 max uint64 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{4096, LockEOF}, }, }, @@ -876,7 +875,7 @@ func TestUnlock(t *testing.T) { // 0 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, LockEOF}, }, }, @@ -889,7 +888,7 @@ func TestUnlock(t *testing.T) { // 0 4096 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 4096}, }, }, @@ -906,7 +905,7 @@ func TestUnlock(t *testing.T) { LockRange: LockRange{0, 1024}, }, { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{1024, 4096}, }, { @@ -974,7 +973,7 @@ func TestUnlock(t *testing.T) { // 0 1024 4096 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 1024}, }, { @@ -991,7 +990,7 @@ func TestUnlock(t *testing.T) { // 0 8 4096 max uint64 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 8}, }, { @@ -1008,7 +1007,7 @@ func TestUnlock(t *testing.T) { // 0 1024 4096 max uint64 before: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 1024}, }, { @@ -1025,7 +1024,7 @@ func TestUnlock(t *testing.T) { // 0 1024 4096 8192 max uint64 after: []entry{ { - Lock: Lock{HasWriter: true, Writer: 0}, + Lock: Lock{Writer: 0}, LockRange: LockRange{0, 1024}, }, { @@ -1041,19 +1040,21 @@ func TestUnlock(t *testing.T) { } for _, test := range tests { - l := fill(test.before) + t.Run(test.name, func(t *testing.T) { + l := fill(test.before) - r := LockRange{Start: test.start, End: test.end} - l.unlock(test.uid, r) - var got []entry - for seg := l.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { - got = append(got, entry{ - Lock: seg.Value(), - LockRange: seg.Range(), - }) - } - if !equals(got, test.after) { - t.Errorf("%s: got set %+v, want %+v", test.name, got, test.after) - } + r := LockRange{Start: test.start, End: test.end} + l.unlock(test.uid, r) + var got []entry + for seg := l.FirstSegment(); seg.Ok(); seg = seg.NextSegment() { + got = append(got, entry{ + Lock: seg.Value(), + LockRange: seg.Range(), + }) + } + if !equals(got, test.after) { + t.Errorf("got set %+v, want %+v", got, test.after) + } + }) } } diff --git a/pkg/sentry/fs/mount.go b/pkg/sentry/fs/mount.go index 37bae6810..ee69b10e8 100644 --- a/pkg/sentry/fs/mount.go +++ b/pkg/sentry/fs/mount.go @@ -51,7 +51,7 @@ type MountSourceOperations interface { DirentOperations // Destroy destroys the MountSource. - Destroy() + Destroy(ctx context.Context) // Below are MountSourceOperations that do not conform to Linux. @@ -165,16 +165,16 @@ func (msrc *MountSource) DecDirentRefs() { } } -func (msrc *MountSource) destroy() { +func (msrc *MountSource) destroy(ctx context.Context) { if c := msrc.DirentRefs(); c != 0 { panic(fmt.Sprintf("MountSource with non-zero direntRefs is being destroyed: %d", c)) } - msrc.MountSourceOperations.Destroy() + msrc.MountSourceOperations.Destroy(ctx) } // DecRef drops a reference on the MountSource. -func (msrc *MountSource) DecRef() { - msrc.DecRefWithDestructor(msrc.destroy) +func (msrc *MountSource) DecRef(ctx context.Context) { + msrc.DecRefWithDestructor(ctx, msrc.destroy) } // FlushDirentRefs drops all references held by the MountSource on Dirents. @@ -264,7 +264,7 @@ func (*SimpleMountSourceOperations) ResetInodeMappings() {} func (*SimpleMountSourceOperations) SaveInodeMapping(*Inode, string) {} // Destroy implements MountSourceOperations.Destroy. -func (*SimpleMountSourceOperations) Destroy() {} +func (*SimpleMountSourceOperations) Destroy(context.Context) {} // Info defines attributes of a filesystem. type Info struct { diff --git a/pkg/sentry/fs/mount_overlay.go b/pkg/sentry/fs/mount_overlay.go index 78e35b1e6..7badc75d6 100644 --- a/pkg/sentry/fs/mount_overlay.go +++ b/pkg/sentry/fs/mount_overlay.go @@ -115,9 +115,9 @@ func (o *overlayMountSourceOperations) SaveInodeMapping(inode *Inode, path strin } // Destroy drops references on the upper and lower MountSource. -func (o *overlayMountSourceOperations) Destroy() { - o.upper.DecRef() - o.lower.DecRef() +func (o *overlayMountSourceOperations) Destroy(ctx context.Context) { + o.upper.DecRef(ctx) + o.lower.DecRef(ctx) } // type overlayFilesystem is the filesystem for overlay mounts. diff --git a/pkg/sentry/fs/mount_test.go b/pkg/sentry/fs/mount_test.go index a3d10770b..6c296f5d0 100644 --- a/pkg/sentry/fs/mount_test.go +++ b/pkg/sentry/fs/mount_test.go @@ -18,6 +18,7 @@ import ( "fmt" "testing" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/contexttest" ) @@ -32,13 +33,13 @@ func cacheReallyContains(cache *DirentCache, d *Dirent) bool { return false } -func mountPathsAre(root *Dirent, got []*Mount, want ...string) error { +func mountPathsAre(ctx context.Context, root *Dirent, got []*Mount, want ...string) error { gotPaths := make(map[string]struct{}, len(got)) gotStr := make([]string, len(got)) for i, g := range got { if groot := g.Root(); groot != nil { name, _ := groot.FullName(root) - groot.DecRef() + groot.DecRef(ctx) gotStr[i] = name gotPaths[name] = struct{}{} } @@ -69,7 +70,7 @@ func TestMountSourceOnlyCachedOnce(t *testing.T) { t.Fatalf("NewMountNamespace failed: %v", err) } rootDirent := mm.Root() - defer rootDirent.DecRef() + defer rootDirent.DecRef(ctx) // Get a child of the root which we will mount over. Note that the // MockInodeOperations causes Walk to always succeed. @@ -125,7 +126,7 @@ func TestAllMountsUnder(t *testing.T) { t.Fatalf("NewMountNamespace failed: %v", err) } rootDirent := mm.Root() - defer rootDirent.DecRef() + defer rootDirent.DecRef(ctx) // Add mounts at the following paths: paths := []string{ @@ -150,14 +151,14 @@ func TestAllMountsUnder(t *testing.T) { if err := mm.Mount(ctx, d, submountInode); err != nil { t.Fatalf("could not mount at %q: %v", p, err) } - d.DecRef() + d.DecRef(ctx) } // mm root should contain all submounts (and does not include the root mount). rootMnt := mm.FindMount(rootDirent) submounts := mm.AllMountsUnder(rootMnt) allPaths := append(paths, "/") - if err := mountPathsAre(rootDirent, submounts, allPaths...); err != nil { + if err := mountPathsAre(ctx, rootDirent, submounts, allPaths...); err != nil { t.Error(err) } @@ -181,9 +182,9 @@ func TestAllMountsUnder(t *testing.T) { if err != nil { t.Fatalf("could not find path %q in mount manager: %v", "/foo", err) } - defer d.DecRef() + defer d.DecRef(ctx) submounts = mm.AllMountsUnder(mm.FindMount(d)) - if err := mountPathsAre(rootDirent, submounts, "/foo", "/foo/bar", "/foo/qux", "/foo/bar/baz"); err != nil { + if err := mountPathsAre(ctx, rootDirent, submounts, "/foo", "/foo/bar", "/foo/qux", "/foo/bar/baz"); err != nil { t.Error(err) } @@ -193,9 +194,9 @@ func TestAllMountsUnder(t *testing.T) { if err != nil { t.Fatalf("could not find path %q in mount manager: %v", "/waldo", err) } - defer waldo.DecRef() + defer waldo.DecRef(ctx) submounts = mm.AllMountsUnder(mm.FindMount(waldo)) - if err := mountPathsAre(rootDirent, submounts, "/waldo"); err != nil { + if err := mountPathsAre(ctx, rootDirent, submounts, "/waldo"); err != nil { t.Error(err) } } @@ -212,7 +213,7 @@ func TestUnmount(t *testing.T) { t.Fatalf("NewMountNamespace failed: %v", err) } rootDirent := mm.Root() - defer rootDirent.DecRef() + defer rootDirent.DecRef(ctx) // Add mounts at the following paths: paths := []string{ @@ -240,7 +241,7 @@ func TestUnmount(t *testing.T) { if err := mm.Mount(ctx, d, submountInode); err != nil { t.Fatalf("could not mount at %q: %v", p, err) } - d.DecRef() + d.DecRef(ctx) } allPaths := make([]string, len(paths)+1) @@ -259,13 +260,13 @@ func TestUnmount(t *testing.T) { if err := mm.Unmount(ctx, d, false); err != nil { t.Fatalf("could not unmount at %q: %v", p, err) } - d.DecRef() + d.DecRef(ctx) // Remove the path that has been unmounted and the check that the remaining // mounts are still there. allPaths = allPaths[:len(allPaths)-1] submounts := mm.AllMountsUnder(rootMnt) - if err := mountPathsAre(rootDirent, submounts, allPaths...); err != nil { + if err := mountPathsAre(ctx, rootDirent, submounts, allPaths...); err != nil { t.Error(err) } } diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go index b414ddaee..d741c4339 100644 --- a/pkg/sentry/fs/mounts.go +++ b/pkg/sentry/fs/mounts.go @@ -17,13 +17,9 @@ package fs import ( "fmt" "math" - "path" - "strings" "syscall" - "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sync" @@ -238,7 +234,7 @@ func (mns *MountNamespace) flushMountSourceRefsLocked() { // After destroy is called, the MountNamespace may continue to be referenced (for // example via /proc/mounts), but should free all resources and shouldn't have // Find* methods called. -func (mns *MountNamespace) destroy() { +func (mns *MountNamespace) destroy(ctx context.Context) { mns.mu.Lock() defer mns.mu.Unlock() @@ -251,13 +247,13 @@ func (mns *MountNamespace) destroy() { for _, mp := range mns.mounts { // Drop the mount reference on all mounted dirents. for ; mp != nil; mp = mp.previous { - mp.root.DecRef() + mp.root.DecRef(ctx) } } mns.mounts = nil // Drop reference on the root. - mns.root.DecRef() + mns.root.DecRef(ctx) // Ensure that root cannot be accessed via this MountNamespace any // more. @@ -269,8 +265,8 @@ func (mns *MountNamespace) destroy() { } // DecRef implements RefCounter.DecRef with destructor mns.destroy. -func (mns *MountNamespace) DecRef() { - mns.DecRefWithDestructor(mns.destroy) +func (mns *MountNamespace) DecRef(ctx context.Context) { + mns.DecRefWithDestructor(ctx, mns.destroy) } // withMountLocked prevents further walks to `node`, because `node` is about to @@ -316,7 +312,7 @@ func (mns *MountNamespace) Mount(ctx context.Context, mountPoint *Dirent, inode if err != nil { return err } - defer replacement.DecRef() + defer replacement.DecRef(ctx) // Set the mount's root dirent and id. parentMnt := mns.findMountLocked(mountPoint) @@ -398,7 +394,7 @@ func (mns *MountNamespace) Unmount(ctx context.Context, node *Dirent, detachOnly panic(fmt.Sprintf("Last mount in the chain must be a undo mount: %+v", prev)) } // Drop mount reference taken at the end of MountNamespace.Mount. - prev.root.DecRef() + prev.root.DecRef(ctx) } else { mns.mounts[prev.root] = prev } @@ -500,11 +496,11 @@ func (mns *MountNamespace) FindLink(ctx context.Context, root, wd *Dirent, path // non-directory root is hopeless. if current != root { if !IsDir(current.Inode.StableAttr) { - current.DecRef() // Drop reference from above. + current.DecRef(ctx) // Drop reference from above. return nil, syserror.ENOTDIR } if err := current.Inode.CheckPermission(ctx, PermMask{Execute: true}); err != nil { - current.DecRef() // Drop reference from above. + current.DecRef(ctx) // Drop reference from above. return nil, err } } @@ -515,12 +511,12 @@ func (mns *MountNamespace) FindLink(ctx context.Context, root, wd *Dirent, path // Allow failed walks to cache the dirent, because no // children will acquire a reference at the end. current.maybeExtendReference() - current.DecRef() + current.DecRef(ctx) return nil, err } // Drop old reference. - current.DecRef() + current.DecRef(ctx) if remainder != "" { // Ensure it's resolved, unless it's the last level. @@ -574,11 +570,11 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema case nil: // Make sure we didn't exhaust the traversal budget. if *remainingTraversals == 0 { - target.DecRef() + target.DecRef(ctx) return nil, syscall.ELOOP } - node.DecRef() // Drop the original reference. + node.DecRef(ctx) // Drop the original reference. return target, nil case syscall.ENOLINK: @@ -586,7 +582,7 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema return node, nil case ErrResolveViaReadlink: - defer node.DecRef() // See above. + defer node.DecRef(ctx) // See above. // First, check if we should traverse. if *remainingTraversals == 0 { @@ -612,7 +608,7 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema return d, err default: - node.DecRef() // Drop for err; see above. + node.DecRef(ctx) // Drop for err; see above. // Propagate the error. return nil, err @@ -625,71 +621,3 @@ func (mns *MountNamespace) SyncAll(ctx context.Context) { defer mns.mu.Unlock() mns.root.SyncAll(ctx) } - -// ResolveExecutablePath resolves the given executable name given a set of -// paths that might contain it. -func (mns *MountNamespace) ResolveExecutablePath(ctx context.Context, wd, name string, paths []string) (string, error) { - // Absolute paths can be used directly. - if path.IsAbs(name) { - return name, nil - } - - // Paths with '/' in them should be joined to the working directory, or - // to the root if working directory is not set. - if strings.IndexByte(name, '/') > 0 { - if wd == "" { - wd = "/" - } - if !path.IsAbs(wd) { - return "", fmt.Errorf("working directory %q must be absolute", wd) - } - return path.Join(wd, name), nil - } - - // Otherwise, We must lookup the name in the paths, starting from the - // calling context's root directory. - root := RootFromContext(ctx) - if root == nil { - // Caller has no root. Don't bother traversing anything. - return "", syserror.ENOENT - } - defer root.DecRef() - for _, p := range paths { - binPath := path.Join(p, name) - traversals := uint(linux.MaxSymlinkTraversals) - d, err := mns.FindInode(ctx, root, nil, binPath, &traversals) - if err == syserror.ENOENT || err == syserror.EACCES { - // Didn't find it here. - continue - } - if err != nil { - return "", err - } - defer d.DecRef() - - // Check that it is a regular file. - if !IsRegular(d.Inode.StableAttr) { - continue - } - - // Check whether we can read and execute the found file. - if err := d.Inode.CheckPermission(ctx, PermMask{Read: true, Execute: true}); err != nil { - log.Infof("Found executable at %q, but user cannot execute it: %v", binPath, err) - continue - } - return path.Join("/", p, name), nil - } - return "", syserror.ENOENT -} - -// GetPath returns the PATH as a slice of strings given the environment -// variables. -func GetPath(env []string) []string { - const prefix = "PATH=" - for _, e := range env { - if strings.HasPrefix(e, prefix) { - return strings.Split(strings.TrimPrefix(e, prefix), ":") - } - } - return nil -} diff --git a/pkg/sentry/fs/mounts_test.go b/pkg/sentry/fs/mounts_test.go index a69b41468..975d6cbc9 100644 --- a/pkg/sentry/fs/mounts_test.go +++ b/pkg/sentry/fs/mounts_test.go @@ -51,7 +51,7 @@ func TestFindLink(t *testing.T) { } root := mm.Root() - defer root.DecRef() + defer root.DecRef(ctx) foo, err := root.Walk(ctx, root, "foo") if err != nil { t.Fatalf("Error walking to foo: %v", err) diff --git a/pkg/sentry/fs/overlay.go b/pkg/sentry/fs/overlay.go index a8ae7d81d..35013a21b 100644 --- a/pkg/sentry/fs/overlay.go +++ b/pkg/sentry/fs/overlay.go @@ -107,7 +107,7 @@ func NewOverlayRoot(ctx context.Context, upper *Inode, lower *Inode, flags Mount msrc := newOverlayMountSource(ctx, upper.MountSource, lower.MountSource, flags) overlay, err := newOverlayEntry(ctx, upper, lower, true) if err != nil { - msrc.DecRef() + msrc.DecRef(ctx) return nil, err } @@ -130,7 +130,7 @@ func NewOverlayRootFile(ctx context.Context, upperMS *MountSource, lower *Inode, msrc := newOverlayMountSource(ctx, upperMS, lower.MountSource, flags) overlay, err := newOverlayEntry(ctx, nil, lower, true) if err != nil { - msrc.DecRef() + msrc.DecRef(ctx) return nil, err } return newOverlayInode(ctx, overlay, msrc), nil @@ -230,16 +230,16 @@ func newOverlayEntry(ctx context.Context, upper *Inode, lower *Inode, lowerExist }, nil } -func (o *overlayEntry) release() { +func (o *overlayEntry) release(ctx context.Context) { // We drop a reference on upper and lower file system Inodes // rather than releasing them, because in-memory filesystems // may hold an extra reference to these Inodes so that they // stay in memory. if o.upper != nil { - o.upper.DecRef() + o.upper.DecRef(ctx) } if o.lower != nil { - o.lower.DecRef() + o.lower.DecRef(ctx) } } diff --git a/pkg/sentry/fs/proc/fds.go b/pkg/sentry/fs/proc/fds.go index 35972e23c..45523adf8 100644 --- a/pkg/sentry/fs/proc/fds.go +++ b/pkg/sentry/fs/proc/fds.go @@ -56,11 +56,11 @@ func walkDescriptors(t *kernel.Task, p string, toInode func(*fs.File, kernel.FDF // readDescriptors reads fds in the task starting at offset, and calls the // toDentAttr callback for each to get a DentAttr, which it then emits. This is // a helper for implementing fs.InodeOperations.Readdir. -func readDescriptors(t *kernel.Task, c *fs.DirCtx, offset int64, toDentAttr func(int) fs.DentAttr) (int64, error) { +func readDescriptors(ctx context.Context, t *kernel.Task, c *fs.DirCtx, offset int64, toDentAttr func(int) fs.DentAttr) (int64, error) { var fds []int32 t.WithMuLocked(func(t *kernel.Task) { if fdTable := t.FDTable(); fdTable != nil { - fds = fdTable.GetFDs() + fds = fdTable.GetFDs(ctx) } }) @@ -116,7 +116,7 @@ func (f *fd) GetFile(context.Context, *fs.Dirent, fs.FileFlags) (*fs.File, error func (f *fd) Readlink(ctx context.Context, _ *fs.Inode) (string, error) { root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } n, _ := f.file.Dirent.FullName(root) return n, nil @@ -135,13 +135,7 @@ func (f *fd) Truncate(context.Context, *fs.Inode, int64) error { func (f *fd) Release(ctx context.Context) { f.Symlink.Release(ctx) - f.file.DecRef() -} - -// Close releases the reference on the file. -func (f *fd) Close() error { - f.file.DecRef() - return nil + f.file.DecRef(ctx) } // fdDir is an InodeOperations for /proc/TID/fd. @@ -227,7 +221,7 @@ func (f *fdDirFile) Readdir(ctx context.Context, file *fs.File, ser fs.DentrySer if f.isInfoFile { typ = fs.Symlink } - return readDescriptors(f.t, dirCtx, file.Offset(), func(fd int) fs.DentAttr { + return readDescriptors(ctx, f.t, dirCtx, file.Offset(), func(fd int) fs.DentAttr { return fs.GenericDentAttr(typ, device.ProcDevice) }) } @@ -261,7 +255,7 @@ func (fdid *fdInfoDir) Lookup(ctx context.Context, dir *fs.Inode, p string) (*fs // locks, and other data. For now we only have flags. // See https://www.kernel.org/doc/Documentation/filesystems/proc.txt flags := file.Flags().ToLinux() | fdFlags.ToLinuxFileFlags() - file.DecRef() + file.DecRef(ctx) contents := []byte(fmt.Sprintf("flags:\t0%o\n", flags)) return newStaticProcInode(ctx, dir.MountSource, contents) }) diff --git a/pkg/sentry/fs/proc/mounts.go b/pkg/sentry/fs/proc/mounts.go index 1fc9c703c..6a63c47b3 100644 --- a/pkg/sentry/fs/proc/mounts.go +++ b/pkg/sentry/fs/proc/mounts.go @@ -47,7 +47,7 @@ func forEachMount(t *kernel.Task, fn func(string, *fs.Mount)) { // The task has been destroyed. Nothing to show here. return } - defer rootDir.DecRef() + defer rootDir.DecRef(t) mnt := t.MountNamespace().FindMount(rootDir) if mnt == nil { @@ -64,7 +64,7 @@ func forEachMount(t *kernel.Task, fn func(string, *fs.Mount)) { continue // No longer valid. } mountPath, desc := mroot.FullName(rootDir) - mroot.DecRef() + mroot.DecRef(t) if !desc { // MountSources that are not descendants of the chroot jail are ignored. continue @@ -97,7 +97,7 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se if mroot == nil { return // No longer valid. } - defer mroot.DecRef() + defer mroot.DecRef(ctx) // Format: // 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue @@ -216,7 +216,7 @@ func (mf *mountsFile) ReadSeqFileData(ctx context.Context, handle seqfile.SeqHan if root == nil { return // No longer valid. } - defer root.DecRef() + defer root.DecRef(ctx) flags := root.Inode.MountSource.Flags opts := "rw" diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go index bd18177d4..83a43aa26 100644 --- a/pkg/sentry/fs/proc/net.go +++ b/pkg/sentry/fs/proc/net.go @@ -419,7 +419,7 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s } sfile := s.(*fs.File) if family, _, _ := sfile.FileOperations.(socket.Socket).Type(); family != linux.AF_UNIX { - s.DecRef() + s.DecRef(ctx) // Not a unix socket. continue } @@ -479,7 +479,7 @@ func (n *netUnix) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]s } fmt.Fprintf(&buf, "\n") - s.DecRef() + s.DecRef(ctx) } data := []seqfile.SeqData{ @@ -574,7 +574,7 @@ func commonReadSeqFileDataTCP(ctx context.Context, n seqfile.SeqHandle, k *kerne panic(fmt.Sprintf("Found non-socket file in socket table: %+v", sfile)) } if family, stype, _ := sops.Type(); !(family == fa && stype == linux.SOCK_STREAM) { - s.DecRef() + s.DecRef(ctx) // Not tcp4 sockets. continue } @@ -664,7 +664,7 @@ func commonReadSeqFileDataTCP(ctx context.Context, n seqfile.SeqHandle, k *kerne fmt.Fprintf(&buf, "\n") - s.DecRef() + s.DecRef(ctx) } data := []seqfile.SeqData{ @@ -752,7 +752,7 @@ func (n *netUDP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se panic(fmt.Sprintf("Found non-socket file in socket table: %+v", sfile)) } if family, stype, _ := sops.Type(); family != linux.AF_INET || stype != linux.SOCK_DGRAM { - s.DecRef() + s.DecRef(ctx) // Not udp4 socket. continue } @@ -822,7 +822,7 @@ func (n *netUDP) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]se fmt.Fprintf(&buf, "\n") - s.DecRef() + s.DecRef(ctx) } data := []seqfile.SeqData{ diff --git a/pkg/sentry/fs/proc/proc.go b/pkg/sentry/fs/proc/proc.go index c659224a7..77e0e1d26 100644 --- a/pkg/sentry/fs/proc/proc.go +++ b/pkg/sentry/fs/proc/proc.go @@ -213,7 +213,7 @@ func (rpf *rootProcFile) Readdir(ctx context.Context, file *fs.File, ser fs.Dent // Add dot and dotdot. root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dot, dotdot := file.Dirent.GetDotAttrs(root) names = append(names, ".", "..") diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go index 702fdd392..8615b60f0 100644 --- a/pkg/sentry/fs/proc/sys_net.go +++ b/pkg/sentry/fs/proc/sys_net.go @@ -272,6 +272,96 @@ func (f *tcpSackFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSeque return n, f.tcpSack.stack.SetTCPSACKEnabled(*f.tcpSack.enabled) } +// +stateify savable +type tcpRecovery struct { + fsutil.SimpleFileInode + + stack inet.Stack `state:"wait"` + recovery inet.TCPLossRecovery +} + +func newTCPRecoveryInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *fs.Inode { + ts := &tcpRecovery{ + SimpleFileInode: *fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0644), linux.PROC_SUPER_MAGIC), + stack: s, + } + sattr := fs.StableAttr{ + DeviceID: device.ProcDevice.DeviceID(), + InodeID: device.ProcDevice.NextIno(), + BlockSize: usermem.PageSize, + Type: fs.SpecialFile, + } + return fs.NewInode(ctx, ts, msrc, sattr) +} + +// Truncate implements fs.InodeOperations.Truncate. +func (*tcpRecovery) Truncate(context.Context, *fs.Inode, int64) error { + return nil +} + +// GetFile implements fs.InodeOperations.GetFile. +func (r *tcpRecovery) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) { + flags.Pread = true + flags.Pwrite = true + return fs.NewFile(ctx, dirent, flags, &tcpRecoveryFile{ + tcpRecovery: r, + stack: r.stack, + }), nil +} + +// +stateify savable +type tcpRecoveryFile struct { + fsutil.FileGenericSeek `state:"nosave"` + fsutil.FileNoIoctl `state:"nosave"` + fsutil.FileNoMMap `state:"nosave"` + fsutil.FileNoSplice `state:"nosave"` + fsutil.FileNoopRelease `state:"nosave"` + fsutil.FileNoopFlush `state:"nosave"` + fsutil.FileNoopFsync `state:"nosave"` + fsutil.FileNotDirReaddir `state:"nosave"` + fsutil.FileUseInodeUnstableAttr `state:"nosave"` + waiter.AlwaysReady `state:"nosave"` + + tcpRecovery *tcpRecovery + + stack inet.Stack `state:"wait"` +} + +// Read implements fs.FileOperations.Read. +func (f *tcpRecoveryFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { + if offset != 0 { + return 0, io.EOF + } + + recovery, err := f.stack.TCPRecovery() + if err != nil { + return 0, err + } + f.tcpRecovery.recovery = recovery + s := fmt.Sprintf("%d\n", f.tcpRecovery.recovery) + n, err := dst.CopyOut(ctx, []byte(s)) + return int64(n), err +} + +// Write implements fs.FileOperations.Write. +func (f *tcpRecoveryFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSequence, offset int64) (int64, error) { + if src.NumBytes() == 0 { + return 0, nil + } + src = src.TakeFirst(usermem.PageSize - 1) + + var v int32 + n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts) + if err != nil { + return 0, err + } + f.tcpRecovery.recovery = inet.TCPLossRecovery(v) + if err := f.tcpRecovery.stack.SetTCPRecovery(f.tcpRecovery.recovery); err != nil { + return 0, err + } + return n, nil +} + func (p *proc) newSysNetCore(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *fs.Inode { // The following files are simple stubs until they are implemented in // netstack, most of these files are configuration related. We use the @@ -351,6 +441,11 @@ func (p *proc) newSysNetIPv4Dir(ctx context.Context, msrc *fs.MountSource, s ine contents["tcp_wmem"] = newTCPMemInode(ctx, msrc, s, tcpWMem) } + // Add tcp_recovery. + if _, err := s.TCPRecovery(); err == nil { + contents["tcp_recovery"] = newTCPRecoveryInode(ctx, msrc, s) + } + d := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555)) return newProcInode(ctx, d, msrc, fs.SpecialDirectory, nil) } diff --git a/pkg/sentry/fs/proc/task.go b/pkg/sentry/fs/proc/task.go index 4bbe90198..9cf7f2a62 100644 --- a/pkg/sentry/fs/proc/task.go +++ b/pkg/sentry/fs/proc/task.go @@ -185,7 +185,7 @@ func (f *subtasksFile) Readdir(ctx context.Context, file *fs.File, ser fs.Dentry // Serialize "." and "..". root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dot, dotdot := file.Dirent.GetDotAttrs(root) if err := dirCtx.DirEmit(".", dot); err != nil { @@ -295,7 +295,7 @@ func (e *exe) Readlink(ctx context.Context, inode *fs.Inode) (string, error) { if err != nil { return "", err } - defer exec.DecRef() + defer exec.DecRef(ctx) return exec.PathnameWithDeleted(ctx), nil } diff --git a/pkg/sentry/fs/ramfs/dir.go b/pkg/sentry/fs/ramfs/dir.go index bfa304552..f4fcddecb 100644 --- a/pkg/sentry/fs/ramfs/dir.go +++ b/pkg/sentry/fs/ramfs/dir.go @@ -219,7 +219,7 @@ func (d *Dir) Remove(ctx context.Context, _ *fs.Inode, name string) error { } // Remove our reference on the inode. - inode.DecRef() + inode.DecRef(ctx) return nil } @@ -250,7 +250,7 @@ func (d *Dir) RemoveDirectory(ctx context.Context, _ *fs.Inode, name string) err } // Remove our reference on the inode. - inode.DecRef() + inode.DecRef(ctx) return nil } @@ -326,7 +326,7 @@ func (d *Dir) Create(ctx context.Context, dir *fs.Inode, name string, flags fs.F // Create the Dirent and corresponding file. created := fs.NewDirent(ctx, inode, name) - defer created.DecRef() + defer created.DecRef(ctx) return created.Inode.GetFile(ctx, created, flags) } @@ -412,11 +412,11 @@ func (*Dir) Rename(ctx context.Context, inode *fs.Inode, oldParent *fs.Inode, ol } // Release implements fs.InodeOperation.Release. -func (d *Dir) Release(_ context.Context) { +func (d *Dir) Release(ctx context.Context) { // Drop references on all children. d.mu.Lock() for _, i := range d.children { - i.DecRef() + i.DecRef(ctx) } d.mu.Unlock() } @@ -456,7 +456,7 @@ func (dfo *dirFileOperations) IterateDir(ctx context.Context, d *fs.Dirent, dirC func (dfo *dirFileOperations) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) { root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dirCtx := &fs.DirCtx{ Serializer: serializer, @@ -473,13 +473,13 @@ func hasChildren(ctx context.Context, inode *fs.Inode) (bool, error) { // dropped when that dirent is destroyed. inode.IncRef() d := fs.NewTransientDirent(inode) - defer d.DecRef() + defer d.DecRef(ctx) file, err := inode.GetFile(ctx, d, fs.FileFlags{Read: true}) if err != nil { return false, err } - defer file.DecRef() + defer file.DecRef(ctx) ser := &fs.CollectEntriesSerializer{} if err := file.Readdir(ctx, ser); err != nil { @@ -530,7 +530,7 @@ func Rename(ctx context.Context, oldParent fs.InodeOperations, oldName string, n if err != nil { return err } - inode.DecRef() + inode.DecRef(ctx) } // Be careful, we may have already grabbed this mutex above. diff --git a/pkg/sentry/fs/ramfs/tree_test.go b/pkg/sentry/fs/ramfs/tree_test.go index a6ed8b2c5..3e0d1e07e 100644 --- a/pkg/sentry/fs/ramfs/tree_test.go +++ b/pkg/sentry/fs/ramfs/tree_test.go @@ -67,7 +67,7 @@ func TestMakeDirectoryTree(t *testing.T) { continue } root := mm.Root() - defer mm.DecRef() + defer mm.DecRef(ctx) for _, p := range test.subdirs { maxTraversals := uint(0) diff --git a/pkg/sentry/fs/timerfd/timerfd.go b/pkg/sentry/fs/timerfd/timerfd.go index 88c344089..f362ca9b6 100644 --- a/pkg/sentry/fs/timerfd/timerfd.go +++ b/pkg/sentry/fs/timerfd/timerfd.go @@ -55,7 +55,7 @@ type TimerOperations struct { func NewFile(ctx context.Context, c ktime.Clock) *fs.File { dirent := fs.NewDirent(ctx, anon.NewInode(ctx), "anon_inode:[timerfd]") // Release the initial dirent reference after NewFile takes a reference. - defer dirent.DecRef() + defer dirent.DecRef(ctx) tops := &TimerOperations{} tops.timer = ktime.NewTimer(c, tops) // Timerfds reject writes, but the Write flag must be set in order to @@ -65,7 +65,7 @@ func NewFile(ctx context.Context, c ktime.Clock) *fs.File { } // Release implements fs.FileOperations.Release. -func (t *TimerOperations) Release() { +func (t *TimerOperations) Release(context.Context) { t.timer.Destroy() } diff --git a/pkg/sentry/fs/tmpfs/file_test.go b/pkg/sentry/fs/tmpfs/file_test.go index aaba35502..d4d613ea9 100644 --- a/pkg/sentry/fs/tmpfs/file_test.go +++ b/pkg/sentry/fs/tmpfs/file_test.go @@ -46,7 +46,7 @@ func newFile(ctx context.Context) *fs.File { func TestGrow(t *testing.T) { ctx := contexttest.Context(t) f := newFile(ctx) - defer f.DecRef() + defer f.DecRef(ctx) abuf := bytes.Repeat([]byte{'a'}, 68) n, err := f.Pwritev(ctx, usermem.BytesIOSequence(abuf), 0) diff --git a/pkg/sentry/fs/tty/dir.go b/pkg/sentry/fs/tty/dir.go index 108654827..463f6189e 100644 --- a/pkg/sentry/fs/tty/dir.go +++ b/pkg/sentry/fs/tty/dir.go @@ -132,7 +132,7 @@ func (d *dirInodeOperations) Release(ctx context.Context) { d.mu.Lock() defer d.mu.Unlock() - d.master.DecRef() + d.master.DecRef(ctx) if len(d.slaves) != 0 { panic(fmt.Sprintf("devpts directory still contains active terminals: %+v", d)) } @@ -263,7 +263,7 @@ func (d *dirInodeOperations) allocateTerminal(ctx context.Context) (*Terminal, e } // masterClose is called when the master end of t is closed. -func (d *dirInodeOperations) masterClose(t *Terminal) { +func (d *dirInodeOperations) masterClose(ctx context.Context, t *Terminal) { d.mu.Lock() defer d.mu.Unlock() @@ -277,7 +277,7 @@ func (d *dirInodeOperations) masterClose(t *Terminal) { panic(fmt.Sprintf("Terminal %+v doesn't exist in %+v?", t, d)) } - s.DecRef() + s.DecRef(ctx) delete(d.slaves, t.n) d.dentryMap.Remove(strconv.FormatUint(uint64(t.n), 10)) } @@ -322,7 +322,7 @@ func (df *dirFileOperations) IterateDir(ctx context.Context, d *fs.Dirent, dirCt func (df *dirFileOperations) Readdir(ctx context.Context, file *fs.File, serializer fs.DentrySerializer) (int64, error) { root := fs.RootFromContext(ctx) if root != nil { - defer root.DecRef() + defer root.DecRef(ctx) } dirCtx := &fs.DirCtx{ Serializer: serializer, diff --git a/pkg/sentry/fs/tty/fs.go b/pkg/sentry/fs/tty/fs.go index 8fe05ebe5..2d4d44bf3 100644 --- a/pkg/sentry/fs/tty/fs.go +++ b/pkg/sentry/fs/tty/fs.go @@ -108,4 +108,4 @@ func (superOperations) ResetInodeMappings() {} func (superOperations) SaveInodeMapping(*fs.Inode, string) {} // Destroy implements MountSourceOperations.Destroy. -func (superOperations) Destroy() {} +func (superOperations) Destroy(context.Context) {} diff --git a/pkg/sentry/fs/tty/master.go b/pkg/sentry/fs/tty/master.go index fe07fa929..e00746017 100644 --- a/pkg/sentry/fs/tty/master.go +++ b/pkg/sentry/fs/tty/master.go @@ -75,7 +75,7 @@ func newMasterInode(ctx context.Context, d *dirInodeOperations, owner fs.FileOwn } // Release implements fs.InodeOperations.Release. -func (mi *masterInodeOperations) Release(ctx context.Context) { +func (mi *masterInodeOperations) Release(context.Context) { } // Truncate implements fs.InodeOperations.Truncate. @@ -120,9 +120,9 @@ type masterFileOperations struct { var _ fs.FileOperations = (*masterFileOperations)(nil) // Release implements fs.FileOperations.Release. -func (mf *masterFileOperations) Release() { - mf.d.masterClose(mf.t) - mf.t.DecRef() +func (mf *masterFileOperations) Release(ctx context.Context) { + mf.d.masterClose(ctx, mf.t) + mf.t.DecRef(ctx) } // EventRegister implements waiter.Waitable.EventRegister. diff --git a/pkg/sentry/fs/tty/slave.go b/pkg/sentry/fs/tty/slave.go index 9871f6fc6..7c7292687 100644 --- a/pkg/sentry/fs/tty/slave.go +++ b/pkg/sentry/fs/tty/slave.go @@ -71,7 +71,7 @@ func newSlaveInode(ctx context.Context, d *dirInodeOperations, t *Terminal, owne // Release implements fs.InodeOperations.Release. func (si *slaveInodeOperations) Release(ctx context.Context) { - si.t.DecRef() + si.t.DecRef(ctx) } // Truncate implements fs.InodeOperations.Truncate. @@ -106,7 +106,7 @@ type slaveFileOperations struct { var _ fs.FileOperations = (*slaveFileOperations)(nil) // Release implements fs.FileOperations.Release. -func (sf *slaveFileOperations) Release() { +func (sf *slaveFileOperations) Release(context.Context) { } // EventRegister implements waiter.Waitable.EventRegister. diff --git a/pkg/sentry/fs/user/BUILD b/pkg/sentry/fs/user/BUILD index f37f979f1..66e949c95 100644 --- a/pkg/sentry/fs/user/BUILD +++ b/pkg/sentry/fs/user/BUILD @@ -4,15 +4,21 @@ package(licenses = ["notice"]) go_library( name = "user", - srcs = ["user.go"], + srcs = [ + "path.go", + "user.go", + ], visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", "//pkg/context", "//pkg/fspath", + "//pkg/log", "//pkg/sentry/fs", + "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", "//pkg/sentry/vfs", + "//pkg/syserror", "//pkg/usermem", ], ) diff --git a/pkg/sentry/fs/user/path.go b/pkg/sentry/fs/user/path.go new file mode 100644 index 000000000..2f5a43b84 --- /dev/null +++ b/pkg/sentry/fs/user/path.go @@ -0,0 +1,170 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package user + +import ( + "fmt" + "path" + "strings" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/sentry/fs" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" +) + +// ResolveExecutablePath resolves the given executable name given the working +// dir and environment. +func ResolveExecutablePath(ctx context.Context, args *kernel.CreateProcessArgs) (string, error) { + name := args.Filename + if len(name) == 0 { + if len(args.Argv) == 0 { + return "", fmt.Errorf("no filename or command provided") + } + name = args.Argv[0] + } + + // Absolute paths can be used directly. + if path.IsAbs(name) { + return name, nil + } + + // Paths with '/' in them should be joined to the working directory, or + // to the root if working directory is not set. + if strings.IndexByte(name, '/') > 0 { + wd := args.WorkingDirectory + if wd == "" { + wd = "/" + } + if !path.IsAbs(wd) { + return "", fmt.Errorf("working directory %q must be absolute", wd) + } + return path.Join(wd, name), nil + } + + // Otherwise, We must lookup the name in the paths. + paths := getPath(args.Envv) + if kernel.VFS2Enabled { + f, err := resolveVFS2(ctx, args.Credentials, args.MountNamespaceVFS2, paths, name) + if err != nil { + return "", fmt.Errorf("error finding executable %q in PATH %v: %v", name, paths, err) + } + return f, nil + } + + f, err := resolve(ctx, args.MountNamespace, paths, name) + if err != nil { + return "", fmt.Errorf("error finding executable %q in PATH %v: %v", name, paths, err) + } + return f, nil +} + +func resolve(ctx context.Context, mns *fs.MountNamespace, paths []string, name string) (string, error) { + root := fs.RootFromContext(ctx) + if root == nil { + // Caller has no root. Don't bother traversing anything. + return "", syserror.ENOENT + } + defer root.DecRef(ctx) + for _, p := range paths { + if !path.IsAbs(p) { + // Relative paths aren't safe, no one should be using them. + log.Warningf("Skipping relative path %q in $PATH", p) + continue + } + + binPath := path.Join(p, name) + traversals := uint(linux.MaxSymlinkTraversals) + d, err := mns.FindInode(ctx, root, nil, binPath, &traversals) + if err == syserror.ENOENT || err == syserror.EACCES { + // Didn't find it here. + continue + } + if err != nil { + return "", err + } + defer d.DecRef(ctx) + + // Check that it is a regular file. + if !fs.IsRegular(d.Inode.StableAttr) { + continue + } + + // Check whether we can read and execute the found file. + if err := d.Inode.CheckPermission(ctx, fs.PermMask{Read: true, Execute: true}); err != nil { + log.Infof("Found executable at %q, but user cannot execute it: %v", binPath, err) + continue + } + return path.Join("/", p, name), nil + } + + // Couldn't find it. + return "", syserror.ENOENT +} + +func resolveVFS2(ctx context.Context, creds *auth.Credentials, mns *vfs.MountNamespace, paths []string, name string) (string, error) { + root := mns.Root() + defer root.DecRef(ctx) + for _, p := range paths { + if !path.IsAbs(p) { + // Relative paths aren't safe, no one should be using them. + log.Warningf("Skipping relative path %q in $PATH", p) + continue + } + + binPath := path.Join(p, name) + pop := &vfs.PathOperation{ + Root: root, + Start: root, + Path: fspath.Parse(binPath), + FollowFinalSymlink: true, + } + opts := &vfs.OpenOptions{ + FileExec: true, + Flags: linux.O_RDONLY, + } + dentry, err := root.Mount().Filesystem().VirtualFilesystem().OpenAt(ctx, creds, pop, opts) + if err == syserror.ENOENT || err == syserror.EACCES { + // Didn't find it here. + continue + } + if err != nil { + return "", err + } + dentry.DecRef(ctx) + + return binPath, nil + } + + // Couldn't find it. + return "", syserror.ENOENT +} + +// getPath returns the PATH as a slice of strings given the environment +// variables. +func getPath(env []string) []string { + const prefix = "PATH=" + for _, e := range env { + if strings.HasPrefix(e, prefix) { + return strings.Split(strings.TrimPrefix(e, prefix), ":") + } + } + return nil +} diff --git a/pkg/sentry/fs/user/user.go b/pkg/sentry/fs/user/user.go index fe7f67c00..936fd3932 100644 --- a/pkg/sentry/fs/user/user.go +++ b/pkg/sentry/fs/user/user.go @@ -12,6 +12,8 @@ // See the License for the specific language governing permissions and // limitations under the License. +// Package user contains methods for resolving filesystem paths based on the +// user and their environment. package user import ( @@ -60,7 +62,7 @@ func getExecUserHome(ctx context.Context, rootMns *fs.MountNamespace, uid auth.K // doesn't exist we will return the default home directory. return defaultHome, nil } - defer dirent.DecRef() + defer dirent.DecRef(ctx) // Check read permissions on the file. if err := dirent.Inode.CheckPermission(ctx, fs.PermMask{Read: true}); err != nil { @@ -79,7 +81,7 @@ func getExecUserHome(ctx context.Context, rootMns *fs.MountNamespace, uid auth.K if err != nil { return "", err } - defer f.DecRef() + defer f.DecRef(ctx) r := &fileReader{ Ctx: ctx, @@ -103,7 +105,7 @@ func getExecUserHomeVFS2(ctx context.Context, mns *vfs.MountNamespace, uid auth. const defaultHome = "/" root := mns.Root() - defer root.DecRef() + defer root.DecRef(ctx) creds := auth.CredentialsFromContext(ctx) @@ -121,7 +123,7 @@ func getExecUserHomeVFS2(ctx context.Context, mns *vfs.MountNamespace, uid auth. if err != nil { return defaultHome, nil } - defer fd.DecRef() + defer fd.DecRef(ctx) r := &fileReaderVFS2{ ctx: ctx, diff --git a/pkg/sentry/fs/user/user_test.go b/pkg/sentry/fs/user/user_test.go index 7d8e9ac7c..12b786224 100644 --- a/pkg/sentry/fs/user/user_test.go +++ b/pkg/sentry/fs/user/user_test.go @@ -39,7 +39,7 @@ func createEtcPasswd(ctx context.Context, root *fs.Dirent, contents string, mode if err != nil { return err } - defer etc.DecRef() + defer etc.DecRef(ctx) switch mode.FileType() { case 0: // Don't create anything. @@ -49,7 +49,7 @@ func createEtcPasswd(ctx context.Context, root *fs.Dirent, contents string, mode if err != nil { return err } - defer passwd.DecRef() + defer passwd.DecRef(ctx) if _, err := passwd.Writev(ctx, usermem.BytesIOSequence([]byte(contents))); err != nil { return err } @@ -110,9 +110,9 @@ func TestGetExecUserHome(t *testing.T) { if err != nil { t.Fatalf("NewMountNamespace failed: %v", err) } - defer mns.DecRef() + defer mns.DecRef(ctx) root := mns.Root() - defer root.DecRef() + defer root.DecRef(ctx) ctx = fs.WithRoot(ctx, root) if err := createEtcPasswd(ctx, root, tc.passwdContents, tc.passwdMode); err != nil { diff --git a/pkg/sentry/fsbridge/bridge.go b/pkg/sentry/fsbridge/bridge.go index 8e7590721..7e61209ee 100644 --- a/pkg/sentry/fsbridge/bridge.go +++ b/pkg/sentry/fsbridge/bridge.go @@ -44,7 +44,7 @@ type File interface { IncRef() // DecRef decrements reference. - DecRef() + DecRef(ctx context.Context) } // Lookup provides a common interface to open files. diff --git a/pkg/sentry/fsbridge/fs.go b/pkg/sentry/fsbridge/fs.go index 093ce1fb3..9785fd62a 100644 --- a/pkg/sentry/fsbridge/fs.go +++ b/pkg/sentry/fsbridge/fs.go @@ -49,7 +49,7 @@ func (f *fsFile) PathnameWithDeleted(ctx context.Context) string { // global there. return "" } - defer root.DecRef() + defer root.DecRef(ctx) name, _ := f.file.Dirent.FullName(root) return name @@ -87,8 +87,8 @@ func (f *fsFile) IncRef() { } // DecRef implements File. -func (f *fsFile) DecRef() { - f.file.DecRef() +func (f *fsFile) DecRef(ctx context.Context) { + f.file.DecRef(ctx) } // fsLookup implements Lookup interface using fs.File. @@ -124,7 +124,7 @@ func (l *fsLookup) OpenPath(ctx context.Context, path string, opts vfs.OpenOptio if err != nil { return nil, err } - defer d.DecRef() + defer d.DecRef(ctx) if !resolveFinal && fs.IsSymlink(d.Inode.StableAttr) { return nil, syserror.ELOOP diff --git a/pkg/sentry/fsbridge/vfs.go b/pkg/sentry/fsbridge/vfs.go index 89168220a..323506d33 100644 --- a/pkg/sentry/fsbridge/vfs.go +++ b/pkg/sentry/fsbridge/vfs.go @@ -43,7 +43,7 @@ func NewVFSFile(file *vfs.FileDescription) File { // PathnameWithDeleted implements File. func (f *VFSFile) PathnameWithDeleted(ctx context.Context) string { root := vfs.RootFromContext(ctx) - defer root.DecRef() + defer root.DecRef(ctx) vfsObj := f.file.VirtualDentry().Mount().Filesystem().VirtualFilesystem() name, _ := vfsObj.PathnameWithDeleted(ctx, root, f.file.VirtualDentry()) @@ -86,8 +86,8 @@ func (f *VFSFile) IncRef() { } // DecRef implements File. -func (f *VFSFile) DecRef() { - f.file.DecRef() +func (f *VFSFile) DecRef(ctx context.Context) { + f.file.DecRef(ctx) } // FileDescription returns the FileDescription represented by f. It does not diff --git a/pkg/sentry/fsimpl/devpts/BUILD b/pkg/sentry/fsimpl/devpts/BUILD index 585764223..93512c9b6 100644 --- a/pkg/sentry/fsimpl/devpts/BUILD +++ b/pkg/sentry/fsimpl/devpts/BUILD @@ -18,6 +18,7 @@ go_library( "//pkg/context", "//pkg/safemem", "//pkg/sentry/arch", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/kernfs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", diff --git a/pkg/sentry/fsimpl/devpts/devpts.go b/pkg/sentry/fsimpl/devpts/devpts.go index c03c65445..7169e91af 100644 --- a/pkg/sentry/fsimpl/devpts/devpts.go +++ b/pkg/sentry/fsimpl/devpts/devpts.go @@ -103,9 +103,9 @@ func (fstype FilesystemType) newFilesystem(vfsObj *vfs.VirtualFilesystem, creds } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) - fs.Filesystem.Release() + fs.Filesystem.Release(ctx) } // rootInode is the root directory inode for the devpts mounts. @@ -116,6 +116,8 @@ type rootInode struct { kernfs.InodeNotSymlink kernfs.OrderedChildren + locks vfs.FileLocks + // Keep a reference to this inode's dentry. dentry kernfs.Dentry @@ -183,7 +185,7 @@ func (i *rootInode) masterClose(t *Terminal) { // Open implements kernfs.Inode.Open. func (i *rootInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts) if err != nil { return nil, err } diff --git a/pkg/sentry/fsimpl/devpts/master.go b/pkg/sentry/fsimpl/devpts/master.go index 7a7ce5d81..3bb397f71 100644 --- a/pkg/sentry/fsimpl/devpts/master.go +++ b/pkg/sentry/fsimpl/devpts/master.go @@ -18,6 +18,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/unimpl" @@ -34,6 +35,8 @@ type masterInode struct { kernfs.InodeNotDirectory kernfs.InodeNotSymlink + locks vfs.FileLocks + // Keep a reference to this inode's dentry. dentry kernfs.Dentry @@ -55,16 +58,17 @@ func (mi *masterInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vf inode: mi, t: t, } + fd.LockFD.Init(&mi.locks) if err := fd.vfsfd.Init(fd, opts.Flags, rp.Mount(), vfsd, &vfs.FileDescriptionOptions{}); err != nil { - mi.DecRef() + mi.DecRef(ctx) return nil, err } return &fd.vfsfd, nil } // Stat implements kernfs.Inode.Stat. -func (mi *masterInode) Stat(vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { - statx, err := mi.InodeAttrs.Stat(vfsfs, opts) +func (mi *masterInode) Stat(ctx context.Context, vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { + statx, err := mi.InodeAttrs.Stat(ctx, vfsfs, opts) if err != nil { return linux.Statx{}, err } @@ -85,6 +89,7 @@ func (mi *masterInode) SetStat(ctx context.Context, vfsfs *vfs.Filesystem, creds type masterFileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD inode *masterInode t *Terminal @@ -93,9 +98,9 @@ type masterFileDescription struct { var _ vfs.FileDescriptionImpl = (*masterFileDescription)(nil) // Release implements vfs.FileDescriptionImpl.Release. -func (mfd *masterFileDescription) Release() { +func (mfd *masterFileDescription) Release(ctx context.Context) { mfd.inode.root.masterClose(mfd.t) - mfd.inode.DecRef() + mfd.inode.DecRef(ctx) } // EventRegister implements waiter.Waitable.EventRegister. @@ -181,7 +186,17 @@ func (mfd *masterFileDescription) SetStat(ctx context.Context, opts vfs.SetStatO // Stat implements vfs.FileDescriptionImpl.Stat. func (mfd *masterFileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { fs := mfd.vfsfd.VirtualDentry().Mount().Filesystem() - return mfd.inode.Stat(fs, opts) + return mfd.inode.Stat(ctx, fs, opts) +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (mfd *masterFileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return mfd.Locks().LockPOSIX(ctx, &mfd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (mfd *masterFileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return mfd.Locks().UnlockPOSIX(ctx, &mfd.vfsfd, uid, start, length, whence) } // maybeEmitUnimplementedEvent emits unimplemented event if cmd is valid. diff --git a/pkg/sentry/fsimpl/devpts/slave.go b/pkg/sentry/fsimpl/devpts/slave.go index 526cd406c..32e4e1908 100644 --- a/pkg/sentry/fsimpl/devpts/slave.go +++ b/pkg/sentry/fsimpl/devpts/slave.go @@ -18,6 +18,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/vfs" @@ -33,6 +34,8 @@ type slaveInode struct { kernfs.InodeNotDirectory kernfs.InodeNotSymlink + locks vfs.FileLocks + // Keep a reference to this inode's dentry. dentry kernfs.Dentry @@ -51,8 +54,9 @@ func (si *slaveInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs fd := &slaveFileDescription{ inode: si, } + fd.LockFD.Init(&si.locks) if err := fd.vfsfd.Init(fd, opts.Flags, rp.Mount(), vfsd, &vfs.FileDescriptionOptions{}); err != nil { - si.DecRef() + si.DecRef(ctx) return nil, err } return &fd.vfsfd, nil @@ -69,8 +73,8 @@ func (si *slaveInode) Valid(context.Context) bool { } // Stat implements kernfs.Inode.Stat. -func (si *slaveInode) Stat(vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { - statx, err := si.InodeAttrs.Stat(vfsfs, opts) +func (si *slaveInode) Stat(ctx context.Context, vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { + statx, err := si.InodeAttrs.Stat(ctx, vfsfs, opts) if err != nil { return linux.Statx{}, err } @@ -91,6 +95,7 @@ func (si *slaveInode) SetStat(ctx context.Context, vfsfs *vfs.Filesystem, creds type slaveFileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD inode *slaveInode } @@ -98,8 +103,8 @@ type slaveFileDescription struct { var _ vfs.FileDescriptionImpl = (*slaveFileDescription)(nil) // Release implements fs.FileOperations.Release. -func (sfd *slaveFileDescription) Release() { - sfd.inode.DecRef() +func (sfd *slaveFileDescription) Release(ctx context.Context) { + sfd.inode.DecRef(ctx) } // EventRegister implements waiter.Waitable.EventRegister. @@ -127,7 +132,7 @@ func (sfd *slaveFileDescription) Write(ctx context.Context, src usermem.IOSequen return sfd.inode.t.ld.outputQueueWrite(ctx, src) } -// Ioctl implements vfs.FileDescripionImpl.Ioctl. +// Ioctl implements vfs.FileDescriptionImpl.Ioctl. func (sfd *slaveFileDescription) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { switch cmd := args[1].Uint(); cmd { case linux.FIONREAD: // linux.FIONREAD == linux.TIOCINQ @@ -178,5 +183,15 @@ func (sfd *slaveFileDescription) SetStat(ctx context.Context, opts vfs.SetStatOp // Stat implements vfs.FileDescriptionImpl.Stat. func (sfd *slaveFileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { fs := sfd.vfsfd.VirtualDentry().Mount().Filesystem() - return sfd.inode.Stat(fs, opts) + return sfd.inode.Stat(ctx, fs, opts) +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (sfd *slaveFileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return sfd.Locks().LockPOSIX(ctx, &sfd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (sfd *slaveFileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return sfd.Locks().UnlockPOSIX(ctx, &sfd.vfsfd, uid, start, length, whence) } diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go index 142ee53b0..2ed5fa8a9 100644 --- a/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go +++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs.go @@ -92,9 +92,9 @@ func NewAccessor(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth } // Release must be called when a is no longer in use. -func (a *Accessor) Release() { - a.root.DecRef() - a.mntns.DecRef() +func (a *Accessor) Release(ctx context.Context) { + a.root.DecRef(ctx) + a.mntns.DecRef(ctx) } // accessorContext implements context.Context by extending an existing @@ -136,6 +136,8 @@ func (a *Accessor) pathOperationAt(pathname string) *vfs.PathOperation { // CreateDeviceFile creates a device special file at the given pathname in the // devtmpfs instance accessed by the Accessor. func (a *Accessor) CreateDeviceFile(ctx context.Context, pathname string, kind vfs.DeviceKind, major, minor uint32, perms uint16) error { + actx := a.wrapContext(ctx) + mode := (linux.FileMode)(perms) switch kind { case vfs.BlockDevice: @@ -145,12 +147,24 @@ func (a *Accessor) CreateDeviceFile(ctx context.Context, pathname string, kind v default: panic(fmt.Sprintf("invalid vfs.DeviceKind: %v", kind)) } + + // Create any parent directories. See + // devtmpfs.c:handle_create()=>path_create(). + for it := fspath.Parse(pathname).Begin; it.NextOk(); it = it.Next() { + pop := a.pathOperationAt(it.String()) + if err := a.vfsObj.MkdirAt(actx, a.creds, pop, &vfs.MkdirOptions{ + Mode: 0755, + }); err != nil { + return fmt.Errorf("failed to create directory %q: %v", it.String(), err) + } + } + // NOTE: Linux's devtmpfs refuses to automatically delete files it didn't // create, which it recognizes by storing a pointer to the kdevtmpfs struct // thread in struct inode::i_private. Accessor doesn't yet support deletion // of files at all, and probably won't as long as we don't need to support // kernel modules, so this is moot for now. - return a.vfsObj.MknodAt(a.wrapContext(ctx), a.creds, a.pathOperationAt(pathname), &vfs.MknodOptions{ + return a.vfsObj.MknodAt(actx, a.creds, a.pathOperationAt(pathname), &vfs.MknodOptions{ Mode: mode, DevMajor: major, DevMinor: minor, diff --git a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go index b6d52c015..747867cca 100644 --- a/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go +++ b/pkg/sentry/fsimpl/devtmpfs/devtmpfs_test.go @@ -30,7 +30,7 @@ func TestDevtmpfs(t *testing.T) { creds := auth.CredentialsFromContext(ctx) vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } // Register tmpfs just so that we can have a root filesystem that isn't @@ -48,9 +48,9 @@ func TestDevtmpfs(t *testing.T) { if err != nil { t.Fatalf("failed to create tmpfs root mount: %v", err) } - defer mntns.DecRef() + defer mntns.DecRef(ctx) root := mntns.Root() - defer root.DecRef() + defer root.DecRef(ctx) devpop := vfs.PathOperation{ Root: root, Start: root, @@ -69,7 +69,7 @@ func TestDevtmpfs(t *testing.T) { if err != nil { t.Fatalf("failed to create devtmpfs.Accessor: %v", err) } - defer a.Release() + defer a.Release(ctx) // Create "userspace-initialized" files using a devtmpfs.Accessor. if err := a.UserspaceInit(ctx); err != nil { diff --git a/pkg/sentry/fsimpl/eventfd/eventfd.go b/pkg/sentry/fsimpl/eventfd/eventfd.go index c573d7935..812171fa3 100644 --- a/pkg/sentry/fsimpl/eventfd/eventfd.go +++ b/pkg/sentry/fsimpl/eventfd/eventfd.go @@ -37,6 +37,7 @@ type EventFileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD // queue is used to notify interested parties when the event object // becomes readable or writable. @@ -58,9 +59,9 @@ type EventFileDescription struct { var _ vfs.FileDescriptionImpl = (*EventFileDescription)(nil) // New creates a new event fd. -func New(vfsObj *vfs.VirtualFilesystem, initVal uint64, semMode bool, flags uint32) (*vfs.FileDescription, error) { +func New(ctx context.Context, vfsObj *vfs.VirtualFilesystem, initVal uint64, semMode bool, flags uint32) (*vfs.FileDescription, error) { vd := vfsObj.NewAnonVirtualDentry("[eventfd]") - defer vd.DecRef() + defer vd.DecRef(ctx) efd := &EventFileDescription{ val: initVal, semMode: semMode, @@ -106,7 +107,7 @@ func (efd *EventFileDescription) HostFD() (int, error) { } // Release implements FileDescriptionImpl.Release() -func (efd *EventFileDescription) Release() { +func (efd *EventFileDescription) Release(context.Context) { efd.mu.Lock() defer efd.mu.Unlock() if efd.hostfd >= 0 { diff --git a/pkg/sentry/fsimpl/eventfd/eventfd_test.go b/pkg/sentry/fsimpl/eventfd/eventfd_test.go index 20e3adffc..49916fa81 100644 --- a/pkg/sentry/fsimpl/eventfd/eventfd_test.go +++ b/pkg/sentry/fsimpl/eventfd/eventfd_test.go @@ -36,16 +36,16 @@ func TestEventFD(t *testing.T) { for _, initVal := range initVals { ctx := contexttest.Context(t) vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } // Make a new eventfd that is writable. - eventfd, err := New(vfsObj, initVal, false, linux.O_RDWR) + eventfd, err := New(ctx, vfsObj, initVal, false, linux.O_RDWR) if err != nil { t.Fatalf("New() failed: %v", err) } - defer eventfd.DecRef() + defer eventfd.DecRef(ctx) // Register a callback for a write event. w, ch := waiter.NewChannelEntry(nil) @@ -74,16 +74,16 @@ func TestEventFD(t *testing.T) { func TestEventFDStat(t *testing.T) { ctx := contexttest.Context(t) vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } // Make a new eventfd that is writable. - eventfd, err := New(vfsObj, 0, false, linux.O_RDWR) + eventfd, err := New(ctx, vfsObj, 0, false, linux.O_RDWR) if err != nil { t.Fatalf("New() failed: %v", err) } - defer eventfd.DecRef() + defer eventfd.DecRef(ctx) statx, err := eventfd.Stat(ctx, vfs.StatOptions{ Mask: linux.STATX_BASIC_STATS, diff --git a/pkg/sentry/fsimpl/ext/BUILD b/pkg/sentry/fsimpl/ext/BUILD index ff861d0fe..abc610ef3 100644 --- a/pkg/sentry/fsimpl/ext/BUILD +++ b/pkg/sentry/fsimpl/ext/BUILD @@ -54,6 +54,7 @@ go_library( "//pkg/safemem", "//pkg/sentry/arch", "//pkg/sentry/fs", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/ext/disklayout", "//pkg/sentry/kernel/auth", "//pkg/sentry/memmap", @@ -95,7 +96,7 @@ go_test( "//pkg/syserror", "//pkg/test/testutil", "//pkg/usermem", - "@com_github_google_go-cmp//cmp:go_default_library", - "@com_github_google_go-cmp//cmp/cmpopts:go_default_library", + "@com_github_google_go_cmp//cmp:go_default_library", + "@com_github_google_go_cmp//cmp/cmpopts:go_default_library", ], ) diff --git a/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go b/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go index 89caee3df..8f7d5a9bb 100644 --- a/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go +++ b/pkg/sentry/fsimpl/ext/benchmark/benchmark_test.go @@ -53,7 +53,7 @@ func setUp(b *testing.B, imagePath string) (context.Context, *vfs.VirtualFilesys // Create VFS. vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { return nil, nil, nil, nil, err } vfsObj.MustRegisterFilesystemType("extfs", ext.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ @@ -68,7 +68,7 @@ func setUp(b *testing.B, imagePath string) (context.Context, *vfs.VirtualFilesys root := mntns.Root() tearDown := func() { - root.DecRef() + root.DecRef(ctx) if err := f.Close(); err != nil { b.Fatalf("tearDown failed: %v", err) @@ -169,7 +169,7 @@ func BenchmarkVFS2ExtfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to mount point: %v", err) } - defer mountPoint.DecRef() + defer mountPoint.DecRef(ctx) // Create extfs submount. mountTearDown := mount(b, fmt.Sprintf("/tmp/image-%d.ext4", depth), vfsfs, &pop) diff --git a/pkg/sentry/fsimpl/ext/block_map_file.go b/pkg/sentry/fsimpl/ext/block_map_file.go index a2d8c3ad6..8bb104ff0 100644 --- a/pkg/sentry/fsimpl/ext/block_map_file.go +++ b/pkg/sentry/fsimpl/ext/block_map_file.go @@ -58,15 +58,16 @@ var _ io.ReaderAt = (*blockMapFile)(nil) // newBlockMapFile is the blockMapFile constructor. It initializes the file to // physical blocks map with (at most) the first 12 (direct) blocks. -func newBlockMapFile(regFile regularFile) (*blockMapFile, error) { - file := &blockMapFile{regFile: regFile} +func newBlockMapFile(args inodeArgs) (*blockMapFile, error) { + file := &blockMapFile{} file.regFile.impl = file + file.regFile.inode.init(args, &file.regFile) for i := uint(0); i < 4; i++ { - file.coverage[i] = getCoverage(regFile.inode.blkSize, i) + file.coverage[i] = getCoverage(file.regFile.inode.blkSize, i) } - blkMap := regFile.inode.diskInode.Data() + blkMap := file.regFile.inode.diskInode.Data() binary.Unmarshal(blkMap[:numDirectBlks*4], binary.LittleEndian, &file.directBlks) binary.Unmarshal(blkMap[numDirectBlks*4:(numDirectBlks+1)*4], binary.LittleEndian, &file.indirectBlk) binary.Unmarshal(blkMap[(numDirectBlks+1)*4:(numDirectBlks+2)*4], binary.LittleEndian, &file.doubleIndirectBlk) diff --git a/pkg/sentry/fsimpl/ext/block_map_test.go b/pkg/sentry/fsimpl/ext/block_map_test.go index 181727ef7..6fa84e7aa 100644 --- a/pkg/sentry/fsimpl/ext/block_map_test.go +++ b/pkg/sentry/fsimpl/ext/block_map_test.go @@ -85,20 +85,6 @@ func (n *blkNumGen) next() uint32 { // the inode covers and that is written to disk. func blockMapSetUp(t *testing.T) (*blockMapFile, []byte) { mockDisk := make([]byte, mockBMDiskSize) - regFile := regularFile{ - inode: inode{ - fs: &filesystem{ - dev: bytes.NewReader(mockDisk), - }, - diskInode: &disklayout.InodeNew{ - InodeOld: disklayout.InodeOld{ - SizeLo: getMockBMFileFize(), - }, - }, - blkSize: uint64(mockBMBlkSize), - }, - } - var fileData []byte blkNums := newBlkNumGen() var data []byte @@ -125,9 +111,20 @@ func blockMapSetUp(t *testing.T) (*blockMapFile, []byte) { data = binary.Marshal(data, binary.LittleEndian, triplyIndirectBlk) fileData = append(fileData, writeFileDataToBlock(mockDisk, triplyIndirectBlk, 3, blkNums)...) - copy(regFile.inode.diskInode.Data(), data) + args := inodeArgs{ + fs: &filesystem{ + dev: bytes.NewReader(mockDisk), + }, + diskInode: &disklayout.InodeNew{ + InodeOld: disklayout.InodeOld{ + SizeLo: getMockBMFileFize(), + }, + }, + blkSize: uint64(mockBMBlkSize), + } + copy(args.diskInode.Data(), data) - mockFile, err := newBlockMapFile(regFile) + mockFile, err := newBlockMapFile(args) if err != nil { t.Fatalf("newBlockMapFile failed: %v", err) } diff --git a/pkg/sentry/fsimpl/ext/dentry.go b/pkg/sentry/fsimpl/ext/dentry.go index bfbd7c3d4..7a1b4219f 100644 --- a/pkg/sentry/fsimpl/ext/dentry.go +++ b/pkg/sentry/fsimpl/ext/dentry.go @@ -15,6 +15,7 @@ package ext import ( + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/vfs" ) @@ -55,8 +56,25 @@ func (d *dentry) TryIncRef() bool { } // DecRef implements vfs.DentryImpl.DecRef. -func (d *dentry) DecRef() { +func (d *dentry) DecRef(ctx context.Context) { // FIXME(b/134676337): filesystem.mu may not be locked as required by // inode.decRef(). d.inode.decRef() } + +// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent. +// +// TODO(b/134676337): Implement inotify. +func (d *dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et vfs.EventType) {} + +// Watches implements vfs.DentryImpl.Watches. +// +// TODO(b/134676337): Implement inotify. +func (d *dentry) Watches() *vfs.Watches { + return nil +} + +// OnZeroWatches implements vfs.Dentry.OnZeroWatches. +// +// TODO(b/134676337): Implement inotify. +func (d *dentry) OnZeroWatches(context.Context) {} diff --git a/pkg/sentry/fsimpl/ext/directory.go b/pkg/sentry/fsimpl/ext/directory.go index 12b875c8f..0fc01668d 100644 --- a/pkg/sentry/fsimpl/ext/directory.go +++ b/pkg/sentry/fsimpl/ext/directory.go @@ -20,6 +20,7 @@ import ( "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/fs" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/ext/disklayout" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/sync" @@ -54,16 +55,15 @@ type directory struct { } // newDirectory is the directory constructor. -func newDirectory(inode inode, newDirent bool) (*directory, error) { +func newDirectory(args inodeArgs, newDirent bool) (*directory, error) { file := &directory{ - inode: inode, childCache: make(map[string]*dentry), childMap: make(map[string]*dirent), } - file.inode.impl = file + file.inode.init(args, file) // Initialize childList by reading dirents from the underlying file. - if inode.diskInode.Flags().Index { + if args.diskInode.Flags().Index { // TODO(b/134676337): Support hash tree directories. Currently only the '.' // and '..' entries are read in. @@ -74,7 +74,7 @@ func newDirectory(inode inode, newDirent bool) (*directory, error) { // The dirents are organized in a linear array in the file data. // Extract the file data and decode the dirents. - regFile, err := newRegularFile(inode) + regFile, err := newRegularFile(args) if err != nil { return nil, err } @@ -82,7 +82,7 @@ func newDirectory(inode inode, newDirent bool) (*directory, error) { // buf is used as scratch space for reading in dirents from disk and // unmarshalling them into dirent structs. buf := make([]byte, disklayout.DirentSize) - size := inode.diskInode.Size() + size := args.diskInode.Size() for off, inc := uint64(0), uint64(0); off < size; off += inc { toRead := size - off if toRead > disklayout.DirentSize { @@ -142,7 +142,7 @@ type directoryFD struct { var _ vfs.FileDescriptionImpl = (*directoryFD)(nil) // Release implements vfs.FileDescriptionImpl.Release. -func (fd *directoryFD) Release() { +func (fd *directoryFD) Release(ctx context.Context) { if fd.iter == nil { return } @@ -306,3 +306,13 @@ func (fd *directoryFD) Seek(ctx context.Context, offset int64, whence int32) (in fd.off = offset return offset, nil } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *directoryFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *directoryFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/ext/ext.go b/pkg/sentry/fsimpl/ext/ext.go index dac6effbf..08ffc2834 100644 --- a/pkg/sentry/fsimpl/ext/ext.go +++ b/pkg/sentry/fsimpl/ext/ext.go @@ -123,32 +123,32 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt fs.vfsfs.Init(vfsObj, &fsType, &fs) fs.sb, err = readSuperBlock(dev) if err != nil { - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, err } if fs.sb.Magic() != linux.EXT_SUPER_MAGIC { // mount(2) specifies that EINVAL should be returned if the superblock is // invalid. - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, syserror.EINVAL } // Refuse to mount if the filesystem is incompatible. if !isCompatible(fs.sb) { - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, syserror.EINVAL } fs.bgs, err = readBlockGroups(dev, fs.sb) if err != nil { - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, err } rootInode, err := fs.getOrCreateInodeLocked(disklayout.RootDirInode) if err != nil { - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, err } rootInode.incRef() diff --git a/pkg/sentry/fsimpl/ext/ext_test.go b/pkg/sentry/fsimpl/ext/ext_test.go index 64e9a579f..2dbaee287 100644 --- a/pkg/sentry/fsimpl/ext/ext_test.go +++ b/pkg/sentry/fsimpl/ext/ext_test.go @@ -65,7 +65,7 @@ func setUp(t *testing.T, imagePath string) (context.Context, *vfs.VirtualFilesys // Create VFS. vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } vfsObj.MustRegisterFilesystemType("extfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ @@ -80,7 +80,7 @@ func setUp(t *testing.T, imagePath string) (context.Context, *vfs.VirtualFilesys root := mntns.Root() tearDown := func() { - root.DecRef() + root.DecRef(ctx) if err := f.Close(); err != nil { t.Fatalf("tearDown failed: %v", err) diff --git a/pkg/sentry/fsimpl/ext/extent_file.go b/pkg/sentry/fsimpl/ext/extent_file.go index 11dcc0346..c36225a7c 100644 --- a/pkg/sentry/fsimpl/ext/extent_file.go +++ b/pkg/sentry/fsimpl/ext/extent_file.go @@ -38,9 +38,10 @@ var _ io.ReaderAt = (*extentFile)(nil) // newExtentFile is the extent file constructor. It reads the entire extent // tree into memory. // TODO(b/134676337): Build extent tree on demand to reduce memory usage. -func newExtentFile(regFile regularFile) (*extentFile, error) { - file := &extentFile{regFile: regFile} +func newExtentFile(args inodeArgs) (*extentFile, error) { + file := &extentFile{} file.regFile.impl = file + file.regFile.inode.init(args, &file.regFile) err := file.buildExtTree() if err != nil { return nil, err diff --git a/pkg/sentry/fsimpl/ext/extent_test.go b/pkg/sentry/fsimpl/ext/extent_test.go index a2382daa3..cd10d46ee 100644 --- a/pkg/sentry/fsimpl/ext/extent_test.go +++ b/pkg/sentry/fsimpl/ext/extent_test.go @@ -177,21 +177,19 @@ func extentTreeSetUp(t *testing.T, root *disklayout.ExtentNode) (*extentFile, [] t.Helper() mockDisk := make([]byte, mockExtentBlkSize*10) - mockExtentFile := &extentFile{ - regFile: regularFile{ - inode: inode{ - fs: &filesystem{ - dev: bytes.NewReader(mockDisk), - }, - diskInode: &disklayout.InodeNew{ - InodeOld: disklayout.InodeOld{ - SizeLo: uint32(mockExtentBlkSize) * getNumPhyBlks(root), - }, - }, - blkSize: mockExtentBlkSize, + mockExtentFile := &extentFile{} + args := inodeArgs{ + fs: &filesystem{ + dev: bytes.NewReader(mockDisk), + }, + diskInode: &disklayout.InodeNew{ + InodeOld: disklayout.InodeOld{ + SizeLo: uint32(mockExtentBlkSize) * getNumPhyBlks(root), }, }, + blkSize: mockExtentBlkSize, } + mockExtentFile.regFile.inode.init(args, &mockExtentFile.regFile) fileData := writeTree(&mockExtentFile.regFile.inode, mockDisk, node0, mockExtentBlkSize) diff --git a/pkg/sentry/fsimpl/ext/file_description.go b/pkg/sentry/fsimpl/ext/file_description.go index 92f7da40d..90b086468 100644 --- a/pkg/sentry/fsimpl/ext/file_description.go +++ b/pkg/sentry/fsimpl/ext/file_description.go @@ -26,6 +26,7 @@ import ( type fileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD } func (fd *fileDescription) filesystem() *filesystem { diff --git a/pkg/sentry/fsimpl/ext/filesystem.go b/pkg/sentry/fsimpl/ext/filesystem.go index 557963e03..c714ddf73 100644 --- a/pkg/sentry/fsimpl/ext/filesystem.go +++ b/pkg/sentry/fsimpl/ext/filesystem.go @@ -84,7 +84,7 @@ var _ vfs.FilesystemImpl = (*filesystem)(nil) // - filesystem.mu must be locked (for writing if write param is true). // - !rp.Done(). // - inode == vfsd.Impl().(*Dentry).inode. -func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write bool) (*vfs.Dentry, *inode, error) { +func stepLocked(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write bool) (*vfs.Dentry, *inode, error) { if !inode.isDir() { return nil, nil, syserror.ENOTDIR } @@ -100,7 +100,7 @@ func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write boo } d := vfsd.Impl().(*dentry) if name == ".." { - isRoot, err := rp.CheckRoot(vfsd) + isRoot, err := rp.CheckRoot(ctx, vfsd) if err != nil { return nil, nil, err } @@ -108,7 +108,7 @@ func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write boo rp.Advance() return vfsd, inode, nil } - if err := rp.CheckMount(&d.parent.vfsd); err != nil { + if err := rp.CheckMount(ctx, &d.parent.vfsd); err != nil { return nil, nil, err } rp.Advance() @@ -143,7 +143,7 @@ func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write boo child.name = name dir.childCache[name] = child } - if err := rp.CheckMount(&child.vfsd); err != nil { + if err := rp.CheckMount(ctx, &child.vfsd); err != nil { return nil, nil, err } if child.inode.isSymlink() && rp.ShouldFollowSymlink() { @@ -167,12 +167,12 @@ func stepLocked(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, inode *inode, write boo // // Preconditions: // - filesystem.mu must be locked (for writing if write param is true). -func walkLocked(rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) { +func walkLocked(ctx context.Context, rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) { vfsd := rp.Start() inode := vfsd.Impl().(*dentry).inode for !rp.Done() { var err error - vfsd, inode, err = stepLocked(rp, vfsd, inode, write) + vfsd, inode, err = stepLocked(ctx, rp, vfsd, inode, write) if err != nil { return nil, nil, err } @@ -196,12 +196,12 @@ func walkLocked(rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) // Preconditions: // - filesystem.mu must be locked (for writing if write param is true). // - !rp.Done(). -func walkParentLocked(rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) { +func walkParentLocked(ctx context.Context, rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, error) { vfsd := rp.Start() inode := vfsd.Impl().(*dentry).inode for !rp.Final() { var err error - vfsd, inode, err = stepLocked(rp, vfsd, inode, write) + vfsd, inode, err = stepLocked(ctx, rp, vfsd, inode, write) if err != nil { return nil, nil, err } @@ -216,7 +216,7 @@ func walkParentLocked(rp *vfs.ResolvingPath, write bool) (*vfs.Dentry, *inode, e // the rp till the parent of the last component which should be an existing // directory. If parent is false then resolves rp entirely. Attemps to resolve // the path as far as it can with a read lock and upgrades the lock if needed. -func (fs *filesystem) walk(rp *vfs.ResolvingPath, parent bool) (*vfs.Dentry, *inode, error) { +func (fs *filesystem) walk(ctx context.Context, rp *vfs.ResolvingPath, parent bool) (*vfs.Dentry, *inode, error) { var ( vfsd *vfs.Dentry inode *inode @@ -227,9 +227,9 @@ func (fs *filesystem) walk(rp *vfs.ResolvingPath, parent bool) (*vfs.Dentry, *in // of disk. This reduces congestion (allows concurrent walks). fs.mu.RLock() if parent { - vfsd, inode, err = walkParentLocked(rp, false) + vfsd, inode, err = walkParentLocked(ctx, rp, false) } else { - vfsd, inode, err = walkLocked(rp, false) + vfsd, inode, err = walkLocked(ctx, rp, false) } fs.mu.RUnlock() @@ -238,9 +238,9 @@ func (fs *filesystem) walk(rp *vfs.ResolvingPath, parent bool) (*vfs.Dentry, *in // walk is fine as this is a read only filesystem. fs.mu.Lock() if parent { - vfsd, inode, err = walkParentLocked(rp, true) + vfsd, inode, err = walkParentLocked(ctx, rp, true) } else { - vfsd, inode, err = walkLocked(rp, true) + vfsd, inode, err = walkLocked(ctx, rp, true) } fs.mu.Unlock() } @@ -283,7 +283,7 @@ func (fs *filesystem) statTo(stat *linux.Statfs) { // AccessAt implements vfs.Filesystem.Impl.AccessAt. func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error { - _, inode, err := fs.walk(rp, false) + _, inode, err := fs.walk(ctx, rp, false) if err != nil { return err } @@ -292,7 +292,7 @@ func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds // GetDentryAt implements vfs.FilesystemImpl.GetDentryAt. func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { - vfsd, inode, err := fs.walk(rp, false) + vfsd, inode, err := fs.walk(ctx, rp, false) if err != nil { return nil, err } @@ -312,7 +312,7 @@ func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op // GetParentDentryAt implements vfs.FilesystemImpl.GetParentDentryAt. func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { - vfsd, inode, err := fs.walk(rp, true) + vfsd, inode, err := fs.walk(ctx, rp, true) if err != nil { return nil, err } @@ -322,7 +322,7 @@ func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPa // OpenAt implements vfs.FilesystemImpl.OpenAt. func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - vfsd, inode, err := fs.walk(rp, false) + vfsd, inode, err := fs.walk(ctx, rp, false) if err != nil { return nil, err } @@ -336,7 +336,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf // ReadlinkAt implements vfs.FilesystemImpl.ReadlinkAt. func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) { - _, inode, err := fs.walk(rp, false) + _, inode, err := fs.walk(ctx, rp, false) if err != nil { return "", err } @@ -349,7 +349,7 @@ func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (st // StatAt implements vfs.FilesystemImpl.StatAt. func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) { - _, inode, err := fs.walk(rp, false) + _, inode, err := fs.walk(ctx, rp, false) if err != nil { return linux.Statx{}, err } @@ -360,7 +360,7 @@ func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf // StatFSAt implements vfs.FilesystemImpl.StatFSAt. func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) { - if _, _, err := fs.walk(rp, false); err != nil { + if _, _, err := fs.walk(ctx, rp, false); err != nil { return linux.Statfs{}, err } @@ -370,7 +370,7 @@ func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linu } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.vfsfs.VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) } @@ -390,7 +390,7 @@ func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs. return syserror.EEXIST } - if _, _, err := fs.walk(rp, true); err != nil { + if _, _, err := fs.walk(ctx, rp, true); err != nil { return err } @@ -403,7 +403,7 @@ func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts v return syserror.EEXIST } - if _, _, err := fs.walk(rp, true); err != nil { + if _, _, err := fs.walk(ctx, rp, true); err != nil { return err } @@ -416,7 +416,7 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v return syserror.EEXIST } - _, _, err := fs.walk(rp, true) + _, _, err := fs.walk(ctx, rp, true) if err != nil { return err } @@ -430,7 +430,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa return syserror.ENOENT } - _, _, err := fs.walk(rp, false) + _, _, err := fs.walk(ctx, rp, false) if err != nil { return err } @@ -440,7 +440,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa // RmdirAt implements vfs.FilesystemImpl.RmdirAt. func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error { - _, inode, err := fs.walk(rp, false) + _, inode, err := fs.walk(ctx, rp, false) if err != nil { return err } @@ -454,7 +454,7 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error // SetStatAt implements vfs.FilesystemImpl.SetStatAt. func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error { - _, _, err := fs.walk(rp, false) + _, _, err := fs.walk(ctx, rp, false) if err != nil { return err } @@ -468,7 +468,7 @@ func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ return syserror.EEXIST } - _, _, err := fs.walk(rp, true) + _, _, err := fs.walk(ctx, rp, true) if err != nil { return err } @@ -478,7 +478,7 @@ func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ // UnlinkAt implements vfs.FilesystemImpl.UnlinkAt. func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error { - _, inode, err := fs.walk(rp, false) + _, inode, err := fs.walk(ctx, rp, false) if err != nil { return err } @@ -492,7 +492,7 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error // BoundEndpointAt implements FilesystemImpl.BoundEndpointAt. func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { - _, inode, err := fs.walk(rp, false) + _, inode, err := fs.walk(ctx, rp, false) if err != nil { return nil, err } @@ -506,7 +506,7 @@ func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath // ListxattrAt implements vfs.FilesystemImpl.ListxattrAt. func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, size uint64) ([]string, error) { - _, _, err := fs.walk(rp, false) + _, _, err := fs.walk(ctx, rp, false) if err != nil { return nil, err } @@ -515,7 +515,7 @@ func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, si // GetxattrAt implements vfs.FilesystemImpl.GetxattrAt. func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetxattrOptions) (string, error) { - _, _, err := fs.walk(rp, false) + _, _, err := fs.walk(ctx, rp, false) if err != nil { return "", err } @@ -524,7 +524,7 @@ func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt // SetxattrAt implements vfs.FilesystemImpl.SetxattrAt. func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error { - _, _, err := fs.walk(rp, false) + _, _, err := fs.walk(ctx, rp, false) if err != nil { return err } @@ -533,7 +533,7 @@ func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt // RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt. func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error { - _, _, err := fs.walk(rp, false) + _, _, err := fs.walk(ctx, rp, false) if err != nil { return err } diff --git a/pkg/sentry/fsimpl/ext/inode.go b/pkg/sentry/fsimpl/ext/inode.go index 485f86f4b..30636cf66 100644 --- a/pkg/sentry/fsimpl/ext/inode.go +++ b/pkg/sentry/fsimpl/ext/inode.go @@ -54,6 +54,8 @@ type inode struct { // diskInode gives us access to the inode struct on disk. Immutable. diskInode disklayout.Inode + locks vfs.FileLocks + // This is immutable. The first field of the implementations must have inode // as the first field to ensure temporality. impl interface{} @@ -115,7 +117,7 @@ func newInode(fs *filesystem, inodeNum uint32) (*inode, error) { } // Build the inode based on its type. - inode := inode{ + args := inodeArgs{ fs: fs, inodeNum: inodeNum, blkSize: blkSize, @@ -124,19 +126,19 @@ func newInode(fs *filesystem, inodeNum uint32) (*inode, error) { switch diskInode.Mode().FileType() { case linux.ModeSymlink: - f, err := newSymlink(inode) + f, err := newSymlink(args) if err != nil { return nil, err } return &f.inode, nil case linux.ModeRegular: - f, err := newRegularFile(inode) + f, err := newRegularFile(args) if err != nil { return nil, err } return &f.inode, nil case linux.ModeDirectory: - f, err := newDirectory(inode, fs.sb.IncompatibleFeatures().DirentFileType) + f, err := newDirectory(args, fs.sb.IncompatibleFeatures().DirentFileType) if err != nil { return nil, err } @@ -147,6 +149,21 @@ func newInode(fs *filesystem, inodeNum uint32) (*inode, error) { } } +type inodeArgs struct { + fs *filesystem + inodeNum uint32 + blkSize uint64 + diskInode disklayout.Inode +} + +func (in *inode) init(args inodeArgs, impl interface{}) { + in.fs = args.fs + in.inodeNum = args.inodeNum + in.blkSize = args.blkSize + in.diskInode = args.diskInode + in.impl = impl +} + // open creates and returns a file description for the dentry passed in. func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts *vfs.OpenOptions) (*vfs.FileDescription, error) { ats := vfs.AccessTypesForOpenFlags(opts) @@ -157,6 +174,7 @@ func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts *vfs.OpenOpt switch in.impl.(type) { case *regularFile: var fd regularFileFD + fd.LockFD.Init(&in.locks) if err := fd.vfsfd.Init(&fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{}); err != nil { return nil, err } @@ -168,6 +186,7 @@ func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts *vfs.OpenOpt return nil, syserror.EISDIR } var fd directoryFD + fd.LockFD.Init(&in.locks) if err := fd.vfsfd.Init(&fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{}); err != nil { return nil, err } @@ -178,6 +197,7 @@ func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts *vfs.OpenOpt return nil, syserror.ELOOP } var fd symlinkFD + fd.LockFD.Init(&in.locks) fd.vfsfd.Init(&fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{}) return &fd.vfsfd, nil default: diff --git a/pkg/sentry/fsimpl/ext/regular_file.go b/pkg/sentry/fsimpl/ext/regular_file.go index 30135ddb0..e73e740d6 100644 --- a/pkg/sentry/fsimpl/ext/regular_file.go +++ b/pkg/sentry/fsimpl/ext/regular_file.go @@ -20,6 +20,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/safemem" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/sync" @@ -43,28 +44,19 @@ type regularFile struct { // newRegularFile is the regularFile constructor. It figures out what kind of // file this is and initializes the fileReader. -func newRegularFile(inode inode) (*regularFile, error) { - regFile := regularFile{ - inode: inode, - } - - inodeFlags := inode.diskInode.Flags() - - if inodeFlags.Extents { - file, err := newExtentFile(regFile) +func newRegularFile(args inodeArgs) (*regularFile, error) { + if args.diskInode.Flags().Extents { + file, err := newExtentFile(args) if err != nil { return nil, err } - - file.regFile.inode.impl = &file.regFile return &file.regFile, nil } - file, err := newBlockMapFile(regFile) + file, err := newBlockMapFile(args) if err != nil { return nil, err } - file.regFile.inode.impl = &file.regFile return &file.regFile, nil } @@ -77,6 +69,7 @@ func (in *inode) isRegular() bool { // vfs.FileDescriptionImpl. type regularFileFD struct { fileDescription + vfs.LockFD // off is the file offset. off is accessed using atomic memory operations. off int64 @@ -86,7 +79,7 @@ type regularFileFD struct { } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *regularFileFD) Release() {} +func (fd *regularFileFD) Release(context.Context) {} // PRead implements vfs.FileDescriptionImpl.PRead. func (fd *regularFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { @@ -157,3 +150,13 @@ func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpt // TODO(b/134676337): Implement mmap(2). return syserror.ENODEV } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *regularFileFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *regularFileFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/ext/symlink.go b/pkg/sentry/fsimpl/ext/symlink.go index 1447a4dc1..2fd0d1fa8 100644 --- a/pkg/sentry/fsimpl/ext/symlink.go +++ b/pkg/sentry/fsimpl/ext/symlink.go @@ -30,18 +30,17 @@ type symlink struct { // newSymlink is the symlink constructor. It reads out the symlink target from // the inode (however it might have been stored). -func newSymlink(inode inode) (*symlink, error) { - var file *symlink +func newSymlink(args inodeArgs) (*symlink, error) { var link []byte // If the symlink target is lesser than 60 bytes, its stores in inode.Data(). // Otherwise either extents or block maps will be used to store the link. - size := inode.diskInode.Size() + size := args.diskInode.Size() if size < 60 { - link = inode.diskInode.Data()[:size] + link = args.diskInode.Data()[:size] } else { // Create a regular file out of this inode and read out the target. - regFile, err := newRegularFile(inode) + regFile, err := newRegularFile(args) if err != nil { return nil, err } @@ -52,8 +51,8 @@ func newSymlink(inode inode) (*symlink, error) { } } - file = &symlink{inode: inode, target: string(link)} - file.inode.impl = file + file := &symlink{target: string(link)} + file.inode.init(args, file) return file, nil } @@ -67,13 +66,14 @@ func (in *inode) isSymlink() bool { // O_PATH. For this reason most of the functions return EBADF. type symlinkFD struct { fileDescription + vfs.NoLockFD } // Compiles only if symlinkFD implements vfs.FileDescriptionImpl. var _ vfs.FileDescriptionImpl = (*symlinkFD)(nil) // Release implements vfs.FileDescriptionImpl.Release. -func (fd *symlinkFD) Release() {} +func (fd *symlinkFD) Release(context.Context) {} // PRead implements vfs.FileDescriptionImpl.PRead. func (fd *symlinkFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { diff --git a/pkg/sentry/fsimpl/fuse/BUILD b/pkg/sentry/fsimpl/fuse/BUILD new file mode 100644 index 000000000..999111deb --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/BUILD @@ -0,0 +1,63 @@ +load("//tools:defs.bzl", "go_library", "go_test") +load("//tools/go_generics:defs.bzl", "go_template_instance") + +licenses(["notice"]) + +go_template_instance( + name = "request_list", + out = "request_list.go", + package = "fuse", + prefix = "request", + template = "//pkg/ilist:generic_list", + types = { + "Element": "*Request", + "Linker": "*Request", + }, +) + +go_library( + name = "fuse", + srcs = [ + "connection.go", + "dev.go", + "fusefs.go", + "init.go", + "register.go", + "request_list.go", + ], + visibility = ["//pkg/sentry:internal"], + deps = [ + "//pkg/abi/linux", + "//pkg/context", + "//pkg/log", + "//pkg/sentry/fsimpl/devtmpfs", + "//pkg/sentry/fsimpl/kernfs", + "//pkg/sentry/kernel", + "//pkg/sentry/kernel/auth", + "//pkg/sentry/vfs", + "//pkg/sync", + "//pkg/syserror", + "//pkg/usermem", + "//pkg/waiter", + "//tools/go_marshal/marshal", + "@org_golang_x_sys//unix:go_default_library", + ], +) + +go_test( + name = "fuse_test", + size = "small", + srcs = ["dev_test.go"], + library = ":fuse", + deps = [ + "//pkg/abi/linux", + "//pkg/sentry/fsimpl/testutil", + "//pkg/sentry/kernel", + "//pkg/sentry/kernel/auth", + "//pkg/sentry/vfs", + "//pkg/syserror", + "//pkg/usermem", + "//pkg/waiter", + "//tools/go_marshal/marshal", + ], +) diff --git a/pkg/sentry/fsimpl/fuse/connection.go b/pkg/sentry/fsimpl/fuse/connection.go new file mode 100644 index 000000000..6df2728ab --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/connection.go @@ -0,0 +1,437 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package fuse + +import ( + "errors" + "fmt" + "sync" + "sync/atomic" + "syscall" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" +) + +// maxActiveRequestsDefault is the default setting controlling the upper bound +// on the number of active requests at any given time. +const maxActiveRequestsDefault = 10000 + +// Ordinary requests have even IDs, while interrupts IDs are odd. +// Used to increment the unique ID for each FUSE request. +var reqIDStep uint64 = 2 + +const ( + // fuseDefaultMaxBackground is the default value for MaxBackground. + fuseDefaultMaxBackground = 12 + + // fuseDefaultCongestionThreshold is the default value for CongestionThreshold, + // and is 75% of the default maximum of MaxGround. + fuseDefaultCongestionThreshold = (fuseDefaultMaxBackground * 3 / 4) + + // fuseDefaultMaxPagesPerReq is the default value for MaxPagesPerReq. + fuseDefaultMaxPagesPerReq = 32 +) + +// Request represents a FUSE operation request that hasn't been sent to the +// server yet. +// +// +stateify savable +type Request struct { + requestEntry + + id linux.FUSEOpID + hdr *linux.FUSEHeaderIn + data []byte +} + +// Response represents an actual response from the server, including the +// response payload. +// +// +stateify savable +type Response struct { + opcode linux.FUSEOpcode + hdr linux.FUSEHeaderOut + data []byte +} + +// connection is the struct by which the sentry communicates with the FUSE server daemon. +type connection struct { + fd *DeviceFD + + // The following FUSE_INIT flags are currently unsupported by this implementation: + // - FUSE_ATOMIC_O_TRUNC: requires open(..., O_TRUNC) + // - FUSE_EXPORT_SUPPORT + // - FUSE_HANDLE_KILLPRIV + // - FUSE_POSIX_LOCKS: requires POSIX locks + // - FUSE_FLOCK_LOCKS: requires POSIX locks + // - FUSE_AUTO_INVAL_DATA: requires page caching eviction + // - FUSE_EXPLICIT_INVAL_DATA: requires page caching eviction + // - FUSE_DO_READDIRPLUS/FUSE_READDIRPLUS_AUTO: requires FUSE_READDIRPLUS implementation + // - FUSE_ASYNC_DIO + // - FUSE_POSIX_ACL: affects defaultPermissions, posixACL, xattr handler + + // initialized after receiving FUSE_INIT reply. + // Until it's set, suspend sending FUSE requests. + // Use SetInitialized() and IsInitialized() for atomic access. + initialized int32 + + // initializedChan is used to block requests before initialization. + initializedChan chan struct{} + + // blocked when there are too many outstading backgrounds requests (NumBackground == MaxBackground). + // TODO(gvisor.dev/issue/3185): update the numBackground accordingly; use a channel to block. + blocked bool + + // connected (connection established) when a new FUSE file system is created. + // Set to false when: + // umount, + // connection abort, + // device release. + connected bool + + // aborted via sysfs. + // TODO(gvisor.dev/issue/3185): abort all queued requests. + aborted bool + + // connInitError if FUSE_INIT encountered error (major version mismatch). + // Only set in INIT. + connInitError bool + + // connInitSuccess if FUSE_INIT is successful. + // Only set in INIT. + // Used for destory. + connInitSuccess bool + + // TODO(gvisor.dev/issue/3185): All the queue logic are working in progress. + + // NumberBackground is the number of requests in the background. + numBackground uint16 + + // congestionThreshold for NumBackground. + // Negotiated in FUSE_INIT. + congestionThreshold uint16 + + // maxBackground is the maximum number of NumBackground. + // Block connection when it is reached. + // Negotiated in FUSE_INIT. + maxBackground uint16 + + // numActiveBackground is the number of requests in background and has being marked as active. + numActiveBackground uint16 + + // numWating is the number of requests waiting for completion. + numWaiting uint32 + + // TODO(gvisor.dev/issue/3185): BgQueue + // some queue for background queued requests. + + // bgLock protects: + // MaxBackground, CongestionThreshold, NumBackground, + // NumActiveBackground, BgQueue, Blocked. + bgLock sync.Mutex + + // maxRead is the maximum size of a read buffer in in bytes. + maxRead uint32 + + // maxWrite is the maximum size of a write buffer in bytes. + // Negotiated in FUSE_INIT. + maxWrite uint32 + + // maxPages is the maximum number of pages for a single request to use. + // Negotiated in FUSE_INIT. + maxPages uint16 + + // minor version of the FUSE protocol. + // Negotiated and only set in INIT. + minor uint32 + + // asyncRead if read pages asynchronously. + // Negotiated and only set in INIT. + asyncRead bool + + // abortErr is true if kernel need to return an unique read error after abort. + // Negotiated and only set in INIT. + abortErr bool + + // writebackCache is true for write-back cache policy, + // false for write-through policy. + // Negotiated and only set in INIT. + writebackCache bool + + // cacheSymlinks if filesystem needs to cache READLINK responses in page cache. + // Negotiated and only set in INIT. + cacheSymlinks bool + + // bigWrites if doing multi-page cached writes. + // Negotiated and only set in INIT. + bigWrites bool + + // dontMask if filestestem does not apply umask to creation modes. + // Negotiated in INIT. + dontMask bool +} + +// newFUSEConnection creates a FUSE connection to fd. +func newFUSEConnection(_ context.Context, fd *vfs.FileDescription, maxInFlightRequests uint64) (*connection, error) { + // Mark the device as ready so it can be used. /dev/fuse can only be used if the FD was used to + // mount a FUSE filesystem. + fuseFD := fd.Impl().(*DeviceFD) + fuseFD.mounted = true + + // Create the writeBuf for the header to be stored in. + hdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes()) + fuseFD.writeBuf = make([]byte, hdrLen) + fuseFD.completions = make(map[linux.FUSEOpID]*futureResponse) + fuseFD.fullQueueCh = make(chan struct{}, maxInFlightRequests) + fuseFD.writeCursor = 0 + + return &connection{ + fd: fuseFD, + maxBackground: fuseDefaultMaxBackground, + congestionThreshold: fuseDefaultCongestionThreshold, + maxPages: fuseDefaultMaxPagesPerReq, + initializedChan: make(chan struct{}), + connected: true, + }, nil +} + +// SetInitialized atomically sets the connection as initialized. +func (conn *connection) SetInitialized() { + // Unblock the requests sent before INIT. + close(conn.initializedChan) + + // Close the channel first to avoid the non-atomic situation + // where conn.initialized is true but there are + // tasks being blocked on the channel. + // And it prevents the newer tasks from gaining + // unnecessary higher chance to be issued before the blocked one. + + atomic.StoreInt32(&(conn.initialized), int32(1)) +} + +// IsInitialized atomically check if the connection is initialized. +// pairs with SetInitialized(). +func (conn *connection) Initialized() bool { + return atomic.LoadInt32(&(conn.initialized)) != 0 +} + +// NewRequest creates a new request that can be sent to the FUSE server. +func (conn *connection) NewRequest(creds *auth.Credentials, pid uint32, ino uint64, opcode linux.FUSEOpcode, payload marshal.Marshallable) (*Request, error) { + conn.fd.mu.Lock() + defer conn.fd.mu.Unlock() + conn.fd.nextOpID += linux.FUSEOpID(reqIDStep) + + hdrLen := (*linux.FUSEHeaderIn)(nil).SizeBytes() + hdr := linux.FUSEHeaderIn{ + Len: uint32(hdrLen + payload.SizeBytes()), + Opcode: opcode, + Unique: conn.fd.nextOpID, + NodeID: ino, + UID: uint32(creds.EffectiveKUID), + GID: uint32(creds.EffectiveKGID), + PID: pid, + } + + buf := make([]byte, hdr.Len) + hdr.MarshalUnsafe(buf[:hdrLen]) + payload.MarshalUnsafe(buf[hdrLen:]) + + return &Request{ + id: hdr.Unique, + hdr: &hdr, + data: buf, + }, nil +} + +// Call makes a request to the server and blocks the invoking task until a +// server responds with a response. Task should never be nil. +// Requests will not be sent before the connection is initialized. +// For async tasks, use CallAsync(). +func (conn *connection) Call(t *kernel.Task, r *Request) (*Response, error) { + // Block requests sent before connection is initalized. + if !conn.Initialized() { + if err := t.Block(conn.initializedChan); err != nil { + return nil, err + } + } + + return conn.call(t, r) +} + +// CallAsync makes an async (aka background) request. +// Those requests either do not expect a response (e.g. release) or +// the response should be handled by others (e.g. init). +// Return immediately unless the connection is blocked (before initialization). +// Async call example: init, release, forget, aio, interrupt. +// When the Request is FUSE_INIT, it will not be blocked before initialization. +func (conn *connection) CallAsync(t *kernel.Task, r *Request) error { + // Block requests sent before connection is initalized. + if !conn.Initialized() && r.hdr.Opcode != linux.FUSE_INIT { + if err := t.Block(conn.initializedChan); err != nil { + return err + } + } + + // This should be the only place that invokes call() with a nil task. + _, err := conn.call(nil, r) + return err +} + +// call makes a call without blocking checks. +func (conn *connection) call(t *kernel.Task, r *Request) (*Response, error) { + if !conn.connected { + return nil, syserror.ENOTCONN + } + + if conn.connInitError { + return nil, syserror.ECONNREFUSED + } + + fut, err := conn.callFuture(t, r) + if err != nil { + return nil, err + } + + return fut.resolve(t) +} + +// Error returns the error of the FUSE call. +func (r *Response) Error() error { + errno := r.hdr.Error + if errno >= 0 { + return nil + } + + sysErrNo := syscall.Errno(-errno) + return error(sysErrNo) +} + +// UnmarshalPayload unmarshals the response data into m. +func (r *Response) UnmarshalPayload(m marshal.Marshallable) error { + hdrLen := r.hdr.SizeBytes() + haveDataLen := r.hdr.Len - uint32(hdrLen) + wantDataLen := uint32(m.SizeBytes()) + + if haveDataLen < wantDataLen { + return fmt.Errorf("payload too small. Minimum data lenth required: %d, but got data length %d", wantDataLen, haveDataLen) + } + + m.UnmarshalUnsafe(r.data[hdrLen:]) + return nil +} + +// callFuture makes a request to the server and returns a future response. +// Call resolve() when the response needs to be fulfilled. +func (conn *connection) callFuture(t *kernel.Task, r *Request) (*futureResponse, error) { + conn.fd.mu.Lock() + defer conn.fd.mu.Unlock() + + // Is the queue full? + // + // We must busy wait here until the request can be queued. We don't + // block on the fd.fullQueueCh with a lock - so after being signalled, + // before we acquire the lock, it is possible that a barging task enters + // and queues a request. As a result, upon acquiring the lock we must + // again check if the room is available. + // + // This can potentially starve a request forever but this can only happen + // if there are always too many ongoing requests all the time. The + // supported maxActiveRequests setting should be really high to avoid this. + for conn.fd.numActiveRequests == conn.fd.fs.opts.maxActiveRequests { + if t == nil { + // Since there is no task that is waiting. We must error out. + return nil, errors.New("FUSE request queue full") + } + + log.Infof("Blocking request %v from being queued. Too many active requests: %v", + r.id, conn.fd.numActiveRequests) + conn.fd.mu.Unlock() + err := t.Block(conn.fd.fullQueueCh) + conn.fd.mu.Lock() + if err != nil { + return nil, err + } + } + + return conn.callFutureLocked(t, r) +} + +// callFutureLocked makes a request to the server and returns a future response. +func (conn *connection) callFutureLocked(t *kernel.Task, r *Request) (*futureResponse, error) { + conn.fd.queue.PushBack(r) + conn.fd.numActiveRequests += 1 + fut := newFutureResponse(r.hdr.Opcode) + conn.fd.completions[r.id] = fut + + // Signal the readers that there is something to read. + conn.fd.waitQueue.Notify(waiter.EventIn) + + return fut, nil +} + +// futureResponse represents an in-flight request, that may or may not have +// completed yet. Convert it to a resolved Response by calling Resolve, but note +// that this may block. +// +// +stateify savable +type futureResponse struct { + opcode linux.FUSEOpcode + ch chan struct{} + hdr *linux.FUSEHeaderOut + data []byte +} + +// newFutureResponse creates a future response to a FUSE request. +func newFutureResponse(opcode linux.FUSEOpcode) *futureResponse { + return &futureResponse{ + opcode: opcode, + ch: make(chan struct{}), + } +} + +// resolve blocks the task until the server responds to its corresponding request, +// then returns a resolved response. +func (f *futureResponse) resolve(t *kernel.Task) (*Response, error) { + // If there is no Task associated with this request - then we don't try to resolve + // the response. Instead, the task writing the response (proxy to the server) will + // process the response on our behalf. + if t == nil { + log.Infof("fuse.Response.resolve: Not waiting on a response from server.") + return nil, nil + } + + if err := t.Block(f.ch); err != nil { + return nil, err + } + + return f.getResponse(), nil +} + +// getResponse creates a Response from the data the futureResponse has. +func (f *futureResponse) getResponse() *Response { + return &Response{ + opcode: f.opcode, + hdr: *f.hdr, + data: f.data, + } +} diff --git a/pkg/sentry/fsimpl/fuse/dev.go b/pkg/sentry/fsimpl/fuse/dev.go new file mode 100644 index 000000000..e522ff9a0 --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/dev.go @@ -0,0 +1,397 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package fuse + +import ( + "syscall" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +const fuseDevMinor = 229 + +// fuseDevice implements vfs.Device for /dev/fuse. +type fuseDevice struct{} + +// Open implements vfs.Device.Open. +func (fuseDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { + if !kernel.FUSEEnabled { + return nil, syserror.ENOENT + } + + var fd DeviceFD + if err := fd.vfsfd.Init(&fd, opts.Flags, mnt, vfsd, &vfs.FileDescriptionOptions{ + UseDentryMetadata: true, + }); err != nil { + return nil, err + } + return &fd.vfsfd, nil +} + +// DeviceFD implements vfs.FileDescriptionImpl for /dev/fuse. +type DeviceFD struct { + vfsfd vfs.FileDescription + vfs.FileDescriptionDefaultImpl + vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD + + // mounted specifies whether a FUSE filesystem was mounted using the DeviceFD. + mounted bool + + // nextOpID is used to create new requests. + nextOpID linux.FUSEOpID + + // queue is the list of requests that need to be processed by the FUSE server. + queue requestList + + // numActiveRequests is the number of requests made by the Sentry that has + // yet to be responded to. + numActiveRequests uint64 + + // completions is used to map a request to its response. A Writer will use this + // to notify the caller of a completed response. + completions map[linux.FUSEOpID]*futureResponse + + writeCursor uint32 + + // writeBuf is the memory buffer used to copy in the FUSE out header from + // userspace. + writeBuf []byte + + // writeCursorFR current FR being copied from server. + writeCursorFR *futureResponse + + // mu protects all the queues, maps, buffers and cursors and nextOpID. + mu sync.Mutex + + // waitQueue is used to notify interested parties when the device becomes + // readable or writable. + waitQueue waiter.Queue + + // fullQueueCh is a channel used to synchronize the readers with the writers. + // Writers (inbound requests to the filesystem) block if there are too many + // unprocessed in-flight requests. + fullQueueCh chan struct{} + + // fs is the FUSE filesystem that this FD is being used for. + fs *filesystem +} + +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *DeviceFD) Release(context.Context) { + fd.fs.conn.connected = false +} + +// PRead implements vfs.FileDescriptionImpl.PRead. +func (fd *DeviceFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { + // Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted. + if !fd.mounted { + return 0, syserror.EPERM + } + + return 0, syserror.ENOSYS +} + +// Read implements vfs.FileDescriptionImpl.Read. +func (fd *DeviceFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + // Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted. + if !fd.mounted { + return 0, syserror.EPERM + } + + // We require that any Read done on this filesystem have a sane minimum + // read buffer. It must have the capacity for the fixed parts of any request + // header (Linux uses the request header and the FUSEWriteIn header for this + // calculation) + the negotiated MaxWrite room for the data. + minBuffSize := linux.FUSE_MIN_READ_BUFFER + inHdrLen := uint32((*linux.FUSEHeaderIn)(nil).SizeBytes()) + writeHdrLen := uint32((*linux.FUSEWriteIn)(nil).SizeBytes()) + negotiatedMinBuffSize := inHdrLen + writeHdrLen + fd.fs.conn.maxWrite + if minBuffSize < negotiatedMinBuffSize { + minBuffSize = negotiatedMinBuffSize + } + + // If the read buffer is too small, error out. + if dst.NumBytes() < int64(minBuffSize) { + return 0, syserror.EINVAL + } + + fd.mu.Lock() + defer fd.mu.Unlock() + return fd.readLocked(ctx, dst, opts) +} + +// readLocked implements the reading of the fuse device while locked with DeviceFD.mu. +func (fd *DeviceFD) readLocked(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + if fd.queue.Empty() { + return 0, syserror.ErrWouldBlock + } + + var readCursor uint32 + var bytesRead int64 + for { + req := fd.queue.Front() + if dst.NumBytes() < int64(req.hdr.Len) { + // The request is too large. Cannot process it. All requests must be smaller than the + // negotiated size as specified by Connection.MaxWrite set as part of the FUSE_INIT + // handshake. + errno := -int32(syscall.EIO) + if req.hdr.Opcode == linux.FUSE_SETXATTR { + errno = -int32(syscall.E2BIG) + } + + // Return the error to the calling task. + if err := fd.sendError(ctx, errno, req); err != nil { + return 0, err + } + + // We're done with this request. + fd.queue.Remove(req) + + // Restart the read as this request was invalid. + log.Warningf("fuse.DeviceFD.Read: request found was too large. Restarting read.") + return fd.readLocked(ctx, dst, opts) + } + + n, err := dst.CopyOut(ctx, req.data[readCursor:]) + if err != nil { + return 0, err + } + readCursor += uint32(n) + bytesRead += int64(n) + + if readCursor >= req.hdr.Len { + // Fully done with this req, remove it from the queue. + fd.queue.Remove(req) + break + } + } + + return bytesRead, nil +} + +// PWrite implements vfs.FileDescriptionImpl.PWrite. +func (fd *DeviceFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + // Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted. + if !fd.mounted { + return 0, syserror.EPERM + } + + return 0, syserror.ENOSYS +} + +// Write implements vfs.FileDescriptionImpl.Write. +func (fd *DeviceFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { + fd.mu.Lock() + defer fd.mu.Unlock() + return fd.writeLocked(ctx, src, opts) +} + +// writeLocked implements writing to the fuse device while locked with DeviceFD.mu. +func (fd *DeviceFD) writeLocked(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { + // Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted. + if !fd.mounted { + return 0, syserror.EPERM + } + + var cn, n int64 + hdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes()) + + for src.NumBytes() > 0 { + if fd.writeCursorFR != nil { + // Already have common header, and we're now copying the payload. + wantBytes := fd.writeCursorFR.hdr.Len + + // Note that the FR data doesn't have the header. Copy it over if its necessary. + if fd.writeCursorFR.data == nil { + fd.writeCursorFR.data = make([]byte, wantBytes) + } + + bytesCopied, err := src.CopyIn(ctx, fd.writeCursorFR.data[fd.writeCursor:wantBytes]) + if err != nil { + return 0, err + } + src = src.DropFirst(bytesCopied) + + cn = int64(bytesCopied) + n += cn + fd.writeCursor += uint32(cn) + if fd.writeCursor == wantBytes { + // Done reading this full response. Clean up and unblock the + // initiator. + break + } + + // Check if we have more data in src. + continue + } + + // Assert that the header isn't read into the writeBuf yet. + if fd.writeCursor >= hdrLen { + return 0, syserror.EINVAL + } + + // We don't have the full common response header yet. + wantBytes := hdrLen - fd.writeCursor + bytesCopied, err := src.CopyIn(ctx, fd.writeBuf[fd.writeCursor:wantBytes]) + if err != nil { + return 0, err + } + src = src.DropFirst(bytesCopied) + + cn = int64(bytesCopied) + n += cn + fd.writeCursor += uint32(cn) + if fd.writeCursor == hdrLen { + // Have full header in the writeBuf. Use it to fetch the actual futureResponse + // from the device's completions map. + var hdr linux.FUSEHeaderOut + hdr.UnmarshalBytes(fd.writeBuf) + + // We have the header now and so the writeBuf has served its purpose. + // We could reset it manually here but instead of doing that, at the + // end of the write, the writeCursor will be set to 0 thereby allowing + // the next request to overwrite whats in the buffer, + + fut, ok := fd.completions[hdr.Unique] + if !ok { + // Server sent us a response for a request we never sent? + return 0, syserror.EINVAL + } + + delete(fd.completions, hdr.Unique) + + // Copy over the header into the future response. The rest of the payload + // will be copied over to the FR's data in the next iteration. + fut.hdr = &hdr + fd.writeCursorFR = fut + + // Next iteration will now try read the complete request, if src has + // any data remaining. Otherwise we're done. + } + } + + if fd.writeCursorFR != nil { + if err := fd.sendResponse(ctx, fd.writeCursorFR); err != nil { + return 0, err + } + + // Ready the device for the next request. + fd.writeCursorFR = nil + fd.writeCursor = 0 + } + + return n, nil +} + +// Readiness implements vfs.FileDescriptionImpl.Readiness. +func (fd *DeviceFD) Readiness(mask waiter.EventMask) waiter.EventMask { + var ready waiter.EventMask + ready |= waiter.EventOut // FD is always writable + if !fd.queue.Empty() { + // Have reqs available, FD is readable. + ready |= waiter.EventIn + } + + return ready & mask +} + +// EventRegister implements waiter.Waitable.EventRegister. +func (fd *DeviceFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + fd.waitQueue.EventRegister(e, mask) +} + +// EventUnregister implements waiter.Waitable.EventUnregister. +func (fd *DeviceFD) EventUnregister(e *waiter.Entry) { + fd.waitQueue.EventUnregister(e) +} + +// Seek implements vfs.FileDescriptionImpl.Seek. +func (fd *DeviceFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { + // Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted. + if !fd.mounted { + return 0, syserror.EPERM + } + + return 0, syserror.ENOSYS +} + +// sendResponse sends a response to the waiting task (if any). +func (fd *DeviceFD) sendResponse(ctx context.Context, fut *futureResponse) error { + // See if the running task need to perform some action before returning. + // Since we just finished writing the future, we can be sure that + // getResponse generates a populated response. + if err := fd.noReceiverAction(ctx, fut.getResponse()); err != nil { + return err + } + + // Signal that the queue is no longer full. + select { + case fd.fullQueueCh <- struct{}{}: + default: + } + fd.numActiveRequests -= 1 + + // Signal the task waiting on a response. + close(fut.ch) + return nil +} + +// sendError sends an error response to the waiting task (if any). +func (fd *DeviceFD) sendError(ctx context.Context, errno int32, req *Request) error { + // Return the error to the calling task. + outHdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes()) + respHdr := linux.FUSEHeaderOut{ + Len: outHdrLen, + Error: errno, + Unique: req.hdr.Unique, + } + + fut, ok := fd.completions[respHdr.Unique] + if !ok { + // Server sent us a response for a request we never sent? + return syserror.EINVAL + } + delete(fd.completions, respHdr.Unique) + + fut.hdr = &respHdr + if err := fd.sendResponse(ctx, fut); err != nil { + return err + } + + return nil +} + +// noReceiverAction has the calling kernel.Task do some action if its known that no +// receiver is going to be waiting on the future channel. This is to be used by: +// FUSE_INIT. +func (fd *DeviceFD) noReceiverAction(ctx context.Context, r *Response) error { + if r.opcode == linux.FUSE_INIT { + creds := auth.CredentialsFromContext(ctx) + rootUserNs := kernel.KernelFromContext(ctx).RootUserNamespace() + return fd.fs.conn.InitRecv(r, creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, rootUserNs)) + } + + return nil +} diff --git a/pkg/sentry/fsimpl/fuse/dev_test.go b/pkg/sentry/fsimpl/fuse/dev_test.go new file mode 100644 index 000000000..1ffe7ccd2 --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/dev_test.go @@ -0,0 +1,428 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package fuse + +import ( + "fmt" + "io" + "math/rand" + "testing" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/testutil" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" +) + +// echoTestOpcode is the Opcode used during testing. The server used in tests +// will simply echo the payload back with the appropriate headers. +const echoTestOpcode linux.FUSEOpcode = 1000 + +type testPayload struct { + data uint32 +} + +// TestFUSECommunication tests that the communication layer between the Sentry and the +// FUSE server daemon works as expected. +func TestFUSECommunication(t *testing.T) { + s := setup(t) + defer s.Destroy() + + k := kernel.KernelFromContext(s.Ctx) + creds := auth.CredentialsFromContext(s.Ctx) + + // Create test cases with different number of concurrent clients and servers. + testCases := []struct { + Name string + NumClients int + NumServers int + MaxActiveRequests uint64 + }{ + { + Name: "SingleClientSingleServer", + NumClients: 1, + NumServers: 1, + MaxActiveRequests: maxActiveRequestsDefault, + }, + { + Name: "SingleClientMultipleServers", + NumClients: 1, + NumServers: 10, + MaxActiveRequests: maxActiveRequestsDefault, + }, + { + Name: "MultipleClientsSingleServer", + NumClients: 10, + NumServers: 1, + MaxActiveRequests: maxActiveRequestsDefault, + }, + { + Name: "MultipleClientsMultipleServers", + NumClients: 10, + NumServers: 10, + MaxActiveRequests: maxActiveRequestsDefault, + }, + { + Name: "RequestCapacityFull", + NumClients: 10, + NumServers: 1, + MaxActiveRequests: 1, + }, + { + Name: "RequestCapacityContinuouslyFull", + NumClients: 100, + NumServers: 2, + MaxActiveRequests: 2, + }, + } + + for _, testCase := range testCases { + t.Run(testCase.Name, func(t *testing.T) { + conn, fd, err := newTestConnection(s, k, testCase.MaxActiveRequests) + if err != nil { + t.Fatalf("newTestConnection: %v", err) + } + + clientsDone := make([]chan struct{}, testCase.NumClients) + serversDone := make([]chan struct{}, testCase.NumServers) + serversKill := make([]chan struct{}, testCase.NumServers) + + // FUSE clients. + for i := 0; i < testCase.NumClients; i++ { + clientsDone[i] = make(chan struct{}) + go func(i int) { + fuseClientRun(t, s, k, conn, creds, uint32(i), uint64(i), clientsDone[i]) + }(i) + } + + // FUSE servers. + for j := 0; j < testCase.NumServers; j++ { + serversDone[j] = make(chan struct{}) + serversKill[j] = make(chan struct{}, 1) // The kill command shouldn't block. + go func(j int) { + fuseServerRun(t, s, k, fd, serversDone[j], serversKill[j]) + }(j) + } + + // Tear down. + // + // Make sure all the clients are done. + for i := 0; i < testCase.NumClients; i++ { + <-clientsDone[i] + } + + // Kill any server that is potentially waiting. + for j := 0; j < testCase.NumServers; j++ { + serversKill[j] <- struct{}{} + } + + // Make sure all the servers are done. + for j := 0; j < testCase.NumServers; j++ { + <-serversDone[j] + } + }) + } +} + +// CallTest makes a request to the server and blocks the invoking +// goroutine until a server responds with a response. Doesn't block +// a kernel.Task. Analogous to Connection.Call but used for testing. +func CallTest(conn *connection, t *kernel.Task, r *Request, i uint32) (*Response, error) { + conn.fd.mu.Lock() + + // Wait until we're certain that a new request can be processed. + for conn.fd.numActiveRequests == conn.fd.fs.opts.maxActiveRequests { + conn.fd.mu.Unlock() + select { + case <-conn.fd.fullQueueCh: + } + conn.fd.mu.Lock() + } + + fut, err := conn.callFutureLocked(t, r) // No task given. + conn.fd.mu.Unlock() + + if err != nil { + return nil, err + } + + // Resolve the response. + // + // Block without a task. + select { + case <-fut.ch: + } + + // A response is ready. Resolve and return it. + return fut.getResponse(), nil +} + +// ReadTest is analogous to vfs.FileDescription.Read and reads from the FUSE +// device. However, it does so by - not blocking the task that is calling - and +// instead just waits on a channel. The behaviour is essentially the same as +// DeviceFD.Read except it guarantees that the task is not blocked. +func ReadTest(serverTask *kernel.Task, fd *vfs.FileDescription, inIOseq usermem.IOSequence, killServer chan struct{}) (int64, bool, error) { + var err error + var n, total int64 + + dev := fd.Impl().(*DeviceFD) + + // Register for notifications. + w, ch := waiter.NewChannelEntry(nil) + dev.EventRegister(&w, waiter.EventIn) + for { + // Issue the request and break out if it completes with anything other than + // "would block". + n, err = dev.Read(serverTask, inIOseq, vfs.ReadOptions{}) + total += n + if err != syserror.ErrWouldBlock { + break + } + + // Wait for a notification that we should retry. + // Emulate the blocking for when no requests are available + select { + case <-ch: + case <-killServer: + // Server killed by the main program. + return 0, true, nil + } + } + + dev.EventUnregister(&w) + return total, false, err +} + +// fuseClientRun emulates all the actions of a normal FUSE request. It creates +// a header, a payload, calls the server, waits for the response, and processes +// the response. +func fuseClientRun(t *testing.T, s *testutil.System, k *kernel.Kernel, conn *connection, creds *auth.Credentials, pid uint32, inode uint64, clientDone chan struct{}) { + defer func() { clientDone <- struct{}{} }() + + tc := k.NewThreadGroup(nil, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, k.GlobalInit().Limits()) + clientTask, err := testutil.CreateTask(s.Ctx, fmt.Sprintf("fuse-client-%v", pid), tc, s.MntNs, s.Root, s.Root) + if err != nil { + t.Fatal(err) + } + testObj := &testPayload{ + data: rand.Uint32(), + } + + req, err := conn.NewRequest(creds, pid, inode, echoTestOpcode, testObj) + if err != nil { + t.Fatalf("NewRequest creation failed: %v", err) + } + + // Queue up a request. + // Analogous to Call except it doesn't block on the task. + resp, err := CallTest(conn, clientTask, req, pid) + if err != nil { + t.Fatalf("CallTaskNonBlock failed: %v", err) + } + + if err = resp.Error(); err != nil { + t.Fatalf("Server responded with an error: %v", err) + } + + var respTestPayload testPayload + if err := resp.UnmarshalPayload(&respTestPayload); err != nil { + t.Fatalf("Unmarshalling payload error: %v", err) + } + + if resp.hdr.Unique != req.hdr.Unique { + t.Fatalf("got response for another request. Expected response for req %v but got response for req %v", + req.hdr.Unique, resp.hdr.Unique) + } + + if respTestPayload.data != testObj.data { + t.Fatalf("read incorrect data. Data expected: %v, but got %v", testObj.data, respTestPayload.data) + } + +} + +// fuseServerRun creates a task and emulates all the actions of a simple FUSE server +// that simply reads a request and echos the same struct back as a response using the +// appropriate headers. +func fuseServerRun(t *testing.T, s *testutil.System, k *kernel.Kernel, fd *vfs.FileDescription, serverDone, killServer chan struct{}) { + defer func() { serverDone <- struct{}{} }() + + // Create the tasks that the server will be using. + tc := k.NewThreadGroup(nil, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, k.GlobalInit().Limits()) + var readPayload testPayload + + serverTask, err := testutil.CreateTask(s.Ctx, "fuse-server", tc, s.MntNs, s.Root, s.Root) + if err != nil { + t.Fatal(err) + } + + // Read the request. + for { + inHdrLen := uint32((*linux.FUSEHeaderIn)(nil).SizeBytes()) + payloadLen := uint32(readPayload.SizeBytes()) + + // The raed buffer must meet some certain size criteria. + buffSize := inHdrLen + payloadLen + if buffSize < linux.FUSE_MIN_READ_BUFFER { + buffSize = linux.FUSE_MIN_READ_BUFFER + } + inBuf := make([]byte, buffSize) + inIOseq := usermem.BytesIOSequence(inBuf) + + n, serverKilled, err := ReadTest(serverTask, fd, inIOseq, killServer) + if err != nil { + t.Fatalf("Read failed :%v", err) + } + + // Server should shut down. No new requests are going to be made. + if serverKilled { + break + } + + if n <= 0 { + t.Fatalf("Read read no bytes") + } + + var readFUSEHeaderIn linux.FUSEHeaderIn + readFUSEHeaderIn.UnmarshalUnsafe(inBuf[:inHdrLen]) + readPayload.UnmarshalUnsafe(inBuf[inHdrLen : inHdrLen+payloadLen]) + + if readFUSEHeaderIn.Opcode != echoTestOpcode { + t.Fatalf("read incorrect data. Header: %v, Payload: %v", readFUSEHeaderIn, readPayload) + } + + // Write the response. + outHdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes()) + outBuf := make([]byte, outHdrLen+payloadLen) + outHeader := linux.FUSEHeaderOut{ + Len: outHdrLen + payloadLen, + Error: 0, + Unique: readFUSEHeaderIn.Unique, + } + + // Echo the payload back. + outHeader.MarshalUnsafe(outBuf[:outHdrLen]) + readPayload.MarshalUnsafe(outBuf[outHdrLen:]) + outIOseq := usermem.BytesIOSequence(outBuf) + + n, err = fd.Write(s.Ctx, outIOseq, vfs.WriteOptions{}) + if err != nil { + t.Fatalf("Write failed :%v", err) + } + } +} + +func setup(t *testing.T) *testutil.System { + k, err := testutil.Boot() + if err != nil { + t.Fatalf("Error creating kernel: %v", err) + } + + ctx := k.SupervisorContext() + creds := auth.CredentialsFromContext(ctx) + + k.VFS().MustRegisterFilesystemType(Name, &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ + AllowUserList: true, + AllowUserMount: true, + }) + + mntns, err := k.VFS().NewMountNamespace(ctx, creds, "", "tmpfs", &vfs.GetFilesystemOptions{}) + if err != nil { + t.Fatalf("NewMountNamespace(): %v", err) + } + + return testutil.NewSystem(ctx, t, k.VFS(), mntns) +} + +// newTestConnection creates a fuse connection that the sentry can communicate with +// and the FD for the server to communicate with. +func newTestConnection(system *testutil.System, k *kernel.Kernel, maxActiveRequests uint64) (*connection, *vfs.FileDescription, error) { + vfsObj := &vfs.VirtualFilesystem{} + fuseDev := &DeviceFD{} + + if err := vfsObj.Init(system.Ctx); err != nil { + return nil, nil, err + } + + vd := vfsObj.NewAnonVirtualDentry("genCountFD") + defer vd.DecRef(system.Ctx) + if err := fuseDev.vfsfd.Init(fuseDev, linux.O_RDWR|linux.O_CREAT, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{}); err != nil { + return nil, nil, err + } + + fsopts := filesystemOptions{ + maxActiveRequests: maxActiveRequests, + } + fs, err := NewFUSEFilesystem(system.Ctx, 0, &fsopts, &fuseDev.vfsfd) + if err != nil { + return nil, nil, err + } + + return fs.conn, &fuseDev.vfsfd, nil +} + +// SizeBytes implements marshal.Marshallable.SizeBytes. +func (t *testPayload) SizeBytes() int { + return 4 +} + +// MarshalBytes implements marshal.Marshallable.MarshalBytes. +func (t *testPayload) MarshalBytes(dst []byte) { + usermem.ByteOrder.PutUint32(dst[:4], t.data) +} + +// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes. +func (t *testPayload) UnmarshalBytes(src []byte) { + *t = testPayload{data: usermem.ByteOrder.Uint32(src[:4])} +} + +// Packed implements marshal.Marshallable.Packed. +func (t *testPayload) Packed() bool { + return true +} + +// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe. +func (t *testPayload) MarshalUnsafe(dst []byte) { + t.MarshalBytes(dst) +} + +// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe. +func (t *testPayload) UnmarshalUnsafe(src []byte) { + t.UnmarshalBytes(src) +} + +// CopyOutN implements marshal.Marshallable.CopyOutN. +func (t *testPayload) CopyOutN(task marshal.Task, addr usermem.Addr, limit int) (int, error) { + panic("not implemented") +} + +// CopyOut implements marshal.Marshallable.CopyOut. +func (t *testPayload) CopyOut(task marshal.Task, addr usermem.Addr) (int, error) { + panic("not implemented") +} + +// CopyIn implements marshal.Marshallable.CopyIn. +func (t *testPayload) CopyIn(task marshal.Task, addr usermem.Addr) (int, error) { + panic("not implemented") +} + +// WriteTo implements io.WriterTo.WriteTo. +func (t *testPayload) WriteTo(w io.Writer) (int64, error) { + panic("not implemented") +} diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go new file mode 100644 index 000000000..83c24ec25 --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/fusefs.go @@ -0,0 +1,324 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package fuse implements fusefs. +package fuse + +import ( + "strconv" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" +) + +// Name is the default filesystem name. +const Name = "fuse" + +// FilesystemType implements vfs.FilesystemType. +type FilesystemType struct{} + +type filesystemOptions struct { + // userID specifies the numeric uid of the mount owner. + // This option should not be specified by the filesystem owner. + // It is set by libfuse (or, if libfuse is not used, must be set + // by the filesystem itself). For more information, see man page + // for fuse(8) + userID uint32 + + // groupID specifies the numeric gid of the mount owner. + // This option should not be specified by the filesystem owner. + // It is set by libfuse (or, if libfuse is not used, must be set + // by the filesystem itself). For more information, see man page + // for fuse(8) + groupID uint32 + + // rootMode specifies the the file mode of the filesystem's root. + rootMode linux.FileMode + + // maxActiveRequests specifies the maximum number of active requests that can + // exist at any time. Any further requests will block when trying to + // Call the server. + maxActiveRequests uint64 +} + +// filesystem implements vfs.FilesystemImpl. +type filesystem struct { + kernfs.Filesystem + devMinor uint32 + + // conn is used for communication between the FUSE server + // daemon and the sentry fusefs. + conn *connection + + // opts is the options the fusefs is initialized with. + opts *filesystemOptions +} + +// Name implements vfs.FilesystemType.Name. +func (FilesystemType) Name() string { + return Name +} + +// GetFilesystem implements vfs.FilesystemType.GetFilesystem. +func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) { + devMinor, err := vfsObj.GetAnonBlockDevMinor() + if err != nil { + return nil, nil, err + } + + var fsopts filesystemOptions + mopts := vfs.GenericParseMountOptions(opts.Data) + deviceDescriptorStr, ok := mopts["fd"] + if !ok { + log.Warningf("%s.GetFilesystem: communication file descriptor N (obtained by opening /dev/fuse) must be specified as 'fd=N'", fsType.Name()) + return nil, nil, syserror.EINVAL + } + delete(mopts, "fd") + + deviceDescriptor, err := strconv.ParseInt(deviceDescriptorStr, 10 /* base */, 32 /* bitSize */) + if err != nil { + return nil, nil, err + } + + kernelTask := kernel.TaskFromContext(ctx) + if kernelTask == nil { + log.Warningf("%s.GetFilesystem: couldn't get kernel task from context", fsType.Name()) + return nil, nil, syserror.EINVAL + } + fuseFd := kernelTask.GetFileVFS2(int32(deviceDescriptor)) + + // Parse and set all the other supported FUSE mount options. + // TODO(gVisor.dev/issue/3229): Expand the supported mount options. + if userIDStr, ok := mopts["user_id"]; ok { + delete(mopts, "user_id") + userID, err := strconv.ParseUint(userIDStr, 10, 32) + if err != nil { + log.Warningf("%s.GetFilesystem: invalid user_id: user_id=%s", fsType.Name(), userIDStr) + return nil, nil, syserror.EINVAL + } + fsopts.userID = uint32(userID) + } + + if groupIDStr, ok := mopts["group_id"]; ok { + delete(mopts, "group_id") + groupID, err := strconv.ParseUint(groupIDStr, 10, 32) + if err != nil { + log.Warningf("%s.GetFilesystem: invalid group_id: group_id=%s", fsType.Name(), groupIDStr) + return nil, nil, syserror.EINVAL + } + fsopts.groupID = uint32(groupID) + } + + rootMode := linux.FileMode(0777) + modeStr, ok := mopts["rootmode"] + if ok { + delete(mopts, "rootmode") + mode, err := strconv.ParseUint(modeStr, 8, 32) + if err != nil { + log.Warningf("%s.GetFilesystem: invalid mode: %q", fsType.Name(), modeStr) + return nil, nil, syserror.EINVAL + } + rootMode = linux.FileMode(mode) + } + fsopts.rootMode = rootMode + + // Set the maxInFlightRequests option. + fsopts.maxActiveRequests = maxActiveRequestsDefault + + // Check for unparsed options. + if len(mopts) != 0 { + log.Warningf("%s.GetFilesystem: unknown options: %v", fsType.Name(), mopts) + return nil, nil, syserror.EINVAL + } + + // Create a new FUSE filesystem. + fs, err := NewFUSEFilesystem(ctx, devMinor, &fsopts, fuseFd) + if err != nil { + log.Warningf("%s.NewFUSEFilesystem: failed with error: %v", fsType.Name(), err) + return nil, nil, err + } + + fs.VFSFilesystem().Init(vfsObj, &fsType, fs) + + // Send a FUSE_INIT request to the FUSE daemon server before returning. + // This call is not blocking. + if err := fs.conn.InitSend(creds, uint32(kernelTask.ThreadID())); err != nil { + log.Warningf("%s.InitSend: failed with error: %v", fsType.Name(), err) + return nil, nil, err + } + + // root is the fusefs root directory. + root := fs.newInode(creds, fsopts.rootMode) + + return fs.VFSFilesystem(), root.VFSDentry(), nil +} + +// NewFUSEFilesystem creates a new FUSE filesystem. +func NewFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOptions, device *vfs.FileDescription) (*filesystem, error) { + fs := &filesystem{ + devMinor: devMinor, + opts: opts, + } + + conn, err := newFUSEConnection(ctx, device, opts.maxActiveRequests) + if err != nil { + log.Warningf("fuse.NewFUSEFilesystem: NewFUSEConnection failed with error: %v", err) + return nil, syserror.EINVAL + } + + fs.conn = conn + fuseFD := device.Impl().(*DeviceFD) + fuseFD.fs = fs + + return fs, nil +} + +// Release implements vfs.FilesystemImpl.Release. +func (fs *filesystem) Release(ctx context.Context) { + fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) + fs.Filesystem.Release(ctx) +} + +// inode implements kernfs.Inode. +type inode struct { + kernfs.InodeAttrs + kernfs.InodeNoDynamicLookup + kernfs.InodeNotSymlink + kernfs.InodeDirectoryNoNewChildren + kernfs.OrderedChildren + + locks vfs.FileLocks + + dentry kernfs.Dentry +} + +func (fs *filesystem) newInode(creds *auth.Credentials, mode linux.FileMode) *kernfs.Dentry { + i := &inode{} + i.InodeAttrs.Init(creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0755) + i.OrderedChildren.Init(kernfs.OrderedChildrenOptions{}) + i.dentry.Init(i) + + return &i.dentry +} + +// Open implements kernfs.Inode.Open. +func (i *inode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts) + if err != nil { + return nil, err + } + return fd.VFSFileDescription(), nil +} + +// statFromFUSEAttr makes attributes from linux.FUSEAttr to linux.Statx. The +// opts.Sync attribute is ignored since the synchronization is handled by the +// FUSE server. +func statFromFUSEAttr(attr linux.FUSEAttr, mask, devMinor uint32) linux.Statx { + var stat linux.Statx + stat.Blksize = attr.BlkSize + stat.DevMajor, stat.DevMinor = linux.UNNAMED_MAJOR, devMinor + + rdevMajor, rdevMinor := linux.DecodeDeviceID(attr.Rdev) + stat.RdevMajor, stat.RdevMinor = uint32(rdevMajor), rdevMinor + + if mask&linux.STATX_MODE != 0 { + stat.Mode = uint16(attr.Mode) + } + if mask&linux.STATX_NLINK != 0 { + stat.Nlink = attr.Nlink + } + if mask&linux.STATX_UID != 0 { + stat.UID = attr.UID + } + if mask&linux.STATX_GID != 0 { + stat.GID = attr.GID + } + if mask&linux.STATX_ATIME != 0 { + stat.Atime = linux.StatxTimestamp{ + Sec: int64(attr.Atime), + Nsec: attr.AtimeNsec, + } + } + if mask&linux.STATX_MTIME != 0 { + stat.Mtime = linux.StatxTimestamp{ + Sec: int64(attr.Mtime), + Nsec: attr.MtimeNsec, + } + } + if mask&linux.STATX_CTIME != 0 { + stat.Ctime = linux.StatxTimestamp{ + Sec: int64(attr.Ctime), + Nsec: attr.CtimeNsec, + } + } + if mask&linux.STATX_INO != 0 { + stat.Ino = attr.Ino + } + if mask&linux.STATX_SIZE != 0 { + stat.Size = attr.Size + } + if mask&linux.STATX_BLOCKS != 0 { + stat.Blocks = attr.Blocks + } + return stat +} + +// Stat implements kernfs.Inode.Stat. +func (i *inode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { + fusefs := fs.Impl().(*filesystem) + conn := fusefs.conn + task, creds := kernel.TaskFromContext(ctx), auth.CredentialsFromContext(ctx) + if task == nil { + log.Warningf("couldn't get kernel task from context") + return linux.Statx{}, syserror.EINVAL + } + + var in linux.FUSEGetAttrIn + // We don't set any attribute in the request, because in VFS2 fstat(2) will + // finally be translated into vfs.FilesystemImpl.StatAt() (see + // pkg/sentry/syscalls/linux/vfs2/stat.go), resulting in the same flow + // as stat(2). Thus GetAttrFlags and Fh variable will never be used in VFS2. + req, err := conn.NewRequest(creds, uint32(task.ThreadID()), i.Ino(), linux.FUSE_GETATTR, &in) + if err != nil { + return linux.Statx{}, err + } + + res, err := conn.Call(task, req) + if err != nil { + return linux.Statx{}, err + } + if err := res.Error(); err != nil { + return linux.Statx{}, err + } + + var out linux.FUSEGetAttrOut + if err := res.UnmarshalPayload(&out); err != nil { + return linux.Statx{}, err + } + + // Set all metadata into kernfs.InodeAttrs. + if err := i.SetStat(ctx, fs, creds, vfs.SetStatOptions{ + Stat: statFromFUSEAttr(out.Attr, linux.STATX_ALL, fusefs.devMinor), + }); err != nil { + return linux.Statx{}, err + } + + return statFromFUSEAttr(out.Attr, opts.Mask, fusefs.devMinor), nil +} diff --git a/pkg/sentry/fsimpl/fuse/init.go b/pkg/sentry/fsimpl/fuse/init.go new file mode 100644 index 000000000..779c2bd3f --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/init.go @@ -0,0 +1,166 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package fuse + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" +) + +// consts used by FUSE_INIT negotiation. +const ( + // fuseMaxMaxPages is the maximum value for MaxPages received in InitOut. + // Follow the same behavior as unix fuse implementation. + fuseMaxMaxPages = 256 + + // Maximum value for the time granularity for file time stamps, 1s. + // Follow the same behavior as unix fuse implementation. + fuseMaxTimeGranNs = 1000000000 + + // Minimum value for MaxWrite. + // Follow the same behavior as unix fuse implementation. + fuseMinMaxWrite = 4096 + + // Temporary default value for max readahead, 128kb. + fuseDefaultMaxReadahead = 131072 + + // The FUSE_INIT_IN flags sent to the daemon. + // TODO(gvisor.dev/issue/3199): complete the flags. + fuseDefaultInitFlags = linux.FUSE_MAX_PAGES +) + +// Adjustable maximums for Connection's cogestion control parameters. +// Used as the upperbound of the config values. +// Currently we do not support adjustment to them. +var ( + MaxUserBackgroundRequest uint16 = fuseDefaultMaxBackground + MaxUserCongestionThreshold uint16 = fuseDefaultCongestionThreshold +) + +// InitSend sends a FUSE_INIT request. +func (conn *connection) InitSend(creds *auth.Credentials, pid uint32) error { + in := linux.FUSEInitIn{ + Major: linux.FUSE_KERNEL_VERSION, + Minor: linux.FUSE_KERNEL_MINOR_VERSION, + // TODO(gvisor.dev/issue/3196): find appropriate way to calculate this + MaxReadahead: fuseDefaultMaxReadahead, + Flags: fuseDefaultInitFlags, + } + + req, err := conn.NewRequest(creds, pid, 0, linux.FUSE_INIT, &in) + if err != nil { + return err + } + + // Since there is no task to block on and FUSE_INIT is the request + // to unblock other requests, use nil. + return conn.CallAsync(nil, req) +} + +// InitRecv receives a FUSE_INIT reply and process it. +func (conn *connection) InitRecv(res *Response, hasSysAdminCap bool) error { + if err := res.Error(); err != nil { + return err + } + + var out linux.FUSEInitOut + if err := res.UnmarshalPayload(&out); err != nil { + return err + } + + return conn.initProcessReply(&out, hasSysAdminCap) +} + +// Process the FUSE_INIT reply from the FUSE server. +func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap bool) error { + // No support for old major fuse versions. + if out.Major != linux.FUSE_KERNEL_VERSION { + conn.connInitError = true + + // Set the connection as initialized and unblock the blocked requests + // (i.e. return error for them). + conn.SetInitialized() + + return nil + } + + // Start processing the reply. + conn.connInitSuccess = true + conn.minor = out.Minor + + // No support for limits before minor version 13. + if out.Minor >= 13 { + conn.bgLock.Lock() + + if out.MaxBackground > 0 { + conn.maxBackground = out.MaxBackground + + if !hasSysAdminCap && + conn.maxBackground > MaxUserBackgroundRequest { + conn.maxBackground = MaxUserBackgroundRequest + } + } + + if out.CongestionThreshold > 0 { + conn.congestionThreshold = out.CongestionThreshold + + if !hasSysAdminCap && + conn.congestionThreshold > MaxUserCongestionThreshold { + conn.congestionThreshold = MaxUserCongestionThreshold + } + } + + conn.bgLock.Unlock() + } + + // No support for the following flags before minor version 6. + if out.Minor >= 6 { + conn.asyncRead = out.Flags&linux.FUSE_ASYNC_READ != 0 + conn.bigWrites = out.Flags&linux.FUSE_BIG_WRITES != 0 + conn.dontMask = out.Flags&linux.FUSE_DONT_MASK != 0 + conn.writebackCache = out.Flags&linux.FUSE_WRITEBACK_CACHE != 0 + conn.cacheSymlinks = out.Flags&linux.FUSE_CACHE_SYMLINKS != 0 + conn.abortErr = out.Flags&linux.FUSE_ABORT_ERROR != 0 + + // TODO(gvisor.dev/issue/3195): figure out how to use TimeGran (0 < TimeGran <= fuseMaxTimeGranNs). + + if out.Flags&linux.FUSE_MAX_PAGES != 0 { + maxPages := out.MaxPages + if maxPages < 1 { + maxPages = 1 + } + if maxPages > fuseMaxMaxPages { + maxPages = fuseMaxMaxPages + } + conn.maxPages = maxPages + } + } + + // No support for negotiating MaxWrite before minor version 5. + if out.Minor >= 5 { + conn.maxWrite = out.MaxWrite + } else { + conn.maxWrite = fuseMinMaxWrite + } + if conn.maxWrite < fuseMinMaxWrite { + conn.maxWrite = fuseMinMaxWrite + } + + // Set connection as initialized and unblock the requests + // issued before init. + conn.SetInitialized() + + return nil +} diff --git a/pkg/sentry/fsimpl/fuse/register.go b/pkg/sentry/fsimpl/fuse/register.go new file mode 100644 index 000000000..b5b581152 --- /dev/null +++ b/pkg/sentry/fsimpl/fuse/register.go @@ -0,0 +1,42 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package fuse + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/devtmpfs" + "gvisor.dev/gvisor/pkg/sentry/vfs" +) + +// Register registers the FUSE device with vfsObj. +func Register(vfsObj *vfs.VirtualFilesystem) error { + if err := vfsObj.RegisterDevice(vfs.CharDevice, linux.MISC_MAJOR, fuseDevMinor, fuseDevice{}, &vfs.RegisterDeviceOptions{ + GroupName: "misc", + }); err != nil { + return err + } + + return nil +} + +// CreateDevtmpfsFile creates a device special file in devtmpfs. +func CreateDevtmpfsFile(ctx context.Context, dev *devtmpfs.Accessor) error { + if err := dev.CreateDeviceFile(ctx, "fuse", vfs.CharDevice, linux.MISC_MAJOR, fuseDevMinor, 0666 /* mode */); err != nil { + return err + } + + return nil +} diff --git a/pkg/sentry/fsimpl/gofer/BUILD b/pkg/sentry/fsimpl/gofer/BUILD index 67e916525..16787116f 100644 --- a/pkg/sentry/fsimpl/gofer/BUILD +++ b/pkg/sentry/fsimpl/gofer/BUILD @@ -35,6 +35,7 @@ go_library( "fstree.go", "gofer.go", "handle.go", + "host_named_pipe.go", "p9file.go", "regular_file.go", "socket.go", @@ -47,11 +48,13 @@ go_library( "//pkg/abi/linux", "//pkg/context", "//pkg/fd", + "//pkg/fdnotifier", "//pkg/fspath", "//pkg/log", "//pkg/p9", "//pkg/safemem", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/host", "//pkg/sentry/hostfd", "//pkg/sentry/kernel", @@ -71,6 +74,7 @@ go_library( "//pkg/unet", "//pkg/usermem", "//pkg/waiter", + "@org_golang_x_sys//unix:go_default_library", ], ) @@ -81,5 +85,6 @@ go_test( deps = [ "//pkg/p9", "//pkg/sentry/contexttest", + "//pkg/sentry/pgalloc", ], ) diff --git a/pkg/sentry/fsimpl/gofer/directory.go b/pkg/sentry/fsimpl/gofer/directory.go index b98218753..2a8011eb4 100644 --- a/pkg/sentry/fsimpl/gofer/directory.go +++ b/pkg/sentry/fsimpl/gofer/directory.go @@ -85,14 +85,13 @@ func (d *dentry) createSyntheticChildLocked(opts *createSyntheticOpts) { d2 := &dentry{ refs: 1, // held by d fs: d.fs, + ino: d.fs.nextSyntheticIno(), mode: uint32(opts.mode), uid: uint32(opts.kuid), gid: uint32(opts.kgid), blockSize: usermem.PageSize, // arbitrary - handle: handle{ - fd: -1, - }, - nlink: uint32(2), + hostFD: -1, + nlink: uint32(2), } switch opts.mode.FileType() { case linux.S_IFDIR: @@ -121,7 +120,7 @@ type directoryFD struct { } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *directoryFD) Release() { +func (fd *directoryFD) Release(context.Context) { } // IterDirents implements vfs.FileDescriptionImpl.IterDirents. @@ -138,6 +137,7 @@ func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallba fd.dirents = ds } + d.InotifyWithParent(ctx, linux.IN_ACCESS, 0, vfs.PathEvent) if d.cachedMetadataAuthoritative() { d.touchAtime(fd.vfsfd.Mount()) } @@ -183,13 +183,13 @@ func (d *dentry) getDirents(ctx context.Context) ([]vfs.Dirent, error) { { Name: ".", Type: linux.DT_DIR, - Ino: d.ino, + Ino: uint64(d.ino), NextOff: 1, }, { Name: "..", Type: uint8(atomic.LoadUint32(&parent.mode) >> 12), - Ino: parent.ino, + Ino: uint64(parent.ino), NextOff: 2, }, } @@ -203,14 +203,14 @@ func (d *dentry) getDirents(ctx context.Context) ([]vfs.Dirent, error) { off := uint64(0) const count = 64 * 1024 // for consistency with the vfs1 client d.handleMu.RLock() - if !d.handleReadable { + if d.readFile.isNil() { // This should not be possible because a readable handle should // have been opened when the calling directoryFD was opened. d.handleMu.RUnlock() panic("gofer.dentry.getDirents called without a readable handle") } for { - p9ds, err := d.handle.file.readdir(ctx, off, count) + p9ds, err := d.readFile.readdir(ctx, off, count) if err != nil { d.handleMu.RUnlock() return nil, err @@ -225,7 +225,7 @@ func (d *dentry) getDirents(ctx context.Context) ([]vfs.Dirent, error) { } dirent := vfs.Dirent{ Name: p9d.Name, - Ino: p9d.QID.Path, + Ino: uint64(inoFromPath(p9d.QID.Path)), NextOff: int64(len(dirents) + 1), } // p9 does not expose 9P2000.U's DMDEVICE, DMNAMEDPIPE, or @@ -258,7 +258,7 @@ func (d *dentry) getDirents(ctx context.Context) ([]vfs.Dirent, error) { dirents = append(dirents, vfs.Dirent{ Name: child.name, Type: uint8(atomic.LoadUint32(&child.mode) >> 12), - Ino: child.ino, + Ino: uint64(child.ino), NextOff: int64(len(dirents) + 1), }) } @@ -299,3 +299,8 @@ func (fd *directoryFD) Seek(ctx context.Context, offset int64, whence int32) (in return 0, syserror.EINVAL } } + +// Sync implements vfs.FileDescriptionImpl.Sync. +func (fd *directoryFD) Sync(ctx context.Context) error { + return fd.dentry().syncRemoteFile(ctx) +} diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go index 7f2181216..40fec890a 100644 --- a/pkg/sentry/fsimpl/gofer/filesystem.go +++ b/pkg/sentry/fsimpl/gofer/filesystem.go @@ -15,7 +15,9 @@ package gofer import ( + "math" "sync" + "sync/atomic" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" @@ -53,8 +55,8 @@ func (fs *filesystem) Sync(ctx context.Context) error { // Sync regular files. for _, d := range ds { - err := d.syncSharedHandle(ctx) - d.DecRef() + err := d.syncCachedFile(ctx) + d.DecRef(ctx) if err != nil && retErr == nil { retErr = err } @@ -64,7 +66,7 @@ func (fs *filesystem) Sync(ctx context.Context) error { // handles (so they won't be synced by the above). for _, sffd := range sffds { err := sffd.Sync(ctx) - sffd.vfsfd.DecRef() + sffd.vfsfd.DecRef(ctx) if err != nil && retErr == nil { retErr = err } @@ -118,7 +120,7 @@ func putDentrySlice(ds *[]*dentry) { // must be up to date. // // Postconditions: The returned dentry's cached metadata is up to date. -func (fs *filesystem) stepLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, ds **[]*dentry) (*dentry, error) { +func (fs *filesystem) stepLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, mayFollowSymlinks bool, ds **[]*dentry) (*dentry, error) { if !d.isDir() { return nil, syserror.ENOTDIR } @@ -132,7 +134,7 @@ afterSymlink: return d, nil } if name == ".." { - if isRoot, err := rp.CheckRoot(&d.vfsd); err != nil { + if isRoot, err := rp.CheckRoot(ctx, &d.vfsd); err != nil { return nil, err } else if isRoot || d.parent == nil { rp.Advance() @@ -145,15 +147,13 @@ afterSymlink: // // Call rp.CheckMount() before updating d.parent's metadata, since if // we traverse to another mount then d.parent's metadata is irrelevant. - if err := rp.CheckMount(&d.parent.vfsd); err != nil { + if err := rp.CheckMount(ctx, &d.parent.vfsd); err != nil { return nil, err } if d != d.parent && !d.cachedMetadataAuthoritative() { - _, attrMask, attr, err := d.parent.file.getAttr(ctx, dentryAttrMask()) - if err != nil { + if err := d.parent.updateFromGetattr(ctx); err != nil { return nil, err } - d.parent.updateFromP9Attrs(attrMask, &attr) } rp.Advance() return d.parent, nil @@ -165,10 +165,10 @@ afterSymlink: if child == nil { return nil, syserror.ENOENT } - if err := rp.CheckMount(&child.vfsd); err != nil { + if err := rp.CheckMount(ctx, &child.vfsd); err != nil { return nil, err } - if child.isSymlink() && rp.ShouldFollowSymlink() { + if child.isSymlink() && mayFollowSymlinks && rp.ShouldFollowSymlink() { target, err := child.readlink(ctx, rp.Mount()) if err != nil { return nil, err @@ -208,18 +208,28 @@ func (fs *filesystem) getChildLocked(ctx context.Context, vfsObj *vfs.VirtualFil // Preconditions: As for getChildLocked. !parent.isSynthetic(). func (fs *filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.VirtualFilesystem, parent *dentry, name string, child *dentry, ds **[]*dentry) (*dentry, error) { + if child != nil { + // Need to lock child.metadataMu because we might be updating child + // metadata. We need to hold the lock *before* getting metadata from the + // server and release it after updating local metadata. + child.metadataMu.Lock() + } qid, file, attrMask, attr, err := parent.file.walkGetAttrOne(ctx, name) if err != nil && err != syserror.ENOENT { + if child != nil { + child.metadataMu.Unlock() + } return nil, err } if child != nil { - if !file.isNil() && qid.Path == child.ino { - // The file at this path hasn't changed. Just update cached - // metadata. + if !file.isNil() && inoFromPath(qid.Path) == child.ino { + // The file at this path hasn't changed. Just update cached metadata. file.close(ctx) - child.updateFromP9Attrs(attrMask, &attr) + child.updateFromP9AttrsLocked(attrMask, &attr) + child.metadataMu.Unlock() return child, nil } + child.metadataMu.Unlock() if file.isNil() && child.isSynthetic() { // We have a synthetic file, and no remote file has arisen to // replace it. @@ -230,7 +240,7 @@ func (fs *filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.Vir // has 0 references, drop it). Wait to update parent.children until we // know what to replace the existing dentry with (i.e. one of the // returns below), to avoid a redundant map access. - vfsObj.InvalidateDentry(&child.vfsd) + vfsObj.InvalidateDentry(ctx, &child.vfsd) if child.isSynthetic() { // Normally we don't mark invalidated dentries as deleted since // they may still exist (but at a different path), and also for @@ -275,7 +285,7 @@ func (fs *filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.Vir func (fs *filesystem) walkParentDirLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, ds **[]*dentry) (*dentry, error) { for !rp.Final() { d.dirMu.Lock() - next, err := fs.stepLocked(ctx, rp, d, ds) + next, err := fs.stepLocked(ctx, rp, d, true /* mayFollowSymlinks */, ds) d.dirMu.Unlock() if err != nil { return nil, err @@ -301,7 +311,7 @@ func (fs *filesystem) resolveLocked(ctx context.Context, rp *vfs.ResolvingPath, } for !rp.Done() { d.dirMu.Lock() - next, err := fs.stepLocked(ctx, rp, d, ds) + next, err := fs.stepLocked(ctx, rp, d, true /* mayFollowSymlinks */, ds) d.dirMu.Unlock() if err != nil { return nil, err @@ -323,7 +333,7 @@ func (fs *filesystem) resolveLocked(ctx context.Context, rp *vfs.ResolvingPath, func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir bool, createInRemoteDir func(parent *dentry, name string) error, createInSyntheticDir func(parent *dentry, name string) error) error { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) start := rp.Start().Impl().(*dentry) if !start.cachedMetadataAuthoritative() { // Get updated metadata for start as required by @@ -371,17 +381,33 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir } parent.touchCMtime() parent.dirents = nil + ev := linux.IN_CREATE + if dir { + ev |= linux.IN_ISDIR + } + parent.watches.Notify(ctx, name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */) return nil } if fs.opts.interop == InteropModeShared { - // The existence of a dentry at name would be inconclusive because the - // file it represents may have been deleted from the remote filesystem, - // so we would need to make an RPC to revalidate the dentry. Just - // attempt the file creation RPC instead. If a file does exist, the RPC - // will fail with EEXIST like we would have. If the RPC succeeds, and a - // stale dentry exists, the dentry will fail revalidation next time - // it's used. - return createInRemoteDir(parent, name) + if child := parent.children[name]; child != nil && child.isSynthetic() { + return syserror.EEXIST + } + // The existence of a non-synthetic dentry at name would be inconclusive + // because the file it represents may have been deleted from the remote + // filesystem, so we would need to make an RPC to revalidate the dentry. + // Just attempt the file creation RPC instead. If a file does exist, the + // RPC will fail with EEXIST like we would have. If the RPC succeeds, and a + // stale dentry exists, the dentry will fail revalidation next time it's + // used. + if err := createInRemoteDir(parent, name); err != nil { + return err + } + ev := linux.IN_CREATE + if dir { + ev |= linux.IN_ISDIR + } + parent.watches.Notify(ctx, name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */) + return nil } if child := parent.children[name]; child != nil { return syserror.EEXIST @@ -397,6 +423,11 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir } parent.touchCMtime() parent.dirents = nil + ev := linux.IN_CREATE + if dir { + ev |= linux.IN_ISDIR + } + parent.watches.Notify(ctx, name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */) return nil } @@ -404,7 +435,7 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir bool) error { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) start := rp.Start().Impl().(*dentry) if !start.cachedMetadataAuthoritative() { // Get updated metadata for start as required by @@ -440,24 +471,64 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b } vfsObj := rp.VirtualFilesystem() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) parent.dirMu.Lock() defer parent.dirMu.Unlock() + child, ok := parent.children[name] if ok && child == nil { return syserror.ENOENT } - // We only need a dentry representing the file at name if it can be a mount - // point. If child is nil, then it can't be a mount point. If child is - // non-nil but stale, the actual file can't be a mount point either; we - // detect this case by just speculatively calling PrepareDeleteDentry and - // only revalidating the dentry if that fails (indicating that the existing - // dentry is a mount point). + + sticky := atomic.LoadUint32(&parent.mode)&linux.ModeSticky != 0 + if sticky { + if !ok { + // If the sticky bit is set, we need to retrieve the child to determine + // whether removing it is allowed. + child, err = fs.stepLocked(ctx, rp, parent, false /* mayFollowSymlinks */, &ds) + if err != nil { + return err + } + } else if child != nil && !child.cachedMetadataAuthoritative() { + // Make sure the dentry representing the file at name is up to date + // before examining its metadata. + child, err = fs.revalidateChildLocked(ctx, vfsObj, parent, name, child, &ds) + if err != nil { + return err + } + } + if err := parent.mayDelete(rp.Credentials(), child); err != nil { + return err + } + } + + // If a child dentry exists, prepare to delete it. This should fail if it is + // a mount point. We detect mount points by speculatively calling + // PrepareDeleteDentry, which fails if child is a mount point. However, we + // may need to revalidate the file in this case to make sure that it has not + // been deleted or replaced on the remote fs, in which case the mount point + // will have disappeared. If calling PrepareDeleteDentry fails again on the + // up-to-date dentry, we can be sure that it is a mount point. + // + // Also note that if child is nil, then it can't be a mount point. if child != nil { + // Hold child.dirMu so we can check child.children and + // child.syntheticChildren. We don't access these fields until a bit later, + // but locking child.dirMu after calling vfs.PrepareDeleteDentry() would + // create an inconsistent lock ordering between dentry.dirMu and + // vfs.Dentry.mu (in the VFS lock order, it would make dentry.dirMu both "a + // FilesystemImpl lock" and "a lock acquired by a FilesystemImpl between + // PrepareDeleteDentry and CommitDeleteDentry). To avoid this, lock + // child.dirMu before calling PrepareDeleteDentry. child.dirMu.Lock() defer child.dirMu.Unlock() if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil { - if parent.cachedMetadataAuthoritative() { + // We can skip revalidation in several cases: + // - We are not in InteropModeShared + // - The parent directory is synthetic, in which case the child must also + // be synthetic + // - We already updated the child during the sticky bit check above + if parent.cachedMetadataAuthoritative() || sticky { return err } child, err = fs.revalidateChildLocked(ctx, vfsObj, parent, name, child, &ds) @@ -518,7 +589,7 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b if child == nil { return syserror.ENOENT } - } else { + } else if child == nil || !child.isSynthetic() { err = parent.file.unlinkAt(ctx, name, flags) if err != nil { if child != nil { @@ -527,8 +598,20 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b return err } } + + // Generate inotify events for rmdir or unlink. + if dir { + parent.watches.Notify(ctx, name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent, true /* unlinked */) + } else { + var cw *vfs.Watches + if child != nil { + cw = &child.watches + } + vfs.InotifyRemoveChild(ctx, cw, &parent.watches, name) + } + if child != nil { - vfsObj.CommitDeleteDentry(&child.vfsd) + vfsObj.CommitDeleteDentry(ctx, &child.vfsd) child.setDeleted() if child.isSynthetic() { parent.syntheticChildren-- @@ -555,7 +638,7 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b // but dentry slices are allocated lazily, and it's much easier to say "defer // fs.renameMuRUnlockAndCheckCaching(&ds)" than "defer func() { // fs.renameMuRUnlockAndCheckCaching(ds) }()" to work around this. -func (fs *filesystem) renameMuRUnlockAndCheckCaching(ds **[]*dentry) { +func (fs *filesystem) renameMuRUnlockAndCheckCaching(ctx context.Context, ds **[]*dentry) { fs.renameMu.RUnlock() if *ds == nil { return @@ -563,20 +646,20 @@ func (fs *filesystem) renameMuRUnlockAndCheckCaching(ds **[]*dentry) { if len(**ds) != 0 { fs.renameMu.Lock() for _, d := range **ds { - d.checkCachingLocked() + d.checkCachingLocked(ctx) } fs.renameMu.Unlock() } putDentrySlice(*ds) } -func (fs *filesystem) renameMuUnlockAndCheckCaching(ds **[]*dentry) { +func (fs *filesystem) renameMuUnlockAndCheckCaching(ctx context.Context, ds **[]*dentry) { if *ds == nil { fs.renameMu.Unlock() return } for _, d := range **ds { - d.checkCachingLocked() + d.checkCachingLocked(ctx) } fs.renameMu.Unlock() putDentrySlice(*ds) @@ -586,7 +669,7 @@ func (fs *filesystem) renameMuUnlockAndCheckCaching(ds **[]*dentry) { func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return err @@ -598,7 +681,7 @@ func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return nil, err @@ -619,7 +702,7 @@ func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) start := rp.Start().Impl().(*dentry) if !start.cachedMetadataAuthoritative() { // Get updated metadata for start as required by @@ -642,8 +725,29 @@ func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs. if rp.Mount() != vd.Mount() { return syserror.EXDEV } - // 9P2000.L supports hard links, but we don't. - return syserror.EPERM + d := vd.Dentry().Impl().(*dentry) + if d.isDir() { + return syserror.EPERM + } + gid := auth.KGID(atomic.LoadUint32(&d.gid)) + uid := auth.KUID(atomic.LoadUint32(&d.uid)) + mode := linux.FileMode(atomic.LoadUint32(&d.mode)) + if err := vfs.MayLink(rp.Credentials(), mode, uid, gid); err != nil { + return err + } + if d.nlink == 0 { + return syserror.ENOENT + } + if d.nlink == math.MaxUint32 { + return syserror.EMLINK + } + if err := parent.file.link(ctx, d.file, childName); err != nil { + return err + } + + // Success! + atomic.AddUint32(&d.nlink, 1) + return nil }, nil) } @@ -730,7 +834,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) start := rp.Start().Impl().(*dentry) if !start.cachedMetadataAuthoritative() { @@ -740,6 +844,13 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf } } if rp.Done() { + // Reject attempts to open mount root directory with O_CREAT. + if mayCreate && rp.MustBeDir() { + return nil, syserror.EISDIR + } + if mustCreate { + return nil, syserror.EEXIST + } return start.openLocked(ctx, rp, &opts) } @@ -752,27 +863,33 @@ afterTrailingSymlink: if err := parent.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil { return nil, err } + // Reject attempts to open directories with O_CREAT. + if mayCreate && rp.MustBeDir() { + return nil, syserror.EISDIR + } // Determine whether or not we need to create a file. parent.dirMu.Lock() - child, err := fs.stepLocked(ctx, rp, parent, &ds) + child, err := fs.stepLocked(ctx, rp, parent, false /* mayFollowSymlinks */, &ds) if err == syserror.ENOENT && mayCreate { if parent.isSynthetic() { parent.dirMu.Unlock() return nil, syserror.EPERM } - fd, err := parent.createAndOpenChildLocked(ctx, rp, &opts) + fd, err := parent.createAndOpenChildLocked(ctx, rp, &opts, &ds) parent.dirMu.Unlock() return fd, err } + parent.dirMu.Unlock() if err != nil { - parent.dirMu.Unlock() return nil, err } - // Open existing child or follow symlink. - parent.dirMu.Unlock() if mustCreate { return nil, syserror.EEXIST } + if !child.isDir() && rp.MustBeDir() { + return nil, syserror.ENOTDIR + } + // Open existing child or follow symlink. if child.isSymlink() && rp.ShouldFollowSymlink() { target, err := child.readlink(ctx, rp.Mount()) if err != nil { @@ -793,20 +910,32 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf if err := d.checkPermissions(rp.Credentials(), ats); err != nil { return nil, err } + + trunc := opts.Flags&linux.O_TRUNC != 0 && d.fileType() == linux.S_IFREG + if trunc { + // Lock metadataMu *while* we open a regular file with O_TRUNC because + // open(2) will change the file size on server. + d.metadataMu.Lock() + defer d.metadataMu.Unlock() + } + + var vfd *vfs.FileDescription + var err error mnt := rp.Mount() switch d.fileType() { case linux.S_IFREG: if !d.fs.opts.regularFilesUseSpecialFileFD { - if err := d.ensureSharedHandle(ctx, ats&vfs.MayRead != 0, ats&vfs.MayWrite != 0, opts.Flags&linux.O_TRUNC != 0); err != nil { + if err := d.ensureSharedHandle(ctx, ats&vfs.MayRead != 0, ats&vfs.MayWrite != 0, trunc); err != nil { return nil, err } fd := ®ularFileFD{} + fd.LockFD.Init(&d.locks) if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{ AllowDirectIO: true, }); err != nil { return nil, err } - return &fd.vfsfd, nil + vfd = &fd.vfsfd } case linux.S_IFDIR: // Can't open directories with O_CREAT. @@ -826,6 +955,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf } } fd := &directoryFD{} + fd.LockFD.Init(&d.locks) if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil { return nil, err } @@ -842,10 +972,28 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf } case linux.S_IFIFO: if d.isSynthetic() { - return d.pipe.Open(ctx, mnt, &d.vfsd, opts.Flags) + return d.pipe.Open(ctx, mnt, &d.vfsd, opts.Flags, &d.locks) + } + } + + if vfd == nil { + if vfd, err = d.openSpecialFileLocked(ctx, mnt, opts); err != nil { + return nil, err } } - return d.openSpecialFileLocked(ctx, mnt, opts) + + if trunc { + // If no errors occured so far then update file size in memory. This + // step is required even if !d.cachedMetadataAuthoritative() because + // d.mappings has to be updated. + // d.metadataMu has already been acquired if trunc == true. + d.updateFileSizeLocked(0) + + if d.cachedMetadataAuthoritative() { + d.touchCMtimeLocked() + } + } + return vfd, err } func (d *dentry) connectSocketLocked(ctx context.Context, opts *vfs.OpenOptions) (*vfs.FileDescription, error) { @@ -873,19 +1021,37 @@ func (d *dentry) openSpecialFileLocked(ctx context.Context, mnt *vfs.Mount, opts if opts.Flags&linux.O_DIRECT != 0 { return nil, syserror.EINVAL } - h, err := openHandle(ctx, d.file, ats&vfs.MayRead != 0, ats&vfs.MayWrite != 0, opts.Flags&linux.O_TRUNC != 0) + // We assume that the server silently inserts O_NONBLOCK in the open flags + // for all named pipes (because all existing gofers do this). + // + // NOTE(b/133875563): This makes named pipe opens racy, because the + // mechanisms for translating nonblocking to blocking opens can only detect + // the instantaneous presence of a peer holding the other end of the pipe + // open, not whether the pipe was *previously* opened by a peer that has + // since closed its end. + isBlockingOpenOfNamedPipe := d.fileType() == linux.S_IFIFO && opts.Flags&linux.O_NONBLOCK == 0 +retry: + h, err := openHandle(ctx, d.file, ats.MayRead(), ats.MayWrite(), opts.Flags&linux.O_TRUNC != 0) if err != nil { + if isBlockingOpenOfNamedPipe && ats == vfs.MayWrite && err == syserror.ENXIO { + // An attempt to open a named pipe with O_WRONLY|O_NONBLOCK fails + // with ENXIO if opening the same named pipe with O_WRONLY would + // block because there are no readers of the pipe. + if err := sleepBetweenNamedPipeOpenChecks(ctx); err != nil { + return nil, err + } + goto retry + } return nil, err } - seekable := d.fileType() == linux.S_IFREG - fd := &specialFileFD{ - handle: h, - seekable: seekable, + if isBlockingOpenOfNamedPipe && ats == vfs.MayRead && h.fd >= 0 { + if err := blockUntilNonblockingPipeHasWriter(ctx, h.fd); err != nil { + h.close(ctx) + return nil, err + } } - if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{ - DenyPRead: !seekable, - DenyPWrite: !seekable, - }); err != nil { + fd, err := newSpecialFileFD(h, mnt, d, &d.locks, opts.Flags) + if err != nil { h.close(ctx) return nil, err } @@ -894,7 +1060,7 @@ func (d *dentry) openSpecialFileLocked(ctx context.Context, mnt *vfs.Mount, opts // Preconditions: d.fs.renameMu must be locked. d.dirMu must be locked. // !d.isSynthetic(). -func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) { +func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions, ds **[]*dentry) (*vfs.FileDescription, error) { if err := d.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil { return nil, err } @@ -919,7 +1085,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving // Filter file creation flags and O_LARGEFILE out; the create RPC already // has the semantics of O_CREAT|O_EXCL, while some servers will choke on // O_LARGEFILE. - createFlags := p9.OpenFlags(opts.Flags &^ (linux.O_CREAT | linux.O_EXCL | linux.O_NOCTTY | linux.O_TRUNC | linux.O_LARGEFILE)) + createFlags := p9.OpenFlags(opts.Flags &^ (vfs.FileCreationFlags | linux.O_LARGEFILE)) fdobj, openFile, createQID, _, err := dirfile.create(ctx, name, createFlags, (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID)) if err != nil { dirfile.close(ctx) @@ -947,22 +1113,25 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving } return nil, err } + *ds = appendDentry(*ds, child) // Incorporate the fid that was opened by lcreate. useRegularFileFD := child.fileType() == linux.S_IFREG && !d.fs.opts.regularFilesUseSpecialFileFD if useRegularFileFD { child.handleMu.Lock() - child.handle.file = openFile - if fdobj != nil { - child.handle.fd = int32(fdobj.Release()) + if vfs.MayReadFileWithOpenFlags(opts.Flags) { + child.readFile = openFile + if fdobj != nil { + child.hostFD = int32(fdobj.Release()) + } + } else if fdobj != nil { + // Can't use fdobj if it's not readable. + fdobj.Close() + } + if vfs.MayWriteFileWithOpenFlags(opts.Flags) { + child.writeFile = openFile } - child.handleReadable = vfs.MayReadFileWithOpenFlags(opts.Flags) - child.handleWritable = vfs.MayWriteFileWithOpenFlags(opts.Flags) child.handleMu.Unlock() } - // Take a reference on the new dentry to be held by the new file - // description. (This reference also means that the new dentry is not - // eligible for caching yet, so we don't need to append to a dentry slice.) - child.refs = 1 // Insert the dentry into the tree. d.cacheNewChildLocked(child, name) if d.cachedMetadataAuthoritative() { @@ -974,6 +1143,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving var childVFSFD *vfs.FileDescription if useRegularFileFD { fd := ®ularFileFD{} + fd.LockFD.Init(&child.locks) if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{ AllowDirectIO: true, }); err != nil { @@ -981,26 +1151,21 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving } childVFSFD = &fd.vfsfd } else { - seekable := child.fileType() == linux.S_IFREG - fd := &specialFileFD{ - handle: handle{ - file: openFile, - fd: -1, - }, - seekable: seekable, + h := handle{ + file: openFile, + fd: -1, } if fdobj != nil { - fd.handle.fd = int32(fdobj.Release()) + h.fd = int32(fdobj.Release()) } - if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{ - DenyPRead: !seekable, - DenyPWrite: !seekable, - }); err != nil { - fd.handle.close(ctx) + fd, err := newSpecialFileFD(h, mnt, child, &d.locks, opts.Flags) + if err != nil { + h.close(ctx) return nil, err } childVFSFD = &fd.vfsfd } + d.watches.Notify(ctx, name, linux.IN_CREATE, 0, vfs.PathEvent, false /* unlinked */) return childVFSFD, nil } @@ -1008,7 +1173,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return "", err @@ -1028,7 +1193,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa var ds *[]*dentry fs.renameMu.Lock() - defer fs.renameMuUnlockAndCheckCaching(&ds) + defer fs.renameMuUnlockAndCheckCaching(ctx, &ds) newParent, err := fs.walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry), &ds) if err != nil { return err @@ -1052,7 +1217,8 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa return err } } - if err := oldParent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil { + creds := rp.Credentials() + if err := oldParent.checkPermissions(creds, vfs.MayWrite|vfs.MayExec); err != nil { return err } vfsObj := rp.VirtualFilesystem() @@ -1067,12 +1233,15 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa if renamed == nil { return syserror.ENOENT } + if err := oldParent.mayDelete(creds, renamed); err != nil { + return err + } if renamed.isDir() { if renamed == newParent || genericIsAncestorDentry(renamed, newParent) { return syserror.EINVAL } if oldParent != newParent { - if err := renamed.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil { + if err := renamed.checkPermissions(creds, vfs.MayWrite); err != nil { return err } } @@ -1083,7 +1252,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa } if oldParent != newParent { - if err := newParent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil { + if err := newParent.checkPermissions(creds, vfs.MayWrite|vfs.MayExec); err != nil { return err } newParent.dirMu.Lock() @@ -1114,7 +1283,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa return nil } mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := vfsObj.PrepareRenameDentry(mntns, &renamed.vfsd, replacedVFSD); err != nil { return err } @@ -1139,7 +1308,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa } // Update the dentry tree. - vfsObj.CommitRenameReplaceDentry(&renamed.vfsd, replacedVFSD) + vfsObj.CommitRenameReplaceDentry(ctx, &renamed.vfsd, replacedVFSD) if replaced != nil { replaced.setDeleted() if replaced.isSynthetic() { @@ -1181,10 +1350,12 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa if newParent.cachedMetadataAuthoritative() { newParent.dirents = nil newParent.touchCMtime() - if renamed.isDir() { + if renamed.isDir() && (replaced == nil || !replaced.isDir()) { + // Increase the link count if we did not replace another directory. newParent.incLinks() } } + vfs.InotifyRename(ctx, &renamed.watches, &oldParent.watches, &newParent.watches, oldName, newName, renamed.isDir()) return nil } @@ -1197,19 +1368,28 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) + return err + } + if err := d.setStat(ctx, rp.Credentials(), &opts, rp.Mount()); err != nil { + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) return err } - return d.setStat(ctx, rp.Credentials(), &opts.Stat, rp.Mount()) + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) + + if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 { + d.InotifyWithParent(ctx, ev, 0, vfs.InodeEvent) + } + return nil } // StatAt implements vfs.FilesystemImpl.StatAt. func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return linux.Statx{}, err @@ -1226,7 +1406,7 @@ func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return linux.Statfs{}, err @@ -1276,7 +1456,7 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return nil, err @@ -1302,7 +1482,7 @@ func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, size uint64) ([]string, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return nil, err @@ -1314,7 +1494,7 @@ func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, si func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetxattrOptions) (string, error) { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) + defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { return "", err @@ -1326,24 +1506,38 @@ func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) return err } - return d.setxattr(ctx, rp.Credentials(), &opts) + if err := d.setxattr(ctx, rp.Credentials(), &opts); err != nil { + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) + return err + } + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) + + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt. func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error { var ds *[]*dentry fs.renameMu.RLock() - defer fs.renameMuRUnlockAndCheckCaching(&ds) d, err := fs.resolveLocked(ctx, rp, &ds) if err != nil { + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) return err } - return d.removexattr(ctx, rp.Credentials(), name) + if err := d.removexattr(ctx, rp.Credentials(), name); err != nil { + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) + return err + } + fs.renameMuRUnlockAndCheckCaching(ctx, &ds) + + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // PrependPath implements vfs.FilesystemImpl.PrependPath. @@ -1352,3 +1546,7 @@ func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDe defer fs.renameMu.RUnlock() return genericPrependPath(vfsroot, vd.Mount(), vd.Dentry().Impl().(*dentry), b) } + +func (fs *filesystem) nextSyntheticIno() inodeNumber { + return inodeNumber(atomic.AddUint64(&fs.syntheticSeq, 1) | syntheticInoMask) +} diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go index 6295f6b54..63e589859 100644 --- a/pkg/sentry/fsimpl/gofer/gofer.go +++ b/pkg/sentry/fsimpl/gofer/gofer.go @@ -45,6 +45,7 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/p9" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" @@ -84,12 +85,6 @@ type filesystem struct { // devMinor is the filesystem's minor device number. devMinor is immutable. devMinor uint32 - // uid and gid are the effective KUID and KGID of the filesystem's creator, - // and are used as the owner and group for files that don't specify one. - // uid and gid are immutable. - uid auth.KUID - gid auth.KGID - // renameMu serves two purposes: // // - It synchronizes path resolution with renaming initiated by this @@ -115,6 +110,26 @@ type filesystem struct { syncMu sync.Mutex syncableDentries map[*dentry]struct{} specialFileFDs map[*specialFileFD]struct{} + + // syntheticSeq stores a counter to used to generate unique inodeNumber for + // synthetic dentries. + syntheticSeq uint64 +} + +// inodeNumber represents inode number reported in Dirent.Ino. For regular +// dentries, it comes from QID.Path from the 9P server. Synthetic dentries +// have have their inodeNumber generated sequentially, with the MSB reserved to +// prevent conflicts with regular dentries. +type inodeNumber uint64 + +// Reserve MSB for synthetic mounts. +const syntheticInoMask = uint64(1) << 63 + +func inoFromPath(path uint64) inodeNumber { + if path&syntheticInoMask != 0 { + log.Warningf("Dropping MSB from ino, collision is possible. Original: %d, new: %d", path, path&^syntheticInoMask) + } + return inodeNumber(path &^ syntheticInoMask) } type filesystemOptions struct { @@ -122,6 +137,8 @@ type filesystemOptions struct { fd int aname string interop InteropMode // derived from the "cache" mount option + dfltuid auth.KUID + dfltgid auth.KGID msize uint32 version string @@ -175,10 +192,14 @@ const ( // // - File timestamps are based on client clocks. This ensures that users of // the client observe timestamps that are coherent with their own clocks - // and consistent with Linux's semantics. However, since it is not always - // possible for clients to set arbitrary atimes and mtimes, and never - // possible for clients to set arbitrary ctimes, file timestamp changes are - // stored in the client only and never sent to the remote filesystem. + // and consistent with Linux's semantics (in particular, it is not always + // possible for clients to set arbitrary atimes and mtimes depending on the + // remote filesystem implementation, and never possible for clients to set + // arbitrary ctimes.) If a dentry containing a client-defined atime or + // mtime is evicted from cache, client timestamps will be sent to the + // remote filesystem on a best-effort basis to attempt to ensure that + // timestamps will be preserved when another dentry representing the same + // file is instantiated. InteropModeExclusive InteropMode = iota // InteropModeWritethrough is appropriate when there are read-only users of @@ -230,6 +251,15 @@ type InternalFilesystemOptions struct { OpenSocketsByConnecting bool } +// _V9FS_DEFUID and _V9FS_DEFGID (from Linux's fs/9p/v9fs.h) are the default +// UIDs and GIDs used for files that do not provide a specific owner or group +// respectively. +const ( + // uint32(-2) doesn't work in Go. + _V9FS_DEFUID = auth.KUID(4294967294) + _V9FS_DEFGID = auth.KGID(4294967294) +) + // Name implements vfs.FilesystemType.Name. func (FilesystemType) Name() string { return Name @@ -315,6 +345,31 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt } } + // Parse the default UID and GID. + fsopts.dfltuid = _V9FS_DEFUID + if dfltuidstr, ok := mopts["dfltuid"]; ok { + delete(mopts, "dfltuid") + dfltuid, err := strconv.ParseUint(dfltuidstr, 10, 32) + if err != nil { + ctx.Warningf("gofer.FilesystemType.GetFilesystem: invalid default UID: dfltuid=%s", dfltuidstr) + return nil, nil, syserror.EINVAL + } + // In Linux, dfltuid is interpreted as a UID and is converted to a KUID + // in the caller's user namespace, but goferfs isn't + // application-mountable. + fsopts.dfltuid = auth.KUID(dfltuid) + } + fsopts.dfltgid = _V9FS_DEFGID + if dfltgidstr, ok := mopts["dfltgid"]; ok { + delete(mopts, "dfltgid") + dfltgid, err := strconv.ParseUint(dfltgidstr, 10, 32) + if err != nil { + ctx.Warningf("gofer.FilesystemType.GetFilesystem: invalid default UID: dfltgid=%s", dfltgidstr) + return nil, nil, syserror.EINVAL + } + fsopts.dfltgid = auth.KGID(dfltgid) + } + // Parse the 9P message size. fsopts.msize = 1024 * 1024 // 1M, tested to give good enough performance up to 64M if msizestr, ok := mopts["msize"]; ok { @@ -422,8 +477,6 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt client: client, clock: ktime.RealtimeClockFromContext(ctx), devMinor: devMinor, - uid: creds.EffectiveKUID, - gid: creds.EffectiveKGID, syncableDentries: make(map[*dentry]struct{}), specialFileFDs: make(map[*specialFileFD]struct{}), } @@ -433,7 +486,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt root, err := fs.newDentry(ctx, attachFile, qid, attrMask, &attr) if err != nil { attachFile.close(ctx) - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, err } // Set the root's reference count to 2. One reference is returned to the @@ -446,17 +499,16 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { - ctx := context.Background() +func (fs *filesystem) Release(ctx context.Context) { mf := fs.mfp.MemoryFile() fs.syncMu.Lock() for d := range fs.syncableDentries { d.handleMu.Lock() d.dataMu.Lock() - if d.handleWritable { + if h := d.writeHandleLocked(); h.isOpen() { // Write dirty cached data to the remote file. - if err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, fs.mfp.MemoryFile(), d.handle.writeFromBlocksAt); err != nil { + if err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, fs.mfp.MemoryFile(), h.writeFromBlocksAt); err != nil { log.Warningf("gofer.filesystem.Release: failed to flush dentry: %v", err) } // TODO(jamieliu): Do we need to flushf/fsync d? @@ -466,9 +518,9 @@ func (fs *filesystem) Release() { d.dirty.RemoveAll() d.dataMu.Unlock() // Close the host fd if one exists. - if d.handle.fd >= 0 { - syscall.Close(int(d.handle.fd)) - d.handle.fd = -1 + if d.hostFD >= 0 { + syscall.Close(int(d.hostFD)) + d.hostFD = -1 } d.handleMu.Unlock() } @@ -510,8 +562,6 @@ type dentry struct { // filesystem.renameMu. name string - // We don't support hard links, so each dentry maps 1:1 to an inode. - // file is the unopened p9.File that backs this dentry. file is immutable. // // If file.isNil(), this dentry represents a synthetic file, i.e. a file @@ -553,22 +603,39 @@ type dentry struct { // returned by the server. dirents is protected by dirMu. dirents []vfs.Dirent - // Cached metadata; protected by metadataMu and accessed using atomic - // memory operations unless otherwise specified. + // Cached metadata; protected by metadataMu. + // To access: + // - In situations where consistency is not required (like stat), these + // can be accessed using atomic operations only (without locking). + // - Lock metadataMu and can access without atomic operations. + // To mutate: + // - Lock metadataMu and use atomic operations to update because we might + // have atomic readers that don't hold the lock. metadataMu sync.Mutex - ino uint64 // immutable - mode uint32 // type is immutable, perms are mutable - uid uint32 // auth.KUID, but stored as raw uint32 for sync/atomic - gid uint32 // auth.KGID, but ... - blockSize uint32 // 0 if unknown + ino inodeNumber // immutable + mode uint32 // type is immutable, perms are mutable + uid uint32 // auth.KUID, but stored as raw uint32 for sync/atomic + gid uint32 // auth.KGID, but ... + blockSize uint32 // 0 if unknown // Timestamps, all nsecs from the Unix epoch. atime int64 mtime int64 ctime int64 btime int64 - // File size, protected by both metadataMu and dataMu (i.e. both must be - // locked to mutate it). + // File size, which differs from other metadata in two ways: + // + // - We make a best-effort attempt to keep it up to date even if + // !dentry.cachedMetadataAuthoritative() for the sake of O_APPEND writes. + // + // - size is protected by both metadataMu and dataMu (i.e. both must be + // locked to mutate it; locking either is sufficient to access it). size uint64 + // If this dentry does not represent a synthetic file, deleted is 0, and + // atimeDirty/mtimeDirty are non-zero, atime/mtime may have diverged from the + // remote file's timestamps, which should be updated when this dentry is + // evicted. + atimeDirty uint32 + mtimeDirty uint32 // nlink counts the number of hard links to this dentry. It's updated and // accessed using atomic operations. It's not protected by metadataMu like the @@ -581,30 +648,28 @@ type dentry struct { // the file into memmap.MappingSpaces. mappings is protected by mapsMu. mappings memmap.MappingSet - // If this dentry represents a regular file or directory: - // - // - handle is the I/O handle used by all regularFileFDs/directoryFDs - // representing this dentry. - // - // - handleReadable is true if handle is readable. - // - // - handleWritable is true if handle is writable. - // - // Invariants: + // - If this dentry represents a regular file or directory, readFile is the + // p9.File used for reads by all regularFileFDs/directoryFDs representing + // this dentry. // - // - If handleReadable == handleWritable == false, then handle.file == nil - // (i.e. there is no open handle). Conversely, if handleReadable || - // handleWritable == true, then handle.file != nil (i.e. there is an open - // handle). + // - If this dentry represents a regular file, writeFile is the p9.File + // used for writes by all regularFileFDs representing this dentry. // - // - handleReadable and handleWritable cannot transition from true to false - // (i.e. handles may not be downgraded). + // - If this dentry represents a regular file, hostFD is the host FD used + // for memory mappings and I/O (when applicable) in preference to readFile + // and writeFile. hostFD is always readable; if !writeFile.isNil(), it must + // also be writable. If hostFD is -1, no such host FD is available. // // These fields are protected by handleMu. - handleMu sync.RWMutex - handle handle - handleReadable bool - handleWritable bool + // + // readFile and writeFile may or may not represent the same p9.File. Once + // either p9.File transitions from closed (isNil() == true) to open + // (isNil() == false), it may be mutated with handleMu locked, but cannot + // be closed until the dentry is destroyed. + handleMu sync.RWMutex + readFile p9file + writeFile p9file + hostFD int32 dataMu sync.RWMutex @@ -618,7 +683,7 @@ type dentry struct { // tracks dirty segments in cache. dirty is protected by dataMu. dirty fsutil.DirtySet - // pf implements platform.File for mappings of handle.fd. + // pf implements platform.File for mappings of hostFD. pf dentryPlatformFile // If this dentry represents a symbolic link, InteropModeShared is not in @@ -634,6 +699,11 @@ type dentry struct { // If this dentry represents a synthetic named pipe, pipe is the pipe // endpoint bound to this file. pipe *pipe.VFSPipe + + locks vfs.FileLocks + + // Inotify watches for this dentry. + watches vfs.Watches } // dentryAttrMask returns a p9.AttrMask enabling all attributes used by the @@ -670,14 +740,12 @@ func (fs *filesystem) newDentry(ctx context.Context, file p9file, qid p9.QID, ma d := &dentry{ fs: fs, file: file, - ino: qid.Path, + ino: inoFromPath(qid.Path), mode: uint32(attr.Mode), - uid: uint32(fs.uid), - gid: uint32(fs.gid), + uid: uint32(fs.opts.dfltuid), + gid: uint32(fs.opts.dfltgid), blockSize: usermem.PageSize, - handle: handle{ - fd: -1, - }, + hostFD: -1, } d.pf.dentry = d if mask.UID { @@ -725,8 +793,8 @@ func (d *dentry) cachedMetadataAuthoritative() bool { // updateFromP9Attrs is called to update d's metadata after an update from the // remote filesystem. -func (d *dentry) updateFromP9Attrs(mask p9.AttrMask, attr *p9.Attr) { - d.metadataMu.Lock() +// Precondition: d.metadataMu must be locked. +func (d *dentry) updateFromP9AttrsLocked(mask p9.AttrMask, attr *p9.Attr) { if mask.Mode { if got, want := uint32(attr.Mode.FileType()), d.fileType(); got != want { d.metadataMu.Unlock() @@ -744,10 +812,12 @@ func (d *dentry) updateFromP9Attrs(mask p9.AttrMask, attr *p9.Attr) { if attr.BlockSize != 0 { atomic.StoreUint32(&d.blockSize, uint32(attr.BlockSize)) } - if mask.ATime { + // Don't override newer client-defined timestamps with old server-defined + // ones. + if mask.ATime && atomic.LoadUint32(&d.atimeDirty) == 0 { atomic.StoreInt64(&d.atime, dentryTimestampFromP9(attr.ATimeSeconds, attr.ATimeNanoSeconds)) } - if mask.MTime { + if mask.MTime && atomic.LoadUint32(&d.mtimeDirty) == 0 { atomic.StoreInt64(&d.mtime, dentryTimestampFromP9(attr.MTimeSeconds, attr.MTimeNanoSeconds)) } if mask.CTime { @@ -760,25 +830,33 @@ func (d *dentry) updateFromP9Attrs(mask p9.AttrMask, attr *p9.Attr) { atomic.StoreUint32(&d.nlink, uint32(attr.NLink)) } if mask.Size { - d.dataMu.Lock() - atomic.StoreUint64(&d.size, attr.Size) - d.dataMu.Unlock() + d.updateFileSizeLocked(attr.Size) } - d.metadataMu.Unlock() } // Preconditions: !d.isSynthetic() func (d *dentry) updateFromGetattr(ctx context.Context) error { - // Use d.handle.file, which represents a 9P fid that has been opened, in - // preference to d.file, which represents a 9P fid that has not. This may - // be significantly more efficient in some implementations. + // Use d.readFile or d.writeFile, which represent 9P fids that have been + // opened, in preference to d.file, which represents a 9P fid that has not. + // This may be significantly more efficient in some implementations. Prefer + // d.writeFile over d.readFile since some filesystem implementations may + // update a writable handle's metadata after writes to that handle, without + // making metadata updates immediately visible to read-only handles + // representing the same file. var ( file p9file handleMuRLocked bool ) + // d.metadataMu must be locked *before* we getAttr so that we do not end up + // updating stale attributes in d.updateFromP9AttrsLocked(). + d.metadataMu.Lock() + defer d.metadataMu.Unlock() d.handleMu.RLock() - if !d.handle.file.isNil() { - file = d.handle.file + if !d.writeFile.isNil() { + file = d.writeFile + handleMuRLocked = true + } else if !d.readFile.isNil() { + file = d.readFile handleMuRLocked = true } else { file = d.file @@ -791,7 +869,7 @@ func (d *dentry) updateFromGetattr(ctx context.Context) error { if err != nil { return err } - d.updateFromP9Attrs(attrMask, &attr) + d.updateFromP9AttrsLocked(attrMask, &attr) return nil } @@ -803,10 +881,18 @@ func (d *dentry) statTo(stat *linux.Statx) { stat.Mask = linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_NLINK | linux.STATX_UID | linux.STATX_GID | linux.STATX_ATIME | linux.STATX_MTIME | linux.STATX_CTIME | linux.STATX_INO | linux.STATX_SIZE | linux.STATX_BLOCKS | linux.STATX_BTIME stat.Blksize = atomic.LoadUint32(&d.blockSize) stat.Nlink = atomic.LoadUint32(&d.nlink) + if stat.Nlink == 0 { + // The remote filesystem doesn't support link count; just make + // something up. This is consistent with Linux, where + // fs/inode.c:inode_init_always() initializes link count to 1, and + // fs/9p/vfs_inode_dotl.c:v9fs_stat2inode_dotl() doesn't touch it if + // it's not provided by the remote filesystem. + stat.Nlink = 1 + } stat.UID = atomic.LoadUint32(&d.uid) stat.GID = atomic.LoadUint32(&d.gid) stat.Mode = uint16(atomic.LoadUint32(&d.mode)) - stat.Ino = d.ino + stat.Ino = uint64(d.ino) stat.Size = atomic.LoadUint64(&d.size) // This is consistent with regularFileFD.Seek(), which treats regular files // as having no holes. @@ -819,7 +905,8 @@ func (d *dentry) statTo(stat *linux.Statx) { stat.DevMinor = d.fs.devMinor } -func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *linux.Statx, mnt *vfs.Mount) error { +func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, opts *vfs.SetStatOptions, mnt *vfs.Mount) error { + stat := &opts.Stat if stat.Mask == 0 { return nil } @@ -827,37 +914,47 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin return syserror.EPERM } mode := linux.FileMode(atomic.LoadUint32(&d.mode)) - if err := vfs.CheckSetStat(ctx, creds, stat, mode, auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))); err != nil { + if err := vfs.CheckSetStat(ctx, creds, opts, mode, auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))); err != nil { return err } if err := mnt.CheckBeginWrite(); err != nil { return err } defer mnt.EndWrite() - setLocalAtime := false - setLocalMtime := false + + if stat.Mask&linux.STATX_SIZE != 0 { + // Reject attempts to truncate files other than regular files, since + // filesystem implementations may return the wrong errno. + switch mode.FileType() { + case linux.S_IFREG: + // ok + case linux.S_IFDIR: + return syserror.EISDIR + default: + return syserror.EINVAL + } + } + + var now int64 if d.cachedMetadataAuthoritative() { - // Timestamp updates will be handled locally. - setLocalAtime = stat.Mask&linux.STATX_ATIME != 0 - setLocalMtime = stat.Mask&linux.STATX_MTIME != 0 - stat.Mask &^= linux.STATX_ATIME | linux.STATX_MTIME - - // Prepare for truncate. - if stat.Mask&linux.STATX_SIZE != 0 { - switch d.mode & linux.S_IFMT { - case linux.S_IFREG: - if !setLocalMtime { - // Truncate updates mtime. - setLocalMtime = true - stat.Mtime.Nsec = linux.UTIME_NOW - } - case linux.S_IFDIR: - return syserror.EISDIR - default: - return syserror.EINVAL + // Truncate updates mtime. + if stat.Mask&(linux.STATX_SIZE|linux.STATX_MTIME) == linux.STATX_SIZE { + stat.Mask |= linux.STATX_MTIME + stat.Mtime = linux.StatxTimestamp{ + Nsec: linux.UTIME_NOW, } } + + // Use client clocks for timestamps. + now = d.fs.clock.Now().Nanoseconds() + if stat.Mask&linux.STATX_ATIME != 0 && stat.Atime.Nsec == linux.UTIME_NOW { + stat.Atime = statxTimestampFromDentry(now) + } + if stat.Mask&linux.STATX_MTIME != 0 && stat.Mtime.Nsec == linux.UTIME_NOW { + stat.Mtime = statxTimestampFromDentry(now) + } } + d.metadataMu.Lock() defer d.metadataMu.Unlock() if !d.isSynthetic() { @@ -883,6 +980,12 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin }); err != nil { return err } + if stat.Mask&linux.STATX_SIZE != 0 { + // d.size should be kept up to date, and privatized + // copy-on-write mappings of truncated pages need to be + // invalidated, even if InteropModeShared is in effect. + d.updateFileSizeLocked(stat.Size) + } } if d.fs.opts.interop == InteropModeShared { // There's no point to updating d's metadata in this case since @@ -892,7 +995,6 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin return nil } } - now := d.fs.clock.Now().Nanoseconds() if stat.Mask&linux.STATX_MODE != 0 { atomic.StoreUint32(&d.mode, d.fileType()|uint32(stat.Mode)) } @@ -902,61 +1004,66 @@ func (d *dentry) setStat(ctx context.Context, creds *auth.Credentials, stat *lin if stat.Mask&linux.STATX_GID != 0 { atomic.StoreUint32(&d.gid, stat.GID) } - if setLocalAtime { - if stat.Atime.Nsec == linux.UTIME_NOW { - atomic.StoreInt64(&d.atime, now) - } else { - atomic.StoreInt64(&d.atime, dentryTimestampFromStatx(stat.Atime)) - } + // Note that stat.Atime.Nsec and stat.Mtime.Nsec can't be UTIME_NOW because + // if d.cachedMetadataAuthoritative() then we converted stat.Atime and + // stat.Mtime to client-local timestamps above, and if + // !d.cachedMetadataAuthoritative() then we returned after calling + // d.file.setAttr(). For the same reason, now must have been initialized. + if stat.Mask&linux.STATX_ATIME != 0 { + atomic.StoreInt64(&d.atime, dentryTimestampFromStatx(stat.Atime)) + atomic.StoreUint32(&d.atimeDirty, 0) } - if setLocalMtime { - if stat.Mtime.Nsec == linux.UTIME_NOW { - atomic.StoreInt64(&d.mtime, now) - } else { - atomic.StoreInt64(&d.mtime, dentryTimestampFromStatx(stat.Mtime)) - } + if stat.Mask&linux.STATX_MTIME != 0 { + atomic.StoreInt64(&d.mtime, dentryTimestampFromStatx(stat.Mtime)) + atomic.StoreUint32(&d.mtimeDirty, 0) } atomic.StoreInt64(&d.ctime, now) - if stat.Mask&linux.STATX_SIZE != 0 { + return nil +} + +// Preconditions: d.metadataMu must be locked. +func (d *dentry) updateFileSizeLocked(newSize uint64) { + d.dataMu.Lock() + oldSize := d.size + atomic.StoreUint64(&d.size, newSize) + // d.dataMu must be unlocked to lock d.mapsMu and invalidate mappings + // below. This allows concurrent calls to Read/Translate/etc. These + // functions synchronize with truncation by refusing to use cache + // contents beyond the new d.size. (We are still holding d.metadataMu, + // so we can't race with Write or another truncate.) + d.dataMu.Unlock() + if d.size < oldSize { + oldpgend, _ := usermem.PageRoundUp(oldSize) + newpgend, _ := usermem.PageRoundUp(d.size) + if oldpgend != newpgend { + d.mapsMu.Lock() + d.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{ + // Compare Linux's mm/truncate.c:truncate_setsize() => + // truncate_pagecache() => + // mm/memory.c:unmap_mapping_range(evencows=1). + InvalidatePrivate: true, + }) + d.mapsMu.Unlock() + } + // We are now guaranteed that there are no translations of + // truncated pages, and can remove them from the cache. Since + // truncated pages have been removed from the remote file, they + // should be dropped without being written back. d.dataMu.Lock() - oldSize := d.size - d.size = stat.Size - // d.dataMu must be unlocked to lock d.mapsMu and invalidate mappings - // below. This allows concurrent calls to Read/Translate/etc. These - // functions synchronize with truncation by refusing to use cache - // contents beyond the new d.size. (We are still holding d.metadataMu, - // so we can't race with Write or another truncate.) + d.cache.Truncate(d.size, d.fs.mfp.MemoryFile()) + d.dirty.KeepClean(memmap.MappableRange{d.size, oldpgend}) d.dataMu.Unlock() - if d.size < oldSize { - oldpgend, _ := usermem.PageRoundUp(oldSize) - newpgend, _ := usermem.PageRoundUp(d.size) - if oldpgend != newpgend { - d.mapsMu.Lock() - d.mappings.Invalidate(memmap.MappableRange{newpgend, oldpgend}, memmap.InvalidateOpts{ - // Compare Linux's mm/truncate.c:truncate_setsize() => - // truncate_pagecache() => - // mm/memory.c:unmap_mapping_range(evencows=1). - InvalidatePrivate: true, - }) - d.mapsMu.Unlock() - } - // We are now guaranteed that there are no translations of - // truncated pages, and can remove them from the cache. Since - // truncated pages have been removed from the remote file, they - // should be dropped without being written back. - d.dataMu.Lock() - d.cache.Truncate(d.size, d.fs.mfp.MemoryFile()) - d.dirty.KeepClean(memmap.MappableRange{d.size, oldpgend}) - d.dataMu.Unlock() - } } - return nil } func (d *dentry) checkPermissions(creds *auth.Credentials, ats vfs.AccessTypes) error { return vfs.GenericCheckPermissions(creds, ats, linux.FileMode(atomic.LoadUint32(&d.mode)), auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))) } +func (d *dentry) mayDelete(creds *auth.Credentials, child *dentry) error { + return vfs.CheckDeleteSticky(creds, linux.FileMode(atomic.LoadUint32(&d.mode)), auth.KUID(atomic.LoadUint32(&child.uid))) +} + func dentryUIDFromP9UID(uid p9.UID) uint32 { if !uid.Ok() { return uint32(auth.OverflowUID) @@ -992,10 +1099,10 @@ func (d *dentry) TryIncRef() bool { } // DecRef implements vfs.DentryImpl.DecRef. -func (d *dentry) DecRef() { +func (d *dentry) DecRef(ctx context.Context) { if refs := atomic.AddInt64(&d.refs, -1); refs == 0 { d.fs.renameMu.Lock() - d.checkCachingLocked() + d.checkCachingLocked(ctx) d.fs.renameMu.Unlock() } else if refs < 0 { panic("gofer.dentry.DecRef() called without holding a reference") @@ -1011,6 +1118,37 @@ func (d *dentry) decRefLocked() { } } +// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent. +func (d *dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et vfs.EventType) { + if d.isDir() { + events |= linux.IN_ISDIR + } + + d.fs.renameMu.RLock() + // The ordering below is important, Linux always notifies the parent first. + if d.parent != nil { + d.parent.watches.Notify(ctx, d.name, events, cookie, et, d.isDeleted()) + } + d.watches.Notify(ctx, "", events, cookie, et, d.isDeleted()) + d.fs.renameMu.RUnlock() +} + +// Watches implements vfs.DentryImpl.Watches. +func (d *dentry) Watches() *vfs.Watches { + return &d.watches +} + +// OnZeroWatches implements vfs.DentryImpl.OnZeroWatches. +// +// If no watches are left on this dentry and it has no references, cache it. +func (d *dentry) OnZeroWatches(ctx context.Context) { + if atomic.LoadInt64(&d.refs) == 0 { + d.fs.renameMu.Lock() + d.checkCachingLocked(ctx) + d.fs.renameMu.Unlock() + } +} + // checkCachingLocked should be called after d's reference count becomes 0 or it // becomes disowned. // @@ -1020,8 +1158,9 @@ func (d *dentry) decRefLocked() { // operation. One of the calls may destroy the dentry, so subsequent calls will // do nothing. // -// Preconditions: d.fs.renameMu must be locked for writing. -func (d *dentry) checkCachingLocked() { +// Preconditions: d.fs.renameMu must be locked for writing; it may be +// temporarily unlocked. +func (d *dentry) checkCachingLocked(ctx context.Context) { // Dentries with a non-zero reference count must be retained. (The only way // to obtain a reference on a dentry with zero references is via path // resolution, which requires renameMu, so if d.refs is zero then it will @@ -1042,12 +1181,23 @@ func (d *dentry) checkCachingLocked() { // Deleted and invalidated dentries with zero references are no longer // reachable by path resolution and should be dropped immediately. if d.vfsd.IsDead() { + if d.isDeleted() { + d.watches.HandleDeletion(ctx) + } if d.cached { d.fs.cachedDentries.Remove(d) d.fs.cachedDentriesLen-- d.cached = false } - d.destroyLocked() + d.destroyLocked(ctx) + return + } + // If d still has inotify watches and it is not deleted or invalidated, we + // cannot cache it and allow it to be evicted. Otherwise, we will lose its + // watches, even if a new dentry is created for the same file in the future. + // Note that the size of d.watches cannot concurrently transition from zero + // to non-zero, because adding a watch requires holding a reference on d. + if d.watches.Size() > 0 { return } // If d is already cached, just move it to the front of the LRU. @@ -1074,7 +1224,7 @@ func (d *dentry) checkCachingLocked() { if !victim.vfsd.IsDead() { // Note that victim can't be a mount point (in any mount // namespace), since VFS holds references on mount points. - d.fs.vfsfs.VirtualFilesystem().InvalidateDentry(&victim.vfsd) + d.fs.vfsfs.VirtualFilesystem().InvalidateDentry(ctx, &victim.vfsd) delete(victim.parent.children, victim.name) // We're only deleting the dentry, not the file it // represents, so we don't need to update @@ -1082,19 +1232,21 @@ func (d *dentry) checkCachingLocked() { } victim.parent.dirMu.Unlock() } - victim.destroyLocked() + victim.destroyLocked(ctx) } // Whether or not victim was destroyed, we brought fs.cachedDentriesLen // back down to fs.opts.maxCachedDentries, so we don't loop. } } -// destroyLocked destroys the dentry. It may flushes dirty pages from cache, -// close p9 file and remove reference on parent dentry. +// destroyLocked destroys the dentry. // -// Preconditions: d.fs.renameMu must be locked for writing. d.refs == 0. d is -// not a child dentry. -func (d *dentry) destroyLocked() { +// Preconditions: +// * d.fs.renameMu must be locked for writing; it may be temporarily unlocked. +// * d.refs == 0. +// * d.parent.children[d.name] != d, i.e. d is not reachable by path traversal +// from its former parent dentry. +func (d *dentry) destroyLocked(ctx context.Context) { switch atomic.LoadInt64(&d.refs) { case 0: // Mark the dentry destroyed. @@ -1105,27 +1257,64 @@ func (d *dentry) destroyLocked() { panic("dentry.destroyLocked() called with references on the dentry") } - ctx := context.Background() + // Allow the following to proceed without renameMu locked to improve + // scalability. + d.fs.renameMu.Unlock() + + mf := d.fs.mfp.MemoryFile() d.handleMu.Lock() - if !d.handle.file.isNil() { - mf := d.fs.mfp.MemoryFile() - d.dataMu.Lock() + d.dataMu.Lock() + if h := d.writeHandleLocked(); h.isOpen() { // Write dirty pages back to the remote filesystem. - if d.handleWritable { - if err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, mf, d.handle.writeFromBlocksAt); err != nil { - log.Warningf("gofer.dentry.DecRef: failed to write dirty data back: %v", err) - } + if err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, mf, h.writeFromBlocksAt); err != nil { + log.Warningf("gofer.dentry.destroyLocked: failed to write dirty data back: %v", err) } - // Discard cached data. + } + // Discard cached data. + if !d.cache.IsEmpty() { + mf.MarkAllUnevictable(d) d.cache.DropAll(mf) d.dirty.RemoveAll() - d.dataMu.Unlock() - // Clunk open fids and close open host FDs. - d.handle.close(ctx) + } + d.dataMu.Unlock() + // Clunk open fids and close open host FDs. + if !d.readFile.isNil() { + d.readFile.close(ctx) + } + if !d.writeFile.isNil() && d.readFile != d.writeFile { + d.writeFile.close(ctx) + } + d.readFile = p9file{} + d.writeFile = p9file{} + if d.hostFD >= 0 { + syscall.Close(int(d.hostFD)) + d.hostFD = -1 } d.handleMu.Unlock() if !d.file.isNil() { + if !d.isDeleted() { + // Write dirty timestamps back to the remote filesystem. + atimeDirty := atomic.LoadUint32(&d.atimeDirty) != 0 + mtimeDirty := atomic.LoadUint32(&d.mtimeDirty) != 0 + if atimeDirty || mtimeDirty { + atime := atomic.LoadInt64(&d.atime) + mtime := atomic.LoadInt64(&d.mtime) + if err := d.file.setAttr(ctx, p9.SetAttrMask{ + ATime: atimeDirty, + ATimeNotSystemTime: atimeDirty, + MTime: mtimeDirty, + MTimeNotSystemTime: mtimeDirty, + }, p9.SetAttr{ + ATimeSeconds: uint64(atime / 1e9), + ATimeNanoSeconds: uint64(atime % 1e9), + MTimeSeconds: uint64(mtime / 1e9), + MTimeNanoSeconds: uint64(mtime % 1e9), + }); err != nil { + log.Warningf("gofer.dentry.destroyLocked: failed to write dirty timestamps back: %v", err) + } + } + } d.file.close(ctx) d.file = p9file{} // Remove d from the set of syncable dentries. @@ -1133,11 +1322,14 @@ func (d *dentry) destroyLocked() { delete(d.fs.syncableDentries, d) d.fs.syncMu.Unlock() } + + d.fs.renameMu.Lock() + // Drop the reference held by d on its parent without recursively locking // d.fs.renameMu. if d.parent != nil { if refs := atomic.AddInt64(&d.parent.refs, -1); refs == 0 { - d.parent.checkCachingLocked() + d.parent.checkCachingLocked(ctx) } else if refs < 0 { panic("gofer.dentry.DecRef() called without holding a reference") } @@ -1155,7 +1347,7 @@ func (d *dentry) setDeleted() { // We only support xattrs prefixed with "user." (see b/148380782). Currently, // there is no need to expose any other xattrs through a gofer. func (d *dentry) listxattr(ctx context.Context, creds *auth.Credentials, size uint64) ([]string, error) { - if d.file.isNil() { + if d.file.isNil() || !d.userXattrSupported() { return nil, nil } xattrMap, err := d.file.listXattr(ctx, size) @@ -1181,6 +1373,9 @@ func (d *dentry) getxattr(ctx context.Context, creds *auth.Credentials, opts *vf if !strings.HasPrefix(opts.Name, linux.XATTR_USER_PREFIX) { return "", syserror.EOPNOTSUPP } + if !d.userXattrSupported() { + return "", syserror.ENODATA + } return d.file.getXattr(ctx, opts.Name, opts.Size) } @@ -1194,6 +1389,9 @@ func (d *dentry) setxattr(ctx context.Context, creds *auth.Credentials, opts *vf if !strings.HasPrefix(opts.Name, linux.XATTR_USER_PREFIX) { return syserror.EOPNOTSUPP } + if !d.userXattrSupported() { + return syserror.EPERM + } return d.file.setXattr(ctx, opts.Name, opts.Value, opts.Flags) } @@ -1207,89 +1405,139 @@ func (d *dentry) removexattr(ctx context.Context, creds *auth.Credentials, name if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) { return syserror.EOPNOTSUPP } + if !d.userXattrSupported() { + return syserror.EPERM + } return d.file.removeXattr(ctx, name) } -// Preconditions: !d.isSynthetic(). d.isRegularFile() || d.isDirectory(). +// Extended attributes in the user.* namespace are only supported for regular +// files and directories. +func (d *dentry) userXattrSupported() bool { + filetype := linux.FileMode(atomic.LoadUint32(&d.mode)).FileType() + return filetype == linux.ModeRegular || filetype == linux.ModeDirectory +} + +// Preconditions: !d.isSynthetic(). d.isRegularFile() || d.isDir(). func (d *dentry) ensureSharedHandle(ctx context.Context, read, write, trunc bool) error { // O_TRUNC unconditionally requires us to obtain a new handle (opened with // O_TRUNC). if !trunc { d.handleMu.RLock() - if (!read || d.handleReadable) && (!write || d.handleWritable) { - // The current handle is sufficient. + if (!read || !d.readFile.isNil()) && (!write || !d.writeFile.isNil()) { + // Current handles are sufficient. d.handleMu.RUnlock() return nil } d.handleMu.RUnlock() } - haveOldFD := false + fdToClose := int32(-1) + invalidateTranslations := false d.handleMu.Lock() - if (read && !d.handleReadable) || (write && !d.handleWritable) || trunc { - // Get a new handle. - wantReadable := d.handleReadable || read - wantWritable := d.handleWritable || write - h, err := openHandle(ctx, d.file, wantReadable, wantWritable, trunc) + if (read && d.readFile.isNil()) || (write && d.writeFile.isNil()) || trunc { + // Get a new handle. If this file has been opened for both reading and + // writing, try to get a single handle that is usable for both: + // + // - Writable memory mappings of a host FD require that the host FD is + // opened for both reading and writing. + // + // - NOTE(b/141991141): Some filesystems may not ensure coherence + // between multiple handles for the same file. + openReadable := !d.readFile.isNil() || read + openWritable := !d.writeFile.isNil() || write + h, err := openHandle(ctx, d.file, openReadable, openWritable, trunc) + if err == syserror.EACCES && (openReadable != read || openWritable != write) { + // It may not be possible to use a single handle for both + // reading and writing, since permissions on the file may have + // changed to e.g. disallow reading after previously being + // opened for reading. In this case, we have no choice but to + // use separate handles for reading and writing. + ctx.Debugf("gofer.dentry.ensureSharedHandle: bifurcating read/write handles for dentry %p", d) + openReadable = read + openWritable = write + h, err = openHandle(ctx, d.file, openReadable, openWritable, trunc) + } if err != nil { d.handleMu.Unlock() return err } - if !d.handle.file.isNil() { - // Check that old and new handles are compatible: If the old handle - // includes a host file descriptor but the new one does not, or - // vice versa, old and new memory mappings may be incoherent. - haveOldFD = d.handle.fd >= 0 - haveNewFD := h.fd >= 0 - if haveOldFD != haveNewFD { - d.handleMu.Unlock() - ctx.Warningf("gofer.dentry.ensureSharedHandle: can't change host FD availability from %v to %v across dentry handle upgrade", haveOldFD, haveNewFD) - h.close(ctx) - return syserror.EIO - } - if haveOldFD { - // We may have raced with callers of d.pf.FD() that are now - // using the old file descriptor, preventing us from safely - // closing it. We could handle this by invalidating existing - // memmap.Translations, but this is expensive. Instead, use - // dup3 to make the old file descriptor refer to the new file - // description, then close the new file descriptor (which is no - // longer needed). Racing callers may use the old or new file - // description, but this doesn't matter since they refer to the - // same file (unless d.fs.opts.overlayfsStaleRead is true, - // which we handle separately). - if err := syscall.Dup3(int(h.fd), int(d.handle.fd), syscall.O_CLOEXEC); err != nil { + + if d.hostFD < 0 && openReadable && h.fd >= 0 { + // We have no existing FD; use the new FD for at least reading. + d.hostFD = h.fd + } else if d.hostFD >= 0 && d.writeFile.isNil() && openWritable { + // We have an existing read-only FD, but the file has just been + // opened for writing, so we need to start supporting writable memory + // mappings. This may race with callers of d.pf.FD() using the existing + // FD, so in most cases we need to delay closing the old FD until after + // invalidating memmap.Translations that might have observed it. + if !openReadable || h.fd < 0 { + // We don't have a read/write FD, so we have no FD that can be + // used to create writable memory mappings. Switch to using the + // internal page cache. + invalidateTranslations = true + fdToClose = d.hostFD + d.hostFD = -1 + } else if d.fs.opts.overlayfsStaleRead { + // We do have a read/write FD, but it may not be coherent with + // the existing read-only FD, so we must switch to mappings of + // the new FD in both the application and sentry. + if err := d.pf.hostFileMapper.RegenerateMappings(int(h.fd)); err != nil { d.handleMu.Unlock() - ctx.Warningf("gofer.dentry.ensureSharedHandle: failed to dup fd %d to fd %d: %v", h.fd, d.handle.fd, err) + ctx.Warningf("gofer.dentry.ensureSharedHandle: failed to replace sentry mappings of old FD with mappings of new FD: %v", err) h.close(ctx) return err } - syscall.Close(int(h.fd)) - h.fd = d.handle.fd - if d.fs.opts.overlayfsStaleRead { - // Replace sentry mappings of the old FD with mappings of - // the new FD, since the two are not necessarily coherent. - if err := d.pf.hostFileMapper.RegenerateMappings(int(h.fd)); err != nil { - d.handleMu.Unlock() - ctx.Warningf("gofer.dentry.ensureSharedHandle: failed to replace sentry mappings of old FD with mappings of new FD: %v", err) - h.close(ctx) - return err - } + invalidateTranslations = true + fdToClose = d.hostFD + d.hostFD = h.fd + } else { + // We do have a read/write FD. To avoid invalidating existing + // memmap.Translations (which is expensive), use dup3 to make + // the old file descriptor refer to the new file description, + // then close the new file descriptor (which is no longer + // needed). Racing callers of d.pf.FD() may use the old or new + // file description, but this doesn't matter since they refer + // to the same file, and any racing mappings must be read-only. + if err := syscall.Dup3(int(h.fd), int(d.hostFD), syscall.O_CLOEXEC); err != nil { + oldHostFD := d.hostFD + d.handleMu.Unlock() + ctx.Warningf("gofer.dentry.ensureSharedHandle: failed to dup fd %d to fd %d: %v", h.fd, oldHostFD, err) + h.close(ctx) + return err } - // Clunk the old fid before making the new handle visible (by - // unlocking d.handleMu). - d.handle.file.close(ctx) + fdToClose = h.fd } + } else { + // h.fd is not useful. + fdToClose = h.fd + } + + // Switch to new fids. + var oldReadFile p9file + if openReadable { + oldReadFile = d.readFile + d.readFile = h.file + } + var oldWriteFile p9file + if openWritable { + oldWriteFile = d.writeFile + d.writeFile = h.file + } + // NOTE(b/141991141): Clunk old fids before making new fids visible (by + // unlocking d.handleMu). + if !oldReadFile.isNil() { + oldReadFile.close(ctx) + } + if !oldWriteFile.isNil() && oldReadFile != oldWriteFile { + oldWriteFile.close(ctx) } - // Switch to the new handle. - d.handle = h - d.handleReadable = wantReadable - d.handleWritable = wantWritable } d.handleMu.Unlock() - if d.fs.opts.overlayfsStaleRead && haveOldFD { - // Invalidate application mappings that may be using the old FD; they + if invalidateTranslations { + // Invalidate application mappings that may be using an old FD; they // will be replaced with mappings using the new FD after future calls // to d.Translate(). This requires holding d.mapsMu, which precedes // d.handleMu in the lock order. @@ -1297,28 +1545,70 @@ func (d *dentry) ensureSharedHandle(ctx context.Context, read, write, trunc bool d.mappings.InvalidateAll(memmap.InvalidateOpts{}) d.mapsMu.Unlock() } + if fdToClose >= 0 { + syscall.Close(int(fdToClose)) + } return nil } +// Preconditions: d.handleMu must be locked. +func (d *dentry) readHandleLocked() handle { + return handle{ + file: d.readFile, + fd: d.hostFD, + } +} + +// Preconditions: d.handleMu must be locked. +func (d *dentry) writeHandleLocked() handle { + return handle{ + file: d.writeFile, + fd: d.hostFD, + } +} + +func (d *dentry) syncRemoteFile(ctx context.Context) error { + d.handleMu.RLock() + defer d.handleMu.RUnlock() + return d.syncRemoteFileLocked(ctx) +} + +// Preconditions: d.handleMu must be locked. +func (d *dentry) syncRemoteFileLocked(ctx context.Context) error { + // If we have a host FD, fsyncing it is likely to be faster than an fsync + // RPC. + if d.hostFD >= 0 { + ctx.UninterruptibleSleepStart(false) + err := syscall.Fsync(int(d.hostFD)) + ctx.UninterruptibleSleepFinish(false) + return err + } + if !d.writeFile.isNil() { + return d.writeFile.fsync(ctx) + } + if !d.readFile.isNil() { + return d.readFile.fsync(ctx) + } + return nil +} + // incLinks increments link count. -// -// Preconditions: d.nlink != 0 && d.nlink < math.MaxUint32. func (d *dentry) incLinks() { - v := atomic.AddUint32(&d.nlink, 1) - if v < 2 { - panic(fmt.Sprintf("dentry.nlink is invalid (was 0 or overflowed): %d", v)) + if atomic.LoadUint32(&d.nlink) == 0 { + // The remote filesystem doesn't support link count. + return } + atomic.AddUint32(&d.nlink, 1) } // decLinks decrements link count. -// -// Preconditions: d.nlink > 1. func (d *dentry) decLinks() { - v := atomic.AddUint32(&d.nlink, ^uint32(0)) - if v == 0 { - panic(fmt.Sprintf("dentry.nlink must be greater than 0: %d", v)) + if atomic.LoadUint32(&d.nlink) == 0 { + // The remote filesystem doesn't support link count. + return } + atomic.AddUint32(&d.nlink, ^uint32(0)) } // fileDescription is embedded by gofer implementations of @@ -1326,6 +1616,9 @@ func (d *dentry) decLinks() { type fileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD + + lockLogging sync.Once } func (fd *fileDescription) filesystem() *filesystem { @@ -1354,7 +1647,13 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu // SetStat implements vfs.FileDescriptionImpl.SetStat. func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error { - return fd.dentry().setStat(ctx, auth.CredentialsFromContext(ctx), &opts.Stat, fd.vfsfd.Mount()) + if err := fd.dentry().setStat(ctx, auth.CredentialsFromContext(ctx), &opts, fd.vfsfd.Mount()); err != nil { + return err + } + if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 { + fd.dentry().InotifyWithParent(ctx, ev, 0, vfs.InodeEvent) + } + return nil } // Listxattr implements vfs.FileDescriptionImpl.Listxattr. @@ -1369,10 +1668,41 @@ func (fd *fileDescription) Getxattr(ctx context.Context, opts vfs.GetxattrOption // Setxattr implements vfs.FileDescriptionImpl.Setxattr. func (fd *fileDescription) Setxattr(ctx context.Context, opts vfs.SetxattrOptions) error { - return fd.dentry().setxattr(ctx, auth.CredentialsFromContext(ctx), &opts) + d := fd.dentry() + if err := d.setxattr(ctx, auth.CredentialsFromContext(ctx), &opts); err != nil { + return err + } + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // Removexattr implements vfs.FileDescriptionImpl.Removexattr. func (fd *fileDescription) Removexattr(ctx context.Context, name string) error { - return fd.dentry().removexattr(ctx, auth.CredentialsFromContext(ctx), name) + d := fd.dentry() + if err := d.removexattr(ctx, auth.CredentialsFromContext(ctx), name); err != nil { + return err + } + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil +} + +// LockBSD implements vfs.FileDescriptionImpl.LockBSD. +func (fd *fileDescription) LockBSD(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, block fslock.Blocker) error { + fd.lockLogging.Do(func() { + log.Infof("File lock using gofer file handled internally.") + }) + return fd.LockFD.LockBSD(ctx, uid, t, block) +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + fd.lockLogging.Do(func() { + log.Infof("Range lock using gofer file handled internally.") + }) + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *fileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) } diff --git a/pkg/sentry/fsimpl/gofer/gofer_test.go b/pkg/sentry/fsimpl/gofer/gofer_test.go index adff39490..bfe75dfe4 100644 --- a/pkg/sentry/fsimpl/gofer/gofer_test.go +++ b/pkg/sentry/fsimpl/gofer/gofer_test.go @@ -20,10 +20,13 @@ import ( "gvisor.dev/gvisor/pkg/p9" "gvisor.dev/gvisor/pkg/sentry/contexttest" + "gvisor.dev/gvisor/pkg/sentry/pgalloc" ) func TestDestroyIdempotent(t *testing.T) { + ctx := contexttest.Context(t) fs := filesystem{ + mfp: pgalloc.MemoryFileProviderFromContext(ctx), syncableDentries: make(map[*dentry]struct{}), opts: filesystemOptions{ // Test relies on no dentry being held in the cache. @@ -31,7 +34,6 @@ func TestDestroyIdempotent(t *testing.T) { }, } - ctx := contexttest.Context(t) attr := &p9.Attr{ Mode: p9.ModeRegular, } @@ -50,7 +52,9 @@ func TestDestroyIdempotent(t *testing.T) { } parent.cacheNewChildLocked(child, "child") - child.checkCachingLocked() + fs.renameMu.Lock() + defer fs.renameMu.Unlock() + child.checkCachingLocked(ctx) if got := atomic.LoadInt64(&child.refs); got != -1 { t.Fatalf("child.refs=%d, want: -1", got) } @@ -58,6 +62,6 @@ func TestDestroyIdempotent(t *testing.T) { if got := atomic.LoadInt64(&parent.refs); got != -1 { t.Fatalf("parent.refs=%d, want: -1", got) } - child.checkCachingLocked() - child.checkCachingLocked() + child.checkCachingLocked(ctx) + child.checkCachingLocked(ctx) } diff --git a/pkg/sentry/fsimpl/gofer/handle.go b/pkg/sentry/fsimpl/gofer/handle.go index 724a3f1f7..104157512 100644 --- a/pkg/sentry/fsimpl/gofer/handle.go +++ b/pkg/sentry/fsimpl/gofer/handle.go @@ -63,6 +63,10 @@ func openHandle(ctx context.Context, file p9file, read, write, trunc bool) (hand }, nil } +func (h *handle) isOpen() bool { + return !h.file.isNil() +} + func (h *handle) close(ctx context.Context) { h.file.close(ctx) h.file = p9file{} @@ -124,13 +128,3 @@ func (h *handle) writeFromBlocksAt(ctx context.Context, srcs safemem.BlockSeq, o } return cp, cperr } - -func (h *handle) sync(ctx context.Context) error { - if h.fd >= 0 { - ctx.UninterruptibleSleepStart(false) - err := syscall.Fsync(int(h.fd)) - ctx.UninterruptibleSleepFinish(false) - return err - } - return h.file.fsync(ctx) -} diff --git a/pkg/sentry/fsimpl/gofer/host_named_pipe.go b/pkg/sentry/fsimpl/gofer/host_named_pipe.go new file mode 100644 index 000000000..7294de7d6 --- /dev/null +++ b/pkg/sentry/fsimpl/gofer/host_named_pipe.go @@ -0,0 +1,97 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package gofer + +import ( + "fmt" + "sync" + "time" + + "golang.org/x/sys/unix" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/syserror" +) + +// Global pipe used by blockUntilNonblockingPipeHasWriter since we can't create +// pipes after sentry initialization due to syscall filters. +var ( + tempPipeMu sync.Mutex + tempPipeReadFD int + tempPipeWriteFD int + tempPipeBuf [1]byte +) + +func init() { + var pipeFDs [2]int + if err := unix.Pipe(pipeFDs[:]); err != nil { + panic(fmt.Sprintf("failed to create pipe for gofer.blockUntilNonblockingPipeHasWriter: %v", err)) + } + tempPipeReadFD = pipeFDs[0] + tempPipeWriteFD = pipeFDs[1] +} + +func blockUntilNonblockingPipeHasWriter(ctx context.Context, fd int32) error { + for { + ok, err := nonblockingPipeHasWriter(fd) + if err != nil { + return err + } + if ok { + return nil + } + if err := sleepBetweenNamedPipeOpenChecks(ctx); err != nil { + return err + } + } +} + +func nonblockingPipeHasWriter(fd int32) (bool, error) { + tempPipeMu.Lock() + defer tempPipeMu.Unlock() + // Copy 1 byte from fd into the temporary pipe. + n, err := unix.Tee(int(fd), tempPipeWriteFD, 1, unix.SPLICE_F_NONBLOCK) + if err == syserror.EAGAIN { + // The pipe represented by fd is empty, but has a writer. + return true, nil + } + if err != nil { + return false, err + } + if n == 0 { + // The pipe represented by fd is empty and has no writer. + return false, nil + } + // The pipe represented by fd is non-empty, so it either has, or has + // previously had, a writer. Remove the byte copied to the temporary pipe + // before returning. + if n, err := unix.Read(tempPipeReadFD, tempPipeBuf[:]); err != nil || n != 1 { + panic(fmt.Sprintf("failed to drain pipe for gofer.blockUntilNonblockingPipeHasWriter: got (%d, %v), wanted (1, nil)", n, err)) + } + return true, nil +} + +func sleepBetweenNamedPipeOpenChecks(ctx context.Context) error { + t := time.NewTimer(100 * time.Millisecond) + defer t.Stop() + cancel := ctx.SleepStart() + select { + case <-t.C: + ctx.SleepFinish(true) + return nil + case <-cancel: + ctx.SleepFinish(false) + return syserror.ErrInterrupted + } +} diff --git a/pkg/sentry/fsimpl/gofer/regular_file.go b/pkg/sentry/fsimpl/gofer/regular_file.go index 0d10cf7ac..7e1cbf065 100644 --- a/pkg/sentry/fsimpl/gofer/regular_file.go +++ b/pkg/sentry/fsimpl/gofer/regular_file.go @@ -24,11 +24,11 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/log" + "gvisor.dev/gvisor/pkg/p9" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/syserror" @@ -48,7 +48,7 @@ type regularFileFD struct { } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *regularFileFD) Release() { +func (fd *regularFileFD) Release(context.Context) { } // OnClose implements vfs.FileDescriptionImpl.OnClose. @@ -64,7 +64,37 @@ func (fd *regularFileFD) OnClose(ctx context.Context) error { } d.handleMu.RLock() defer d.handleMu.RUnlock() - return d.handle.file.flush(ctx) + if d.writeFile.isNil() { + return nil + } + return d.writeFile.flush(ctx) +} + +// Allocate implements vfs.FileDescriptionImpl.Allocate. +func (fd *regularFileFD) Allocate(ctx context.Context, mode, offset, length uint64) error { + d := fd.dentry() + d.metadataMu.Lock() + defer d.metadataMu.Unlock() + + // Allocating a smaller size is a noop. + size := offset + length + if d.cachedMetadataAuthoritative() && size <= d.size { + return nil + } + + d.handleMu.RLock() + err := d.writeFile.allocate(ctx, p9.ToAllocateMode(mode), offset, length) + d.handleMu.RUnlock() + if err != nil { + return err + } + d.dataMu.Lock() + atomic.StoreUint64(&d.size, size) + d.dataMu.Unlock() + if d.cachedMetadataAuthoritative() { + d.touchCMtimeLocked() + } + return nil } // PRead implements vfs.FileDescriptionImpl.PRead. @@ -72,14 +102,18 @@ func (fd *regularFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offs if offset < 0 { return 0, syserror.EINVAL } - if opts.Flags != 0 { + + // Check that flags are supported. + // + // TODO(gvisor.dev/issue/2601): Support select preadv2 flags. + if opts.Flags&^linux.RWF_HIPRI != 0 { return 0, syserror.EOPNOTSUPP } // Check for reading at EOF before calling into MM (but not under // InteropModeShared, which makes d.size unreliable). d := fd.dentry() - if d.fs.opts.interop != InteropModeShared && uint64(offset) >= atomic.LoadUint64(&d.size) { + if d.cachedMetadataAuthoritative() && uint64(offset) >= atomic.LoadUint64(&d.size) { return 0, io.EOF } @@ -120,85 +154,134 @@ func (fd *regularFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts // PWrite implements vfs.FileDescriptionImpl.PWrite. func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + n, _, err := fd.pwrite(ctx, src, offset, opts) + return n, err +} + +// pwrite returns the number of bytes written, final offset, error. The final +// offset should be ignored by PWrite. +func (fd *regularFileFD) pwrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (written, finalOff int64, err error) { if offset < 0 { - return 0, syserror.EINVAL + return 0, offset, syserror.EINVAL } - if opts.Flags != 0 { - return 0, syserror.EOPNOTSUPP + + // Check that flags are supported. + // + // TODO(gvisor.dev/issue/2601): Support select pwritev2 flags. + if opts.Flags&^linux.RWF_HIPRI != 0 { + return 0, offset, syserror.EOPNOTSUPP + } + + d := fd.dentry() + // If the fd was opened with O_APPEND, make sure the file size is updated. + // There is a possible race here if size is modified externally after + // metadata cache is updated. + if fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 && !d.cachedMetadataAuthoritative() { + if err := d.updateFromGetattr(ctx); err != nil { + return 0, offset, err + } + } + + d.metadataMu.Lock() + defer d.metadataMu.Unlock() + + // Set offset to file size if the fd was opened with O_APPEND. + if fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 { + // Holding d.metadataMu is sufficient for reading d.size. + offset = int64(d.size) } limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes()) if err != nil { - return 0, err + return 0, offset, err } src = src.TakeFirst64(limit) - d := fd.dentry() - d.metadataMu.Lock() - defer d.metadataMu.Unlock() if d.fs.opts.interop != InteropModeShared { // Compare Linux's mm/filemap.c:__generic_file_write_iter() => // file_update_time(). This is d.touchCMtime(), but without locking // d.metadataMu (recursively). d.touchCMtimeLocked() } - if fd.vfsfd.StatusFlags()&linux.O_DIRECT != 0 { - // Write dirty cached pages that will be touched by the write back to - // the remote file. - if err := d.writeback(ctx, offset, src.NumBytes()); err != nil { - return 0, err - } - // Remove touched pages from the cache. - pgstart := usermem.PageRoundDown(uint64(offset)) - pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes())) - if !ok { - return 0, syserror.EINVAL - } - mr := memmap.MappableRange{pgstart, pgend} - var freed []platform.FileRange - d.dataMu.Lock() - cseg := d.cache.LowerBoundSegment(mr.Start) - for cseg.Ok() && cseg.Start() < mr.End { - cseg = d.cache.Isolate(cseg, mr) - freed = append(freed, platform.FileRange{cseg.Value(), cseg.Value() + cseg.Range().Length()}) - cseg = d.cache.Remove(cseg).NextSegment() - } - d.dataMu.Unlock() - // Invalidate mappings of removed pages. - d.mapsMu.Lock() - d.mappings.Invalidate(mr, memmap.InvalidateOpts{}) - d.mapsMu.Unlock() - // Finally free pages removed from the cache. - mf := d.fs.mfp.MemoryFile() - for _, freedFR := range freed { - mf.DecRef(freedFR) - } - } + rw := getDentryReadWriter(ctx, d, offset) + defer putDentryReadWriter(rw) + if fd.vfsfd.StatusFlags()&linux.O_DIRECT != 0 { + if err := fd.writeCache(ctx, d, offset, src); err != nil { + return 0, offset, err + } + // Require the write to go to the remote file. rw.direct = true } + n, err := src.CopyInTo(ctx, rw) - putDentryReadWriter(rw) - if n != 0 && fd.vfsfd.StatusFlags()&(linux.O_DSYNC|linux.O_SYNC) != 0 { + if err != nil { + return n, offset + n, err + } + if n > 0 && fd.vfsfd.StatusFlags()&(linux.O_DSYNC|linux.O_SYNC) != 0 { + // Note that if any of the following fail, then we can't guarantee that + // any data was actually written with the semantics of O_DSYNC or + // O_SYNC, so we return zero bytes written. Compare Linux's + // mm/filemap.c:generic_file_write_iter() => + // include/linux/fs.h:generic_write_sync(). + // // Write dirty cached pages touched by the write back to the remote // file. if err := d.writeback(ctx, offset, src.NumBytes()); err != nil { - return 0, err + return 0, offset, err } // Request the remote filesystem to sync the remote file. - if err := d.handle.file.fsync(ctx); err != nil { - return 0, err + if err := d.syncRemoteFile(ctx); err != nil { + return 0, offset, err } } - return n, err + return n, offset + n, nil +} + +func (fd *regularFileFD) writeCache(ctx context.Context, d *dentry, offset int64, src usermem.IOSequence) error { + // Write dirty cached pages that will be touched by the write back to + // the remote file. + if err := d.writeback(ctx, offset, src.NumBytes()); err != nil { + return err + } + + // Remove touched pages from the cache. + pgstart := usermem.PageRoundDown(uint64(offset)) + pgend, ok := usermem.PageRoundUp(uint64(offset + src.NumBytes())) + if !ok { + return syserror.EINVAL + } + mr := memmap.MappableRange{pgstart, pgend} + var freed []memmap.FileRange + + d.dataMu.Lock() + cseg := d.cache.LowerBoundSegment(mr.Start) + for cseg.Ok() && cseg.Start() < mr.End { + cseg = d.cache.Isolate(cseg, mr) + freed = append(freed, memmap.FileRange{cseg.Value(), cseg.Value() + cseg.Range().Length()}) + cseg = d.cache.Remove(cseg).NextSegment() + } + d.dataMu.Unlock() + + // Invalidate mappings of removed pages. + d.mapsMu.Lock() + d.mappings.Invalidate(mr, memmap.InvalidateOpts{}) + d.mapsMu.Unlock() + + // Finally free pages removed from the cache. + mf := d.fs.mfp.MemoryFile() + for _, freedFR := range freed { + mf.DecRef(freedFR) + } + return nil } // Write implements vfs.FileDescriptionImpl.Write. func (fd *regularFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { fd.mu.Lock() - n, err := fd.PWrite(ctx, src, fd.off, opts) - fd.off += n + n, off, err := fd.pwrite(ctx, src, fd.off, opts) + fd.off = off fd.mu.Unlock() return n, err } @@ -241,10 +324,11 @@ func (rw *dentryReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) // coherence with memory-mapped I/O), or if InteropModeShared is in effect // (which prevents us from caching file contents and makes dentry.size // unreliable), or if the file was opened O_DIRECT, read directly from - // dentry.handle without locking dentry.dataMu. + // dentry.readHandleLocked() without locking dentry.dataMu. rw.d.handleMu.RLock() - if (rw.d.handle.fd >= 0 && !rw.d.fs.opts.forcePageCache) || rw.d.fs.opts.interop == InteropModeShared || rw.direct { - n, err := rw.d.handle.readToBlocksAt(rw.ctx, dsts, rw.off) + h := rw.d.readHandleLocked() + if (rw.d.hostFD >= 0 && !rw.d.fs.opts.forcePageCache) || rw.d.fs.opts.interop == InteropModeShared || rw.direct { + n, err := h.readToBlocksAt(rw.ctx, dsts, rw.off) rw.d.handleMu.RUnlock() rw.off += n return n, err @@ -312,7 +396,7 @@ func (rw *dentryReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) End: gapEnd, } optMR := gap.Range() - err := rw.d.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), mf, usage.PageCache, rw.d.handle.readToBlocksAt) + err := rw.d.cache.Fill(rw.ctx, reqMR, maxFillRange(reqMR, optMR), mf, usage.PageCache, h.readToBlocksAt) mf.MarkEvictable(rw.d, pgalloc.EvictableRange{optMR.Start, optMR.End}) seg, gap = rw.d.cache.Find(rw.off) if !seg.Ok() { @@ -327,7 +411,7 @@ func (rw *dentryReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) } else { // Read directly from the file. gapDsts := dsts.TakeFirst64(gapMR.Length()) - n, err := rw.d.handle.readToBlocksAt(rw.ctx, gapDsts, gapMR.Start) + n, err := h.readToBlocksAt(rw.ctx, gapDsts, gapMR.Start) done += n rw.off += n dsts = dsts.DropFirst64(n) @@ -359,11 +443,12 @@ func (rw *dentryReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, erro // If we have a mmappable host FD (which must be used here to ensure // coherence with memory-mapped I/O), or if InteropModeShared is in effect // (which prevents us from caching file contents), or if the file was - // opened with O_DIRECT, write directly to dentry.handle without locking - // dentry.dataMu. + // opened with O_DIRECT, write directly to dentry.writeHandleLocked() + // without locking dentry.dataMu. rw.d.handleMu.RLock() - if (rw.d.handle.fd >= 0 && !rw.d.fs.opts.forcePageCache) || rw.d.fs.opts.interop == InteropModeShared || rw.direct { - n, err := rw.d.handle.writeFromBlocksAt(rw.ctx, srcs, rw.off) + h := rw.d.writeHandleLocked() + if (rw.d.hostFD >= 0 && !rw.d.fs.opts.forcePageCache) || rw.d.fs.opts.interop == InteropModeShared || rw.direct { + n, err := h.writeFromBlocksAt(rw.ctx, srcs, rw.off) rw.off += n rw.d.dataMu.Lock() if rw.off > rw.d.size { @@ -425,7 +510,7 @@ func (rw *dentryReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, erro // for detecting or avoiding this. gapMR := gap.Range().Intersect(mr) gapSrcs := srcs.TakeFirst64(gapMR.Length()) - n, err := rw.d.handle.writeFromBlocksAt(rw.ctx, gapSrcs, gapMR.Start) + n, err := h.writeFromBlocksAt(rw.ctx, gapSrcs, gapMR.Start) done += n rw.off += n srcs = srcs.DropFirst64(n) @@ -451,7 +536,7 @@ exitLoop: if err := fsutil.SyncDirty(rw.ctx, memmap.MappableRange{ Start: start, End: rw.off, - }, &rw.d.cache, &rw.d.dirty, rw.d.size, mf, rw.d.handle.writeFromBlocksAt); err != nil { + }, &rw.d.cache, &rw.d.dirty, rw.d.size, mf, h.writeFromBlocksAt); err != nil { // We have no idea how many bytes were actually flushed. rw.off = start done = 0 @@ -469,6 +554,7 @@ func (d *dentry) writeback(ctx context.Context, offset, size int64) error { } d.handleMu.RLock() defer d.handleMu.RUnlock() + h := d.writeHandleLocked() d.dataMu.Lock() defer d.dataMu.Unlock() // Compute the range of valid bytes (overflow-checked). @@ -482,22 +568,31 @@ func (d *dentry) writeback(ctx context.Context, offset, size int64) error { return fsutil.SyncDirty(ctx, memmap.MappableRange{ Start: uint64(offset), End: uint64(end), - }, &d.cache, &d.dirty, d.size, d.fs.mfp.MemoryFile(), d.handle.writeFromBlocksAt) + }, &d.cache, &d.dirty, d.size, d.fs.mfp.MemoryFile(), h.writeFromBlocksAt) } // Seek implements vfs.FileDescriptionImpl.Seek. func (fd *regularFileFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { fd.mu.Lock() defer fd.mu.Unlock() + newOffset, err := regularFileSeekLocked(ctx, fd.dentry(), fd.off, offset, whence) + if err != nil { + return 0, err + } + fd.off = newOffset + return newOffset, nil +} + +// Calculate the new offset for a seek operation on a regular file. +func regularFileSeekLocked(ctx context.Context, d *dentry, fdOffset, offset int64, whence int32) (int64, error) { switch whence { case linux.SEEK_SET: // Use offset as specified. case linux.SEEK_CUR: - offset += fd.off + offset += fdOffset case linux.SEEK_END, linux.SEEK_DATA, linux.SEEK_HOLE: // Ensure file size is up to date. - d := fd.dentry() - if fd.filesystem().opts.interop == InteropModeShared { + if !d.cachedMetadataAuthoritative() { if err := d.updateFromGetattr(ctx); err != nil { return 0, err } @@ -525,31 +620,28 @@ func (fd *regularFileFD) Seek(ctx context.Context, offset int64, whence int32) ( if offset < 0 { return 0, syserror.EINVAL } - fd.off = offset return offset, nil } // Sync implements vfs.FileDescriptionImpl.Sync. func (fd *regularFileFD) Sync(ctx context.Context) error { - return fd.dentry().syncSharedHandle(ctx) + return fd.dentry().syncCachedFile(ctx) } -func (d *dentry) syncSharedHandle(ctx context.Context) error { +func (d *dentry) syncCachedFile(ctx context.Context) error { d.handleMu.RLock() - if !d.handleWritable { - d.handleMu.RUnlock() - return nil - } - d.dataMu.Lock() - // Write dirty cached data to the remote file. - err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, d.fs.mfp.MemoryFile(), d.handle.writeFromBlocksAt) - d.dataMu.Unlock() - if err == nil { - // Sync the remote file. - err = d.handle.sync(ctx) + defer d.handleMu.RUnlock() + + if h := d.writeHandleLocked(); h.isOpen() { + d.dataMu.Lock() + // Write dirty cached data to the remote file. + err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, d.fs.mfp.MemoryFile(), h.writeFromBlocksAt) + d.dataMu.Unlock() + if err != nil { + return err + } } - d.handleMu.RUnlock() - return err + return d.syncRemoteFileLocked(ctx) } // ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap. @@ -573,7 +665,7 @@ func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpt return syserror.ENODEV } d.handleMu.RLock() - haveFD := d.handle.fd >= 0 + haveFD := d.hostFD >= 0 d.handleMu.RUnlock() if !haveFD { return syserror.ENODEV @@ -594,7 +686,7 @@ func (d *dentry) mayCachePages() bool { return true } d.handleMu.RLock() - haveFD := d.handle.fd >= 0 + haveFD := d.hostFD >= 0 d.handleMu.RUnlock() return haveFD } @@ -652,7 +744,7 @@ func (d *dentry) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, // Translate implements memmap.Mappable.Translate. func (d *dentry) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) { d.handleMu.RLock() - if d.handle.fd >= 0 && !d.fs.opts.forcePageCache { + if d.hostFD >= 0 && !d.fs.opts.forcePageCache { d.handleMu.RUnlock() mr := optional if d.fs.opts.limitHostFDTranslation { @@ -688,7 +780,8 @@ func (d *dentry) Translate(ctx context.Context, required, optional memmap.Mappab } mf := d.fs.mfp.MemoryFile() - cerr := d.cache.Fill(ctx, required, maxFillRange(required, optional), mf, usage.PageCache, d.handle.readToBlocksAt) + h := d.readHandleLocked() + cerr := d.cache.Fill(ctx, required, maxFillRange(required, optional), mf, usage.PageCache, h.readToBlocksAt) var ts []memmap.Translation var translatedEnd uint64 @@ -747,7 +840,7 @@ func maxFillRange(required, optional memmap.MappableRange) memmap.MappableRange // InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable. func (d *dentry) InvalidateUnsavable(ctx context.Context) error { - // Whether we have a host fd (and consequently what platform.File is + // Whether we have a host fd (and consequently what memmap.File is // mapped) can change across save/restore, so invalidate all translations // unconditionally. d.mapsMu.Lock() @@ -757,9 +850,12 @@ func (d *dentry) InvalidateUnsavable(ctx context.Context) error { // Write the cache's contents back to the remote file so that if we have a // host fd after restore, the remote file's contents are coherent. mf := d.fs.mfp.MemoryFile() + d.handleMu.RLock() + defer d.handleMu.RUnlock() + h := d.writeHandleLocked() d.dataMu.Lock() defer d.dataMu.Unlock() - if err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, mf, d.handle.writeFromBlocksAt); err != nil { + if err := fsutil.SyncDirtyAll(ctx, &d.cache, &d.dirty, d.size, mf, h.writeFromBlocksAt); err != nil { return err } @@ -774,20 +870,23 @@ func (d *dentry) InvalidateUnsavable(ctx context.Context) error { // Evict implements pgalloc.EvictableMemoryUser.Evict. func (d *dentry) Evict(ctx context.Context, er pgalloc.EvictableRange) { + mr := memmap.MappableRange{er.Start, er.End} + mf := d.fs.mfp.MemoryFile() d.mapsMu.Lock() defer d.mapsMu.Unlock() + d.handleMu.RLock() + defer d.handleMu.RUnlock() + h := d.writeHandleLocked() d.dataMu.Lock() defer d.dataMu.Unlock() - mr := memmap.MappableRange{er.Start, er.End} - mf := d.fs.mfp.MemoryFile() // Only allow pages that are no longer memory-mapped to be evicted. for mgap := d.mappings.LowerBoundGap(mr.Start); mgap.Ok() && mgap.Start() < mr.End; mgap = mgap.NextGap() { mgapMR := mgap.Range().Intersect(mr) if mgapMR.Length() == 0 { continue } - if err := fsutil.SyncDirty(ctx, mgapMR, &d.cache, &d.dirty, d.size, mf, d.handle.writeFromBlocksAt); err != nil { + if err := fsutil.SyncDirty(ctx, mgapMR, &d.cache, &d.dirty, d.size, mf, h.writeFromBlocksAt); err != nil { log.Warningf("Failed to writeback cached data %v: %v", mgapMR, err) } d.cache.Drop(mgapMR, mf) @@ -795,53 +894,51 @@ func (d *dentry) Evict(ctx context.Context, er pgalloc.EvictableRange) { } } -// dentryPlatformFile implements platform.File. It exists solely because dentry -// cannot implement both vfs.DentryImpl.IncRef and platform.File.IncRef. +// dentryPlatformFile implements memmap.File. It exists solely because dentry +// cannot implement both vfs.DentryImpl.IncRef and memmap.File.IncRef. // // dentryPlatformFile is only used when a host FD representing the remote file -// is available (i.e. dentry.handle.fd >= 0), and that FD is used for -// application memory mappings (i.e. !filesystem.opts.forcePageCache). +// is available (i.e. dentry.hostFD >= 0), and that FD is used for application +// memory mappings (i.e. !filesystem.opts.forcePageCache). type dentryPlatformFile struct { *dentry - // fdRefs counts references on platform.File offsets. fdRefs is protected + // fdRefs counts references on memmap.File offsets. fdRefs is protected // by dentry.dataMu. fdRefs fsutil.FrameRefSet - // If this dentry represents a regular file, and handle.fd >= 0, - // hostFileMapper caches mappings of handle.fd. + // If this dentry represents a regular file, and dentry.hostFD >= 0, + // hostFileMapper caches mappings of dentry.hostFD. hostFileMapper fsutil.HostFileMapper // hostFileMapperInitOnce is used to lazily initialize hostFileMapper. hostFileMapperInitOnce sync.Once } -// IncRef implements platform.File.IncRef. -func (d *dentryPlatformFile) IncRef(fr platform.FileRange) { +// IncRef implements memmap.File.IncRef. +func (d *dentryPlatformFile) IncRef(fr memmap.FileRange) { d.dataMu.Lock() d.fdRefs.IncRefAndAccount(fr) d.dataMu.Unlock() } -// DecRef implements platform.File.DecRef. -func (d *dentryPlatformFile) DecRef(fr platform.FileRange) { +// DecRef implements memmap.File.DecRef. +func (d *dentryPlatformFile) DecRef(fr memmap.FileRange) { d.dataMu.Lock() d.fdRefs.DecRefAndAccount(fr) d.dataMu.Unlock() } -// MapInternal implements platform.File.MapInternal. -func (d *dentryPlatformFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { +// MapInternal implements memmap.File.MapInternal. +func (d *dentryPlatformFile) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { d.handleMu.RLock() - bs, err := d.hostFileMapper.MapInternal(fr, int(d.handle.fd), at.Write) - d.handleMu.RUnlock() - return bs, err + defer d.handleMu.RUnlock() + return d.hostFileMapper.MapInternal(fr, int(d.hostFD), at.Write) } -// FD implements platform.File.FD. +// FD implements memmap.File.FD. func (d *dentryPlatformFile) FD() int { d.handleMu.RLock() - fd := d.handle.fd - d.handleMu.RUnlock() - return int(fd) + defer d.handleMu.RUnlock() + return int(d.hostFD) } diff --git a/pkg/sentry/fsimpl/gofer/socket.go b/pkg/sentry/fsimpl/gofer/socket.go index d6dbe9092..85d2bee72 100644 --- a/pkg/sentry/fsimpl/gofer/socket.go +++ b/pkg/sentry/fsimpl/gofer/socket.go @@ -108,7 +108,7 @@ func (e *endpoint) UnidirectionalConnect(ctx context.Context) (transport.Connect // We don't need the receiver. c.CloseRecv() - c.Release() + c.Release(ctx) return c, nil } @@ -136,8 +136,8 @@ func (e *endpoint) newConnectedEndpoint(ctx context.Context, flags p9.ConnectFla } // Release implements transport.BoundEndpoint.Release. -func (e *endpoint) Release() { - e.dentry.DecRef() +func (e *endpoint) Release(ctx context.Context) { + e.dentry.DecRef(ctx) } // Passcred implements transport.BoundEndpoint.Passcred. diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go index a464e6a94..a6368fdd0 100644 --- a/pkg/sentry/fsimpl/gofer/special_file.go +++ b/pkg/sentry/fsimpl/gofer/special_file.go @@ -16,20 +16,23 @@ package gofer import ( "sync" + "sync/atomic" + "syscall" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fdnotifier" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" ) -// specialFileFD implements vfs.FileDescriptionImpl for files other than -// regular files, directories, and symlinks: pipes, sockets, etc. It is also -// used for regular files when filesystemOptions.specialRegularFiles is in -// effect. specialFileFD differs from regularFileFD by using per-FD handles -// instead of shared per-dentry handles, and never buffering I/O. +// specialFileFD implements vfs.FileDescriptionImpl for pipes, sockets, device +// special files, and (when filesystemOptions.regularFilesUseSpecialFileFD is +// in effect) regular files. specialFileFD differs from regularFileFD by using +// per-FD handles instead of shared per-dentry handles, and never buffering I/O. type specialFileFD struct { fileDescription @@ -40,14 +43,49 @@ type specialFileFD struct { // file offset is significant, i.e. a regular file. seekable is immutable. seekable bool + // haveQueue is true if this file description represents a file for which + // queue may send I/O readiness events. haveQueue is immutable. + haveQueue bool + queue waiter.Queue + // If seekable is true, off is the file offset. off is protected by mu. mu sync.Mutex off int64 } +func newSpecialFileFD(h handle, mnt *vfs.Mount, d *dentry, locks *vfs.FileLocks, flags uint32) (*specialFileFD, error) { + ftype := d.fileType() + seekable := ftype == linux.S_IFREG + haveQueue := (ftype == linux.S_IFIFO || ftype == linux.S_IFSOCK) && h.fd >= 0 + fd := &specialFileFD{ + handle: h, + seekable: seekable, + haveQueue: haveQueue, + } + fd.LockFD.Init(locks) + if haveQueue { + if err := fdnotifier.AddFD(h.fd, &fd.queue); err != nil { + return nil, err + } + } + if err := fd.vfsfd.Init(fd, flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{ + DenyPRead: !seekable, + DenyPWrite: !seekable, + }); err != nil { + if haveQueue { + fdnotifier.RemoveFD(h.fd) + } + return nil, err + } + return fd, nil +} + // Release implements vfs.FileDescriptionImpl.Release. -func (fd *specialFileFD) Release() { - fd.handle.close(context.Background()) +func (fd *specialFileFD) Release(ctx context.Context) { + if fd.haveQueue { + fdnotifier.RemoveFD(fd.handle.fd) + } + fd.handle.close(ctx) fs := fd.vfsfd.Mount().Filesystem().Impl().(*filesystem) fs.syncMu.Lock() delete(fs.specialFileFDs, fd) @@ -62,12 +100,44 @@ func (fd *specialFileFD) OnClose(ctx context.Context) error { return fd.handle.file.flush(ctx) } +// Readiness implements waiter.Waitable.Readiness. +func (fd *specialFileFD) Readiness(mask waiter.EventMask) waiter.EventMask { + if fd.haveQueue { + return fdnotifier.NonBlockingPoll(fd.handle.fd, mask) + } + return fd.fileDescription.Readiness(mask) +} + +// EventRegister implements waiter.Waitable.EventRegister. +func (fd *specialFileFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + if fd.haveQueue { + fd.queue.EventRegister(e, mask) + fdnotifier.UpdateFD(fd.handle.fd) + return + } + fd.fileDescription.EventRegister(e, mask) +} + +// EventUnregister implements waiter.Waitable.EventUnregister. +func (fd *specialFileFD) EventUnregister(e *waiter.Entry) { + if fd.haveQueue { + fd.queue.EventUnregister(e) + fdnotifier.UpdateFD(fd.handle.fd) + return + } + fd.fileDescription.EventUnregister(e) +} + // PRead implements vfs.FileDescriptionImpl.PRead. func (fd *specialFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { if fd.seekable && offset < 0 { return 0, syserror.EINVAL } - if opts.Flags != 0 { + + // Check that flags are supported. + // + // TODO(gvisor.dev/issue/2601): Support select preadv2 flags. + if opts.Flags&^linux.RWF_HIPRI != 0 { return 0, syserror.EOPNOTSUPP } @@ -76,11 +146,14 @@ func (fd *specialFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offs // mmap due to lock ordering; MM locks precede dentry.dataMu. That doesn't // hold here since specialFileFD doesn't client-cache data. Just buffer the // read instead. - if d := fd.dentry(); d.fs.opts.interop != InteropModeShared { + if d := fd.dentry(); d.cachedMetadataAuthoritative() { d.touchAtime(fd.vfsfd.Mount()) } buf := make([]byte, dst.NumBytes()) n, err := fd.handle.readToBlocksAt(ctx, safemem.BlockSeqOf(safemem.BlockFromSafeSlice(buf)), uint64(offset)) + if err == syserror.EAGAIN { + err = syserror.ErrWouldBlock + } if n == 0 { return 0, err } @@ -105,32 +178,76 @@ func (fd *specialFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts // PWrite implements vfs.FileDescriptionImpl.PWrite. func (fd *specialFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + n, _, err := fd.pwrite(ctx, src, offset, opts) + return n, err +} + +// pwrite returns the number of bytes written, final offset, error. The final +// offset should be ignored by PWrite. +func (fd *specialFileFD) pwrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (written, finalOff int64, err error) { if fd.seekable && offset < 0 { - return 0, syserror.EINVAL + return 0, offset, syserror.EINVAL } - if opts.Flags != 0 { - return 0, syserror.EOPNOTSUPP + + // Check that flags are supported. + // + // TODO(gvisor.dev/issue/2601): Support select pwritev2 flags. + if opts.Flags&^linux.RWF_HIPRI != 0 { + return 0, offset, syserror.EOPNOTSUPP + } + + d := fd.dentry() + // If the regular file fd was opened with O_APPEND, make sure the file size + // is updated. There is a possible race here if size is modified externally + // after metadata cache is updated. + if fd.seekable && fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 && !d.cachedMetadataAuthoritative() { + if err := d.updateFromGetattr(ctx); err != nil { + return 0, offset, err + } } if fd.seekable { + // We need to hold the metadataMu *while* writing to a regular file. + d.metadataMu.Lock() + defer d.metadataMu.Unlock() + + // Set offset to file size if the regular file was opened with O_APPEND. + if fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 { + // Holding d.metadataMu is sufficient for reading d.size. + offset = int64(d.size) + } limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes()) if err != nil { - return 0, err + return 0, offset, err } src = src.TakeFirst64(limit) } // Do a buffered write. See rationale in PRead. - if d := fd.dentry(); d.fs.opts.interop != InteropModeShared { + if d.cachedMetadataAuthoritative() { d.touchCMtime() } buf := make([]byte, src.NumBytes()) // Don't do partial writes if we get a partial read from src. if _, err := src.CopyIn(ctx, buf); err != nil { - return 0, err + return 0, offset, err } n, err := fd.handle.writeFromBlocksAt(ctx, safemem.BlockSeqOf(safemem.BlockFromSafeSlice(buf)), uint64(offset)) - return int64(n), err + if err == syserror.EAGAIN { + err = syserror.ErrWouldBlock + } + finalOff = offset + // Update file size for regular files. + if fd.seekable { + finalOff += int64(n) + // d.metadataMu is already locked at this point. + if uint64(finalOff) > d.size { + d.dataMu.Lock() + defer d.dataMu.Unlock() + atomic.StoreUint64(&d.size, uint64(finalOff)) + } + } + return int64(n), finalOff, err } // Write implements vfs.FileDescriptionImpl.Write. @@ -140,8 +257,8 @@ func (fd *specialFileFD) Write(ctx context.Context, src usermem.IOSequence, opts } fd.mu.Lock() - n, err := fd.PWrite(ctx, src, fd.off, opts) - fd.off += n + n, off, err := fd.pwrite(ctx, src, fd.off, opts) + fd.off = off fd.mu.Unlock() return n, err } @@ -153,27 +270,23 @@ func (fd *specialFileFD) Seek(ctx context.Context, offset int64, whence int32) ( } fd.mu.Lock() defer fd.mu.Unlock() - switch whence { - case linux.SEEK_SET: - // Use offset as given. - case linux.SEEK_CUR: - offset += fd.off - default: - // SEEK_END, SEEK_DATA, and SEEK_HOLE aren't supported since it's not - // clear that file size is even meaningful for these files. - return 0, syserror.EINVAL - } - if offset < 0 { - return 0, syserror.EINVAL + newOffset, err := regularFileSeekLocked(ctx, fd.dentry(), fd.off, offset, whence) + if err != nil { + return 0, err } - fd.off = offset - return offset, nil + fd.off = newOffset + return newOffset, nil } // Sync implements vfs.FileDescriptionImpl.Sync. func (fd *specialFileFD) Sync(ctx context.Context) error { - if !fd.vfsfd.IsWritable() { - return nil + // If we have a host FD, fsyncing it is likely to be faster than an fsync + // RPC. + if fd.handle.fd >= 0 { + ctx.UninterruptibleSleepStart(false) + err := syscall.Fsync(int(fd.handle.fd)) + ctx.UninterruptibleSleepFinish(false) + return err } - return fd.handle.sync(ctx) + return fd.handle.file.fsync(ctx) } diff --git a/pkg/sentry/fsimpl/gofer/time.go b/pkg/sentry/fsimpl/gofer/time.go index 2608e7e1d..2cb8191b9 100644 --- a/pkg/sentry/fsimpl/gofer/time.go +++ b/pkg/sentry/fsimpl/gofer/time.go @@ -36,20 +36,24 @@ func statxTimestampFromDentry(ns int64) linux.StatxTimestamp { } } -// Preconditions: fs.interop != InteropModeShared. +// Preconditions: d.cachedMetadataAuthoritative() == true. func (d *dentry) touchAtime(mnt *vfs.Mount) { + if mnt.Flags.NoATime { + return + } if err := mnt.CheckBeginWrite(); err != nil { return } now := d.fs.clock.Now().Nanoseconds() d.metadataMu.Lock() atomic.StoreInt64(&d.atime, now) + atomic.StoreUint32(&d.atimeDirty, 1) d.metadataMu.Unlock() mnt.EndWrite() } -// Preconditions: fs.interop != InteropModeShared. The caller has successfully -// called vfs.Mount.CheckBeginWrite(). +// Preconditions: d.cachedMetadataAuthoritative() == true. The caller has +// successfully called vfs.Mount.CheckBeginWrite(). func (d *dentry) touchCtime() { now := d.fs.clock.Now().Nanoseconds() d.metadataMu.Lock() @@ -57,18 +61,22 @@ func (d *dentry) touchCtime() { d.metadataMu.Unlock() } -// Preconditions: fs.interop != InteropModeShared. The caller has successfully -// called vfs.Mount.CheckBeginWrite(). +// Preconditions: d.cachedMetadataAuthoritative() == true. The caller has +// successfully called vfs.Mount.CheckBeginWrite(). func (d *dentry) touchCMtime() { now := d.fs.clock.Now().Nanoseconds() d.metadataMu.Lock() atomic.StoreInt64(&d.mtime, now) atomic.StoreInt64(&d.ctime, now) + atomic.StoreUint32(&d.mtimeDirty, 1) d.metadataMu.Unlock() } +// Preconditions: d.cachedMetadataAuthoritative() == true. The caller has +// locked d.metadataMu. func (d *dentry) touchCMtimeLocked() { now := d.fs.clock.Now().Nanoseconds() atomic.StoreInt64(&d.mtime, now) atomic.StoreInt64(&d.ctime, now) + atomic.StoreUint32(&d.mtimeDirty, 1) } diff --git a/pkg/sentry/fsimpl/host/BUILD b/pkg/sentry/fsimpl/host/BUILD index ca0fe6d2b..bd701bbc7 100644 --- a/pkg/sentry/fsimpl/host/BUILD +++ b/pkg/sentry/fsimpl/host/BUILD @@ -22,17 +22,18 @@ go_library( "//pkg/context", "//pkg/fdnotifier", "//pkg/fspath", + "//pkg/iovec", "//pkg/log", "//pkg/refs", "//pkg/safemem", "//pkg/sentry/arch", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/kernfs", "//pkg/sentry/hostfd", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", "//pkg/sentry/memmap", - "//pkg/sentry/platform", "//pkg/sentry/socket/control", "//pkg/sentry/socket/unix", "//pkg/sentry/socket/unix/transport", diff --git a/pkg/sentry/fsimpl/host/control.go b/pkg/sentry/fsimpl/host/control.go index b9082a20f..0135e4428 100644 --- a/pkg/sentry/fsimpl/host/control.go +++ b/pkg/sentry/fsimpl/host/control.go @@ -58,7 +58,7 @@ func (c *scmRights) Clone() transport.RightsControlMessage { } // Release implements transport.RightsControlMessage.Release. -func (c *scmRights) Release() { +func (c *scmRights) Release(ctx context.Context) { for _, fd := range c.fds { syscall.Close(fd) } diff --git a/pkg/sentry/fsimpl/host/host.go b/pkg/sentry/fsimpl/host/host.go index 18b127521..bd6caba06 100644 --- a/pkg/sentry/fsimpl/host/host.go +++ b/pkg/sentry/fsimpl/host/host.go @@ -28,6 +28,7 @@ import ( "gvisor.dev/gvisor/pkg/fspath" "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/refs" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" "gvisor.dev/gvisor/pkg/sentry/hostfd" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" @@ -90,7 +91,9 @@ func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions) isTTY: opts.IsTTY, wouldBlock: wouldBlock(uint32(fileType)), seekable: seekable, - canMap: canMap(uint32(fileType)), + // NOTE(b/38213152): Technically, some obscure char devices can be memory + // mapped, but we only allow regular files. + canMap: fileType == linux.S_IFREG, } i.pf.inode = i @@ -114,7 +117,7 @@ func NewFD(ctx context.Context, mnt *vfs.Mount, hostFD int, opts *NewFDOptions) d.Init(i) // i.open will take a reference on d. - defer d.DecRef() + defer d.DecRef(ctx) // For simplicity, fileDescription.offset is set to 0. Technically, we // should only set to 0 on files that are not seekable (sockets, pipes, @@ -165,9 +168,9 @@ type filesystem struct { devMinor uint32 } -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) - fs.Filesystem.Release() + fs.Filesystem.Release(ctx) } func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDentry, b *fspath.Builder) error { @@ -182,6 +185,8 @@ type inode struct { kernfs.InodeNotDirectory kernfs.InodeNotSymlink + locks vfs.FileLocks + // When the reference count reaches zero, the host fd is closed. refs.AtomicRefCount @@ -254,7 +259,7 @@ func (i *inode) Mode() linux.FileMode { } // Stat implements kernfs.Inode. -func (i *inode) Stat(vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { +func (i *inode) Stat(ctx context.Context, vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { if opts.Mask&linux.STATX__RESERVED != 0 { return linux.Statx{}, syserror.EINVAL } @@ -368,7 +373,7 @@ func (i *inode) fstat(fs *filesystem) (linux.Statx, error) { // SetStat implements kernfs.Inode. func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error { - s := opts.Stat + s := &opts.Stat m := s.Mask if m == 0 { @@ -381,7 +386,7 @@ func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Cre if err := syscall.Fstat(i.hostFD, &hostStat); err != nil { return err } - if err := vfs.CheckSetStat(ctx, creds, &s, linux.FileMode(hostStat.Mode&linux.PermissionsMask), auth.KUID(hostStat.Uid), auth.KGID(hostStat.Gid)); err != nil { + if err := vfs.CheckSetStat(ctx, creds, &opts, linux.FileMode(hostStat.Mode), auth.KUID(hostStat.Uid), auth.KGID(hostStat.Gid)); err != nil { return err } @@ -391,6 +396,9 @@ func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Cre } } if m&linux.STATX_SIZE != 0 { + if hostStat.Mode&linux.S_IFMT != linux.S_IFREG { + return syserror.EINVAL + } if err := syscall.Ftruncate(i.hostFD, int64(s.Size)); err != nil { return err } @@ -423,12 +431,12 @@ func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Cre } // DecRef implements kernfs.Inode. -func (i *inode) DecRef() { - i.AtomicRefCount.DecRefWithDestructor(i.Destroy) +func (i *inode) DecRef(ctx context.Context) { + i.AtomicRefCount.DecRefWithDestructor(ctx, i.Destroy) } // Destroy implements kernfs.Inode. -func (i *inode) Destroy() { +func (i *inode) Destroy(context.Context) { if i.wouldBlock { fdnotifier.RemoveFD(int32(i.hostFD)) } @@ -454,10 +462,12 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u fileType := s.Mode & linux.FileTypeMask // Constrain flags to a subset we can handle. - // TODO(gvisor.dev/issue/1672): implement behavior corresponding to these allowed flags. - flags &= syscall.O_ACCMODE | syscall.O_DIRECT | syscall.O_NONBLOCK | syscall.O_DSYNC | syscall.O_SYNC | syscall.O_APPEND + // + // TODO(gvisor.dev/issue/2601): Support O_NONBLOCK by adding RWF_NOWAIT to pread/pwrite calls. + flags &= syscall.O_ACCMODE | syscall.O_NONBLOCK | syscall.O_DSYNC | syscall.O_SYNC | syscall.O_APPEND - if fileType == syscall.S_IFSOCK { + switch fileType { + case syscall.S_IFSOCK: if i.isTTY { log.Warningf("cannot use host socket fd %d as TTY", i.hostFD) return nil, syserror.ENOTTY @@ -468,35 +478,41 @@ func (i *inode) open(ctx context.Context, d *vfs.Dentry, mnt *vfs.Mount, flags u return nil, err } // Currently, we only allow Unix sockets to be imported. - return unixsocket.NewFileDescription(ep, ep.Type(), flags, mnt, d) - } + return unixsocket.NewFileDescription(ep, ep.Type(), flags, mnt, d, &i.locks) - // TODO(gvisor.dev/issue/1672): Whitelist specific file types here, so that - // we don't allow importing arbitrary file types without proper support. - if i.isTTY { - fd := &TTYFileDescription{ - fileDescription: fileDescription{inode: i}, - termios: linux.DefaultSlaveTermios, + case syscall.S_IFREG, syscall.S_IFIFO, syscall.S_IFCHR: + if i.isTTY { + fd := &TTYFileDescription{ + fileDescription: fileDescription{inode: i}, + termios: linux.DefaultSlaveTermios, + } + fd.LockFD.Init(&i.locks) + vfsfd := &fd.vfsfd + if err := vfsfd.Init(fd, flags, mnt, d, &vfs.FileDescriptionOptions{}); err != nil { + return nil, err + } + return vfsfd, nil } + + fd := &fileDescription{inode: i} + fd.LockFD.Init(&i.locks) vfsfd := &fd.vfsfd if err := vfsfd.Init(fd, flags, mnt, d, &vfs.FileDescriptionOptions{}); err != nil { return nil, err } return vfsfd, nil - } - fd := &fileDescription{inode: i} - vfsfd := &fd.vfsfd - if err := vfsfd.Init(fd, flags, mnt, d, &vfs.FileDescriptionOptions{}); err != nil { - return nil, err + default: + log.Warningf("cannot import host fd %d with file type %o", i.hostFD, fileType) + return nil, syserror.EPERM } - return vfsfd, nil } // fileDescription is embedded by host fd implementations of FileDescriptionImpl. type fileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD // inode is vfsfd.Dentry().Impl().(*kernfs.Dentry).Inode().(*inode), but // cached to reduce indirections and casting. fileDescription does not hold @@ -521,15 +537,25 @@ func (f *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) } // Stat implements vfs.FileDescriptionImpl. -func (f *fileDescription) Stat(_ context.Context, opts vfs.StatOptions) (linux.Statx, error) { - return f.inode.Stat(f.vfsfd.Mount().Filesystem(), opts) +func (f *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { + return f.inode.Stat(ctx, f.vfsfd.Mount().Filesystem(), opts) } // Release implements vfs.FileDescriptionImpl. -func (f *fileDescription) Release() { +func (f *fileDescription) Release(context.Context) { // noop } +// Allocate implements vfs.FileDescriptionImpl. +func (f *fileDescription) Allocate(ctx context.Context, mode, offset, length uint64) error { + if !f.inode.seekable { + return syserror.ESPIPE + } + + // TODO(gvisor.dev/issue/3589): Implement Allocate for non-pipe hostfds. + return syserror.EOPNOTSUPP +} + // PRead implements FileDescriptionImpl. func (f *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { i := f.inode @@ -556,7 +582,7 @@ func (f *fileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts } return n, err } - // TODO(gvisor.dev/issue/1672): Cache pages, when forced to do so. + f.offsetMu.Lock() n, err := readFromHostFD(ctx, i.hostFD, dst, f.offset, opts.Flags) f.offset += n @@ -565,8 +591,10 @@ func (f *fileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts } func readFromHostFD(ctx context.Context, hostFD int, dst usermem.IOSequence, offset int64, flags uint32) (int64, error) { - // TODO(gvisor.dev/issue/1672): Support select preadv2 flags. - if flags != 0 { + // Check that flags are supported. + // + // TODO(gvisor.dev/issue/2601): Support select preadv2 flags. + if flags&^linux.RWF_HIPRI != 0 { return 0, syserror.EOPNOTSUPP } reader := hostfd.GetReadWriterAt(int32(hostFD), offset, flags) @@ -577,41 +605,58 @@ func readFromHostFD(ctx context.Context, hostFD int, dst usermem.IOSequence, off // PWrite implements FileDescriptionImpl. func (f *fileDescription) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { - i := f.inode - if !i.seekable { + if !f.inode.seekable { return 0, syserror.ESPIPE } - return writeToHostFD(ctx, i.hostFD, src, offset, opts.Flags) + return f.writeToHostFD(ctx, src, offset, opts.Flags) } // Write implements FileDescriptionImpl. func (f *fileDescription) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { i := f.inode if !i.seekable { - n, err := writeToHostFD(ctx, i.hostFD, src, -1, opts.Flags) + n, err := f.writeToHostFD(ctx, src, -1, opts.Flags) if isBlockError(err) { err = syserror.ErrWouldBlock } return n, err } - // TODO(gvisor.dev/issue/1672): Cache pages, when forced to do so. - // TODO(gvisor.dev/issue/1672): Write to end of file and update offset if O_APPEND is set on this file. + f.offsetMu.Lock() - n, err := writeToHostFD(ctx, i.hostFD, src, f.offset, opts.Flags) + // NOTE(gvisor.dev/issue/2983): O_APPEND may cause memory corruption if + // another process modifies the host file between retrieving the file size + // and writing to the host fd. This is an unavoidable race condition because + // we cannot enforce synchronization on the host. + if f.vfsfd.StatusFlags()&linux.O_APPEND != 0 { + var s syscall.Stat_t + if err := syscall.Fstat(i.hostFD, &s); err != nil { + f.offsetMu.Unlock() + return 0, err + } + f.offset = s.Size + } + n, err := f.writeToHostFD(ctx, src, f.offset, opts.Flags) f.offset += n f.offsetMu.Unlock() return n, err } -func writeToHostFD(ctx context.Context, hostFD int, src usermem.IOSequence, offset int64, flags uint32) (int64, error) { - // TODO(gvisor.dev/issue/1672): Support select pwritev2 flags. +func (f *fileDescription) writeToHostFD(ctx context.Context, src usermem.IOSequence, offset int64, flags uint32) (int64, error) { + hostFD := f.inode.hostFD + // TODO(gvisor.dev/issue/2601): Support select pwritev2 flags. if flags != 0 { return 0, syserror.EOPNOTSUPP } writer := hostfd.GetReadWriterAt(int32(hostFD), offset, flags) n, err := src.CopyInTo(ctx, writer) hostfd.PutReadWriterAt(writer) + // NOTE(gvisor.dev/issue/2979): We always sync everything, even for O_DSYNC. + if n > 0 && f.vfsfd.StatusFlags()&(linux.O_DSYNC|linux.O_SYNC) != 0 { + if syncErr := unix.Fsync(hostFD); syncErr != nil { + return int64(n), syncErr + } + } return int64(n), err } @@ -682,7 +727,7 @@ func (f *fileDescription) Seek(_ context.Context, offset int64, whence int32) (i // Sync implements FileDescriptionImpl. func (f *fileDescription) Sync(context.Context) error { - // TODO(gvisor.dev/issue/1672): Currently we do not support the SyncData optimization, so we always sync everything. + // TODO(gvisor.dev/issue/1897): Currently, we always sync everything. return unix.Fsync(f.inode.hostFD) } @@ -712,3 +757,13 @@ func (f *fileDescription) EventUnregister(e *waiter.Entry) { func (f *fileDescription) Readiness(mask waiter.EventMask) waiter.EventMask { return fdnotifier.NonBlockingPoll(int32(f.inode.hostFD), mask) } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (f *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return f.Locks().LockPOSIX(ctx, &f.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (f *fileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return f.Locks().UnlockPOSIX(ctx, &f.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/host/mmap.go b/pkg/sentry/fsimpl/host/mmap.go index 8545a82f0..65d3af38c 100644 --- a/pkg/sentry/fsimpl/host/mmap.go +++ b/pkg/sentry/fsimpl/host/mmap.go @@ -19,13 +19,12 @@ import ( "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" "gvisor.dev/gvisor/pkg/sentry/memmap" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/usermem" ) -// inodePlatformFile implements platform.File. It exists solely because inode -// cannot implement both kernfs.Inode.IncRef and platform.File.IncRef. +// inodePlatformFile implements memmap.File. It exists solely because inode +// cannot implement both kernfs.Inode.IncRef and memmap.File.IncRef. // // inodePlatformFile should only be used if inode.canMap is true. type inodePlatformFile struct { @@ -34,7 +33,7 @@ type inodePlatformFile struct { // fdRefsMu protects fdRefs. fdRefsMu sync.Mutex - // fdRefs counts references on platform.File offsets. It is used solely for + // fdRefs counts references on memmap.File offsets. It is used solely for // memory accounting. fdRefs fsutil.FrameRefSet @@ -45,32 +44,32 @@ type inodePlatformFile struct { fileMapperInitOnce sync.Once } -// IncRef implements platform.File.IncRef. +// IncRef implements memmap.File.IncRef. // // Precondition: i.inode.canMap must be true. -func (i *inodePlatformFile) IncRef(fr platform.FileRange) { +func (i *inodePlatformFile) IncRef(fr memmap.FileRange) { i.fdRefsMu.Lock() i.fdRefs.IncRefAndAccount(fr) i.fdRefsMu.Unlock() } -// DecRef implements platform.File.DecRef. +// DecRef implements memmap.File.DecRef. // // Precondition: i.inode.canMap must be true. -func (i *inodePlatformFile) DecRef(fr platform.FileRange) { +func (i *inodePlatformFile) DecRef(fr memmap.FileRange) { i.fdRefsMu.Lock() i.fdRefs.DecRefAndAccount(fr) i.fdRefsMu.Unlock() } -// MapInternal implements platform.File.MapInternal. +// MapInternal implements memmap.File.MapInternal. // // Precondition: i.inode.canMap must be true. -func (i *inodePlatformFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { +func (i *inodePlatformFile) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { return i.fileMapper.MapInternal(fr, i.hostFD, at.Write) } -// FD implements platform.File.FD. +// FD implements memmap.File.FD. func (i *inodePlatformFile) FD() int { return i.hostFD } diff --git a/pkg/sentry/fsimpl/host/socket.go b/pkg/sentry/fsimpl/host/socket.go index 38f1fbfba..4979dd0a9 100644 --- a/pkg/sentry/fsimpl/host/socket.go +++ b/pkg/sentry/fsimpl/host/socket.go @@ -47,11 +47,6 @@ func newEndpoint(ctx context.Context, hostFD int, queue *waiter.Queue) (transpor return ep, nil } -// maxSendBufferSize is the maximum host send buffer size allowed for endpoint. -// -// N.B. 8MB is the default maximum on Linux (2 * sysctl_wmem_max). -const maxSendBufferSize = 8 << 20 - // ConnectedEndpoint is an implementation of transport.ConnectedEndpoint and // transport.Receiver. It is backed by a host fd that was imported at sentry // startup. This fd is shared with a hostfs inode, which retains ownership of @@ -114,10 +109,6 @@ func (c *ConnectedEndpoint) init() *syserr.Error { if err != nil { return syserr.FromError(err) } - if sndbuf > maxSendBufferSize { - log.Warningf("Socket send buffer too large: %d", sndbuf) - return syserr.ErrInvalidEndpointState - } c.stype = linux.SockType(stype) c.sndbuf = int64(sndbuf) @@ -148,7 +139,7 @@ func NewConnectedEndpoint(ctx context.Context, hostFD int, addr string, saveable } // Send implements transport.ConnectedEndpoint.Send. -func (c *ConnectedEndpoint) Send(data [][]byte, controlMessages transport.ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { +func (c *ConnectedEndpoint) Send(ctx context.Context, data [][]byte, controlMessages transport.ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { c.mu.RLock() defer c.mu.RUnlock() @@ -225,7 +216,7 @@ func (c *ConnectedEndpoint) EventUpdate() { } // Recv implements transport.Receiver.Recv. -func (c *ConnectedEndpoint) Recv(data [][]byte, creds bool, numRights int, peek bool) (int64, int64, transport.ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { +func (c *ConnectedEndpoint) Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (int64, int64, transport.ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { c.mu.RLock() defer c.mu.RUnlock() @@ -326,8 +317,8 @@ func (c *ConnectedEndpoint) destroyLocked() { // Release implements transport.ConnectedEndpoint.Release and // transport.Receiver.Release. -func (c *ConnectedEndpoint) Release() { - c.ref.DecRefWithDestructor(func() { +func (c *ConnectedEndpoint) Release(ctx context.Context) { + c.ref.DecRefWithDestructor(ctx, func(context.Context) { c.mu.Lock() c.destroyLocked() c.mu.Unlock() @@ -356,8 +347,8 @@ func (e *SCMConnectedEndpoint) Init() error { // Release implements transport.ConnectedEndpoint.Release and // transport.Receiver.Release. -func (e *SCMConnectedEndpoint) Release() { - e.ref.DecRefWithDestructor(func() { +func (e *SCMConnectedEndpoint) Release(ctx context.Context) { + e.ref.DecRefWithDestructor(ctx, func(context.Context) { e.mu.Lock() if err := syscall.Close(e.fd); err != nil { log.Warningf("Failed to close host fd %d: %v", err) diff --git a/pkg/sentry/fsimpl/host/socket_iovec.go b/pkg/sentry/fsimpl/host/socket_iovec.go index 584c247d2..fc0d5fd38 100644 --- a/pkg/sentry/fsimpl/host/socket_iovec.go +++ b/pkg/sentry/fsimpl/host/socket_iovec.go @@ -17,13 +17,10 @@ package host import ( "syscall" - "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/iovec" "gvisor.dev/gvisor/pkg/syserror" ) -// maxIovs is the maximum number of iovecs to pass to the host. -var maxIovs = linux.UIO_MAXIOV - // copyToMulti copies as many bytes from src to dst as possible. func copyToMulti(dst [][]byte, src []byte) { for _, d := range dst { @@ -74,7 +71,7 @@ func buildIovec(bufs [][]byte, maxlen int64, truncate bool) (length int64, iovec } } - if iovsRequired > maxIovs { + if iovsRequired > iovec.MaxIovs { // The kernel will reject our call if we pass this many iovs. // Use a single intermediate buffer instead. b := make([]byte, stopLen) diff --git a/pkg/sentry/fsimpl/host/tty.go b/pkg/sentry/fsimpl/host/tty.go index 68af6e5af..d372c60cb 100644 --- a/pkg/sentry/fsimpl/host/tty.go +++ b/pkg/sentry/fsimpl/host/tty.go @@ -18,6 +18,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/unimpl" "gvisor.dev/gvisor/pkg/sentry/vfs" @@ -66,12 +67,12 @@ func (t *TTYFileDescription) ForegroundProcessGroup() *kernel.ProcessGroup { } // Release implements fs.FileOperations.Release. -func (t *TTYFileDescription) Release() { +func (t *TTYFileDescription) Release(ctx context.Context) { t.mu.Lock() t.fgProcessGroup = nil t.mu.Unlock() - t.fileDescription.Release() + t.fileDescription.Release(ctx) } // PRead implements vfs.FileDescriptionImpl. @@ -325,9 +326,9 @@ func (t *TTYFileDescription) checkChange(ctx context.Context, sig linux.Signal) task := kernel.TaskFromContext(ctx) if task == nil { // No task? Linux does not have an analog for this case, but - // tty_check_change is more of a blacklist of cases than a - // whitelist, and is surprisingly permissive. Allowing the - // change seems most appropriate. + // tty_check_change only blocks specific cases and is + // surprisingly permissive. Allowing the change seems + // appropriate. return nil } @@ -377,3 +378,13 @@ func (t *TTYFileDescription) checkChange(ctx context.Context, sig linux.Signal) _ = pg.SendSignal(kernel.SignalInfoPriv(sig)) return kernel.ERESTARTSYS } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (t *TTYFileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, typ fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return t.Locks().LockPOSIX(ctx, &t.vfsfd, uid, typ, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (t *TTYFileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return t.Locks().UnlockPOSIX(ctx, &t.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/host/util.go b/pkg/sentry/fsimpl/host/util.go index 2bc757b1a..412bdb2eb 100644 --- a/pkg/sentry/fsimpl/host/util.go +++ b/pkg/sentry/fsimpl/host/util.go @@ -49,16 +49,6 @@ func wouldBlock(fileType uint32) bool { return fileType == syscall.S_IFIFO || fileType == syscall.S_IFCHR || fileType == syscall.S_IFSOCK } -// canMap returns true if a file with fileType is allowed to be memory mapped. -// This is ported over from VFS1, but it's probably not the best way for us -// to check if a file can be memory mapped. -func canMap(fileType uint32) bool { - // TODO(gvisor.dev/issue/1672): Also allow "special files" to be mapped (see fs/host:canMap()). - // - // TODO(b/38213152): Some obscure character devices can be mapped. - return fileType == syscall.S_IFREG -} - // isBlockError checks if an error is EAGAIN or EWOULDBLOCK. // If so, they can be transformed into syserror.ErrWouldBlock. func isBlockError(err error) bool { diff --git a/pkg/sentry/fsimpl/kernfs/BUILD b/pkg/sentry/fsimpl/kernfs/BUILD index ef34cb28a..3835557fe 100644 --- a/pkg/sentry/fsimpl/kernfs/BUILD +++ b/pkg/sentry/fsimpl/kernfs/BUILD @@ -45,6 +45,7 @@ go_library( "//pkg/fspath", "//pkg/log", "//pkg/refs", + "//pkg/sentry/fs/lock", "//pkg/sentry/kernel/auth", "//pkg/sentry/memmap", "//pkg/sentry/socket/unix/transport", @@ -69,6 +70,6 @@ go_test( "//pkg/sentry/vfs", "//pkg/syserror", "//pkg/usermem", - "@com_github_google_go-cmp//cmp:go_default_library", + "@com_github_google_go_cmp//cmp:go_default_library", ], ) diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go index 1568a9d49..12adf727a 100644 --- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go +++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go @@ -19,6 +19,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/syserror" @@ -38,7 +39,8 @@ type DynamicBytesFile struct { InodeNotDirectory InodeNotSymlink - data vfs.DynamicBytesSource + locks vfs.FileLocks + data vfs.DynamicBytesSource } var _ Inode = (*DynamicBytesFile)(nil) @@ -55,7 +57,7 @@ func (f *DynamicBytesFile) Init(creds *auth.Credentials, devMajor, devMinor uint // Open implements Inode.Open. func (f *DynamicBytesFile) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { fd := &DynamicBytesFD{} - if err := fd.Init(rp.Mount(), vfsd, f.data, opts.Flags); err != nil { + if err := fd.Init(rp.Mount(), vfsd, f.data, &f.locks, opts.Flags); err != nil { return nil, err } return &fd.vfsfd, nil @@ -77,13 +79,15 @@ func (*DynamicBytesFile) SetStat(context.Context, *vfs.Filesystem, *auth.Credent type DynamicBytesFD struct { vfs.FileDescriptionDefaultImpl vfs.DynamicBytesFileDescriptionImpl + vfs.LockFD vfsfd vfs.FileDescription inode Inode } // Init initializes a DynamicBytesFD. -func (fd *DynamicBytesFD) Init(m *vfs.Mount, d *vfs.Dentry, data vfs.DynamicBytesSource, flags uint32) error { +func (fd *DynamicBytesFD) Init(m *vfs.Mount, d *vfs.Dentry, data vfs.DynamicBytesSource, locks *vfs.FileLocks, flags uint32) error { + fd.LockFD.Init(locks) if err := fd.vfsfd.Init(fd, flags, m, d, &vfs.FileDescriptionOptions{}); err != nil { return err } @@ -97,12 +101,12 @@ func (fd *DynamicBytesFD) Seek(ctx context.Context, offset int64, whence int32) return fd.DynamicBytesFileDescriptionImpl.Seek(ctx, offset, whence) } -// Read implmenets vfs.FileDescriptionImpl.Read. +// Read implements vfs.FileDescriptionImpl.Read. func (fd *DynamicBytesFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { return fd.DynamicBytesFileDescriptionImpl.Read(ctx, dst, opts) } -// PRead implmenets vfs.FileDescriptionImpl.PRead. +// PRead implements vfs.FileDescriptionImpl.PRead. func (fd *DynamicBytesFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { return fd.DynamicBytesFileDescriptionImpl.PRead(ctx, dst, offset, opts) } @@ -118,12 +122,12 @@ func (fd *DynamicBytesFD) PWrite(ctx context.Context, src usermem.IOSequence, of } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *DynamicBytesFD) Release() {} +func (fd *DynamicBytesFD) Release(context.Context) {} // Stat implements vfs.FileDescriptionImpl.Stat. func (fd *DynamicBytesFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { fs := fd.vfsfd.VirtualDentry().Mount().Filesystem() - return fd.inode.Stat(fs, opts) + return fd.inode.Stat(ctx, fs, opts) } // SetStat implements vfs.FileDescriptionImpl.SetStat. @@ -131,3 +135,13 @@ func (fd *DynamicBytesFD) SetStat(context.Context, vfs.SetStatOptions) error { // DynamicBytesFiles are immutable. return syserror.EPERM } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *DynamicBytesFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *DynamicBytesFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go index 8284e76a7..fcee6200a 100644 --- a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go +++ b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go @@ -19,6 +19,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/vfs" @@ -42,6 +43,7 @@ import ( type GenericDirectoryFD struct { vfs.FileDescriptionDefaultImpl vfs.DirectoryFileDescriptionDefaultImpl + vfs.LockFD vfsfd vfs.FileDescription children *OrderedChildren @@ -55,9 +57,9 @@ type GenericDirectoryFD struct { // NewGenericDirectoryFD creates a new GenericDirectoryFD and returns its // dentry. -func NewGenericDirectoryFD(m *vfs.Mount, d *vfs.Dentry, children *OrderedChildren, opts *vfs.OpenOptions) (*GenericDirectoryFD, error) { +func NewGenericDirectoryFD(m *vfs.Mount, d *vfs.Dentry, children *OrderedChildren, locks *vfs.FileLocks, opts *vfs.OpenOptions) (*GenericDirectoryFD, error) { fd := &GenericDirectoryFD{} - if err := fd.Init(children, opts); err != nil { + if err := fd.Init(children, locks, opts); err != nil { return nil, err } if err := fd.vfsfd.Init(fd, opts.Flags, m, d, &vfs.FileDescriptionOptions{}); err != nil { @@ -69,11 +71,12 @@ func NewGenericDirectoryFD(m *vfs.Mount, d *vfs.Dentry, children *OrderedChildre // Init initializes a GenericDirectoryFD. Use it when overriding // GenericDirectoryFD. Caller must call fd.VFSFileDescription.Init() with the // correct implementation. -func (fd *GenericDirectoryFD) Init(children *OrderedChildren, opts *vfs.OpenOptions) error { +func (fd *GenericDirectoryFD) Init(children *OrderedChildren, locks *vfs.FileLocks, opts *vfs.OpenOptions) error { if vfs.AccessTypesForOpenFlags(opts)&vfs.MayWrite != 0 { // Can't open directories for writing. return syserror.EISDIR } + fd.LockFD.Init(locks) fd.children = children return nil } @@ -109,8 +112,8 @@ func (fd *GenericDirectoryFD) PWrite(ctx context.Context, src usermem.IOSequence return fd.DirectoryFileDescriptionDefaultImpl.PWrite(ctx, src, offset, opts) } -// Release implements vfs.FileDecriptionImpl.Release. -func (fd *GenericDirectoryFD) Release() {} +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *GenericDirectoryFD) Release(context.Context) {} func (fd *GenericDirectoryFD) filesystem() *vfs.Filesystem { return fd.vfsfd.VirtualDentry().Mount().Filesystem() @@ -120,7 +123,7 @@ func (fd *GenericDirectoryFD) inode() Inode { return fd.vfsfd.VirtualDentry().Dentry().Impl().(*Dentry).inode } -// IterDirents implements vfs.FileDecriptionImpl.IterDirents. IterDirents holds +// IterDirents implements vfs.FileDescriptionImpl.IterDirents. IterDirents holds // o.mu when calling cb. func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback) error { fd.mu.Lock() @@ -129,7 +132,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent opts := vfs.StatOptions{Mask: linux.STATX_INO} // Handle ".". if fd.off == 0 { - stat, err := fd.inode().Stat(fd.filesystem(), opts) + stat, err := fd.inode().Stat(ctx, fd.filesystem(), opts) if err != nil { return err } @@ -149,7 +152,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent if fd.off == 1 { vfsd := fd.vfsfd.VirtualDentry().Dentry() parentInode := genericParentOrSelf(vfsd.Impl().(*Dentry)).inode - stat, err := parentInode.Stat(fd.filesystem(), opts) + stat, err := parentInode.Stat(ctx, fd.filesystem(), opts) if err != nil { return err } @@ -173,7 +176,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent childIdx := fd.off - 2 for it := fd.children.nthLocked(childIdx); it != nil; it = it.Next() { inode := it.Dentry.Impl().(*Dentry).inode - stat, err := inode.Stat(fd.filesystem(), opts) + stat, err := inode.Stat(ctx, fd.filesystem(), opts) if err != nil { return err } @@ -195,7 +198,7 @@ func (fd *GenericDirectoryFD) IterDirents(ctx context.Context, cb vfs.IterDirent return err } -// Seek implements vfs.FileDecriptionImpl.Seek. +// Seek implements vfs.FileDescriptionImpl.Seek. func (fd *GenericDirectoryFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { fd.mu.Lock() defer fd.mu.Unlock() @@ -223,7 +226,7 @@ func (fd *GenericDirectoryFD) Seek(ctx context.Context, offset int64, whence int func (fd *GenericDirectoryFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { fs := fd.filesystem() inode := fd.inode() - return inode.Stat(fs, opts) + return inode.Stat(ctx, fs, opts) } // SetStat implements vfs.FileDescriptionImpl.SetStat. @@ -232,3 +235,18 @@ func (fd *GenericDirectoryFD) SetStat(ctx context.Context, opts vfs.SetStatOptio inode := fd.vfsfd.VirtualDentry().Dentry().Impl().(*Dentry).inode return inode.SetStat(ctx, fd.filesystem(), creds, opts) } + +// Allocate implements vfs.FileDescriptionImpl.Allocate. +func (fd *GenericDirectoryFD) Allocate(ctx context.Context, mode, offset, length uint64) error { + return fd.DirectoryFileDescriptionDefaultImpl.Allocate(ctx, mode, offset, length) +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *GenericDirectoryFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *GenericDirectoryFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go index 4a12ae245..d7edb6342 100644 --- a/pkg/sentry/fsimpl/kernfs/filesystem.go +++ b/pkg/sentry/fsimpl/kernfs/filesystem.go @@ -35,7 +35,7 @@ import ( // Preconditions: Filesystem.mu must be locked for at least reading. !rp.Done(). // // Postcondition: Caller must call fs.processDeferredDecRefs*. -func (fs *Filesystem) stepExistingLocked(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry) (*vfs.Dentry, error) { +func (fs *Filesystem) stepExistingLocked(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, mayFollowSymlinks bool) (*vfs.Dentry, error) { d := vfsd.Impl().(*Dentry) if !d.isDir() { return nil, syserror.ENOTDIR @@ -56,13 +56,13 @@ afterSymlink: return vfsd, nil } if name == ".." { - if isRoot, err := rp.CheckRoot(vfsd); err != nil { + if isRoot, err := rp.CheckRoot(ctx, vfsd); err != nil { return nil, err } else if isRoot || d.parent == nil { rp.Advance() return vfsd, nil } - if err := rp.CheckMount(&d.parent.vfsd); err != nil { + if err := rp.CheckMount(ctx, &d.parent.vfsd); err != nil { return nil, err } rp.Advance() @@ -77,18 +77,18 @@ afterSymlink: if err != nil { return nil, err } - if err := rp.CheckMount(&next.vfsd); err != nil { + if err := rp.CheckMount(ctx, &next.vfsd); err != nil { return nil, err } // Resolve any symlink at current path component. - if rp.ShouldFollowSymlink() && next.isSymlink() { + if mayFollowSymlinks && rp.ShouldFollowSymlink() && next.isSymlink() { targetVD, targetPathname, err := next.inode.Getlink(ctx, rp.Mount()) if err != nil { return nil, err } if targetVD.Ok() { err := rp.HandleJump(targetVD) - targetVD.DecRef() + targetVD.DecRef(ctx) if err != nil { return nil, err } @@ -116,7 +116,7 @@ func (fs *Filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.Vir // Cached dentry exists, revalidate. if !child.inode.Valid(ctx) { delete(parent.children, name) - vfsObj.InvalidateDentry(&child.vfsd) + vfsObj.InvalidateDentry(ctx, &child.vfsd) fs.deferDecRef(&child.vfsd) // Reference from Lookup. child = nil } @@ -152,7 +152,7 @@ func (fs *Filesystem) walkExistingLocked(ctx context.Context, rp *vfs.ResolvingP vfsd := rp.Start() for !rp.Done() { var err error - vfsd, err = fs.stepExistingLocked(ctx, rp, vfsd) + vfsd, err = fs.stepExistingLocked(ctx, rp, vfsd, true /* mayFollowSymlinks */) if err != nil { return nil, nil, err } @@ -178,7 +178,7 @@ func (fs *Filesystem) walkParentDirLocked(ctx context.Context, rp *vfs.Resolving vfsd := rp.Start() for !rp.Final() { var err error - vfsd, err = fs.stepExistingLocked(ctx, rp, vfsd) + vfsd, err = fs.stepExistingLocked(ctx, rp, vfsd, true /* mayFollowSymlinks */) if err != nil { return nil, nil, err } @@ -234,7 +234,7 @@ func checkDeleteLocked(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Den } // Release implements vfs.FilesystemImpl.Release. -func (fs *Filesystem) Release() { +func (fs *Filesystem) Release(context.Context) { } // Sync implements vfs.FilesystemImpl.Sync. @@ -246,7 +246,7 @@ func (fs *Filesystem) Sync(ctx context.Context) error { // AccessAt implements vfs.Filesystem.Impl.AccessAt. func (fs *Filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() _, inode, err := fs.walkExistingLocked(ctx, rp) @@ -259,7 +259,7 @@ func (fs *Filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds // GetDentryAt implements vfs.FilesystemImpl.GetDentryAt. func (fs *Filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() vfsd, inode, err := fs.walkExistingLocked(ctx, rp) if err != nil { @@ -282,7 +282,7 @@ func (fs *Filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op // GetParentDentryAt implements vfs.FilesystemImpl.GetParentDentryAt. func (fs *Filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() vfsd, _, err := fs.walkParentDirLocked(ctx, rp) if err != nil { @@ -300,7 +300,7 @@ func (fs *Filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs. fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -337,7 +337,7 @@ func (fs *Filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts v fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -365,7 +365,7 @@ func (fs *Filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -397,7 +397,7 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf // Do not create new file. if opts.Flags&linux.O_CREAT == 0 { fs.mu.RLock() - defer fs.processDeferredDecRefs() + defer fs.processDeferredDecRefs(ctx) defer fs.mu.RUnlock() vfsd, inode, err := fs.walkExistingLocked(ctx, rp) if err != nil { @@ -429,7 +429,7 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf } afterTrailingSymlink: parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return nil, err } @@ -449,7 +449,7 @@ afterTrailingSymlink: return nil, syserror.ENAMETOOLONG } // Determine whether or not we need to create a file. - childVFSD, err := fs.stepExistingLocked(ctx, rp, parentVFSD) + childVFSD, err := fs.stepExistingLocked(ctx, rp, parentVFSD, false /* mayFollowSymlinks */) if err == syserror.ENOENT { // Already checked for searchability above; now check for writability. if err := parentInode.CheckPermissions(ctx, rp.Credentials(), vfs.MayWrite); err != nil { @@ -483,7 +483,7 @@ afterTrailingSymlink: } if targetVD.Ok() { err := rp.HandleJump(targetVD) - targetVD.DecRef() + targetVD.DecRef(ctx) if err != nil { return nil, err } @@ -507,7 +507,7 @@ func (fs *Filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (st fs.mu.RLock() d, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return "", err } @@ -526,7 +526,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa noReplace := opts.Flags&linux.RENAME_NOREPLACE != 0 fs.mu.Lock() - defer fs.processDeferredDecRefsLocked() + defer fs.processDeferredDecRefsLocked(ctx) defer fs.mu.Unlock() // Resolve the destination directory first to verify that it's on this @@ -584,7 +584,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa } mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) virtfs := rp.VirtualFilesystem() // We can't deadlock here due to lock ordering because we're protected from @@ -615,7 +615,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa dstDir.children = make(map[string]*Dentry) } dstDir.children[pc] = src - virtfs.CommitRenameReplaceDentry(srcVFSD, replaced) + virtfs.CommitRenameReplaceDentry(ctx, srcVFSD, replaced) return nil } @@ -624,7 +624,7 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error fs.mu.Lock() defer fs.mu.Unlock() vfsd, inode, err := fs.walkExistingLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -648,7 +648,7 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error defer parentDentry.dirMu.Unlock() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := virtfs.PrepareDeleteDentry(mntns, vfsd); err != nil { return err } @@ -656,7 +656,7 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error virtfs.AbortDeleteDentry(vfsd) return err } - virtfs.CommitDeleteDentry(vfsd) + virtfs.CommitDeleteDentry(ctx, vfsd) return nil } @@ -665,7 +665,7 @@ func (fs *Filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts fs.mu.RLock() _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return err } @@ -680,11 +680,11 @@ func (fs *Filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf fs.mu.RLock() _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return linux.Statx{}, err } - return inode.Stat(fs.VFSFilesystem(), opts) + return inode.Stat(ctx, fs.VFSFilesystem(), opts) } // StatFSAt implements vfs.FilesystemImpl.StatFSAt. @@ -692,7 +692,7 @@ func (fs *Filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linu fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return linux.Statfs{}, err } @@ -708,7 +708,7 @@ func (fs *Filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ fs.mu.Lock() defer fs.mu.Unlock() parentVFSD, parentInode, err := fs.walkParentDirLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -733,7 +733,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error fs.mu.Lock() defer fs.mu.Unlock() vfsd, _, err := fs.walkExistingLocked(ctx, rp) - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) if err != nil { return err } @@ -753,7 +753,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error parentDentry.dirMu.Lock() defer parentDentry.dirMu.Unlock() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := virtfs.PrepareDeleteDentry(mntns, vfsd); err != nil { return err } @@ -761,7 +761,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error virtfs.AbortDeleteDentry(vfsd) return err } - virtfs.CommitDeleteDentry(vfsd) + virtfs.CommitDeleteDentry(ctx, vfsd) return nil } @@ -770,7 +770,7 @@ func (fs *Filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath fs.mu.RLock() _, inode, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return nil, err } @@ -785,7 +785,7 @@ func (fs *Filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, si fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return nil, err } @@ -798,7 +798,7 @@ func (fs *Filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return "", err } @@ -811,7 +811,7 @@ func (fs *Filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return err } @@ -824,7 +824,7 @@ func (fs *Filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, fs.mu.RLock() _, _, err := fs.walkExistingLocked(ctx, rp) fs.mu.RUnlock() - fs.processDeferredDecRefs() + fs.processDeferredDecRefs(ctx) if err != nil { return err } diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go index 982daa2e6..c3efcf3ec 100644 --- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go +++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go @@ -40,7 +40,7 @@ func (InodeNoopRefCount) IncRef() { } // DecRef implements Inode.DecRef. -func (InodeNoopRefCount) DecRef() { +func (InodeNoopRefCount) DecRef(context.Context) { } // TryIncRef implements Inode.TryIncRef. @@ -49,7 +49,7 @@ func (InodeNoopRefCount) TryIncRef() bool { } // Destroy implements Inode.Destroy. -func (InodeNoopRefCount) Destroy() { +func (InodeNoopRefCount) Destroy(context.Context) { } // InodeDirectoryNoNewChildren partially implements the Inode interface. @@ -243,7 +243,7 @@ func (a *InodeAttrs) Mode() linux.FileMode { // Stat partially implements Inode.Stat. Note that this function doesn't provide // all the stat fields, and the embedder should consider extending the result // with filesystem-specific fields. -func (a *InodeAttrs) Stat(*vfs.Filesystem, vfs.StatOptions) (linux.Statx, error) { +func (a *InodeAttrs) Stat(context.Context, *vfs.Filesystem, vfs.StatOptions) (linux.Statx, error) { var stat linux.Statx stat.Mask = linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO | linux.STATX_NLINK stat.DevMajor = a.devMajor @@ -267,7 +267,7 @@ func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *aut if opts.Stat.Mask&^(linux.STATX_MODE|linux.STATX_UID|linux.STATX_GID) != 0 { return syserror.EPERM } - if err := vfs.CheckSetStat(ctx, creds, &opts.Stat, a.Mode(), auth.KUID(atomic.LoadUint32(&a.uid)), auth.KGID(atomic.LoadUint32(&a.gid))); err != nil { + if err := vfs.CheckSetStat(ctx, creds, &opts, a.Mode(), auth.KUID(atomic.LoadUint32(&a.uid)), auth.KGID(atomic.LoadUint32(&a.gid))); err != nil { return err } @@ -293,6 +293,8 @@ func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *aut // inode numbers are immutable after node creation. // TODO(gvisor.dev/issue/1193): Implement other stat fields like timestamps. + // Also, STATX_SIZE will need some special handling, because read-only static + // files should return EIO for truncate operations. return nil } @@ -364,12 +366,12 @@ func (o *OrderedChildren) Init(opts OrderedChildrenOptions) { } // DecRef implements Inode.DecRef. -func (o *OrderedChildren) DecRef() { - o.AtomicRefCount.DecRefWithDestructor(o.Destroy) +func (o *OrderedChildren) DecRef(ctx context.Context) { + o.AtomicRefCount.DecRefWithDestructor(ctx, o.Destroy) } // Destroy cleans up resources referenced by this OrderedChildren. -func (o *OrderedChildren) Destroy() { +func (o *OrderedChildren) Destroy(context.Context) { o.mu.Lock() defer o.mu.Unlock() o.order.Reset() @@ -469,6 +471,8 @@ func (o *OrderedChildren) Unlink(ctx context.Context, name string, child *vfs.De if err := o.checkExistingLocked(name, child); err != nil { return err } + + // TODO(gvisor.dev/issue/3027): Check sticky bit before removing. o.removeLocked(name) return nil } @@ -516,6 +520,8 @@ func (o *OrderedChildren) Rename(ctx context.Context, oldname, newname string, c if err := o.checkExistingLocked(oldname, child); err != nil { return nil, err } + + // TODO(gvisor.dev/issue/3027): Check sticky bit before removing. replaced := dst.replaceChildLocked(newname, child) return replaced, nil } @@ -555,6 +561,8 @@ type StaticDirectory struct { InodeAttrs InodeNoDynamicLookup OrderedChildren + + locks vfs.FileLocks } var _ Inode = (*StaticDirectory)(nil) @@ -584,7 +592,7 @@ func (s *StaticDirectory) Init(creds *auth.Credentials, devMajor, devMinor uint3 // Open implements kernfs.Inode. func (s *StaticDirectory) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := NewGenericDirectoryFD(rp.Mount(), vfsd, &s.OrderedChildren, &opts) + fd, err := NewGenericDirectoryFD(rp.Mount(), vfsd, &s.OrderedChildren, &s.locks, &opts) if err != nil { return nil, err } diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go index a83151ad3..080118841 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs.go @@ -116,17 +116,17 @@ func (fs *Filesystem) deferDecRef(d *vfs.Dentry) { // processDeferredDecRefs calls vfs.Dentry.DecRef on all dentries in the // droppedDentries list. See comment on Filesystem.mu. -func (fs *Filesystem) processDeferredDecRefs() { +func (fs *Filesystem) processDeferredDecRefs(ctx context.Context) { fs.mu.Lock() - fs.processDeferredDecRefsLocked() + fs.processDeferredDecRefsLocked(ctx) fs.mu.Unlock() } // Precondition: fs.mu must be held for writing. -func (fs *Filesystem) processDeferredDecRefsLocked() { +func (fs *Filesystem) processDeferredDecRefsLocked(ctx context.Context) { fs.droppedDentriesMu.Lock() for _, d := range fs.droppedDentries { - d.DecRef() + d.DecRef(ctx) } fs.droppedDentries = fs.droppedDentries[:0] // Keep slice memory for reuse. fs.droppedDentriesMu.Unlock() @@ -212,22 +212,37 @@ func (d *Dentry) isSymlink() bool { } // DecRef implements vfs.DentryImpl.DecRef. -func (d *Dentry) DecRef() { - d.AtomicRefCount.DecRefWithDestructor(d.destroy) +func (d *Dentry) DecRef(ctx context.Context) { + d.AtomicRefCount.DecRefWithDestructor(ctx, d.destroy) } // Precondition: Dentry must be removed from VFS' dentry cache. -func (d *Dentry) destroy() { - d.inode.DecRef() // IncRef from Init. +func (d *Dentry) destroy(ctx context.Context) { + d.inode.DecRef(ctx) // IncRef from Init. d.inode = nil if d.parent != nil { - d.parent.DecRef() // IncRef from Dentry.InsertChild. + d.parent.DecRef(ctx) // IncRef from Dentry.InsertChild. } } +// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent. +// +// Although Linux technically supports inotify on pseudo filesystems (inotify +// is implemented at the vfs layer), it is not particularly useful. It is left +// unimplemented until someone actually needs it. +func (d *Dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et vfs.EventType) {} + +// Watches implements vfs.DentryImpl.Watches. +func (d *Dentry) Watches() *vfs.Watches { + return nil +} + +// OnZeroWatches implements vfs.Dentry.OnZeroWatches. +func (d *Dentry) OnZeroWatches(context.Context) {} + // InsertChild inserts child into the vfs dentry cache with the given name under // this dentry. This does not update the directory inode, so calling this on -// it's own isn't sufficient to insert a child into a directory. InsertChild +// its own isn't sufficient to insert a child into a directory. InsertChild // updates the link count on d if required. // // Precondition: d must represent a directory inode. @@ -311,12 +326,12 @@ type Inode interface { type inodeRefs interface { IncRef() - DecRef() + DecRef(ctx context.Context) TryIncRef() bool // Destroy is called when the inode reaches zero references. Destroy release // all resources (references) on objects referenced by the inode, including // any child dentries. - Destroy() + Destroy(ctx context.Context) } type inodeMetadata interface { @@ -331,7 +346,7 @@ type inodeMetadata interface { // Stat returns the metadata for this inode. This corresponds to // vfs.FilesystemImpl.StatAt. - Stat(fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) + Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) // SetStat updates the metadata for this inode. This corresponds to // vfs.FilesystemImpl.SetStatAt. Implementations are responsible for checking @@ -413,10 +428,10 @@ type inodeDynamicLookup interface { // IterDirents is used to iterate over dynamically created entries. It invokes // cb on each entry in the directory represented by the FileDescription. // 'offset' is the offset for the entire IterDirents call, which may include - // results from the caller. 'relOffset' is the offset inside the entries - // returned by this IterDirents invocation. In other words, - // 'offset+relOffset+1' is the value that should be set in vfs.Dirent.NextOff, - // while 'relOffset' is the place where iteration should start from. + // results from the caller (e.g. "." and ".."). 'relOffset' is the offset + // inside the entries returned by this IterDirents invocation. In other words, + // 'offset' should be used to calculate each vfs.Dirent.NextOff as well as + // the return value, while 'relOffset' is the place to start iteration. IterDirents(ctx context.Context, callback vfs.IterDirentsCallback, offset, relOffset int64) (newOffset int64, err error) } diff --git a/pkg/sentry/fsimpl/kernfs/kernfs_test.go b/pkg/sentry/fsimpl/kernfs/kernfs_test.go index 412cf6ac9..c5d5afedf 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs_test.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs_test.go @@ -46,7 +46,7 @@ func newTestSystem(t *testing.T, rootFn RootDentryFn) *testutil.System { ctx := contexttest.Context(t) creds := auth.CredentialsFromContext(ctx) v := &vfs.VirtualFilesystem{} - if err := v.Init(); err != nil { + if err := v.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } v.MustRegisterFilesystemType("testfs", &fsType{rootFn: rootFn}, &vfs.RegisterFilesystemTypeOptions{ @@ -100,8 +100,10 @@ type readonlyDir struct { kernfs.InodeNotSymlink kernfs.InodeNoDynamicLookup kernfs.InodeDirectoryNoNewChildren - kernfs.OrderedChildren + + locks vfs.FileLocks + dentry kernfs.Dentry } @@ -117,7 +119,7 @@ func (fs *filesystem) newReadonlyDir(creds *auth.Credentials, mode linux.FileMod } func (d *readonlyDir) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &d.locks, &opts) if err != nil { return nil, err } @@ -128,10 +130,12 @@ type dir struct { attrs kernfs.InodeNotSymlink kernfs.InodeNoDynamicLookup + kernfs.OrderedChildren + + locks vfs.FileLocks fs *filesystem dentry kernfs.Dentry - kernfs.OrderedChildren } func (fs *filesystem) newDir(creds *auth.Credentials, mode linux.FileMode, contents map[string]*kernfs.Dentry) *kernfs.Dentry { @@ -147,7 +151,7 @@ func (fs *filesystem) newDir(creds *auth.Credentials, mode linux.FileMode, conte } func (d *dir) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &d.locks, &opts) if err != nil { return nil, err } @@ -159,7 +163,7 @@ func (d *dir) NewDir(ctx context.Context, name string, opts vfs.MkdirOptions) (* dir := d.fs.newDir(creds, opts.Mode, nil) dirVFSD := dir.VFSDentry() if err := d.OrderedChildren.Insert(name, dirVFSD); err != nil { - dir.DecRef() + dir.DecRef(ctx) return nil, err } d.IncLinks(1) @@ -171,7 +175,7 @@ func (d *dir) NewFile(ctx context.Context, name string, opts vfs.OpenOptions) (* f := d.fs.newFile(creds, "") fVFSD := f.VFSDentry() if err := d.OrderedChildren.Insert(name, fVFSD); err != nil { - f.DecRef() + f.DecRef(ctx) return nil, err } return fVFSD, nil @@ -209,7 +213,7 @@ func TestBasic(t *testing.T) { }) }) defer sys.Destroy() - sys.GetDentryOrDie(sys.PathOpAtRoot("file1")).DecRef() + sys.GetDentryOrDie(sys.PathOpAtRoot("file1")).DecRef(sys.Ctx) } func TestMkdirGetDentry(t *testing.T) { @@ -224,7 +228,7 @@ func TestMkdirGetDentry(t *testing.T) { if err := sys.VFS.MkdirAt(sys.Ctx, sys.Creds, pop, &vfs.MkdirOptions{Mode: 0755}); err != nil { t.Fatalf("MkdirAt for PathOperation %+v failed: %v", pop, err) } - sys.GetDentryOrDie(pop).DecRef() + sys.GetDentryOrDie(pop).DecRef(sys.Ctx) } func TestReadStaticFile(t *testing.T) { @@ -242,7 +246,7 @@ func TestReadStaticFile(t *testing.T) { if err != nil { t.Fatalf("OpenAt for PathOperation %+v failed: %v", pop, err) } - defer fd.DecRef() + defer fd.DecRef(sys.Ctx) content, err := sys.ReadToEnd(fd) if err != nil { @@ -269,7 +273,7 @@ func TestCreateNewFileInStaticDir(t *testing.T) { } // Close the file. The file should persist. - fd.DecRef() + fd.DecRef(sys.Ctx) fd, err = sys.VFS.OpenAt(sys.Ctx, sys.Creds, pop, &vfs.OpenOptions{ Flags: linux.O_RDONLY, @@ -277,7 +281,7 @@ func TestCreateNewFileInStaticDir(t *testing.T) { if err != nil { t.Fatalf("OpenAt(pop:%+v) = %+v failed: %v", pop, fd, err) } - fd.DecRef() + fd.DecRef(sys.Ctx) } func TestDirFDReadWrite(t *testing.T) { @@ -293,7 +297,7 @@ func TestDirFDReadWrite(t *testing.T) { if err != nil { t.Fatalf("OpenAt for PathOperation %+v failed: %v", pop, err) } - defer fd.DecRef() + defer fd.DecRef(sys.Ctx) // Read/Write should fail for directory FDs. if _, err := fd.Read(sys.Ctx, usermem.BytesIOSequence([]byte{}), vfs.ReadOptions{}); err != syserror.EISDIR { diff --git a/pkg/sentry/fsimpl/overlay/BUILD b/pkg/sentry/fsimpl/overlay/BUILD new file mode 100644 index 000000000..8cf5b35d3 --- /dev/null +++ b/pkg/sentry/fsimpl/overlay/BUILD @@ -0,0 +1,41 @@ +load("//tools:defs.bzl", "go_library") +load("//tools/go_generics:defs.bzl", "go_template_instance") + +licenses(["notice"]) + +go_template_instance( + name = "fstree", + out = "fstree.go", + package = "overlay", + prefix = "generic", + template = "//pkg/sentry/vfs/genericfstree:generic_fstree", + types = { + "Dentry": "dentry", + }, +) + +go_library( + name = "overlay", + srcs = [ + "copy_up.go", + "directory.go", + "filesystem.go", + "fstree.go", + "non_directory.go", + "overlay.go", + ], + visibility = ["//pkg/sentry:internal"], + deps = [ + "//pkg/abi/linux", + "//pkg/context", + "//pkg/fspath", + "//pkg/sentry/fs/lock", + "//pkg/sentry/kernel/auth", + "//pkg/sentry/memmap", + "//pkg/sentry/socket/unix/transport", + "//pkg/sentry/vfs", + "//pkg/sync", + "//pkg/syserror", + "//pkg/usermem", + ], +) diff --git a/pkg/sentry/fsimpl/overlay/copy_up.go b/pkg/sentry/fsimpl/overlay/copy_up.go new file mode 100644 index 000000000..b3d19ff82 --- /dev/null +++ b/pkg/sentry/fsimpl/overlay/copy_up.go @@ -0,0 +1,262 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package overlay + +import ( + "fmt" + "io" + "sync/atomic" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" +) + +func (d *dentry) isCopiedUp() bool { + return atomic.LoadUint32(&d.copiedUp) != 0 +} + +// copyUpLocked ensures that d exists on the upper layer, i.e. d.upperVD.Ok(). +// +// Preconditions: filesystem.renameMu must be locked. +func (d *dentry) copyUpLocked(ctx context.Context) error { + // Fast path. + if d.isCopiedUp() { + return nil + } + + ftype := atomic.LoadUint32(&d.mode) & linux.S_IFMT + switch ftype { + case linux.S_IFREG, linux.S_IFDIR, linux.S_IFLNK, linux.S_IFBLK, linux.S_IFCHR: + // Can be copied-up. + default: + // Can't be copied-up. + return syserror.EPERM + } + + // Ensure that our parent directory is copied-up. + if d.parent == nil { + // d is a filesystem root with no upper layer. + return syserror.EROFS + } + if err := d.parent.copyUpLocked(ctx); err != nil { + return err + } + + d.copyMu.Lock() + defer d.copyMu.Unlock() + if d.upperVD.Ok() { + // Raced with another call to d.copyUpLocked(). + return nil + } + if d.vfsd.IsDead() { + // Raced with deletion of d. + return syserror.ENOENT + } + + // Perform copy-up. + vfsObj := d.fs.vfsfs.VirtualFilesystem() + newpop := vfs.PathOperation{ + Root: d.parent.upperVD, + Start: d.parent.upperVD, + Path: fspath.Parse(d.name), + } + cleanupUndoCopyUp := func() { + var err error + if ftype == linux.S_IFDIR { + err = vfsObj.RmdirAt(ctx, d.fs.creds, &newpop) + } else { + err = vfsObj.UnlinkAt(ctx, d.fs.creds, &newpop) + } + if err != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer file after copy-up error: %v", err) + } + } + switch ftype { + case linux.S_IFREG: + oldFD, err := vfsObj.OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: d.lowerVDs[0], + Start: d.lowerVDs[0], + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY, + }) + if err != nil { + return err + } + defer oldFD.DecRef(ctx) + newFD, err := vfsObj.OpenAt(ctx, d.fs.creds, &newpop, &vfs.OpenOptions{ + Flags: linux.O_WRONLY | linux.O_CREAT | linux.O_EXCL, + Mode: linux.FileMode(d.mode &^ linux.S_IFMT), + }) + if err != nil { + return err + } + defer newFD.DecRef(ctx) + bufIOSeq := usermem.BytesIOSequence(make([]byte, 32*1024)) // arbitrary buffer size + for { + readN, readErr := oldFD.Read(ctx, bufIOSeq, vfs.ReadOptions{}) + if readErr != nil && readErr != io.EOF { + cleanupUndoCopyUp() + return readErr + } + total := int64(0) + for total < readN { + writeN, writeErr := newFD.Write(ctx, bufIOSeq.DropFirst64(total), vfs.WriteOptions{}) + total += writeN + if writeErr != nil { + cleanupUndoCopyUp() + return writeErr + } + } + if readErr == io.EOF { + break + } + } + if err := newFD.SetStat(ctx, vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: d.uid, + GID: d.gid, + }, + }); err != nil { + cleanupUndoCopyUp() + return err + } + d.upperVD = newFD.VirtualDentry() + d.upperVD.IncRef() + + case linux.S_IFDIR: + if err := vfsObj.MkdirAt(ctx, d.fs.creds, &newpop, &vfs.MkdirOptions{ + Mode: linux.FileMode(d.mode &^ linux.S_IFMT), + }); err != nil { + return err + } + if err := vfsObj.SetStatAt(ctx, d.fs.creds, &newpop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: d.uid, + GID: d.gid, + }, + }); err != nil { + cleanupUndoCopyUp() + return err + } + upperVD, err := vfsObj.GetDentryAt(ctx, d.fs.creds, &newpop, &vfs.GetDentryOptions{}) + if err != nil { + cleanupUndoCopyUp() + return err + } + d.upperVD = upperVD + + case linux.S_IFLNK: + target, err := vfsObj.ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: d.lowerVDs[0], + Start: d.lowerVDs[0], + }) + if err != nil { + return err + } + if err := vfsObj.SymlinkAt(ctx, d.fs.creds, &newpop, target); err != nil { + return err + } + if err := vfsObj.SetStatAt(ctx, d.fs.creds, &newpop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID, + Mode: uint16(d.mode), + UID: d.uid, + GID: d.gid, + }, + }); err != nil { + cleanupUndoCopyUp() + return err + } + upperVD, err := vfsObj.GetDentryAt(ctx, d.fs.creds, &newpop, &vfs.GetDentryOptions{}) + if err != nil { + cleanupUndoCopyUp() + return err + } + d.upperVD = upperVD + + case linux.S_IFBLK, linux.S_IFCHR: + lowerStat, err := vfsObj.StatAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: d.lowerVDs[0], + Start: d.lowerVDs[0], + }, &vfs.StatOptions{}) + if err != nil { + return err + } + if err := vfsObj.MknodAt(ctx, d.fs.creds, &newpop, &vfs.MknodOptions{ + Mode: linux.FileMode(d.mode), + DevMajor: lowerStat.RdevMajor, + DevMinor: lowerStat.RdevMinor, + }); err != nil { + return err + } + if err := vfsObj.SetStatAt(ctx, d.fs.creds, &newpop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: d.uid, + GID: d.gid, + }, + }); err != nil { + cleanupUndoCopyUp() + return err + } + upperVD, err := vfsObj.GetDentryAt(ctx, d.fs.creds, &newpop, &vfs.GetDentryOptions{}) + if err != nil { + cleanupUndoCopyUp() + return err + } + d.upperVD = upperVD + + default: + // Should have rejected this at the beginning of this function? + panic(fmt.Sprintf("unexpected file type %o", ftype)) + } + + // TODO(gvisor.dev/issue/1199): copy up xattrs + + // Update the dentry's device and inode numbers (except for directories, + // for which these remain overlay-assigned). + if ftype != linux.S_IFDIR { + upperStat, err := vfsObj.StatAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: d.upperVD, + Start: d.upperVD, + }, &vfs.StatOptions{ + Mask: linux.STATX_INO, + }) + if err != nil { + d.upperVD.DecRef(ctx) + d.upperVD = vfs.VirtualDentry{} + cleanupUndoCopyUp() + return err + } + if upperStat.Mask&linux.STATX_INO == 0 { + d.upperVD.DecRef(ctx) + d.upperVD = vfs.VirtualDentry{} + cleanupUndoCopyUp() + return syserror.EREMOTE + } + atomic.StoreUint32(&d.devMajor, upperStat.DevMajor) + atomic.StoreUint32(&d.devMinor, upperStat.DevMinor) + atomic.StoreUint64(&d.ino, upperStat.Ino) + } + + atomic.StoreUint32(&d.copiedUp, 1) + return nil +} diff --git a/pkg/sentry/fsimpl/overlay/directory.go b/pkg/sentry/fsimpl/overlay/directory.go new file mode 100644 index 000000000..6a79f7ffe --- /dev/null +++ b/pkg/sentry/fsimpl/overlay/directory.go @@ -0,0 +1,289 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package overlay + +import ( + "sync/atomic" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/syserror" +) + +func (d *dentry) isDir() bool { + return atomic.LoadUint32(&d.mode)&linux.S_IFMT == linux.S_IFDIR +} + +// Preconditions: d.dirMu must be locked. d.isDir(). +func (d *dentry) collectWhiteoutsForRmdirLocked(ctx context.Context) (map[string]bool, error) { + vfsObj := d.fs.vfsfs.VirtualFilesystem() + var readdirErr error + whiteouts := make(map[string]bool) + var maybeWhiteouts []string + d.iterLayers(func(layerVD vfs.VirtualDentry, isUpper bool) bool { + layerFD, err := vfsObj.OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY | linux.O_DIRECTORY, + }) + if err != nil { + readdirErr = err + return false + } + defer layerFD.DecRef(ctx) + + // Reuse slice allocated for maybeWhiteouts from a previous layer to + // reduce allocations. + maybeWhiteouts = maybeWhiteouts[:0] + err = layerFD.IterDirents(ctx, vfs.IterDirentsCallbackFunc(func(dirent vfs.Dirent) error { + if dirent.Name == "." || dirent.Name == ".." { + return nil + } + if _, ok := whiteouts[dirent.Name]; ok { + // This file has been whited-out in a previous layer. + return nil + } + if dirent.Type == linux.DT_CHR { + // We have to determine if this is a whiteout, which doesn't + // count against the directory's emptiness. However, we can't + // do so while holding locks held by layerFD.IterDirents(). + maybeWhiteouts = append(maybeWhiteouts, dirent.Name) + return nil + } + // Non-whiteout file in the directory prevents rmdir. + return syserror.ENOTEMPTY + })) + if err != nil { + readdirErr = err + return false + } + + for _, maybeWhiteoutName := range maybeWhiteouts { + stat, err := vfsObj.StatAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + Path: fspath.Parse(maybeWhiteoutName), + }, &vfs.StatOptions{}) + if err != nil { + readdirErr = err + return false + } + if stat.RdevMajor != 0 || stat.RdevMinor != 0 { + // This file is a real character device, not a whiteout. + readdirErr = syserror.ENOTEMPTY + return false + } + whiteouts[maybeWhiteoutName] = isUpper + } + // Continue iteration since we haven't found any non-whiteout files in + // this directory yet. + return true + }) + return whiteouts, readdirErr +} + +type directoryFD struct { + fileDescription + vfs.DirectoryFileDescriptionDefaultImpl + vfs.DentryMetadataFileDescriptionImpl + + mu sync.Mutex + off int64 + dirents []vfs.Dirent +} + +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *directoryFD) Release(ctx context.Context) { +} + +// IterDirents implements vfs.FileDescriptionImpl.IterDirents. +func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback) error { + fd.mu.Lock() + defer fd.mu.Unlock() + + d := fd.dentry() + if fd.dirents == nil { + ds, err := d.getDirents(ctx) + if err != nil { + return err + } + fd.dirents = ds + } + + for fd.off < int64(len(fd.dirents)) { + if err := cb.Handle(fd.dirents[fd.off]); err != nil { + return err + } + fd.off++ + } + return nil +} + +// Preconditions: d.isDir(). +func (d *dentry) getDirents(ctx context.Context) ([]vfs.Dirent, error) { + d.fs.renameMu.RLock() + defer d.fs.renameMu.RUnlock() + d.dirMu.Lock() + defer d.dirMu.Unlock() + + if d.dirents != nil { + return d.dirents, nil + } + + parent := genericParentOrSelf(d) + dirents := []vfs.Dirent{ + { + Name: ".", + Type: linux.DT_DIR, + Ino: d.ino, + NextOff: 1, + }, + { + Name: "..", + Type: uint8(atomic.LoadUint32(&parent.mode) >> 12), + Ino: parent.ino, + NextOff: 2, + }, + } + + // Merge dirents from all layers comprising this directory. + vfsObj := d.fs.vfsfs.VirtualFilesystem() + var readdirErr error + prevDirents := make(map[string]struct{}) + var maybeWhiteouts []vfs.Dirent + d.iterLayers(func(layerVD vfs.VirtualDentry, isUpper bool) bool { + layerFD, err := vfsObj.OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }, &vfs.OpenOptions{ + Flags: linux.O_RDONLY | linux.O_DIRECTORY, + }) + if err != nil { + readdirErr = err + return false + } + defer layerFD.DecRef(ctx) + + // Reuse slice allocated for maybeWhiteouts from a previous layer to + // reduce allocations. + maybeWhiteouts = maybeWhiteouts[:0] + err = layerFD.IterDirents(ctx, vfs.IterDirentsCallbackFunc(func(dirent vfs.Dirent) error { + if dirent.Name == "." || dirent.Name == ".." { + return nil + } + if _, ok := prevDirents[dirent.Name]; ok { + // This file is hidden by, or merged with, another file with + // the same name in a previous layer. + return nil + } + prevDirents[dirent.Name] = struct{}{} + if dirent.Type == linux.DT_CHR { + // We can't determine if this file is a whiteout while holding + // locks held by layerFD.IterDirents(). + maybeWhiteouts = append(maybeWhiteouts, dirent) + return nil + } + dirent.NextOff = int64(len(dirents) + 1) + dirents = append(dirents, dirent) + return nil + })) + if err != nil { + readdirErr = err + return false + } + + for _, dirent := range maybeWhiteouts { + stat, err := vfsObj.StatAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + Path: fspath.Parse(dirent.Name), + }, &vfs.StatOptions{}) + if err != nil { + readdirErr = err + return false + } + if stat.RdevMajor == 0 && stat.RdevMinor == 0 { + // This file is a whiteout; don't emit a dirent for it. + continue + } + dirent.NextOff = int64(len(dirents) + 1) + dirents = append(dirents, dirent) + } + return true + }) + if readdirErr != nil { + return nil, readdirErr + } + + // Cache dirents for future directoryFDs. + d.dirents = dirents + return dirents, nil +} + +// Seek implements vfs.FileDescriptionImpl.Seek. +func (fd *directoryFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { + fd.mu.Lock() + defer fd.mu.Unlock() + + switch whence { + case linux.SEEK_SET: + if offset < 0 { + return 0, syserror.EINVAL + } + if offset == 0 { + // Ensure that the next call to fd.IterDirents() calls + // fd.dentry().getDirents(). + fd.dirents = nil + } + fd.off = offset + return fd.off, nil + case linux.SEEK_CUR: + offset += fd.off + if offset < 0 { + return 0, syserror.EINVAL + } + // Don't clear fd.dirents in this case, even if offset == 0. + fd.off = offset + return fd.off, nil + default: + return 0, syserror.EINVAL + } +} + +// Sync implements vfs.FileDescriptionImpl.Sync. Forwards sync to the upper +// layer, if there is one. The lower layer doesn't need to sync because it +// never changes. +func (fd *directoryFD) Sync(ctx context.Context) error { + d := fd.dentry() + if !d.isCopiedUp() { + return nil + } + vfsObj := d.fs.vfsfs.VirtualFilesystem() + pop := vfs.PathOperation{ + Root: d.upperVD, + Start: d.upperVD, + } + upperFD, err := vfsObj.OpenAt(ctx, d.fs.creds, &pop, &vfs.OpenOptions{Flags: linux.O_RDONLY | linux.O_DIRECTORY}) + if err != nil { + return err + } + err = upperFD.Sync(ctx) + upperFD.DecRef(ctx) + return err +} diff --git a/pkg/sentry/fsimpl/overlay/filesystem.go b/pkg/sentry/fsimpl/overlay/filesystem.go new file mode 100644 index 000000000..986b36ead --- /dev/null +++ b/pkg/sentry/fsimpl/overlay/filesystem.go @@ -0,0 +1,1364 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package overlay + +import ( + "sync/atomic" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/syserror" +) + +// _OVL_XATTR_OPAQUE is an extended attribute key whose value is set to "y" for +// opaque directories. +// Linux: fs/overlayfs/overlayfs.h:OVL_XATTR_OPAQUE +const _OVL_XATTR_OPAQUE = "trusted.overlay.opaque" + +func isWhiteout(stat *linux.Statx) bool { + return stat.Mode&linux.S_IFMT == linux.S_IFCHR && stat.RdevMajor == 0 && stat.RdevMinor == 0 +} + +// Sync implements vfs.FilesystemImpl.Sync. +func (fs *filesystem) Sync(ctx context.Context) error { + if fs.opts.UpperRoot.Ok() { + return fs.opts.UpperRoot.Mount().Filesystem().Impl().Sync(ctx) + } + return nil +} + +var dentrySlicePool = sync.Pool{ + New: func() interface{} { + ds := make([]*dentry, 0, 4) // arbitrary non-zero initial capacity + return &ds + }, +} + +func appendDentry(ds *[]*dentry, d *dentry) *[]*dentry { + if ds == nil { + ds = dentrySlicePool.Get().(*[]*dentry) + } + *ds = append(*ds, d) + return ds +} + +// Preconditions: ds != nil. +func putDentrySlice(ds *[]*dentry) { + // Allow dentries to be GC'd. + for i := range *ds { + (*ds)[i] = nil + } + *ds = (*ds)[:0] + dentrySlicePool.Put(ds) +} + +// renameMuRUnlockAndCheckDrop calls fs.renameMu.RUnlock(), then calls +// dentry.checkDropLocked on all dentries in *ds with fs.renameMu locked for +// writing. +// +// ds is a pointer-to-pointer since defer evaluates its arguments immediately, +// but dentry slices are allocated lazily, and it's much easier to say "defer +// fs.renameMuRUnlockAndCheckDrop(&ds)" than "defer func() { +// fs.renameMuRUnlockAndCheckDrop(ds) }()" to work around this. +func (fs *filesystem) renameMuRUnlockAndCheckDrop(ctx context.Context, ds **[]*dentry) { + fs.renameMu.RUnlock() + if *ds == nil { + return + } + if len(**ds) != 0 { + fs.renameMu.Lock() + for _, d := range **ds { + d.checkDropLocked(ctx) + } + fs.renameMu.Unlock() + } + putDentrySlice(*ds) +} + +func (fs *filesystem) renameMuUnlockAndCheckDrop(ctx context.Context, ds **[]*dentry) { + if *ds == nil { + fs.renameMu.Unlock() + return + } + for _, d := range **ds { + d.checkDropLocked(ctx) + } + fs.renameMu.Unlock() + putDentrySlice(*ds) +} + +// stepLocked resolves rp.Component() to an existing file, starting from the +// given directory. +// +// Dentries which may have a reference count of zero, and which therefore +// should be dropped once traversal is complete, are appended to ds. +// +// Preconditions: fs.renameMu must be locked. d.dirMu must be locked. +// !rp.Done(). +func (fs *filesystem) stepLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, mayFollowSymlinks bool, ds **[]*dentry) (*dentry, error) { + if !d.isDir() { + return nil, syserror.ENOTDIR + } + if err := d.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil { + return nil, err + } +afterSymlink: + name := rp.Component() + if name == "." { + rp.Advance() + return d, nil + } + if name == ".." { + if isRoot, err := rp.CheckRoot(ctx, &d.vfsd); err != nil { + return nil, err + } else if isRoot || d.parent == nil { + rp.Advance() + return d, nil + } + if err := rp.CheckMount(ctx, &d.parent.vfsd); err != nil { + return nil, err + } + rp.Advance() + return d.parent, nil + } + child, err := fs.getChildLocked(ctx, d, name, ds) + if err != nil { + return nil, err + } + if err := rp.CheckMount(ctx, &child.vfsd); err != nil { + return nil, err + } + if child.isSymlink() && mayFollowSymlinks && rp.ShouldFollowSymlink() { + target, err := child.readlink(ctx) + if err != nil { + return nil, err + } + if err := rp.HandleSymlink(target); err != nil { + return nil, err + } + goto afterSymlink // don't check the current directory again + } + rp.Advance() + return child, nil +} + +// Preconditions: fs.renameMu must be locked. d.dirMu must be locked. +func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name string, ds **[]*dentry) (*dentry, error) { + if child, ok := parent.children[name]; ok { + return child, nil + } + child, err := fs.lookupLocked(ctx, parent, name) + if err != nil { + return nil, err + } + if parent.children == nil { + parent.children = make(map[string]*dentry) + } + parent.children[name] = child + // child's refcount is initially 0, so it may be dropped after traversal. + *ds = appendDentry(*ds, child) + return child, nil +} + +// Preconditions: fs.renameMu must be locked. parent.dirMu must be locked. +func (fs *filesystem) lookupLocked(ctx context.Context, parent *dentry, name string) (*dentry, error) { + childPath := fspath.Parse(name) + child := fs.newDentry() + existsOnAnyLayer := false + var lookupErr error + + vfsObj := fs.vfsfs.VirtualFilesystem() + parent.iterLayers(func(parentVD vfs.VirtualDentry, isUpper bool) bool { + childVD, err := vfsObj.GetDentryAt(ctx, fs.creds, &vfs.PathOperation{ + Root: parentVD, + Start: parentVD, + Path: childPath, + }, &vfs.GetDentryOptions{}) + if err == syserror.ENOENT || err == syserror.ENAMETOOLONG { + // The file doesn't exist on this layer. Proceed to the next one. + return true + } + if err != nil { + lookupErr = err + return false + } + + mask := uint32(linux.STATX_TYPE) + if !existsOnAnyLayer { + // Mode, UID, GID, and (for non-directories) inode number come from + // the topmost layer on which the file exists. + mask |= linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO + } + stat, err := vfsObj.StatAt(ctx, fs.creds, &vfs.PathOperation{ + Root: childVD, + Start: childVD, + }, &vfs.StatOptions{ + Mask: mask, + }) + if err != nil { + lookupErr = err + return false + } + if stat.Mask&mask != mask { + lookupErr = syserror.EREMOTE + return false + } + + if isWhiteout(&stat) { + // This is a whiteout, so it "doesn't exist" on this layer, and + // layers below this one are ignored. + return false + } + isDir := stat.Mode&linux.S_IFMT == linux.S_IFDIR + if existsOnAnyLayer && !isDir { + // Directories are not merged with non-directory files from lower + // layers; instead, layers including and below the first + // non-directory file are ignored. (This file must be a directory + // on previous layers, since lower layers aren't searched for + // non-directory files.) + return false + } + + // Update child to include this layer. + if isUpper { + child.upperVD = childVD + child.copiedUp = 1 + } else { + child.lowerVDs = append(child.lowerVDs, childVD) + } + if !existsOnAnyLayer { + existsOnAnyLayer = true + child.mode = uint32(stat.Mode) + child.uid = stat.UID + child.gid = stat.GID + child.devMajor = stat.DevMajor + child.devMinor = stat.DevMinor + child.ino = stat.Ino + } + + // For non-directory files, only the topmost layer that contains a file + // matters. + if !isDir { + return false + } + + // Directories are merged with directories from lower layers if they + // are not explicitly opaque. + opaqueVal, err := vfsObj.GetxattrAt(ctx, fs.creds, &vfs.PathOperation{ + Root: childVD, + Start: childVD, + }, &vfs.GetxattrOptions{ + Name: _OVL_XATTR_OPAQUE, + Size: 1, + }) + return !(err == nil && opaqueVal == "y") + }) + + if lookupErr != nil { + child.destroyLocked(ctx) + return nil, lookupErr + } + if !existsOnAnyLayer { + child.destroyLocked(ctx) + return nil, syserror.ENOENT + } + + // Device and inode numbers were copied from the topmost layer above; + // override them if necessary. + if child.isDir() { + child.devMajor = linux.UNNAMED_MAJOR + child.devMinor = fs.dirDevMinor + child.ino = fs.newDirIno() + } else if !child.upperVD.Ok() { + child.devMajor = linux.UNNAMED_MAJOR + child.devMinor = fs.lowerDevMinors[child.lowerVDs[0].Mount().Filesystem()] + } + + parent.IncRef() + child.parent = parent + child.name = name + return child, nil +} + +// lookupLayerLocked is similar to lookupLocked, but only returns information +// about the file rather than a dentry. +// +// Preconditions: fs.renameMu must be locked. parent.dirMu must be locked. +func (fs *filesystem) lookupLayerLocked(ctx context.Context, parent *dentry, name string) (lookupLayer, error) { + childPath := fspath.Parse(name) + lookupLayer := lookupLayerNone + var lookupErr error + + parent.iterLayers(func(parentVD vfs.VirtualDentry, isUpper bool) bool { + stat, err := fs.vfsfs.VirtualFilesystem().StatAt(ctx, fs.creds, &vfs.PathOperation{ + Root: parentVD, + Start: parentVD, + Path: childPath, + }, &vfs.StatOptions{ + Mask: linux.STATX_TYPE, + }) + if err == syserror.ENOENT || err == syserror.ENAMETOOLONG { + // The file doesn't exist on this layer. Proceed to the next + // one. + return true + } + if err != nil { + lookupErr = err + return false + } + if stat.Mask&linux.STATX_TYPE == 0 { + // Linux's overlayfs tends to return EREMOTE in cases where a file + // is unusable for reasons that are not better captured by another + // errno. + lookupErr = syserror.EREMOTE + return false + } + if isWhiteout(&stat) { + // This is a whiteout, so it "doesn't exist" on this layer, and + // layers below this one are ignored. + if isUpper { + lookupLayer = lookupLayerUpperWhiteout + } + return false + } + // The file exists; we can stop searching. + if isUpper { + lookupLayer = lookupLayerUpper + } else { + lookupLayer = lookupLayerLower + } + return false + }) + + return lookupLayer, lookupErr +} + +type lookupLayer int + +const ( + // lookupLayerNone indicates that no file exists at the given path on the + // upper layer, and is either whited out or does not exist on lower layers. + // Therefore, the file does not exist in the overlay filesystem, and file + // creation may proceed normally (if an upper layer exists). + lookupLayerNone lookupLayer = iota + + // lookupLayerLower indicates that no file exists at the given path on the + // upper layer, but exists on a lower layer. Therefore, the file exists in + // the overlay filesystem, but must be copied-up before mutation. + lookupLayerLower + + // lookupLayerUpper indicates that a non-whiteout file exists at the given + // path on the upper layer. Therefore, the file exists in the overlay + // filesystem, and is already copied-up. + lookupLayerUpper + + // lookupLayerUpperWhiteout indicates that a whiteout exists at the given + // path on the upper layer. Therefore, the file does not exist in the + // overlay filesystem, and file creation must remove the whiteout before + // proceeding. + lookupLayerUpperWhiteout +) + +func (ll lookupLayer) existsInOverlay() bool { + return ll == lookupLayerLower || ll == lookupLayerUpper +} + +// walkParentDirLocked resolves all but the last path component of rp to an +// existing directory, starting from the given directory (which is usually +// rp.Start().Impl().(*dentry)). It does not check that the returned directory +// is searchable by the provider of rp. +// +// Preconditions: fs.renameMu must be locked. !rp.Done(). +func (fs *filesystem) walkParentDirLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry, ds **[]*dentry) (*dentry, error) { + for !rp.Final() { + d.dirMu.Lock() + next, err := fs.stepLocked(ctx, rp, d, true /* mayFollowSymlinks */, ds) + d.dirMu.Unlock() + if err != nil { + return nil, err + } + d = next + } + if !d.isDir() { + return nil, syserror.ENOTDIR + } + return d, nil +} + +// resolveLocked resolves rp to an existing file. +// +// Preconditions: fs.renameMu must be locked. +func (fs *filesystem) resolveLocked(ctx context.Context, rp *vfs.ResolvingPath, ds **[]*dentry) (*dentry, error) { + d := rp.Start().Impl().(*dentry) + for !rp.Done() { + d.dirMu.Lock() + next, err := fs.stepLocked(ctx, rp, d, true /* mayFollowSymlinks */, ds) + d.dirMu.Unlock() + if err != nil { + return nil, err + } + d = next + } + if rp.MustBeDir() && !d.isDir() { + return nil, syserror.ENOTDIR + } + return d, nil +} + +// doCreateAt checks that creating a file at rp is permitted, then invokes +// create to do so. +// +// Preconditions: !rp.Done(). For the final path component in rp, +// !rp.ShouldFollowSymlink(). +func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir bool, create func(parent *dentry, name string, haveUpperWhiteout bool) error) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + start := rp.Start().Impl().(*dentry) + parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds) + if err != nil { + return err + } + if err := parent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil { + return err + } + name := rp.Component() + if name == "." || name == ".." { + return syserror.EEXIST + } + if !dir && rp.MustBeDir() { + return syserror.ENOENT + } + if parent.vfsd.IsDead() { + return syserror.ENOENT + } + mnt := rp.Mount() + if err := mnt.CheckBeginWrite(); err != nil { + return err + } + defer mnt.EndWrite() + parent.dirMu.Lock() + defer parent.dirMu.Unlock() + + // Determine if a file already exists at name. + if _, ok := parent.children[name]; ok { + return syserror.EEXIST + } + childLayer, err := fs.lookupLayerLocked(ctx, parent, name) + if err != nil { + return err + } + if childLayer.existsInOverlay() { + return syserror.EEXIST + } + + // Ensure that the parent directory is copied-up so that we can create the + // new file in the upper layer. + if err := parent.copyUpLocked(ctx); err != nil { + return err + } + + // Finally create the new file. + if err := create(parent, name, childLayer == lookupLayerUpperWhiteout); err != nil { + return err + } + parent.dirents = nil + return nil +} + +// Preconditions: pop's parent directory has been copied up. +func (fs *filesystem) createWhiteout(ctx context.Context, vfsObj *vfs.VirtualFilesystem, pop *vfs.PathOperation) error { + return vfsObj.MknodAt(ctx, fs.creds, pop, &vfs.MknodOptions{ + Mode: linux.S_IFCHR, // permissions == include/linux/fs.h:WHITEOUT_MODE == 0 + // DevMajor == DevMinor == 0, from include/linux/fs.h:WHITEOUT_DEV + }) +} + +func (fs *filesystem) cleanupRecreateWhiteout(ctx context.Context, vfsObj *vfs.VirtualFilesystem, pop *vfs.PathOperation) { + if err := fs.createWhiteout(ctx, vfsObj, pop); err != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to recreate whiteout after failed file creation: %v", err) + } +} + +// AccessAt implements vfs.Filesystem.Impl.AccessAt. +func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + d, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return err + } + return d.checkPermissions(creds, ats) +} + +// BoundEndpointAt implements vfs.FilesystemImpl.BoundEndpointAt. +func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + d, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return nil, err + } + if err := d.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil { + return nil, err + } + layerVD := d.topLayer() + return fs.vfsfs.VirtualFilesystem().BoundEndpointAt(ctx, fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }, &opts) +} + +// GetDentryAt implements vfs.FilesystemImpl.GetDentryAt. +func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + d, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return nil, err + } + if opts.CheckSearchable { + if !d.isDir() { + return nil, syserror.ENOTDIR + } + if err := d.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil { + return nil, err + } + } + d.IncRef() + return &d.vfsd, nil +} + +// GetParentDentryAt implements vfs.FilesystemImpl.GetParentDentryAt. +func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + start := rp.Start().Impl().(*dentry) + d, err := fs.walkParentDirLocked(ctx, rp, start, &ds) + if err != nil { + return nil, err + } + d.IncRef() + return &d.vfsd, nil +} + +// LinkAt implements vfs.FilesystemImpl.LinkAt. +func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry) error { + return fs.doCreateAt(ctx, rp, false /* dir */, func(parent *dentry, childName string, haveUpperWhiteout bool) error { + if rp.Mount() != vd.Mount() { + return syserror.EXDEV + } + old := vd.Dentry().Impl().(*dentry) + if old.isDir() { + return syserror.EPERM + } + if err := old.copyUpLocked(ctx); err != nil { + return err + } + vfsObj := fs.vfsfs.VirtualFilesystem() + newpop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(childName), + } + if haveUpperWhiteout { + if err := vfsObj.UnlinkAt(ctx, fs.creds, &newpop); err != nil { + return err + } + } + if err := vfsObj.LinkAt(ctx, fs.creds, &vfs.PathOperation{ + Root: old.upperVD, + Start: old.upperVD, + }, &newpop); err != nil { + if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &newpop) + } + return err + } + creds := rp.Credentials() + if err := vfsObj.SetStatAt(ctx, fs.creds, &newpop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: uint32(creds.EffectiveKUID), + GID: uint32(creds.EffectiveKGID), + }, + }); err != nil { + if cleanupErr := vfsObj.UnlinkAt(ctx, fs.creds, &newpop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer file after LinkAt metadata update failure: %v", cleanupErr) + } else if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &newpop) + } + return err + } + return nil + }) +} + +// MkdirAt implements vfs.FilesystemImpl.MkdirAt. +func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error { + return fs.doCreateAt(ctx, rp, true /* dir */, func(parent *dentry, childName string, haveUpperWhiteout bool) error { + vfsObj := fs.vfsfs.VirtualFilesystem() + pop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(childName), + } + if haveUpperWhiteout { + if err := vfsObj.UnlinkAt(ctx, fs.creds, &pop); err != nil { + return err + } + } + if err := vfsObj.MkdirAt(ctx, fs.creds, &pop, &opts); err != nil { + if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + creds := rp.Credentials() + if err := vfsObj.SetStatAt(ctx, fs.creds, &pop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: uint32(creds.EffectiveKUID), + GID: uint32(creds.EffectiveKGID), + }, + }); err != nil { + if cleanupErr := vfsObj.RmdirAt(ctx, fs.creds, &pop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer directory after MkdirAt metadata update failure: %v", cleanupErr) + } else if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + if haveUpperWhiteout { + // There may be directories on lower layers (previously hidden by + // the whiteout) that the new directory should not be merged with. + // Mark it opaque to prevent merging. + if err := vfsObj.SetxattrAt(ctx, fs.creds, &pop, &vfs.SetxattrOptions{ + Name: _OVL_XATTR_OPAQUE, + Value: "y", + }); err != nil { + if cleanupErr := vfsObj.RmdirAt(ctx, fs.creds, &pop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer directory after MkdirAt set-opaque failure: %v", cleanupErr) + } else { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + } + return nil + }) +} + +// MknodAt implements vfs.FilesystemImpl.MknodAt. +func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error { + return fs.doCreateAt(ctx, rp, false /* dir */, func(parent *dentry, childName string, haveUpperWhiteout bool) error { + // Disallow attempts to create whiteouts. + if opts.Mode&linux.S_IFMT == linux.S_IFCHR && opts.DevMajor == 0 && opts.DevMinor == 0 { + return syserror.EPERM + } + vfsObj := fs.vfsfs.VirtualFilesystem() + pop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(childName), + } + if haveUpperWhiteout { + if err := vfsObj.UnlinkAt(ctx, fs.creds, &pop); err != nil { + return err + } + } + if err := vfsObj.MknodAt(ctx, fs.creds, &pop, &opts); err != nil { + if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + creds := rp.Credentials() + if err := vfsObj.SetStatAt(ctx, fs.creds, &pop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: uint32(creds.EffectiveKUID), + GID: uint32(creds.EffectiveKGID), + }, + }); err != nil { + if cleanupErr := vfsObj.UnlinkAt(ctx, fs.creds, &pop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer file after MknodAt metadata update failure: %v", cleanupErr) + } else if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + return nil + }) +} + +// OpenAt implements vfs.FilesystemImpl.OpenAt. +func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.OpenOptions) (*vfs.FileDescription, error) { + mayCreate := opts.Flags&linux.O_CREAT != 0 + mustCreate := opts.Flags&(linux.O_CREAT|linux.O_EXCL) == (linux.O_CREAT | linux.O_EXCL) + + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + + start := rp.Start().Impl().(*dentry) + if rp.Done() { + if mustCreate { + return nil, syserror.EEXIST + } + return start.openLocked(ctx, rp, &opts) + } + +afterTrailingSymlink: + parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds) + if err != nil { + return nil, err + } + // Check for search permission in the parent directory. + if err := parent.checkPermissions(rp.Credentials(), vfs.MayExec); err != nil { + return nil, err + } + // Determine whether or not we need to create a file. + parent.dirMu.Lock() + child, err := fs.stepLocked(ctx, rp, parent, false /* mayFollowSymlinks */, &ds) + if err == syserror.ENOENT && mayCreate { + fd, err := fs.createAndOpenLocked(ctx, rp, parent, &opts, &ds) + parent.dirMu.Unlock() + return fd, err + } + if err != nil { + parent.dirMu.Unlock() + return nil, err + } + // Open existing child or follow symlink. + parent.dirMu.Unlock() + if mustCreate { + return nil, syserror.EEXIST + } + if child.isSymlink() && rp.ShouldFollowSymlink() { + target, err := child.readlink(ctx) + if err != nil { + return nil, err + } + if err := rp.HandleSymlink(target); err != nil { + return nil, err + } + start = parent + goto afterTrailingSymlink + } + return child.openLocked(ctx, rp, &opts) +} + +// Preconditions: fs.renameMu must be locked. +func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) { + ats := vfs.AccessTypesForOpenFlags(opts) + if err := d.checkPermissions(rp.Credentials(), ats); err != nil { + return nil, err + } + if ats.MayWrite() { + if err := d.copyUpLocked(ctx); err != nil { + return nil, err + } + } + mnt := rp.Mount() + + // Directory FDs open FDs from each layer when directory entries are read, + // so they don't require opening an FD from d.topLayer() up front. + ftype := atomic.LoadUint32(&d.mode) & linux.S_IFMT + if ftype == linux.S_IFDIR { + // Can't open directories with O_CREAT. + if opts.Flags&linux.O_CREAT != 0 { + return nil, syserror.EISDIR + } + // Can't open directories writably. + if ats&vfs.MayWrite != 0 { + return nil, syserror.EISDIR + } + if opts.Flags&linux.O_DIRECT != 0 { + return nil, syserror.EINVAL + } + fd := &directoryFD{} + fd.LockFD.Init(&d.locks) + if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{ + UseDentryMetadata: true, + }); err != nil { + return nil, err + } + return &fd.vfsfd, nil + } + + layerVD, isUpper := d.topLayerInfo() + layerFD, err := rp.VirtualFilesystem().OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }, opts) + if err != nil { + return nil, err + } + layerFlags := layerFD.StatusFlags() + fd := &nonDirectoryFD{ + copiedUp: isUpper, + cachedFD: layerFD, + cachedFlags: layerFlags, + } + fd.LockFD.Init(&d.locks) + layerFDOpts := layerFD.Options() + if err := fd.vfsfd.Init(fd, layerFlags, mnt, &d.vfsd, &layerFDOpts); err != nil { + layerFD.DecRef(ctx) + return nil, err + } + return &fd.vfsfd, nil +} + +// Preconditions: parent.dirMu must be locked. parent does not already contain +// a child named rp.Component(). +func (fs *filesystem) createAndOpenLocked(ctx context.Context, rp *vfs.ResolvingPath, parent *dentry, opts *vfs.OpenOptions, ds **[]*dentry) (*vfs.FileDescription, error) { + creds := rp.Credentials() + if err := parent.checkPermissions(creds, vfs.MayWrite); err != nil { + return nil, err + } + if parent.vfsd.IsDead() { + return nil, syserror.ENOENT + } + mnt := rp.Mount() + if err := mnt.CheckBeginWrite(); err != nil { + return nil, err + } + defer mnt.EndWrite() + + if err := parent.copyUpLocked(ctx); err != nil { + return nil, err + } + + vfsObj := fs.vfsfs.VirtualFilesystem() + childName := rp.Component() + pop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(childName), + } + // We don't know if a whiteout exists on the upper layer; speculatively + // unlink it. + // + // TODO(gvisor.dev/issue/1199): Modify OpenAt => stepLocked so that we do + // know whether a whiteout exists. + var haveUpperWhiteout bool + switch err := vfsObj.UnlinkAt(ctx, fs.creds, &pop); err { + case nil: + haveUpperWhiteout = true + case syserror.ENOENT: + haveUpperWhiteout = false + default: + return nil, err + } + // Create the file on the upper layer, and get an FD representing it. + upperFD, err := vfsObj.OpenAt(ctx, fs.creds, &pop, &vfs.OpenOptions{ + Flags: opts.Flags&^vfs.FileCreationFlags | linux.O_CREAT | linux.O_EXCL, + Mode: opts.Mode, + }) + if err != nil { + if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return nil, err + } + // Change the file's owner to the caller. We can't use upperFD.SetStat() + // because it will pick up creds from ctx. + if err := vfsObj.SetStatAt(ctx, fs.creds, &pop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: uint32(creds.EffectiveKUID), + GID: uint32(creds.EffectiveKGID), + }, + }); err != nil { + if cleanupErr := vfsObj.UnlinkAt(ctx, fs.creds, &pop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer file after OpenAt(O_CREAT) metadata update failure: %v", cleanupErr) + } else if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return nil, err + } + // Re-lookup to get a dentry representing the new file, which is needed for + // the returned FD. + child, err := fs.getChildLocked(ctx, parent, childName, ds) + if err != nil { + if cleanupErr := vfsObj.UnlinkAt(ctx, fs.creds, &pop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer file after OpenAt(O_CREAT) dentry lookup failure: %v", cleanupErr) + } else if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return nil, err + } + // Finally construct the overlay FD. + upperFlags := upperFD.StatusFlags() + fd := &nonDirectoryFD{ + copiedUp: true, + cachedFD: upperFD, + cachedFlags: upperFlags, + } + fd.LockFD.Init(&child.locks) + upperFDOpts := upperFD.Options() + if err := fd.vfsfd.Init(fd, upperFlags, mnt, &child.vfsd, &upperFDOpts); err != nil { + upperFD.DecRef(ctx) + // Don't bother with cleanup; the file was created successfully, we + // just can't open it anymore for some reason. + return nil, err + } + return &fd.vfsfd, nil +} + +// ReadlinkAt implements vfs.FilesystemImpl.ReadlinkAt. +func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + d, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return "", err + } + layerVD := d.topLayer() + return fs.vfsfs.VirtualFilesystem().ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }) +} + +// RenameAt implements vfs.FilesystemImpl.RenameAt. +func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldParentVD vfs.VirtualDentry, oldName string, opts vfs.RenameOptions) error { + if opts.Flags != 0 { + return syserror.EINVAL + } + + var ds *[]*dentry + fs.renameMu.Lock() + defer fs.renameMuUnlockAndCheckDrop(ctx, &ds) + newParent, err := fs.walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry), &ds) + if err != nil { + return err + } + newName := rp.Component() + if newName == "." || newName == ".." { + return syserror.EBUSY + } + mnt := rp.Mount() + if mnt != oldParentVD.Mount() { + return syserror.EXDEV + } + if err := mnt.CheckBeginWrite(); err != nil { + return err + } + defer mnt.EndWrite() + + // FIXME(gvisor.dev/issue/1199): Actually implement rename. + _ = newParent + return syserror.EXDEV +} + +// RmdirAt implements vfs.FilesystemImpl.RmdirAt. +func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + start := rp.Start().Impl().(*dentry) + parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds) + if err != nil { + return err + } + if err := parent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil { + return err + } + if err := rp.Mount().CheckBeginWrite(); err != nil { + return err + } + defer rp.Mount().EndWrite() + name := rp.Component() + if name == "." { + return syserror.EINVAL + } + if name == ".." { + return syserror.ENOTEMPTY + } + vfsObj := rp.VirtualFilesystem() + mntns := vfs.MountNamespaceFromContext(ctx) + defer mntns.DecRef(ctx) + parent.dirMu.Lock() + defer parent.dirMu.Unlock() + + // Ensure that parent is copied-up before potentially holding child.copyMu + // below. + if err := parent.copyUpLocked(ctx); err != nil { + return err + } + + // Unlike UnlinkAt, we need a dentry representing the child directory being + // removed in order to verify that it's empty. + child, err := fs.getChildLocked(ctx, parent, name, &ds) + if err != nil { + return err + } + if !child.isDir() { + return syserror.ENOTDIR + } + child.dirMu.Lock() + defer child.dirMu.Unlock() + whiteouts, err := child.collectWhiteoutsForRmdirLocked(ctx) + if err != nil { + return err + } + child.copyMu.RLock() + defer child.copyMu.RUnlock() + if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil { + return err + } + + pop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(name), + } + if child.upperVD.Ok() { + cleanupRecreateWhiteouts := func() { + if !child.upperVD.Ok() { + return + } + for whiteoutName, whiteoutUpper := range whiteouts { + if !whiteoutUpper { + continue + } + if err := fs.createWhiteout(ctx, vfsObj, &vfs.PathOperation{ + Root: child.upperVD, + Start: child.upperVD, + Path: fspath.Parse(whiteoutName), + }); err != nil && err != syserror.EEXIST { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to recreate deleted whiteout after RmdirAt failure: %v", err) + } + } + } + // Remove existing whiteouts on the upper layer. + for whiteoutName, whiteoutUpper := range whiteouts { + if !whiteoutUpper { + continue + } + if err := vfsObj.UnlinkAt(ctx, fs.creds, &vfs.PathOperation{ + Root: child.upperVD, + Start: child.upperVD, + Path: fspath.Parse(whiteoutName), + }); err != nil { + cleanupRecreateWhiteouts() + vfsObj.AbortDeleteDentry(&child.vfsd) + return err + } + } + // Remove the existing directory on the upper layer. + if err := vfsObj.RmdirAt(ctx, fs.creds, &pop); err != nil { + cleanupRecreateWhiteouts() + vfsObj.AbortDeleteDentry(&child.vfsd) + return err + } + } + if err := fs.createWhiteout(ctx, vfsObj, &pop); err != nil { + // Don't attempt to recover from this: the original directory is + // already gone, so any dentries representing it are invalid, and + // creating a new directory won't undo that. + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to create whiteout during RmdirAt: %v", err) + vfsObj.AbortDeleteDentry(&child.vfsd) + return err + } + + vfsObj.CommitDeleteDentry(ctx, &child.vfsd) + delete(parent.children, name) + ds = appendDentry(ds, child) + parent.dirents = nil + return nil +} + +// SetStatAt implements vfs.FilesystemImpl.SetStatAt. +func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + d, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return err + } + + mode := linux.FileMode(atomic.LoadUint32(&d.mode)) + if err := vfs.CheckSetStat(ctx, rp.Credentials(), &opts, mode, auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))); err != nil { + return err + } + mnt := rp.Mount() + if err := mnt.CheckBeginWrite(); err != nil { + return err + } + defer mnt.EndWrite() + if err := d.copyUpLocked(ctx); err != nil { + return err + } + // Changes to d's attributes are serialized by d.copyMu. + d.copyMu.Lock() + defer d.copyMu.Unlock() + if err := d.fs.vfsfs.VirtualFilesystem().SetStatAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: d.upperVD, + Start: d.upperVD, + }, &opts); err != nil { + return err + } + d.updateAfterSetStatLocked(&opts) + return nil +} + +// StatAt implements vfs.FilesystemImpl.StatAt. +func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + d, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return linux.Statx{}, err + } + + var stat linux.Statx + if layerMask := opts.Mask &^ statInternalMask; layerMask != 0 { + layerVD := d.topLayer() + stat, err = fs.vfsfs.VirtualFilesystem().StatAt(ctx, fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }, &vfs.StatOptions{ + Mask: layerMask, + Sync: opts.Sync, + }) + if err != nil { + return linux.Statx{}, err + } + } + d.statInternalTo(ctx, &opts, &stat) + return stat, nil +} + +// StatFSAt implements vfs.FilesystemImpl.StatFSAt. +func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + _, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return linux.Statfs{}, err + } + return fs.statFS(ctx) +} + +// SymlinkAt implements vfs.FilesystemImpl.SymlinkAt. +func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, target string) error { + return fs.doCreateAt(ctx, rp, false /* dir */, func(parent *dentry, childName string, haveUpperWhiteout bool) error { + vfsObj := fs.vfsfs.VirtualFilesystem() + pop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(childName), + } + if haveUpperWhiteout { + if err := vfsObj.UnlinkAt(ctx, fs.creds, &pop); err != nil { + return err + } + } + if err := vfsObj.SymlinkAt(ctx, fs.creds, &pop, target); err != nil { + if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + creds := rp.Credentials() + if err := vfsObj.SetStatAt(ctx, fs.creds, &pop, &vfs.SetStatOptions{ + Stat: linux.Statx{ + Mask: linux.STATX_UID | linux.STATX_GID, + UID: uint32(creds.EffectiveKUID), + GID: uint32(creds.EffectiveKGID), + }, + }); err != nil { + if cleanupErr := vfsObj.UnlinkAt(ctx, fs.creds, &pop); cleanupErr != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to delete upper layer file after SymlinkAt metadata update failure: %v", cleanupErr) + } else if haveUpperWhiteout { + fs.cleanupRecreateWhiteout(ctx, vfsObj, &pop) + } + return err + } + return nil + }) +} + +// UnlinkAt implements vfs.FilesystemImpl.UnlinkAt. +func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + start := rp.Start().Impl().(*dentry) + parent, err := fs.walkParentDirLocked(ctx, rp, start, &ds) + if err != nil { + return err + } + if err := parent.checkPermissions(rp.Credentials(), vfs.MayWrite|vfs.MayExec); err != nil { + return err + } + if err := rp.Mount().CheckBeginWrite(); err != nil { + return err + } + defer rp.Mount().EndWrite() + name := rp.Component() + if name == "." || name == ".." { + return syserror.EISDIR + } + if rp.MustBeDir() { + return syserror.ENOTDIR + } + vfsObj := rp.VirtualFilesystem() + mntns := vfs.MountNamespaceFromContext(ctx) + defer mntns.DecRef(ctx) + parent.dirMu.Lock() + defer parent.dirMu.Unlock() + + // Ensure that parent is copied-up before potentially holding child.copyMu + // below. + if err := parent.copyUpLocked(ctx); err != nil { + return err + } + + child := parent.children[name] + var childLayer lookupLayer + if child != nil { + if child.isDir() { + return syserror.EISDIR + } + if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil { + return err + } + // Hold child.copyMu to prevent it from being copied-up during + // deletion. + child.copyMu.RLock() + defer child.copyMu.RUnlock() + if child.upperVD.Ok() { + childLayer = lookupLayerUpper + } else { + childLayer = lookupLayerLower + } + } else { + // Determine if the file being unlinked actually exists. Holding + // parent.dirMu prevents a dentry from being instantiated for the file, + // which in turn prevents it from being copied-up, so this result is + // stable. + childLayer, err = fs.lookupLayerLocked(ctx, parent, name) + if err != nil { + return err + } + if !childLayer.existsInOverlay() { + return syserror.ENOENT + } + } + + pop := vfs.PathOperation{ + Root: parent.upperVD, + Start: parent.upperVD, + Path: fspath.Parse(name), + } + if childLayer == lookupLayerUpper { + // Remove the existing file on the upper layer. + if err := vfsObj.UnlinkAt(ctx, fs.creds, &pop); err != nil { + if child != nil { + vfsObj.AbortDeleteDentry(&child.vfsd) + } + return err + } + } + if err := fs.createWhiteout(ctx, vfsObj, &pop); err != nil { + ctx.Warningf("Unrecoverable overlayfs inconsistency: failed to create whiteout during UnlinkAt: %v", err) + if child != nil { + vfsObj.AbortDeleteDentry(&child.vfsd) + } + return err + } + + if child != nil { + vfsObj.CommitDeleteDentry(ctx, &child.vfsd) + delete(parent.children, name) + ds = appendDentry(ds, child) + } + parent.dirents = nil + return nil +} + +// ListxattrAt implements vfs.FilesystemImpl.ListxattrAt. +func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, size uint64) ([]string, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + _, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return nil, err + } + // TODO(gvisor.dev/issue/1199): Linux overlayfs actually allows listxattr, + // but not any other xattr syscalls. For now we just reject all of them. + return nil, syserror.ENOTSUP +} + +// GetxattrAt implements vfs.FilesystemImpl.GetxattrAt. +func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetxattrOptions) (string, error) { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + _, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return "", err + } + return "", syserror.ENOTSUP +} + +// SetxattrAt implements vfs.FilesystemImpl.SetxattrAt. +func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + _, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return err + } + return syserror.ENOTSUP +} + +// RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt. +func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error { + var ds *[]*dentry + fs.renameMu.RLock() + defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds) + _, err := fs.resolveLocked(ctx, rp, &ds) + if err != nil { + return err + } + return syserror.ENOTSUP +} + +// PrependPath implements vfs.FilesystemImpl.PrependPath. +func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDentry, b *fspath.Builder) error { + fs.renameMu.RLock() + defer fs.renameMu.RUnlock() + return genericPrependPath(vfsroot, vd.Mount(), vd.Dentry().Impl().(*dentry), b) +} diff --git a/pkg/sentry/fsimpl/overlay/non_directory.go b/pkg/sentry/fsimpl/overlay/non_directory.go new file mode 100644 index 000000000..d3060a481 --- /dev/null +++ b/pkg/sentry/fsimpl/overlay/non_directory.go @@ -0,0 +1,266 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package overlay + +import ( + "sync/atomic" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/memmap" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/usermem" +) + +func (d *dentry) isSymlink() bool { + return atomic.LoadUint32(&d.mode)&linux.S_IFMT == linux.S_IFLNK +} + +func (d *dentry) readlink(ctx context.Context) (string, error) { + layerVD := d.topLayer() + return d.fs.vfsfs.VirtualFilesystem().ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: layerVD, + Start: layerVD, + }) +} + +type nonDirectoryFD struct { + fileDescription + + // If copiedUp is false, cachedFD represents + // fileDescription.dentry().lowerVDs[0]; otherwise, cachedFD represents + // fileDescription.dentry().upperVD. cachedFlags is the last known value of + // cachedFD.StatusFlags(). copiedUp, cachedFD, and cachedFlags are + // protected by mu. + mu sync.Mutex + copiedUp bool + cachedFD *vfs.FileDescription + cachedFlags uint32 +} + +func (fd *nonDirectoryFD) getCurrentFD(ctx context.Context) (*vfs.FileDescription, error) { + fd.mu.Lock() + defer fd.mu.Unlock() + wrappedFD, err := fd.currentFDLocked(ctx) + if err != nil { + return nil, err + } + wrappedFD.IncRef() + return wrappedFD, nil +} + +func (fd *nonDirectoryFD) currentFDLocked(ctx context.Context) (*vfs.FileDescription, error) { + d := fd.dentry() + statusFlags := fd.vfsfd.StatusFlags() + if !fd.copiedUp && d.isCopiedUp() { + // Switch to the copied-up file. + upperVD := d.topLayer() + upperFD, err := fd.filesystem().vfsfs.VirtualFilesystem().OpenAt(ctx, d.fs.creds, &vfs.PathOperation{ + Root: upperVD, + Start: upperVD, + }, &vfs.OpenOptions{ + Flags: statusFlags, + }) + if err != nil { + return nil, err + } + oldOff, oldOffErr := fd.cachedFD.Seek(ctx, 0, linux.SEEK_CUR) + if oldOffErr == nil { + if _, err := upperFD.Seek(ctx, oldOff, linux.SEEK_SET); err != nil { + upperFD.DecRef(ctx) + return nil, err + } + } + fd.cachedFD.DecRef(ctx) + fd.copiedUp = true + fd.cachedFD = upperFD + fd.cachedFlags = statusFlags + } else if fd.cachedFlags != statusFlags { + if err := fd.cachedFD.SetStatusFlags(ctx, d.fs.creds, statusFlags); err != nil { + return nil, err + } + fd.cachedFlags = statusFlags + } + return fd.cachedFD, nil +} + +// Release implements vfs.FileDescriptionImpl.Release. +func (fd *nonDirectoryFD) Release(ctx context.Context) { + fd.cachedFD.DecRef(ctx) + fd.cachedFD = nil +} + +// OnClose implements vfs.FileDescriptionImpl.OnClose. +func (fd *nonDirectoryFD) OnClose(ctx context.Context) error { + // Linux doesn't define ovl_file_operations.flush at all (i.e. its + // equivalent to OnClose is a no-op). We pass through to + // fd.cachedFD.OnClose() without upgrading if fd.dentry() has been + // copied-up, since OnClose is mostly used to define post-close writeback, + // and if fd.cachedFD hasn't been updated then it can't have been used to + // mutate fd.dentry() anyway. + fd.mu.Lock() + if statusFlags := fd.vfsfd.StatusFlags(); fd.cachedFlags != statusFlags { + if err := fd.cachedFD.SetStatusFlags(ctx, fd.filesystem().creds, statusFlags); err != nil { + fd.mu.Unlock() + return err + } + fd.cachedFlags = statusFlags + } + wrappedFD := fd.cachedFD + defer wrappedFD.IncRef() + fd.mu.Unlock() + return wrappedFD.OnClose(ctx) +} + +// Stat implements vfs.FileDescriptionImpl.Stat. +func (fd *nonDirectoryFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { + var stat linux.Statx + if layerMask := opts.Mask &^ statInternalMask; layerMask != 0 { + wrappedFD, err := fd.getCurrentFD(ctx) + if err != nil { + return linux.Statx{}, err + } + stat, err = wrappedFD.Stat(ctx, vfs.StatOptions{ + Mask: layerMask, + Sync: opts.Sync, + }) + wrappedFD.DecRef(ctx) + if err != nil { + return linux.Statx{}, err + } + } + fd.dentry().statInternalTo(ctx, &opts, &stat) + return stat, nil +} + +// SetStat implements vfs.FileDescriptionImpl.SetStat. +func (fd *nonDirectoryFD) SetStat(ctx context.Context, opts vfs.SetStatOptions) error { + d := fd.dentry() + mode := linux.FileMode(atomic.LoadUint32(&d.mode)) + if err := vfs.CheckSetStat(ctx, auth.CredentialsFromContext(ctx), &opts, mode, auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))); err != nil { + return err + } + mnt := fd.vfsfd.Mount() + if err := mnt.CheckBeginWrite(); err != nil { + return err + } + defer mnt.EndWrite() + if err := d.copyUpLocked(ctx); err != nil { + return err + } + // Changes to d's attributes are serialized by d.copyMu. + d.copyMu.Lock() + defer d.copyMu.Unlock() + wrappedFD, err := fd.currentFDLocked(ctx) + if err != nil { + return err + } + if err := wrappedFD.SetStat(ctx, opts); err != nil { + return err + } + d.updateAfterSetStatLocked(&opts) + return nil +} + +// StatFS implements vfs.FileDescriptionImpl.StatFS. +func (fd *nonDirectoryFD) StatFS(ctx context.Context) (linux.Statfs, error) { + return fd.filesystem().statFS(ctx) +} + +// PRead implements vfs.FileDescriptionImpl.PRead. +func (fd *nonDirectoryFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { + wrappedFD, err := fd.getCurrentFD(ctx) + if err != nil { + return 0, err + } + defer wrappedFD.DecRef(ctx) + return wrappedFD.PRead(ctx, dst, offset, opts) +} + +// Read implements vfs.FileDescriptionImpl.Read. +func (fd *nonDirectoryFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + // Hold fd.mu during the read to serialize the file offset. + fd.mu.Lock() + defer fd.mu.Unlock() + wrappedFD, err := fd.currentFDLocked(ctx) + if err != nil { + return 0, err + } + return wrappedFD.Read(ctx, dst, opts) +} + +// PWrite implements vfs.FileDescriptionImpl.PWrite. +func (fd *nonDirectoryFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + wrappedFD, err := fd.getCurrentFD(ctx) + if err != nil { + return 0, err + } + defer wrappedFD.DecRef(ctx) + return wrappedFD.PWrite(ctx, src, offset, opts) +} + +// Write implements vfs.FileDescriptionImpl.Write. +func (fd *nonDirectoryFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { + // Hold fd.mu during the write to serialize the file offset. + fd.mu.Lock() + defer fd.mu.Unlock() + wrappedFD, err := fd.currentFDLocked(ctx) + if err != nil { + return 0, err + } + return wrappedFD.Write(ctx, src, opts) +} + +// Seek implements vfs.FileDescriptionImpl.Seek. +func (fd *nonDirectoryFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { + // Hold fd.mu during the seek to serialize the file offset. + fd.mu.Lock() + defer fd.mu.Unlock() + wrappedFD, err := fd.currentFDLocked(ctx) + if err != nil { + return 0, err + } + return wrappedFD.Seek(ctx, offset, whence) +} + +// Sync implements vfs.FileDescriptionImpl.Sync. +func (fd *nonDirectoryFD) Sync(ctx context.Context) error { + fd.mu.Lock() + if !fd.dentry().isCopiedUp() { + fd.mu.Unlock() + return nil + } + wrappedFD, err := fd.currentFDLocked(ctx) + if err != nil { + fd.mu.Unlock() + return err + } + wrappedFD.IncRef() + defer wrappedFD.DecRef(ctx) + fd.mu.Unlock() + return wrappedFD.Sync(ctx) +} + +// ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap. +func (fd *nonDirectoryFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error { + wrappedFD, err := fd.getCurrentFD(ctx) + if err != nil { + return err + } + defer wrappedFD.DecRef(ctx) + return wrappedFD.ConfigureMMap(ctx, opts) +} diff --git a/pkg/sentry/fsimpl/overlay/overlay.go b/pkg/sentry/fsimpl/overlay/overlay.go new file mode 100644 index 000000000..75cc006bf --- /dev/null +++ b/pkg/sentry/fsimpl/overlay/overlay.go @@ -0,0 +1,627 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package overlay provides an overlay filesystem implementation, which +// synthesizes a filesystem by composing one or more immutable filesystems +// ("lower layers") with an optional mutable filesystem ("upper layer"). +// +// Lock order: +// +// directoryFD.mu / nonDirectoryFD.mu +// filesystem.renameMu +// dentry.dirMu +// dentry.copyMu +// +// Locking dentry.dirMu in multiple dentries requires that parent dentries are +// locked before child dentries, and that filesystem.renameMu is locked to +// stabilize this relationship. +package overlay + +import ( + "strings" + "sync/atomic" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/fspath" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/syserror" +) + +// Name is the default filesystem name. +const Name = "overlay" + +// FilesystemType implements vfs.FilesystemType. +type FilesystemType struct{} + +// Name implements vfs.FilesystemType.Name. +func (FilesystemType) Name() string { + return Name +} + +// FilesystemOptions may be passed as vfs.GetFilesystemOptions.InternalData to +// FilesystemType.GetFilesystem. +type FilesystemOptions struct { + // Callers passing FilesystemOptions to + // overlay.FilesystemType.GetFilesystem() are responsible for ensuring that + // the vfs.Mounts comprising the layers of the overlay filesystem do not + // contain submounts. + + // If UpperRoot.Ok(), it is the root of the writable upper layer of the + // overlay. + UpperRoot vfs.VirtualDentry + + // LowerRoots contains the roots of the immutable lower layers of the + // overlay. LowerRoots is immutable. + LowerRoots []vfs.VirtualDentry +} + +// filesystem implements vfs.FilesystemImpl. +type filesystem struct { + vfsfs vfs.Filesystem + + // Immutable options. + opts FilesystemOptions + + // creds is a copy of the filesystem's creator's credentials, which are + // used for accesses to the filesystem's layers. creds is immutable. + creds *auth.Credentials + + // dirDevMinor is the device minor number used for directories. dirDevMinor + // is immutable. + dirDevMinor uint32 + + // lowerDevMinors maps lower layer filesystems to device minor numbers + // assigned to non-directory files originating from that filesystem. + // lowerDevMinors is immutable. + lowerDevMinors map[*vfs.Filesystem]uint32 + + // renameMu synchronizes renaming with non-renaming operations in order to + // ensure consistent lock ordering between dentry.dirMu in different + // dentries. + renameMu sync.RWMutex + + // lastDirIno is the last inode number assigned to a directory. lastDirIno + // is accessed using atomic memory operations. + lastDirIno uint64 +} + +// GetFilesystem implements vfs.FilesystemType.GetFilesystem. +func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) { + mopts := vfs.GenericParseMountOptions(opts.Data) + fsoptsRaw := opts.InternalData + fsopts, haveFSOpts := fsoptsRaw.(FilesystemOptions) + if fsoptsRaw != nil && !haveFSOpts { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: GetFilesystemOptions.InternalData has type %T, wanted overlay.FilesystemOptions or nil", fsoptsRaw) + return nil, nil, syserror.EINVAL + } + if haveFSOpts { + if len(fsopts.LowerRoots) == 0 { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: LowerRoots must be non-empty") + return nil, nil, syserror.EINVAL + } + if len(fsopts.LowerRoots) < 2 && !fsopts.UpperRoot.Ok() { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: at least two LowerRoots are required when UpperRoot is unspecified") + return nil, nil, syserror.EINVAL + } + // We don't enforce a maximum number of lower layers when not + // configured by applications; the sandbox owner can have an overlay + // filesystem with any number of lower layers. + } else { + vfsroot := vfs.RootFromContext(ctx) + defer vfsroot.DecRef(ctx) + upperPathname, ok := mopts["upperdir"] + if ok { + delete(mopts, "upperdir") + // Linux overlayfs also requires a workdir when upperdir is + // specified; we don't, so silently ignore this option. + delete(mopts, "workdir") + upperPath := fspath.Parse(upperPathname) + if !upperPath.Absolute { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: upperdir %q must be absolute", upperPathname) + return nil, nil, syserror.EINVAL + } + upperRoot, err := vfsObj.GetDentryAt(ctx, creds, &vfs.PathOperation{ + Root: vfsroot, + Start: vfsroot, + Path: upperPath, + FollowFinalSymlink: true, + }, &vfs.GetDentryOptions{ + CheckSearchable: true, + }) + if err != nil { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: failed to resolve upperdir %q: %v", upperPathname, err) + return nil, nil, err + } + defer upperRoot.DecRef(ctx) + privateUpperRoot, err := clonePrivateMount(vfsObj, upperRoot, false /* forceReadOnly */) + if err != nil { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: failed to make private bind mount of upperdir %q: %v", upperPathname, err) + return nil, nil, err + } + defer privateUpperRoot.DecRef(ctx) + fsopts.UpperRoot = privateUpperRoot + } + lowerPathnamesStr, ok := mopts["lowerdir"] + if !ok { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: missing required option lowerdir") + return nil, nil, syserror.EINVAL + } + delete(mopts, "lowerdir") + lowerPathnames := strings.Split(lowerPathnamesStr, ":") + const maxLowerLayers = 500 // Linux: fs/overlay/super.c:OVL_MAX_STACK + if len(lowerPathnames) < 2 && !fsopts.UpperRoot.Ok() { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: at least two lowerdirs are required when upperdir is unspecified") + return nil, nil, syserror.EINVAL + } + if len(lowerPathnames) > maxLowerLayers { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: %d lowerdirs specified, maximum %d", len(lowerPathnames), maxLowerLayers) + return nil, nil, syserror.EINVAL + } + for _, lowerPathname := range lowerPathnames { + lowerPath := fspath.Parse(lowerPathname) + if !lowerPath.Absolute { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: lowerdir %q must be absolute", lowerPathname) + return nil, nil, syserror.EINVAL + } + lowerRoot, err := vfsObj.GetDentryAt(ctx, creds, &vfs.PathOperation{ + Root: vfsroot, + Start: vfsroot, + Path: lowerPath, + FollowFinalSymlink: true, + }, &vfs.GetDentryOptions{ + CheckSearchable: true, + }) + if err != nil { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: failed to resolve lowerdir %q: %v", lowerPathname, err) + return nil, nil, err + } + defer lowerRoot.DecRef(ctx) + privateLowerRoot, err := clonePrivateMount(vfsObj, lowerRoot, true /* forceReadOnly */) + if err != nil { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: failed to make private bind mount of lowerdir %q: %v", lowerPathname, err) + return nil, nil, err + } + defer privateLowerRoot.DecRef(ctx) + fsopts.LowerRoots = append(fsopts.LowerRoots, privateLowerRoot) + } + } + if len(mopts) != 0 { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: unused options: %v", mopts) + return nil, nil, syserror.EINVAL + } + + // Allocate device numbers. + dirDevMinor, err := vfsObj.GetAnonBlockDevMinor() + if err != nil { + return nil, nil, err + } + lowerDevMinors := make(map[*vfs.Filesystem]uint32) + for _, lowerRoot := range fsopts.LowerRoots { + lowerFS := lowerRoot.Mount().Filesystem() + if _, ok := lowerDevMinors[lowerFS]; !ok { + devMinor, err := vfsObj.GetAnonBlockDevMinor() + if err != nil { + vfsObj.PutAnonBlockDevMinor(dirDevMinor) + for _, lowerDevMinor := range lowerDevMinors { + vfsObj.PutAnonBlockDevMinor(lowerDevMinor) + } + return nil, nil, err + } + lowerDevMinors[lowerFS] = devMinor + } + } + + // Take extra references held by the filesystem. + if fsopts.UpperRoot.Ok() { + fsopts.UpperRoot.IncRef() + } + for _, lowerRoot := range fsopts.LowerRoots { + lowerRoot.IncRef() + } + + fs := &filesystem{ + opts: fsopts, + creds: creds.Fork(), + dirDevMinor: dirDevMinor, + lowerDevMinors: lowerDevMinors, + } + fs.vfsfs.Init(vfsObj, &fstype, fs) + + // Construct the root dentry. + root := fs.newDentry() + root.refs = 1 + if fs.opts.UpperRoot.Ok() { + fs.opts.UpperRoot.IncRef() + root.copiedUp = 1 + root.upperVD = fs.opts.UpperRoot + } + for _, lowerRoot := range fs.opts.LowerRoots { + lowerRoot.IncRef() + root.lowerVDs = append(root.lowerVDs, lowerRoot) + } + rootTopVD := root.topLayer() + // Get metadata from the topmost layer. See fs.lookupLocked(). + const rootStatMask = linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO + rootStat, err := vfsObj.StatAt(ctx, creds, &vfs.PathOperation{ + Root: rootTopVD, + Start: rootTopVD, + }, &vfs.StatOptions{ + Mask: rootStatMask, + }) + if err != nil { + root.destroyLocked(ctx) + fs.vfsfs.DecRef(ctx) + return nil, nil, err + } + if rootStat.Mask&rootStatMask != rootStatMask { + root.destroyLocked(ctx) + fs.vfsfs.DecRef(ctx) + return nil, nil, syserror.EREMOTE + } + if isWhiteout(&rootStat) { + ctx.Warningf("overlay.FilesystemType.GetFilesystem: filesystem root is a whiteout") + root.destroyLocked(ctx) + fs.vfsfs.DecRef(ctx) + return nil, nil, syserror.EINVAL + } + root.mode = uint32(rootStat.Mode) + root.uid = rootStat.UID + root.gid = rootStat.GID + if rootStat.Mode&linux.S_IFMT == linux.S_IFDIR { + root.devMajor = linux.UNNAMED_MAJOR + root.devMinor = fs.dirDevMinor + root.ino = fs.newDirIno() + } else if !root.upperVD.Ok() { + root.devMajor = linux.UNNAMED_MAJOR + root.devMinor = fs.lowerDevMinors[root.lowerVDs[0].Mount().Filesystem()] + root.ino = rootStat.Ino + } else { + root.devMajor = rootStat.DevMajor + root.devMinor = rootStat.DevMinor + root.ino = rootStat.Ino + } + + return &fs.vfsfs, &root.vfsd, nil +} + +// clonePrivateMount creates a non-recursive bind mount rooted at vd, not +// associated with any MountNamespace, and returns the root of the new mount. +// (This is required to ensure that each layer of an overlay comprises only a +// single mount, and therefore can't cross into e.g. the overlay filesystem +// itself, risking lock recursion.) A reference is held on the returned +// VirtualDentry. +func clonePrivateMount(vfsObj *vfs.VirtualFilesystem, vd vfs.VirtualDentry, forceReadOnly bool) (vfs.VirtualDentry, error) { + oldmnt := vd.Mount() + opts := oldmnt.Options() + if forceReadOnly { + opts.ReadOnly = true + } + newmnt, err := vfsObj.NewDisconnectedMount(oldmnt.Filesystem(), vd.Dentry(), &opts) + if err != nil { + return vfs.VirtualDentry{}, err + } + return vfs.MakeVirtualDentry(newmnt, vd.Dentry()), nil +} + +// Release implements vfs.FilesystemImpl.Release. +func (fs *filesystem) Release(ctx context.Context) { + vfsObj := fs.vfsfs.VirtualFilesystem() + vfsObj.PutAnonBlockDevMinor(fs.dirDevMinor) + for _, lowerDevMinor := range fs.lowerDevMinors { + vfsObj.PutAnonBlockDevMinor(lowerDevMinor) + } + if fs.opts.UpperRoot.Ok() { + fs.opts.UpperRoot.DecRef(ctx) + } + for _, lowerRoot := range fs.opts.LowerRoots { + lowerRoot.DecRef(ctx) + } +} + +func (fs *filesystem) statFS(ctx context.Context) (linux.Statfs, error) { + // Always statfs the root of the topmost layer. Compare Linux's + // fs/overlayfs/super.c:ovl_statfs(). + var rootVD vfs.VirtualDentry + if fs.opts.UpperRoot.Ok() { + rootVD = fs.opts.UpperRoot + } else { + rootVD = fs.opts.LowerRoots[0] + } + fsstat, err := fs.vfsfs.VirtualFilesystem().StatFSAt(ctx, fs.creds, &vfs.PathOperation{ + Root: rootVD, + Start: rootVD, + }) + if err != nil { + return linux.Statfs{}, err + } + fsstat.Type = linux.OVERLAYFS_SUPER_MAGIC + return fsstat, nil +} + +func (fs *filesystem) newDirIno() uint64 { + return atomic.AddUint64(&fs.lastDirIno, 1) +} + +// dentry implements vfs.DentryImpl. +type dentry struct { + vfsd vfs.Dentry + + refs int64 + + // fs is the owning filesystem. fs is immutable. + fs *filesystem + + // mode, uid, and gid are the file mode, owner, and group of the file in + // the topmost layer (and therefore the overlay file as well), and are used + // for permission checks on this dentry. These fields are protected by + // copyMu and accessed using atomic memory operations. + mode uint32 + uid uint32 + gid uint32 + + // copiedUp is 1 if this dentry has been copied-up (i.e. upperVD.Ok()) and + // 0 otherwise. copiedUp is accessed using atomic memory operations. + copiedUp uint32 + + // parent is the dentry corresponding to this dentry's parent directory. + // name is this dentry's name in parent. If this dentry is a filesystem + // root, parent is nil and name is the empty string. parent and name are + // protected by fs.renameMu. + parent *dentry + name string + + // If this dentry represents a directory, children maps the names of + // children for which dentries have been instantiated to those dentries, + // and dirents (if not nil) is a cache of dirents as returned by + // directoryFDs representing this directory. children is protected by + // dirMu. + dirMu sync.Mutex + children map[string]*dentry + dirents []vfs.Dirent + + // upperVD and lowerVDs are the files from the overlay filesystem's layers + // that comprise the file on the overlay filesystem. + // + // If !upperVD.Ok(), it can transition to a valid vfs.VirtualDentry (i.e. + // be copied up) with copyMu locked for writing; otherwise, it is + // immutable. lowerVDs is always immutable. + copyMu sync.RWMutex + upperVD vfs.VirtualDentry + lowerVDs []vfs.VirtualDentry + + // inlineLowerVDs backs lowerVDs in the common case where len(lowerVDs) <= + // len(inlineLowerVDs). + inlineLowerVDs [1]vfs.VirtualDentry + + // devMajor, devMinor, and ino are the device major/minor and inode numbers + // used by this dentry. These fields are protected by copyMu and accessed + // using atomic memory operations. + devMajor uint32 + devMinor uint32 + ino uint64 + + locks vfs.FileLocks +} + +// newDentry creates a new dentry. The dentry initially has no references; it +// is the caller's responsibility to set the dentry's reference count and/or +// call dentry.destroy() as appropriate. The dentry is initially invalid in +// that it contains no layers; the caller is responsible for setting them. +func (fs *filesystem) newDentry() *dentry { + d := &dentry{ + fs: fs, + } + d.lowerVDs = d.inlineLowerVDs[:0] + d.vfsd.Init(d) + return d +} + +// IncRef implements vfs.DentryImpl.IncRef. +func (d *dentry) IncRef() { + // d.refs may be 0 if d.fs.renameMu is locked, which serializes against + // d.checkDropLocked(). + atomic.AddInt64(&d.refs, 1) +} + +// TryIncRef implements vfs.DentryImpl.TryIncRef. +func (d *dentry) TryIncRef() bool { + for { + refs := atomic.LoadInt64(&d.refs) + if refs <= 0 { + return false + } + if atomic.CompareAndSwapInt64(&d.refs, refs, refs+1) { + return true + } + } +} + +// DecRef implements vfs.DentryImpl.DecRef. +func (d *dentry) DecRef(ctx context.Context) { + if refs := atomic.AddInt64(&d.refs, -1); refs == 0 { + d.fs.renameMu.Lock() + d.checkDropLocked(ctx) + d.fs.renameMu.Unlock() + } else if refs < 0 { + panic("overlay.dentry.DecRef() called without holding a reference") + } +} + +// checkDropLocked should be called after d's reference count becomes 0 or it +// becomes deleted. +// +// Preconditions: d.fs.renameMu must be locked for writing. +func (d *dentry) checkDropLocked(ctx context.Context) { + // Dentries with a positive reference count must be retained. (The only way + // to obtain a reference on a dentry with zero references is via path + // resolution, which requires renameMu, so if d.refs is zero then it will + // remain zero while we hold renameMu for writing.) Dentries with a + // negative reference count have already been destroyed. + if atomic.LoadInt64(&d.refs) != 0 { + return + } + // Refs is still zero; destroy it. + d.destroyLocked(ctx) + return +} + +// destroyLocked destroys the dentry. +// +// Preconditions: d.fs.renameMu must be locked for writing. d.refs == 0. +func (d *dentry) destroyLocked(ctx context.Context) { + switch atomic.LoadInt64(&d.refs) { + case 0: + // Mark the dentry destroyed. + atomic.StoreInt64(&d.refs, -1) + case -1: + panic("overlay.dentry.destroyLocked() called on already destroyed dentry") + default: + panic("overlay.dentry.destroyLocked() called with references on the dentry") + } + + if d.upperVD.Ok() { + d.upperVD.DecRef(ctx) + } + for _, lowerVD := range d.lowerVDs { + lowerVD.DecRef(ctx) + } + + if d.parent != nil { + d.parent.dirMu.Lock() + if !d.vfsd.IsDead() { + delete(d.parent.children, d.name) + } + d.parent.dirMu.Unlock() + // Drop the reference held by d on its parent without recursively + // locking d.fs.renameMu. + if refs := atomic.AddInt64(&d.parent.refs, -1); refs == 0 { + d.parent.checkDropLocked(ctx) + } else if refs < 0 { + panic("overlay.dentry.DecRef() called without holding a reference") + } + } +} + +// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent. +func (d *dentry) InotifyWithParent(ctx context.Context, events uint32, cookie uint32, et vfs.EventType) { + // TODO(gvisor.dev/issue/1479): Implement inotify. +} + +// Watches implements vfs.DentryImpl.Watches. +func (d *dentry) Watches() *vfs.Watches { + // TODO(gvisor.dev/issue/1479): Implement inotify. + return nil +} + +// OnZeroWatches implements vfs.DentryImpl.OnZeroWatches. +// +// TODO(gvisor.dev/issue/1479): Implement inotify. +func (d *dentry) OnZeroWatches(context.Context) {} + +// iterLayers invokes yield on each layer comprising d, from top to bottom. If +// any call to yield returns false, iterLayer stops iteration. +func (d *dentry) iterLayers(yield func(vd vfs.VirtualDentry, isUpper bool) bool) { + if d.isCopiedUp() { + if !yield(d.upperVD, true) { + return + } + } + for _, lowerVD := range d.lowerVDs { + if !yield(lowerVD, false) { + return + } + } +} + +func (d *dentry) topLayerInfo() (vd vfs.VirtualDentry, isUpper bool) { + if d.isCopiedUp() { + return d.upperVD, true + } + return d.lowerVDs[0], false +} + +func (d *dentry) topLayer() vfs.VirtualDentry { + vd, _ := d.topLayerInfo() + return vd +} + +func (d *dentry) checkPermissions(creds *auth.Credentials, ats vfs.AccessTypes) error { + return vfs.GenericCheckPermissions(creds, ats, linux.FileMode(atomic.LoadUint32(&d.mode)), auth.KUID(atomic.LoadUint32(&d.uid)), auth.KGID(atomic.LoadUint32(&d.gid))) +} + +// statInternalMask is the set of stat fields that is set by +// dentry.statInternalTo(). +const statInternalMask = linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID | linux.STATX_INO + +// statInternalTo writes fields to stat that are stored in d, and therefore do +// not requiring invoking StatAt on the overlay's layers. +func (d *dentry) statInternalTo(ctx context.Context, opts *vfs.StatOptions, stat *linux.Statx) { + stat.Mask |= statInternalMask + if d.isDir() { + // Linux sets nlink to 1 for merged directories + // (fs/overlayfs/inode.c:ovl_getattr()); we set it to 2 because this is + // correct more often ("." and the directory's entry in its parent), + // and some of our tests expect this. + stat.Nlink = 2 + } + stat.UID = atomic.LoadUint32(&d.uid) + stat.GID = atomic.LoadUint32(&d.gid) + stat.Mode = uint16(atomic.LoadUint32(&d.mode)) + stat.Ino = atomic.LoadUint64(&d.ino) + stat.DevMajor = atomic.LoadUint32(&d.devMajor) + stat.DevMinor = atomic.LoadUint32(&d.devMinor) +} + +// Preconditions: d.copyMu must be locked for writing. +func (d *dentry) updateAfterSetStatLocked(opts *vfs.SetStatOptions) { + if opts.Stat.Mask&linux.STATX_MODE != 0 { + atomic.StoreUint32(&d.mode, (d.mode&linux.S_IFMT)|uint32(opts.Stat.Mode&^linux.S_IFMT)) + } + if opts.Stat.Mask&linux.STATX_UID != 0 { + atomic.StoreUint32(&d.uid, opts.Stat.UID) + } + if opts.Stat.Mask&linux.STATX_GID != 0 { + atomic.StoreUint32(&d.gid, opts.Stat.GID) + } +} + +// fileDescription is embedded by overlay implementations of +// vfs.FileDescriptionImpl. +type fileDescription struct { + vfsfd vfs.FileDescription + vfs.FileDescriptionDefaultImpl + vfs.LockFD +} + +func (fd *fileDescription) filesystem() *filesystem { + return fd.vfsfd.Mount().Filesystem().Impl().(*filesystem) +} + +func (fd *fileDescription) dentry() *dentry { + return fd.vfsfd.Dentry().Impl().(*dentry) +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *fileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/fsimpl/pipefs/pipefs.go b/pkg/sentry/fsimpl/pipefs/pipefs.go index cab771211..2ca793db9 100644 --- a/pkg/sentry/fsimpl/pipefs/pipefs.go +++ b/pkg/sentry/fsimpl/pipefs/pipefs.go @@ -63,9 +63,9 @@ func NewFilesystem(vfsObj *vfs.VirtualFilesystem) (*vfs.Filesystem, error) { } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) - fs.Filesystem.Release() + fs.Filesystem.Release(ctx) } // PrependPath implements vfs.FilesystemImpl.PrependPath. @@ -81,7 +81,8 @@ type inode struct { kernfs.InodeNotSymlink kernfs.InodeNoopRefCount - pipe *pipe.VFSPipe + locks vfs.FileLocks + pipe *pipe.VFSPipe ino uint64 uid auth.KUID @@ -114,7 +115,7 @@ func (i *inode) Mode() linux.FileMode { } // Stat implements kernfs.Inode.Stat. -func (i *inode) Stat(vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { +func (i *inode) Stat(_ context.Context, vfsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { ts := linux.NsecToStatxTimestamp(i.ctime.Nanoseconds()) return linux.Statx{ Mask: linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_NLINK | linux.STATX_UID | linux.STATX_GID | linux.STATX_ATIME | linux.STATX_MTIME | linux.STATX_CTIME | linux.STATX_INO | linux.STATX_SIZE | linux.STATX_BLOCKS, @@ -147,7 +148,7 @@ func (i *inode) SetStat(ctx context.Context, vfsfs *vfs.Filesystem, creds *auth. // Open implements kernfs.Inode.Open. func (i *inode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - return i.pipe.Open(ctx, rp.Mount(), vfsd, opts.Flags) + return i.pipe.Open(ctx, rp.Mount(), vfsd, opts.Flags, &i.locks) } // NewConnectedPipeFDs returns a pair of FileDescriptions representing the read @@ -159,6 +160,6 @@ func NewConnectedPipeFDs(ctx context.Context, mnt *vfs.Mount, flags uint32) (*vf inode := newInode(ctx, fs) var d kernfs.Dentry d.Init(inode) - defer d.DecRef() + defer d.DecRef(ctx) return inode.pipe.ReaderWriterPair(mnt, d.VFSDentry(), flags) } diff --git a/pkg/sentry/fsimpl/proc/BUILD b/pkg/sentry/fsimpl/proc/BUILD index 17c1342b5..6014138ff 100644 --- a/pkg/sentry/fsimpl/proc/BUILD +++ b/pkg/sentry/fsimpl/proc/BUILD @@ -22,6 +22,7 @@ go_library( "//pkg/log", "//pkg/refs", "//pkg/safemem", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsbridge", "//pkg/sentry/fsimpl/kernfs", "//pkg/sentry/inet", diff --git a/pkg/sentry/fsimpl/proc/filesystem.go b/pkg/sentry/fsimpl/proc/filesystem.go index 609210253..2463d51cd 100644 --- a/pkg/sentry/fsimpl/proc/filesystem.go +++ b/pkg/sentry/fsimpl/proc/filesystem.go @@ -77,9 +77,9 @@ func (ft FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualF } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) - fs.Filesystem.Release() + fs.Filesystem.Release(ctx) } // dynamicInode is an overfitted interface for common Inodes with diff --git a/pkg/sentry/fsimpl/proc/subtasks.go b/pkg/sentry/fsimpl/proc/subtasks.go index 36a911db4..79c2725f3 100644 --- a/pkg/sentry/fsimpl/proc/subtasks.go +++ b/pkg/sentry/fsimpl/proc/subtasks.go @@ -37,6 +37,8 @@ type subtasksInode struct { kernfs.OrderedChildren kernfs.AlwaysValid + locks vfs.FileLocks + fs *filesystem task *kernel.Task pidns *kernel.PIDNamespace @@ -126,7 +128,7 @@ func (fd *subtasksFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallbac return fd.GenericDirectoryFD.IterDirents(ctx, cb) } -// Seek implements vfs.FileDecriptionImpl.Seek. +// Seek implements vfs.FileDescriptionImpl.Seek. func (fd *subtasksFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) { if fd.task.ExitState() >= kernel.TaskExitZombie { return 0, syserror.ENOENT @@ -153,7 +155,7 @@ func (fd *subtasksFD) SetStat(ctx context.Context, opts vfs.SetStatOptions) erro // Open implements kernfs.Inode. func (i *subtasksInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { fd := &subtasksFD{task: i.task} - if err := fd.Init(&i.OrderedChildren, &opts); err != nil { + if err := fd.Init(&i.OrderedChildren, &i.locks, &opts); err != nil { return nil, err } if err := fd.VFSFileDescription().Init(fd, opts.Flags, rp.Mount(), vfsd, &vfs.FileDescriptionOptions{}); err != nil { @@ -163,8 +165,8 @@ func (i *subtasksInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *v } // Stat implements kernfs.Inode. -func (i *subtasksInode) Stat(vsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { - stat, err := i.InodeAttrs.Stat(vsfs, opts) +func (i *subtasksInode) Stat(ctx context.Context, vsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { + stat, err := i.InodeAttrs.Stat(ctx, vsfs, opts) if err != nil { return linux.Statx{}, err } diff --git a/pkg/sentry/fsimpl/proc/task.go b/pkg/sentry/fsimpl/proc/task.go index 482055db1..a5c7aa470 100644 --- a/pkg/sentry/fsimpl/proc/task.go +++ b/pkg/sentry/fsimpl/proc/task.go @@ -38,6 +38,8 @@ type taskInode struct { kernfs.InodeAttrs kernfs.OrderedChildren + locks vfs.FileLocks + task *kernel.Task } @@ -103,7 +105,7 @@ func (i *taskInode) Valid(ctx context.Context) bool { // Open implements kernfs.Inode. func (i *taskInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts) if err != nil { return nil, err } @@ -154,8 +156,8 @@ func (fs *filesystem) newTaskOwnedDir(task *kernel.Task, ino uint64, perm linux. } // Stat implements kernfs.Inode. -func (i *taskOwnedInode) Stat(fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { - stat, err := i.Inode.Stat(fs, opts) +func (i *taskOwnedInode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { + stat, err := i.Inode.Stat(ctx, fs, opts) if err != nil { return linux.Statx{}, err } diff --git a/pkg/sentry/fsimpl/proc/task_fds.go b/pkg/sentry/fsimpl/proc/task_fds.go index 44ccc9e4a..f0d3f7f5e 100644 --- a/pkg/sentry/fsimpl/proc/task_fds.go +++ b/pkg/sentry/fsimpl/proc/task_fds.go @@ -43,16 +43,18 @@ func getTaskFD(t *kernel.Task, fd int32) (*vfs.FileDescription, kernel.FDFlags) return file, flags } -func taskFDExists(t *kernel.Task, fd int32) bool { +func taskFDExists(ctx context.Context, t *kernel.Task, fd int32) bool { file, _ := getTaskFD(t, fd) if file == nil { return false } - file.DecRef() + file.DecRef(ctx) return true } type fdDir struct { + locks vfs.FileLocks + fs *filesystem task *kernel.Task @@ -62,15 +64,14 @@ type fdDir struct { } // IterDirents implements kernfs.inodeDynamicLookup. -func (i *fdDir) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, absOffset, relOffset int64) (int64, error) { +func (i *fdDir) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, offset, relOffset int64) (int64, error) { var fds []int32 i.task.WithMuLocked(func(t *kernel.Task) { if fdTable := t.FDTable(); fdTable != nil { - fds = fdTable.GetFDs() + fds = fdTable.GetFDs(ctx) } }) - offset := absOffset + relOffset typ := uint8(linux.DT_REG) if i.produceSymlink { typ = linux.DT_LNK @@ -134,7 +135,7 @@ func (i *fdDirInode) Lookup(ctx context.Context, name string) (*vfs.Dentry, erro return nil, syserror.ENOENT } fd := int32(fdInt) - if !taskFDExists(i.task, fd) { + if !taskFDExists(ctx, i.task, fd) { return nil, syserror.ENOENT } taskDentry := i.fs.newFDSymlink(i.task, fd, i.fs.NextIno()) @@ -143,7 +144,7 @@ func (i *fdDirInode) Lookup(ctx context.Context, name string) (*vfs.Dentry, erro // Open implements kernfs.Inode. func (i *fdDirInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts) if err != nil { return nil, err } @@ -203,9 +204,9 @@ func (s *fdSymlink) Readlink(ctx context.Context) (string, error) { if file == nil { return "", syserror.ENOENT } - defer file.DecRef() + defer file.DecRef(ctx) root := vfs.RootFromContext(ctx) - defer root.DecRef() + defer root.DecRef(ctx) return s.task.Kernel().VFS().PathnameWithDeleted(ctx, root, file.VirtualDentry()) } @@ -214,7 +215,7 @@ func (s *fdSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDen if file == nil { return vfs.VirtualDentry{}, "", syserror.ENOENT } - defer file.DecRef() + defer file.DecRef(ctx) vd := file.VirtualDentry() vd.IncRef() return vd, "", nil @@ -257,7 +258,7 @@ func (i *fdInfoDirInode) Lookup(ctx context.Context, name string) (*vfs.Dentry, return nil, syserror.ENOENT } fd := int32(fdInt) - if !taskFDExists(i.task, fd) { + if !taskFDExists(ctx, i.task, fd) { return nil, syserror.ENOENT } data := &fdInfoData{ @@ -270,7 +271,7 @@ func (i *fdInfoDirInode) Lookup(ctx context.Context, name string) (*vfs.Dentry, // Open implements kernfs.Inode. func (i *fdInfoDirInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts) if err != nil { return nil, err } @@ -296,7 +297,7 @@ func (d *fdInfoData) Generate(ctx context.Context, buf *bytes.Buffer) error { if file == nil { return syserror.ENOENT } - defer file.DecRef() + defer file.DecRef(ctx) // TODO(b/121266871): Include pos, locks, and other data. For now we only // have flags. // See https://www.kernel.org/doc/Documentation/filesystems/proc.txt diff --git a/pkg/sentry/fsimpl/proc/task_files.go b/pkg/sentry/fsimpl/proc/task_files.go index 2f297e48a..830b78949 100644 --- a/pkg/sentry/fsimpl/proc/task_files.go +++ b/pkg/sentry/fsimpl/proc/task_files.go @@ -22,6 +22,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/safemem" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs" "gvisor.dev/gvisor/pkg/sentry/kernel" @@ -34,6 +35,10 @@ import ( "gvisor.dev/gvisor/pkg/usermem" ) +// "There is an (arbitrary) limit on the number of lines in the file. As at +// Linux 3.18, the limit is five lines." - user_namespaces(7) +const maxIDMapLines = 5 + // mm gets the kernel task's MemoryManager. No additional reference is taken on // mm here. This is safe because MemoryManager.destroy is required to leave the // MemoryManager in a state where it's still usable as a DynamicBytesSource. @@ -226,8 +231,9 @@ func (d *cmdlineData) Generate(ctx context.Context, buf *bytes.Buffer) error { // Linux will return envp up to and including the first NULL character, // so find it. - if end := bytes.IndexByte(buf.Bytes()[ar.Length():], 0); end != -1 { - buf.Truncate(end) + envStart := int(ar.Length()) + if nullIdx := bytes.IndexByte(buf.Bytes()[envStart:], 0); nullIdx != -1 { + buf.Truncate(envStart + nullIdx) } } @@ -282,7 +288,8 @@ func (d *commData) Generate(ctx context.Context, buf *bytes.Buffer) error { return nil } -// idMapData implements vfs.DynamicBytesSource for /proc/[pid]/{gid_map|uid_map}. +// idMapData implements vfs.WritableDynamicBytesSource for +// /proc/[pid]/{gid_map|uid_map}. // // +stateify savable type idMapData struct { @@ -294,7 +301,7 @@ type idMapData struct { var _ dynamicInode = (*idMapData)(nil) -// Generate implements vfs.DynamicBytesSource.Generate. +// Generate implements vfs.WritableDynamicBytesSource.Generate. func (d *idMapData) Generate(ctx context.Context, buf *bytes.Buffer) error { var entries []auth.IDMapEntry if d.gids { @@ -308,6 +315,60 @@ func (d *idMapData) Generate(ctx context.Context, buf *bytes.Buffer) error { return nil } +// Write implements vfs.WritableDynamicBytesSource.Write. +func (d *idMapData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) { + // "In addition, the number of bytes written to the file must be less than + // the system page size, and the write must be performed at the start of + // the file ..." - user_namespaces(7) + srclen := src.NumBytes() + if srclen >= usermem.PageSize || offset != 0 { + return 0, syserror.EINVAL + } + b := make([]byte, srclen) + if _, err := src.CopyIn(ctx, b); err != nil { + return 0, err + } + + // Truncate from the first NULL byte. + var nul int64 + nul = int64(bytes.IndexByte(b, 0)) + if nul == -1 { + nul = srclen + } + b = b[:nul] + // Remove the last \n. + if nul >= 1 && b[nul-1] == '\n' { + b = b[:nul-1] + } + lines := bytes.SplitN(b, []byte("\n"), maxIDMapLines+1) + if len(lines) > maxIDMapLines { + return 0, syserror.EINVAL + } + + entries := make([]auth.IDMapEntry, len(lines)) + for i, l := range lines { + var e auth.IDMapEntry + _, err := fmt.Sscan(string(l), &e.FirstID, &e.FirstParentID, &e.Length) + if err != nil { + return 0, syserror.EINVAL + } + entries[i] = e + } + var err error + if d.gids { + err = d.task.UserNamespace().SetGIDMap(ctx, entries) + } else { + err = d.task.UserNamespace().SetUIDMap(ctx, entries) + } + if err != nil { + return 0, err + } + + // On success, Linux's kernel/user_namespace.c:map_write() always returns + // count, even if fewer bytes were used. + return int64(srclen), nil +} + // mapsData implements vfs.DynamicBytesSource for /proc/[pid]/maps. // // +stateify savable @@ -616,7 +677,7 @@ func (s *exeSymlink) Readlink(ctx context.Context) (string, error) { if err != nil { return "", err } - defer exec.DecRef() + defer exec.DecRef(ctx) return exec.PathnameWithDeleted(ctx), nil } @@ -631,7 +692,7 @@ func (s *exeSymlink) Getlink(ctx context.Context, _ *vfs.Mount) (vfs.VirtualDent if err != nil { return vfs.VirtualDentry{}, "", err } - defer exec.DecRef() + defer exec.DecRef(ctx) vd := exec.(*fsbridge.VFSFile).FileDescription().VirtualDentry() vd.IncRef() @@ -687,7 +748,7 @@ func (i *mountInfoData) Generate(ctx context.Context, buf *bytes.Buffer) error { // Root has been destroyed. Don't try to read mounts. return nil } - defer rootDir.DecRef() + defer rootDir.DecRef(ctx) i.task.Kernel().VFS().GenerateProcMountInfo(ctx, rootDir, buf) return nil } @@ -718,7 +779,7 @@ func (i *mountsData) Generate(ctx context.Context, buf *bytes.Buffer) error { // Root has been destroyed. Don't try to read mounts. return nil } - defer rootDir.DecRef() + defer rootDir.DecRef(ctx) i.task.Kernel().VFS().GenerateProcMounts(ctx, rootDir, buf) return nil } @@ -764,7 +825,7 @@ func (s *namespaceSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.Vir dentry.Init(&namespaceInode{}) vd := vfs.MakeVirtualDentry(mnt, dentry.VFSDentry()) vd.IncRef() - dentry.DecRef() + dentry.DecRef(ctx) return vd, "", nil } @@ -775,6 +836,8 @@ type namespaceInode struct { kernfs.InodeNoopRefCount kernfs.InodeNotDirectory kernfs.InodeNotSymlink + + locks vfs.FileLocks } var _ kernfs.Inode = (*namespaceInode)(nil) @@ -791,6 +854,7 @@ func (i *namespaceInode) Init(creds *auth.Credentials, devMajor, devMinor uint32 func (i *namespaceInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { fd := &namespaceFD{inode: i} i.IncRef() + fd.LockFD.Init(&i.locks) if err := fd.vfsfd.Init(fd, opts.Flags, rp.Mount(), vfsd, &vfs.FileDescriptionOptions{}); err != nil { return nil, err } @@ -801,6 +865,7 @@ func (i *namespaceInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd * // /proc/[pid]/ns/*. type namespaceFD struct { vfs.FileDescriptionDefaultImpl + vfs.LockFD vfsfd vfs.FileDescription inode *namespaceInode @@ -811,7 +876,7 @@ var _ vfs.FileDescriptionImpl = (*namespaceFD)(nil) // Stat implements FileDescriptionImpl. func (fd *namespaceFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) { vfs := fd.vfsfd.VirtualDentry().Mount().Filesystem() - return fd.inode.Stat(vfs, opts) + return fd.inode.Stat(ctx, vfs, opts) } // SetStat implements FileDescriptionImpl. @@ -822,11 +887,16 @@ func (fd *namespaceFD) SetStat(ctx context.Context, opts vfs.SetStatOptions) err } // Release implements FileDescriptionImpl. -func (fd *namespaceFD) Release() { - fd.inode.DecRef() +func (fd *namespaceFD) Release(ctx context.Context) { + fd.inode.DecRef(ctx) } -// OnClose implements FileDescriptionImpl. -func (*namespaceFD) OnClose(context.Context) error { - return nil +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *namespaceFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *namespaceFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) } diff --git a/pkg/sentry/fsimpl/proc/task_net.go b/pkg/sentry/fsimpl/proc/task_net.go index 6bde27376..a4c884bf9 100644 --- a/pkg/sentry/fsimpl/proc/task_net.go +++ b/pkg/sentry/fsimpl/proc/task_net.go @@ -212,7 +212,7 @@ func (n *netUnixData) Generate(ctx context.Context, buf *bytes.Buffer) error { continue } if family, _, _ := s.Impl().(socket.SocketVFS2).Type(); family != linux.AF_UNIX { - s.DecRef() + s.DecRef(ctx) // Not a unix socket. continue } @@ -281,7 +281,7 @@ func (n *netUnixData) Generate(ctx context.Context, buf *bytes.Buffer) error { } fmt.Fprintf(buf, "\n") - s.DecRef() + s.DecRef(ctx) } return nil } @@ -359,7 +359,7 @@ func commonGenerateTCP(ctx context.Context, buf *bytes.Buffer, k *kernel.Kernel, panic(fmt.Sprintf("Found non-socket file in socket table: %+v", s)) } if fa, stype, _ := sops.Type(); !(family == fa && stype == linux.SOCK_STREAM) { - s.DecRef() + s.DecRef(ctx) // Not tcp4 sockets. continue } @@ -455,7 +455,7 @@ func commonGenerateTCP(ctx context.Context, buf *bytes.Buffer, k *kernel.Kernel, fmt.Fprintf(buf, "\n") - s.DecRef() + s.DecRef(ctx) } return nil @@ -524,7 +524,7 @@ func (d *netUDPData) Generate(ctx context.Context, buf *bytes.Buffer) error { panic(fmt.Sprintf("Found non-socket file in socket table: %+v", s)) } if family, stype, _ := sops.Type(); family != linux.AF_INET || stype != linux.SOCK_DGRAM { - s.DecRef() + s.DecRef(ctx) // Not udp4 socket. continue } @@ -600,7 +600,7 @@ func (d *netUDPData) Generate(ctx context.Context, buf *bytes.Buffer) error { fmt.Fprintf(buf, "\n") - s.DecRef() + s.DecRef(ctx) } return nil } diff --git a/pkg/sentry/fsimpl/proc/tasks.go b/pkg/sentry/fsimpl/proc/tasks.go index b51d43954..6d2b90a8b 100644 --- a/pkg/sentry/fsimpl/proc/tasks.go +++ b/pkg/sentry/fsimpl/proc/tasks.go @@ -43,6 +43,8 @@ type tasksInode struct { kernfs.OrderedChildren kernfs.AlwaysValid + locks vfs.FileLocks + fs *filesystem pidns *kernel.PIDNamespace @@ -197,15 +199,15 @@ func (i *tasksInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback // Open implements kernfs.Inode. func (i *tasksInode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts) if err != nil { return nil, err } return fd.VFSFileDescription(), nil } -func (i *tasksInode) Stat(vsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { - stat, err := i.InodeAttrs.Stat(vsfs, opts) +func (i *tasksInode) Stat(ctx context.Context, vsfs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) { + stat, err := i.InodeAttrs.Stat(ctx, vsfs, opts) if err != nil { return linux.Statx{}, err } diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go index 6dac2afa4..b71778128 100644 --- a/pkg/sentry/fsimpl/proc/tasks_sys.go +++ b/pkg/sentry/fsimpl/proc/tasks_sys.go @@ -55,7 +55,8 @@ func (fs *filesystem) newSysNetDir(root *auth.Credentials, k *kernel.Kernel) *ke if stack := k.RootNetworkNamespace().Stack(); stack != nil { contents = map[string]*kernfs.Dentry{ "ipv4": kernfs.NewStaticDir(root, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), 0555, map[string]*kernfs.Dentry{ - "tcp_sack": fs.newDentry(root, fs.NextIno(), 0644, &tcpSackData{stack: stack}), + "tcp_recovery": fs.newDentry(root, fs.NextIno(), 0644, &tcpRecoveryData{stack: stack}), + "tcp_sack": fs.newDentry(root, fs.NextIno(), 0644, &tcpSackData{stack: stack}), // The following files are simple stubs until they are implemented in // netstack, most of these files are configuration related. We use the @@ -207,3 +208,49 @@ func (d *tcpSackData) Write(ctx context.Context, src usermem.IOSequence, offset *d.enabled = v != 0 return n, d.stack.SetTCPSACKEnabled(*d.enabled) } + +// tcpRecoveryData implements vfs.WritableDynamicBytesSource for +// /proc/sys/net/ipv4/tcp_recovery. +// +// +stateify savable +type tcpRecoveryData struct { + kernfs.DynamicBytesFile + + stack inet.Stack `state:"wait"` +} + +var _ vfs.WritableDynamicBytesSource = (*tcpRecoveryData)(nil) + +// Generate implements vfs.DynamicBytesSource. +func (d *tcpRecoveryData) Generate(ctx context.Context, buf *bytes.Buffer) error { + recovery, err := d.stack.TCPRecovery() + if err != nil { + return err + } + + buf.WriteString(fmt.Sprintf("%d\n", recovery)) + return nil +} + +func (d *tcpRecoveryData) Write(ctx context.Context, src usermem.IOSequence, offset int64) (int64, error) { + if offset != 0 { + // No need to handle partial writes thus far. + return 0, syserror.EINVAL + } + if src.NumBytes() == 0 { + return 0, nil + } + + // Limit the amount of memory allocated. + src = src.TakeFirst(usermem.PageSize - 1) + + var v int32 + n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts) + if err != nil { + return 0, err + } + if err := d.stack.SetTCPRecovery(inet.TCPLossRecovery(v)); err != nil { + return 0, err + } + return n, nil +} diff --git a/pkg/sentry/fsimpl/proc/tasks_test.go b/pkg/sentry/fsimpl/proc/tasks_test.go index 19abb5034..3c9297dee 100644 --- a/pkg/sentry/fsimpl/proc/tasks_test.go +++ b/pkg/sentry/fsimpl/proc/tasks_test.go @@ -218,7 +218,7 @@ func TestTasks(t *testing.T) { if err != nil { t.Fatalf("vfsfs.OpenAt(%q) failed: %v", path, err) } - defer fd.DecRef() + defer fd.DecRef(s.Ctx) buf := make([]byte, 1) bufIOSeq := usermem.BytesIOSequence(buf) if _, err := fd.Read(s.Ctx, bufIOSeq, vfs.ReadOptions{}); err != syserror.EISDIR { @@ -336,7 +336,7 @@ func TestTasksOffset(t *testing.T) { if err != nil { t.Fatalf("vfsfs.OpenAt(/) failed: %v", err) } - defer fd.DecRef() + defer fd.DecRef(s.Ctx) if _, err := fd.Seek(s.Ctx, tc.offset, linux.SEEK_SET); err != nil { t.Fatalf("Seek(%d, SEEK_SET): %v", tc.offset, err) } @@ -441,7 +441,7 @@ func iterateDir(ctx context.Context, t *testing.T, s *testutil.System, fd *vfs.F t.Errorf("vfsfs.OpenAt(%v) failed: %v", absPath, err) continue } - defer child.DecRef() + defer child.DecRef(ctx) stat, err := child.Stat(ctx, vfs.StatOptions{}) if err != nil { t.Errorf("Stat(%v) failed: %v", absPath, err) @@ -476,7 +476,7 @@ func TestTree(t *testing.T) { if err != nil { t.Fatalf("failed to create test file: %v", err) } - defer file.DecRef() + defer file.DecRef(s.Ctx) var tasks []*kernel.Task for i := 0; i < 5; i++ { @@ -501,5 +501,5 @@ func TestTree(t *testing.T) { t.Fatalf("vfsfs.OpenAt(/proc) failed: %v", err) } iterateDir(ctx, t, s, fd) - fd.DecRef() + fd.DecRef(ctx) } diff --git a/pkg/sentry/fsimpl/signalfd/signalfd.go b/pkg/sentry/fsimpl/signalfd/signalfd.go index d29ef3f83..6297e1df4 100644 --- a/pkg/sentry/fsimpl/signalfd/signalfd.go +++ b/pkg/sentry/fsimpl/signalfd/signalfd.go @@ -31,6 +31,7 @@ type SignalFileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD // target is the original signal target task. // @@ -53,7 +54,7 @@ var _ vfs.FileDescriptionImpl = (*SignalFileDescription)(nil) // New creates a new signal fd. func New(vfsObj *vfs.VirtualFilesystem, target *kernel.Task, mask linux.SignalSet, flags uint32) (*vfs.FileDescription, error) { vd := vfsObj.NewAnonVirtualDentry("[signalfd]") - defer vd.DecRef() + defer vd.DecRef(target) sfd := &SignalFileDescription{ target: target, mask: mask, @@ -132,4 +133,4 @@ func (sfd *SignalFileDescription) EventUnregister(entry *waiter.Entry) { } // Release implements FileDescriptionImpl.Release() -func (sfd *SignalFileDescription) Release() {} +func (sfd *SignalFileDescription) Release(context.Context) {} diff --git a/pkg/sentry/fsimpl/sockfs/sockfs.go b/pkg/sentry/fsimpl/sockfs/sockfs.go index ee0828a15..c61818ff6 100644 --- a/pkg/sentry/fsimpl/sockfs/sockfs.go +++ b/pkg/sentry/fsimpl/sockfs/sockfs.go @@ -67,9 +67,9 @@ func NewFilesystem(vfsObj *vfs.VirtualFilesystem) (*vfs.Filesystem, error) { } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) - fs.Filesystem.Release() + fs.Filesystem.Release(ctx) } // PrependPath implements vfs.FilesystemImpl.PrependPath. diff --git a/pkg/sentry/fsimpl/sys/BUILD b/pkg/sentry/fsimpl/sys/BUILD index a741e2bb6..1b548ccd4 100644 --- a/pkg/sentry/fsimpl/sys/BUILD +++ b/pkg/sentry/fsimpl/sys/BUILD @@ -29,6 +29,6 @@ go_test( "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", "//pkg/sentry/vfs", - "@com_github_google_go-cmp//cmp:go_default_library", + "@com_github_google_go_cmp//cmp:go_default_library", ], ) diff --git a/pkg/sentry/fsimpl/sys/sys.go b/pkg/sentry/fsimpl/sys/sys.go index 0af373604..0401726b6 100644 --- a/pkg/sentry/fsimpl/sys/sys.go +++ b/pkg/sentry/fsimpl/sys/sys.go @@ -30,6 +30,7 @@ import ( // Name is the default filesystem name. const Name = "sysfs" +const defaultSysDirMode = linux.FileMode(0755) // FilesystemType implements vfs.FilesystemType. type FilesystemType struct{} @@ -57,9 +58,6 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt devMinor: devMinor, } fs.VFSFilesystem().Init(vfsObj, &fsType, fs) - k := kernel.KernelFromContext(ctx) - maxCPUCores := k.ApplicationCores() - defaultSysDirMode := linux.FileMode(0755) root := fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{ "block": fs.newDir(creds, defaultSysDirMode, nil), @@ -70,11 +68,7 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt "dev": fs.newDir(creds, defaultSysDirMode, nil), "devices": fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{ "system": fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{ - "cpu": fs.newDir(creds, defaultSysDirMode, map[string]*kernfs.Dentry{ - "online": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)), - "possible": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)), - "present": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)), - }), + "cpu": cpuDir(ctx, fs, creds), }), }), "firmware": fs.newDir(creds, defaultSysDirMode, nil), @@ -86,10 +80,24 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt return fs.VFSFilesystem(), root.VFSDentry(), nil } +func cpuDir(ctx context.Context, fs *filesystem, creds *auth.Credentials) *kernfs.Dentry { + k := kernel.KernelFromContext(ctx) + maxCPUCores := k.ApplicationCores() + children := map[string]*kernfs.Dentry{ + "online": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)), + "possible": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)), + "present": fs.newCPUFile(creds, maxCPUCores, linux.FileMode(0444)), + } + for i := uint(0); i < maxCPUCores; i++ { + children[fmt.Sprintf("cpu%d", i)] = fs.newDir(creds, linux.FileMode(0555), nil) + } + return fs.newDir(creds, defaultSysDirMode, children) +} + // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) - fs.Filesystem.Release() + fs.Filesystem.Release(ctx) } // dir implements kernfs.Inode. @@ -98,8 +106,10 @@ type dir struct { kernfs.InodeNoDynamicLookup kernfs.InodeNotSymlink kernfs.InodeDirectoryNoNewChildren - kernfs.OrderedChildren + + locks vfs.FileLocks + dentry kernfs.Dentry } @@ -121,7 +131,7 @@ func (*dir) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials, vfs.Set // Open implements kernfs.Inode.Open. func (d *dir) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) { - fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &opts) + fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &d.OrderedChildren, &d.locks, &opts) if err != nil { return nil, err } @@ -136,7 +146,7 @@ type cpuFile struct { // Generate implements vfs.DynamicBytesSource.Generate. func (c *cpuFile) Generate(ctx context.Context, buf *bytes.Buffer) error { - fmt.Fprintf(buf, "0-%d", c.maxCores-1) + fmt.Fprintf(buf, "0-%d\n", c.maxCores-1) return nil } diff --git a/pkg/sentry/fsimpl/sys/sys_test.go b/pkg/sentry/fsimpl/sys/sys_test.go index 4b3602d47..9fd38b295 100644 --- a/pkg/sentry/fsimpl/sys/sys_test.go +++ b/pkg/sentry/fsimpl/sys/sys_test.go @@ -51,7 +51,7 @@ func TestReadCPUFile(t *testing.T) { k := kernel.KernelFromContext(s.Ctx) maxCPUCores := k.ApplicationCores() - expected := fmt.Sprintf("0-%d", maxCPUCores-1) + expected := fmt.Sprintf("0-%d\n", maxCPUCores-1) for _, fname := range []string{"online", "possible", "present"} { pop := s.PathOpAtRoot(fmt.Sprintf("devices/system/cpu/%s", fname)) @@ -59,7 +59,7 @@ func TestReadCPUFile(t *testing.T) { if err != nil { t.Fatalf("OpenAt(pop:%+v) = %+v failed: %v", pop, fd, err) } - defer fd.DecRef() + defer fd.DecRef(s.Ctx) content, err := s.ReadToEnd(fd) if err != nil { t.Fatalf("Read failed: %v", err) diff --git a/pkg/sentry/fsimpl/testutil/BUILD b/pkg/sentry/fsimpl/testutil/BUILD index 0e4053a46..400a97996 100644 --- a/pkg/sentry/fsimpl/testutil/BUILD +++ b/pkg/sentry/fsimpl/testutil/BUILD @@ -32,6 +32,6 @@ go_library( "//pkg/sentry/vfs", "//pkg/sync", "//pkg/usermem", - "@com_github_google_go-cmp//cmp:go_default_library", + "@com_github_google_go_cmp//cmp:go_default_library", ], ) diff --git a/pkg/sentry/fsimpl/testutil/kernel.go b/pkg/sentry/fsimpl/testutil/kernel.go index c16a36cdb..1813269e0 100644 --- a/pkg/sentry/fsimpl/testutil/kernel.go +++ b/pkg/sentry/fsimpl/testutil/kernel.go @@ -62,6 +62,7 @@ func Boot() (*kernel.Kernel, error) { return nil, fmt.Errorf("creating platform: %v", err) } + kernel.VFS2Enabled = true k := &kernel.Kernel{ Platform: plat, } @@ -73,7 +74,7 @@ func Boot() (*kernel.Kernel, error) { k.SetMemoryFile(mf) // Pass k as the platform since it is savable, unlike the actual platform. - vdso, err := loader.PrepareVDSO(nil, k) + vdso, err := loader.PrepareVDSO(k) if err != nil { return nil, fmt.Errorf("creating vdso: %v", err) } @@ -103,11 +104,6 @@ func Boot() (*kernel.Kernel, error) { return nil, fmt.Errorf("initializing kernel: %v", err) } - kernel.VFS2Enabled = true - - if err := k.VFS().Init(); err != nil { - return nil, fmt.Errorf("VFS init: %v", err) - } k.VFS().MustRegisterFilesystemType(tmpfs.Name, &tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ AllowUserMount: true, AllowUserList: true, @@ -126,12 +122,16 @@ func Boot() (*kernel.Kernel, error) { // CreateTask creates a new bare bones task for tests. func CreateTask(ctx context.Context, name string, tc *kernel.ThreadGroup, mntns *vfs.MountNamespace, root, cwd vfs.VirtualDentry) (*kernel.Task, error) { k := kernel.KernelFromContext(ctx) + if k == nil { + return nil, fmt.Errorf("cannot find kernel from context") + } + exe, err := newFakeExecutable(ctx, k.VFS(), auth.CredentialsFromContext(ctx), root) if err != nil { return nil, err } m := mm.NewMemoryManager(k, k, k.SleepForAddressSpaceActivation) - m.SetExecutable(fsbridge.NewVFSFile(exe)) + m.SetExecutable(ctx, fsbridge.NewVFSFile(exe)) config := &kernel.TaskConfig{ Kernel: k, diff --git a/pkg/sentry/fsimpl/testutil/testutil.go b/pkg/sentry/fsimpl/testutil/testutil.go index 0556af877..568132121 100644 --- a/pkg/sentry/fsimpl/testutil/testutil.go +++ b/pkg/sentry/fsimpl/testutil/testutil.go @@ -97,8 +97,8 @@ func (s *System) WithTemporaryContext(ctx context.Context) *System { // Destroy release resources associated with a test system. func (s *System) Destroy() { - s.Root.DecRef() - s.MntNs.DecRef() // Reference on MntNs passed to NewSystem. + s.Root.DecRef(s.Ctx) + s.MntNs.DecRef(s.Ctx) // Reference on MntNs passed to NewSystem. } // ReadToEnd reads the contents of fd until EOF to a string. @@ -149,7 +149,7 @@ func (s *System) ListDirents(pop *vfs.PathOperation) *DirentCollector { if err != nil { s.t.Fatalf("OpenAt for PathOperation %+v failed: %v", pop, err) } - defer fd.DecRef() + defer fd.DecRef(s.Ctx) collector := &DirentCollector{} if err := fd.IterDirents(s.Ctx, collector); err != nil { diff --git a/pkg/sentry/fsimpl/timerfd/timerfd.go b/pkg/sentry/fsimpl/timerfd/timerfd.go index 60c92d626..86beaa0a8 100644 --- a/pkg/sentry/fsimpl/timerfd/timerfd.go +++ b/pkg/sentry/fsimpl/timerfd/timerfd.go @@ -32,6 +32,7 @@ type TimerFileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.NoLockFD events waiter.Queue timer *ktime.Timer @@ -46,9 +47,9 @@ var _ vfs.FileDescriptionImpl = (*TimerFileDescription)(nil) var _ ktime.TimerListener = (*TimerFileDescription)(nil) // New returns a new timer fd. -func New(vfsObj *vfs.VirtualFilesystem, clock ktime.Clock, flags uint32) (*vfs.FileDescription, error) { +func New(ctx context.Context, vfsObj *vfs.VirtualFilesystem, clock ktime.Clock, flags uint32) (*vfs.FileDescription, error) { vd := vfsObj.NewAnonVirtualDentry("[timerfd]") - defer vd.DecRef() + defer vd.DecRef(ctx) tfd := &TimerFileDescription{} tfd.timer = ktime.NewTimer(clock, tfd) if err := tfd.vfsfd.Init(tfd, flags, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{ @@ -128,7 +129,7 @@ func (tfd *TimerFileDescription) ResumeTimer() { } // Release implements FileDescriptionImpl.Release() -func (tfd *TimerFileDescription) Release() { +func (tfd *TimerFileDescription) Release(context.Context) { tfd.timer.Destroy() } diff --git a/pkg/sentry/fsimpl/tmpfs/BUILD b/pkg/sentry/fsimpl/tmpfs/BUILD index 007be1572..5cd428d64 100644 --- a/pkg/sentry/fsimpl/tmpfs/BUILD +++ b/pkg/sentry/fsimpl/tmpfs/BUILD @@ -26,6 +26,17 @@ go_template_instance( }, ) +go_template_instance( + name = "inode_refs", + out = "inode_refs.go", + package = "tmpfs", + prefix = "inode", + template = "//pkg/refs_vfs2:refs_template", + types = { + "T": "inode", + }, +) + go_library( name = "tmpfs", srcs = [ @@ -34,6 +45,7 @@ go_library( "directory.go", "filesystem.go", "fstree.go", + "inode_refs.go", "named_pipe.go", "regular_file.go", "socket_file.go", @@ -47,6 +59,7 @@ go_library( "//pkg/context", "//pkg/fspath", "//pkg/log", + "//pkg/refs", "//pkg/safemem", "//pkg/sentry/arch", "//pkg/sentry/fs", @@ -59,9 +72,9 @@ go_library( "//pkg/sentry/pgalloc", "//pkg/sentry/platform", "//pkg/sentry/socket/unix/transport", + "//pkg/sentry/uniqueid", "//pkg/sentry/usage", "//pkg/sentry/vfs", - "//pkg/sentry/vfs/lock", "//pkg/sentry/vfs/memxattr", "//pkg/sync", "//pkg/syserror", diff --git a/pkg/sentry/fsimpl/tmpfs/benchmark_test.go b/pkg/sentry/fsimpl/tmpfs/benchmark_test.go index 2fb5c4d84..d263147c2 100644 --- a/pkg/sentry/fsimpl/tmpfs/benchmark_test.go +++ b/pkg/sentry/fsimpl/tmpfs/benchmark_test.go @@ -83,7 +83,7 @@ func fileOpOn(ctx context.Context, mntns *fs.MountNamespace, root, wd *fs.Dirent } err = fn(root, d) - d.DecRef() + d.DecRef(ctx) return err } @@ -105,17 +105,17 @@ func BenchmarkVFS1TmpfsStat(b *testing.B) { if err != nil { b.Fatalf("failed to create mount namespace: %v", err) } - defer mntns.DecRef() + defer mntns.DecRef(ctx) var filePathBuilder strings.Builder filePathBuilder.WriteByte('/') // Create nested directories with given depth. root := mntns.Root() - defer root.DecRef() + defer root.DecRef(ctx) d := root d.IncRef() - defer d.DecRef() + defer d.DecRef(ctx) for i := depth; i > 0; i-- { name := fmt.Sprintf("%d", i) if err := d.Inode.CreateDirectory(ctx, d, name, fs.FilePermsFromMode(0755)); err != nil { @@ -125,7 +125,7 @@ func BenchmarkVFS1TmpfsStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to directory %q: %v", name, err) } - d.DecRef() + d.DecRef(ctx) d = next filePathBuilder.WriteString(name) filePathBuilder.WriteByte('/') @@ -136,7 +136,7 @@ func BenchmarkVFS1TmpfsStat(b *testing.B) { if err != nil { b.Fatalf("failed to create file %q: %v", filename, err) } - file.DecRef() + file.DecRef(ctx) filePathBuilder.WriteString(filename) filePath := filePathBuilder.String() @@ -176,7 +176,7 @@ func BenchmarkVFS2TmpfsStat(b *testing.B) { // Create VFS. vfsObj := vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { b.Fatalf("VFS init: %v", err) } vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ @@ -186,14 +186,14 @@ func BenchmarkVFS2TmpfsStat(b *testing.B) { if err != nil { b.Fatalf("failed to create tmpfs root mount: %v", err) } - defer mntns.DecRef() + defer mntns.DecRef(ctx) var filePathBuilder strings.Builder filePathBuilder.WriteByte('/') // Create nested directories with given depth. root := mntns.Root() - defer root.DecRef() + defer root.DecRef(ctx) vd := root vd.IncRef() for i := depth; i > 0; i-- { @@ -212,7 +212,7 @@ func BenchmarkVFS2TmpfsStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to directory %q: %v", name, err) } - vd.DecRef() + vd.DecRef(ctx) vd = nextVD filePathBuilder.WriteString(name) filePathBuilder.WriteByte('/') @@ -228,12 +228,12 @@ func BenchmarkVFS2TmpfsStat(b *testing.B) { Flags: linux.O_RDWR | linux.O_CREAT | linux.O_EXCL, Mode: 0644, }) - vd.DecRef() + vd.DecRef(ctx) vd = vfs.VirtualDentry{} if err != nil { b.Fatalf("failed to create file %q: %v", filename, err) } - defer fd.DecRef() + defer fd.DecRef(ctx) filePathBuilder.WriteString(filename) filePath := filePathBuilder.String() @@ -278,14 +278,14 @@ func BenchmarkVFS1TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to create mount namespace: %v", err) } - defer mntns.DecRef() + defer mntns.DecRef(ctx) var filePathBuilder strings.Builder filePathBuilder.WriteByte('/') // Create and mount the submount. root := mntns.Root() - defer root.DecRef() + defer root.DecRef(ctx) if err := root.Inode.CreateDirectory(ctx, root, mountPointName, fs.FilePermsFromMode(0755)); err != nil { b.Fatalf("failed to create mount point: %v", err) } @@ -293,7 +293,7 @@ func BenchmarkVFS1TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to mount point: %v", err) } - defer mountPoint.DecRef() + defer mountPoint.DecRef(ctx) submountInode, err := tmpfsFS.Mount(ctx, "tmpfs", fs.MountSourceFlags{}, "", nil) if err != nil { b.Fatalf("failed to create tmpfs submount: %v", err) @@ -309,7 +309,7 @@ func BenchmarkVFS1TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to mount root: %v", err) } - defer d.DecRef() + defer d.DecRef(ctx) for i := depth; i > 0; i-- { name := fmt.Sprintf("%d", i) if err := d.Inode.CreateDirectory(ctx, d, name, fs.FilePermsFromMode(0755)); err != nil { @@ -319,7 +319,7 @@ func BenchmarkVFS1TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to directory %q: %v", name, err) } - d.DecRef() + d.DecRef(ctx) d = next filePathBuilder.WriteString(name) filePathBuilder.WriteByte('/') @@ -330,7 +330,7 @@ func BenchmarkVFS1TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to create file %q: %v", filename, err) } - file.DecRef() + file.DecRef(ctx) filePathBuilder.WriteString(filename) filePath := filePathBuilder.String() @@ -370,7 +370,7 @@ func BenchmarkVFS2TmpfsMountStat(b *testing.B) { // Create VFS. vfsObj := vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { b.Fatalf("VFS init: %v", err) } vfsObj.MustRegisterFilesystemType("tmpfs", tmpfs.FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ @@ -380,14 +380,14 @@ func BenchmarkVFS2TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to create tmpfs root mount: %v", err) } - defer mntns.DecRef() + defer mntns.DecRef(ctx) var filePathBuilder strings.Builder filePathBuilder.WriteByte('/') // Create the mount point. root := mntns.Root() - defer root.DecRef() + defer root.DecRef(ctx) pop := vfs.PathOperation{ Root: root, Start: root, @@ -403,7 +403,7 @@ func BenchmarkVFS2TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to mount point: %v", err) } - defer mountPoint.DecRef() + defer mountPoint.DecRef(ctx) // Create and mount the submount. if err := vfsObj.MountAt(ctx, creds, "", &pop, "tmpfs", &vfs.MountOptions{}); err != nil { b.Fatalf("failed to mount tmpfs submount: %v", err) @@ -432,7 +432,7 @@ func BenchmarkVFS2TmpfsMountStat(b *testing.B) { if err != nil { b.Fatalf("failed to walk to directory %q: %v", name, err) } - vd.DecRef() + vd.DecRef(ctx) vd = nextVD filePathBuilder.WriteString(name) filePathBuilder.WriteByte('/') @@ -448,11 +448,11 @@ func BenchmarkVFS2TmpfsMountStat(b *testing.B) { Flags: linux.O_RDWR | linux.O_CREAT | linux.O_EXCL, Mode: 0644, }) - vd.DecRef() + vd.DecRef(ctx) if err != nil { b.Fatalf("failed to create file %q: %v", filename, err) } - fd.DecRef() + fd.DecRef(ctx) filePathBuilder.WriteString(filename) filePath := filePathBuilder.String() diff --git a/pkg/sentry/fsimpl/tmpfs/device_file.go b/pkg/sentry/fsimpl/tmpfs/device_file.go index 83bf885ee..ac54d420d 100644 --- a/pkg/sentry/fsimpl/tmpfs/device_file.go +++ b/pkg/sentry/fsimpl/tmpfs/device_file.go @@ -29,7 +29,7 @@ type deviceFile struct { minor uint32 } -func (fs *filesystem) newDeviceFile(creds *auth.Credentials, mode linux.FileMode, kind vfs.DeviceKind, major, minor uint32) *inode { +func (fs *filesystem) newDeviceFile(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode, kind vfs.DeviceKind, major, minor uint32) *inode { file := &deviceFile{ kind: kind, major: major, @@ -43,7 +43,7 @@ func (fs *filesystem) newDeviceFile(creds *auth.Credentials, mode linux.FileMode default: panic(fmt.Sprintf("invalid DeviceKind: %v", kind)) } - file.inode.init(file, fs, creds, mode) + file.inode.init(file, fs, kuid, kgid, mode) file.inode.nlink = 1 // from parent directory return &file.inode } diff --git a/pkg/sentry/fsimpl/tmpfs/directory.go b/pkg/sentry/fsimpl/tmpfs/directory.go index f2399981b..78b4fc5be 100644 --- a/pkg/sentry/fsimpl/tmpfs/directory.go +++ b/pkg/sentry/fsimpl/tmpfs/directory.go @@ -48,9 +48,9 @@ type directory struct { childList dentryList } -func (fs *filesystem) newDirectory(creds *auth.Credentials, mode linux.FileMode) *directory { +func (fs *filesystem) newDirectory(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode) *directory { dir := &directory{} - dir.inode.init(dir, fs, creds, linux.S_IFDIR|mode) + dir.inode.init(dir, fs, kuid, kgid, linux.S_IFDIR|mode) dir.inode.nlink = 2 // from "." and parent directory or ".." for root dir.dentry.inode = &dir.inode dir.dentry.vfsd.Init(&dir.dentry) @@ -81,6 +81,10 @@ func (dir *directory) removeChildLocked(child *dentry) { dir.iterMu.Unlock() } +func (dir *directory) mayDelete(creds *auth.Credentials, child *dentry) error { + return vfs.CheckDeleteSticky(creds, linux.FileMode(atomic.LoadUint32(&dir.inode.mode)), auth.KUID(atomic.LoadUint32(&child.inode.uid))) +} + type directoryFD struct { fileDescription vfs.DirectoryFileDescriptionDefaultImpl @@ -91,7 +95,7 @@ type directoryFD struct { } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *directoryFD) Release() { +func (fd *directoryFD) Release(ctx context.Context) { if fd.iter != nil { dir := fd.inode().impl.(*directory) dir.iterMu.Lock() @@ -106,6 +110,8 @@ func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallba fs := fd.filesystem() dir := fd.inode().impl.(*directory) + defer fd.dentry().InotifyWithParent(ctx, linux.IN_ACCESS, 0, vfs.PathEvent) + // fs.mu is required to read d.parent and dentry.name. fs.mu.RLock() defer fs.mu.RUnlock() diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go index 80fa7b29d..a4864df53 100644 --- a/pkg/sentry/fsimpl/tmpfs/filesystem.go +++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go @@ -40,7 +40,7 @@ func (fs *filesystem) Sync(ctx context.Context) error { // stepLocked is loosely analogous to fs/namei.c:walk_component(). // // Preconditions: filesystem.mu must be locked. !rp.Done(). -func stepLocked(rp *vfs.ResolvingPath, d *dentry) (*dentry, error) { +func stepLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry) (*dentry, error) { dir, ok := d.inode.impl.(*directory) if !ok { return nil, syserror.ENOTDIR @@ -55,13 +55,13 @@ afterSymlink: return d, nil } if name == ".." { - if isRoot, err := rp.CheckRoot(&d.vfsd); err != nil { + if isRoot, err := rp.CheckRoot(ctx, &d.vfsd); err != nil { return nil, err } else if isRoot || d.parent == nil { rp.Advance() return d, nil } - if err := rp.CheckMount(&d.parent.vfsd); err != nil { + if err := rp.CheckMount(ctx, &d.parent.vfsd); err != nil { return nil, err } rp.Advance() @@ -74,12 +74,12 @@ afterSymlink: if !ok { return nil, syserror.ENOENT } - if err := rp.CheckMount(&child.vfsd); err != nil { + if err := rp.CheckMount(ctx, &child.vfsd); err != nil { return nil, err } if symlink, ok := child.inode.impl.(*symlink); ok && rp.ShouldFollowSymlink() { // Symlink traversal updates access time. - atomic.StoreInt64(&d.inode.atime, d.inode.fs.clock.Now().Nanoseconds()) + child.inode.touchAtime(rp.Mount()) if err := rp.HandleSymlink(symlink.target); err != nil { return nil, err } @@ -98,9 +98,9 @@ afterSymlink: // fs/namei.c:path_parentat(). // // Preconditions: filesystem.mu must be locked. !rp.Done(). -func walkParentDirLocked(rp *vfs.ResolvingPath, d *dentry) (*directory, error) { +func walkParentDirLocked(ctx context.Context, rp *vfs.ResolvingPath, d *dentry) (*directory, error) { for !rp.Final() { - next, err := stepLocked(rp, d) + next, err := stepLocked(ctx, rp, d) if err != nil { return nil, err } @@ -118,10 +118,10 @@ func walkParentDirLocked(rp *vfs.ResolvingPath, d *dentry) (*directory, error) { // resolveLocked is loosely analogous to Linux's fs/namei.c:path_lookupat(). // // Preconditions: filesystem.mu must be locked. -func resolveLocked(rp *vfs.ResolvingPath) (*dentry, error) { +func resolveLocked(ctx context.Context, rp *vfs.ResolvingPath) (*dentry, error) { d := rp.Start().Impl().(*dentry) for !rp.Done() { - next, err := stepLocked(rp, d) + next, err := stepLocked(ctx, rp, d) if err != nil { return nil, err } @@ -141,10 +141,10 @@ func resolveLocked(rp *vfs.ResolvingPath) (*dentry, error) { // // Preconditions: !rp.Done(). For the final path component in rp, // !rp.ShouldFollowSymlink(). -func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(parentDir *directory, name string) error) error { +func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir bool, create func(parentDir *directory, name string) error) error { fs.mu.Lock() defer fs.mu.Unlock() - parentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry)) + parentDir, err := walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry)) if err != nil { return err } @@ -177,6 +177,12 @@ func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(pa if err := create(parentDir, name); err != nil { return err } + + ev := linux.IN_CREATE + if dir { + ev |= linux.IN_ISDIR + } + parentDir.inode.watches.Notify(ctx, name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */) parentDir.inode.touchCMtime() return nil } @@ -185,7 +191,7 @@ func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(pa func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds *auth.Credentials, ats vfs.AccessTypes) error { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return err } @@ -196,7 +202,7 @@ func (fs *filesystem) AccessAt(ctx context.Context, rp *vfs.ResolvingPath, creds func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetDentryOptions) (*vfs.Dentry, error) { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return nil, err } @@ -216,7 +222,7 @@ func (fs *filesystem) GetDentryAt(ctx context.Context, rp *vfs.ResolvingPath, op func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPath) (*vfs.Dentry, error) { fs.mu.RLock() defer fs.mu.RUnlock() - dir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry)) + dir, err := walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry)) if err != nil { return nil, err } @@ -226,34 +232,40 @@ func (fs *filesystem) GetParentDentryAt(ctx context.Context, rp *vfs.ResolvingPa // LinkAt implements vfs.FilesystemImpl.LinkAt. func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.VirtualDentry) error { - return fs.doCreateAt(rp, false /* dir */, func(parentDir *directory, name string) error { + return fs.doCreateAt(ctx, rp, false /* dir */, func(parentDir *directory, name string) error { if rp.Mount() != vd.Mount() { return syserror.EXDEV } d := vd.Dentry().Impl().(*dentry) - if d.inode.isDir() { + i := d.inode + if i.isDir() { return syserror.EPERM } - if d.inode.nlink == 0 { + if err := vfs.MayLink(auth.CredentialsFromContext(ctx), linux.FileMode(atomic.LoadUint32(&i.mode)), auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil { + return err + } + if i.nlink == 0 { return syserror.ENOENT } - if d.inode.nlink == maxLinks { + if i.nlink == maxLinks { return syserror.EMLINK } - d.inode.incLinksLocked() - parentDir.insertChildLocked(fs.newDentry(d.inode), name) + i.incLinksLocked() + i.watches.Notify(ctx, "", linux.IN_ATTRIB, 0, vfs.InodeEvent, false /* unlinked */) + parentDir.insertChildLocked(fs.newDentry(i), name) return nil }) } // MkdirAt implements vfs.FilesystemImpl.MkdirAt. func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MkdirOptions) error { - return fs.doCreateAt(rp, true /* dir */, func(parentDir *directory, name string) error { + return fs.doCreateAt(ctx, rp, true /* dir */, func(parentDir *directory, name string) error { + creds := rp.Credentials() if parentDir.inode.nlink == maxLinks { return syserror.EMLINK } parentDir.inode.incLinksLocked() // from child's ".." - childDir := fs.newDirectory(rp.Credentials(), opts.Mode) + childDir := fs.newDirectory(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode) parentDir.insertChildLocked(&childDir.dentry, name) return nil }) @@ -261,19 +273,20 @@ func (fs *filesystem) MkdirAt(ctx context.Context, rp *vfs.ResolvingPath, opts v // MknodAt implements vfs.FilesystemImpl.MknodAt. func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.MknodOptions) error { - return fs.doCreateAt(rp, false /* dir */, func(parentDir *directory, name string) error { + return fs.doCreateAt(ctx, rp, false /* dir */, func(parentDir *directory, name string) error { + creds := rp.Credentials() var childInode *inode switch opts.Mode.FileType() { - case 0, linux.S_IFREG: - childInode = fs.newRegularFile(rp.Credentials(), opts.Mode) + case linux.S_IFREG: + childInode = fs.newRegularFile(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode) case linux.S_IFIFO: - childInode = fs.newNamedPipe(rp.Credentials(), opts.Mode) + childInode = fs.newNamedPipe(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode) case linux.S_IFBLK: - childInode = fs.newDeviceFile(rp.Credentials(), opts.Mode, vfs.BlockDevice, opts.DevMajor, opts.DevMinor) + childInode = fs.newDeviceFile(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode, vfs.BlockDevice, opts.DevMajor, opts.DevMinor) case linux.S_IFCHR: - childInode = fs.newDeviceFile(rp.Credentials(), opts.Mode, vfs.CharDevice, opts.DevMajor, opts.DevMinor) + childInode = fs.newDeviceFile(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode, vfs.CharDevice, opts.DevMajor, opts.DevMinor) case linux.S_IFSOCK: - childInode = fs.newSocketFile(rp.Credentials(), opts.Mode, opts.Endpoint) + childInode = fs.newSocketFile(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode, opts.Endpoint) default: return syserror.EINVAL } @@ -295,7 +308,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf if opts.Flags&linux.O_CREAT == 0 { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return nil, err } @@ -307,7 +320,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf fs.mu.Lock() defer fs.mu.Unlock() if rp.Done() { - // Reject attempts to open directories with O_CREAT. + // Reject attempts to open mount root directory with O_CREAT. if rp.MustBeDir() { return nil, syserror.EISDIR } @@ -317,7 +330,7 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf return start.open(ctx, rp, &opts, false /* afterCreate */) } afterTrailingSymlink: - parentDir, err := walkParentDirLocked(rp, start) + parentDir, err := walkParentDirLocked(ctx, rp, start) if err != nil { return nil, err } @@ -348,23 +361,28 @@ afterTrailingSymlink: } defer rp.Mount().EndWrite() // Create and open the child. - child := fs.newDentry(fs.newRegularFile(rp.Credentials(), opts.Mode)) + creds := rp.Credentials() + child := fs.newDentry(fs.newRegularFile(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode)) parentDir.insertChildLocked(child, name) fd, err := child.open(ctx, rp, &opts, true) if err != nil { return nil, err } + parentDir.inode.watches.Notify(ctx, name, linux.IN_CREATE, 0, vfs.PathEvent, false /* unlinked */) parentDir.inode.touchCMtime() return fd, nil } + if mustCreate { + return nil, syserror.EEXIST + } // Is the file mounted over? - if err := rp.CheckMount(&child.vfsd); err != nil { + if err := rp.CheckMount(ctx, &child.vfsd); err != nil { return nil, err } // Do we need to resolve a trailing symlink? if symlink, ok := child.inode.impl.(*symlink); ok && rp.ShouldFollowSymlink() { // Symlink traversal updates access time. - atomic.StoreInt64(&child.inode.atime, child.inode.fs.clock.Now().Nanoseconds()) + child.inode.touchAtime(rp.Mount()) if err := rp.HandleSymlink(symlink.target); err != nil { return nil, err } @@ -388,10 +406,11 @@ func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.Open switch impl := d.inode.impl.(type) { case *regularFile: var fd regularFileFD - if err := fd.vfsfd.Init(&fd, opts.Flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil { + fd.LockFD.Init(&d.inode.locks) + if err := fd.vfsfd.Init(&fd, opts.Flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{AllowDirectIO: true}); err != nil { return nil, err } - if opts.Flags&linux.O_TRUNC != 0 { + if !afterCreate && opts.Flags&linux.O_TRUNC != 0 { if _, err := impl.truncate(0); err != nil { return nil, err } @@ -403,15 +422,16 @@ func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.Open return nil, syserror.EISDIR } var fd directoryFD - if err := fd.vfsfd.Init(&fd, opts.Flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil { + fd.LockFD.Init(&d.inode.locks) + if err := fd.vfsfd.Init(&fd, opts.Flags, rp.Mount(), &d.vfsd, &vfs.FileDescriptionOptions{AllowDirectIO: true}); err != nil { return nil, err } return &fd.vfsfd, nil case *symlink: - // Can't open symlinks without O_PATH (which is unimplemented). + // TODO(gvisor.dev/issue/2782): Can't open symlinks without O_PATH. return nil, syserror.ELOOP case *namedPipe: - return impl.pipe.Open(ctx, rp.Mount(), &d.vfsd, opts.Flags) + return impl.pipe.Open(ctx, rp.Mount(), &d.vfsd, opts.Flags, &d.inode.locks) case *deviceFile: return rp.VirtualFilesystem().OpenDeviceSpecialFile(ctx, rp.Mount(), &d.vfsd, impl.kind, impl.major, impl.minor, opts) case *socketFile: @@ -425,7 +445,7 @@ func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.Open func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (string, error) { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return "", err } @@ -447,7 +467,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa // Resolve newParent first to verify that it's on this Mount. fs.mu.Lock() defer fs.mu.Unlock() - newParentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry)) + newParentDir, err := walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry)) if err != nil { return err } @@ -472,6 +492,9 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa if !ok { return syserror.ENOENT } + if err := oldParentDir.mayDelete(rp.Credentials(), renamed); err != nil { + return err + } // Note that we don't need to call rp.CheckMount(), since if renamed is a // mount point then we want to rename the mount point, not anything in the // mounted filesystem. @@ -532,7 +555,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa } vfsObj := rp.VirtualFilesystem() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) var replacedVFSD *vfs.Dentry if replaced != nil { replacedVFSD = &replaced.vfsd @@ -543,22 +566,26 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa if replaced != nil { newParentDir.removeChildLocked(replaced) if replaced.inode.isDir() { - newParentDir.inode.decLinksLocked() // from replaced's ".." + // Remove links for replaced/. and replaced/.. + replaced.inode.decLinksLocked(ctx) + newParentDir.inode.decLinksLocked(ctx) } - replaced.inode.decLinksLocked() + replaced.inode.decLinksLocked(ctx) } oldParentDir.removeChildLocked(renamed) newParentDir.insertChildLocked(renamed, newName) - vfsObj.CommitRenameReplaceDentry(&renamed.vfsd, replacedVFSD) + vfsObj.CommitRenameReplaceDentry(ctx, &renamed.vfsd, replacedVFSD) oldParentDir.inode.touchCMtime() if oldParentDir != newParentDir { if renamed.inode.isDir() { - oldParentDir.inode.decLinksLocked() + oldParentDir.inode.decLinksLocked(ctx) newParentDir.inode.incLinksLocked() } newParentDir.inode.touchCMtime() } renamed.inode.touchCtime() + + vfs.InotifyRename(ctx, &renamed.inode.watches, &oldParentDir.inode.watches, &newParentDir.inode.watches, oldName, newName, renamed.inode.isDir()) return nil } @@ -566,7 +593,7 @@ func (fs *filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error { fs.mu.Lock() defer fs.mu.Unlock() - parentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry)) + parentDir, err := walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry)) if err != nil { return err } @@ -584,6 +611,9 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error if !ok { return syserror.ENOENT } + if err := parentDir.mayDelete(rp.Credentials(), child); err != nil { + return err + } childDir, ok := child.inode.impl.(*directory) if !ok { return syserror.ENOTDIR @@ -598,14 +628,17 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error defer mnt.EndWrite() vfsObj := rp.VirtualFilesystem() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil { return err } parentDir.removeChildLocked(child) - parentDir.inode.decLinksLocked() // from child's ".." - child.inode.decLinksLocked() - vfsObj.CommitDeleteDentry(&child.vfsd) + parentDir.inode.watches.Notify(ctx, name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent, true /* unlinked */) + // Remove links for child, child/., and child/.. + child.inode.decLinksLocked(ctx) + child.inode.decLinksLocked(ctx) + parentDir.inode.decLinksLocked(ctx) + vfsObj.CommitDeleteDentry(ctx, &child.vfsd) parentDir.inode.touchCMtime() return nil } @@ -613,19 +646,28 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error // SetStatAt implements vfs.FilesystemImpl.SetStatAt. func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetStatOptions) error { fs.mu.RLock() - defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { + fs.mu.RUnlock() return err } - return d.inode.setStat(ctx, rp.Credentials(), &opts.Stat) + if err := d.inode.setStat(ctx, rp.Credentials(), &opts); err != nil { + fs.mu.RUnlock() + return err + } + fs.mu.RUnlock() + + if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 { + d.InotifyWithParent(ctx, ev, 0, vfs.InodeEvent) + } + return nil } // StatAt implements vfs.FilesystemImpl.StatAt. func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.StatOptions) (linux.Statx, error) { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return linux.Statx{}, err } @@ -638,7 +680,7 @@ func (fs *filesystem) StatAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linux.Statfs, error) { fs.mu.RLock() defer fs.mu.RUnlock() - if _, err := resolveLocked(rp); err != nil { + if _, err := resolveLocked(ctx, rp); err != nil { return linux.Statfs{}, err } statfs := linux.Statfs{ @@ -655,8 +697,9 @@ func (fs *filesystem) StatFSAt(ctx context.Context, rp *vfs.ResolvingPath) (linu // SymlinkAt implements vfs.FilesystemImpl.SymlinkAt. func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, target string) error { - return fs.doCreateAt(rp, false /* dir */, func(parentDir *directory, name string) error { - child := fs.newDentry(fs.newSymlink(rp.Credentials(), target)) + return fs.doCreateAt(ctx, rp, false /* dir */, func(parentDir *directory, name string) error { + creds := rp.Credentials() + child := fs.newDentry(fs.newSymlink(creds.EffectiveKUID, creds.EffectiveKGID, 0777, target)) parentDir.insertChildLocked(child, name) return nil }) @@ -666,7 +709,7 @@ func (fs *filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error { fs.mu.Lock() defer fs.mu.Unlock() - parentDir, err := walkParentDirLocked(rp, rp.Start().Impl().(*dentry)) + parentDir, err := walkParentDirLocked(ctx, rp, rp.Start().Impl().(*dentry)) if err != nil { return err } @@ -681,6 +724,9 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error if !ok { return syserror.ENOENT } + if err := parentDir.mayDelete(rp.Credentials(), child); err != nil { + return err + } if child.inode.isDir() { return syserror.EISDIR } @@ -694,13 +740,19 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error defer mnt.EndWrite() vfsObj := rp.VirtualFilesystem() mntns := vfs.MountNamespaceFromContext(ctx) - defer mntns.DecRef() + defer mntns.DecRef(ctx) if err := vfsObj.PrepareDeleteDentry(mntns, &child.vfsd); err != nil { return err } + + // Generate inotify events. Note that this must take place before the link + // count of the child is decremented, or else the watches may be dropped + // before these events are added. + vfs.InotifyRemoveChild(ctx, &child.inode.watches, &parentDir.inode.watches, name) + parentDir.removeChildLocked(child) - child.inode.decLinksLocked() - vfsObj.CommitDeleteDentry(&child.vfsd) + child.inode.decLinksLocked(ctx) + vfsObj.CommitDeleteDentry(ctx, &child.vfsd) parentDir.inode.touchCMtime() return nil } @@ -709,7 +761,7 @@ func (fs *filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.BoundEndpointOptions) (transport.BoundEndpoint, error) { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return nil, err } @@ -728,7 +780,7 @@ func (fs *filesystem) BoundEndpointAt(ctx context.Context, rp *vfs.ResolvingPath func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, size uint64) ([]string, error) { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return nil, err } @@ -739,7 +791,7 @@ func (fs *filesystem) ListxattrAt(ctx context.Context, rp *vfs.ResolvingPath, si func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.GetxattrOptions) (string, error) { fs.mu.RLock() defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { return "", err } @@ -749,23 +801,37 @@ func (fs *filesystem) GetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt // SetxattrAt implements vfs.FilesystemImpl.SetxattrAt. func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.SetxattrOptions) error { fs.mu.RLock() - defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { + fs.mu.RUnlock() + return err + } + if err := d.inode.setxattr(rp.Credentials(), &opts); err != nil { + fs.mu.RUnlock() return err } - return d.inode.setxattr(rp.Credentials(), &opts) + fs.mu.RUnlock() + + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // RemovexattrAt implements vfs.FilesystemImpl.RemovexattrAt. func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath, name string) error { fs.mu.RLock() - defer fs.mu.RUnlock() - d, err := resolveLocked(rp) + d, err := resolveLocked(ctx, rp) if err != nil { + fs.mu.RUnlock() return err } - return d.inode.removexattr(rp.Credentials(), name) + if err := d.inode.removexattr(rp.Credentials(), name); err != nil { + fs.mu.RUnlock() + return err + } + fs.mu.RUnlock() + + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // PrependPath implements vfs.FilesystemImpl.PrependPath. diff --git a/pkg/sentry/fsimpl/tmpfs/named_pipe.go b/pkg/sentry/fsimpl/tmpfs/named_pipe.go index 8d77b3fa8..739350cf0 100644 --- a/pkg/sentry/fsimpl/tmpfs/named_pipe.go +++ b/pkg/sentry/fsimpl/tmpfs/named_pipe.go @@ -30,9 +30,9 @@ type namedPipe struct { // Preconditions: // * fs.mu must be locked. // * rp.Mount().CheckBeginWrite() has been called successfully. -func (fs *filesystem) newNamedPipe(creds *auth.Credentials, mode linux.FileMode) *inode { +func (fs *filesystem) newNamedPipe(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode) *inode { file := &namedPipe{pipe: pipe.NewVFSPipe(true /* isNamed */, pipe.DefaultPipeSize, usermem.PageSize)} - file.inode.init(file, fs, creds, linux.S_IFIFO|mode) + file.inode.init(file, fs, kuid, kgid, linux.S_IFIFO|mode) file.inode.nlink = 1 // Only the parent has a link. return &file.inode } diff --git a/pkg/sentry/fsimpl/tmpfs/pipe_test.go b/pkg/sentry/fsimpl/tmpfs/pipe_test.go index 1614f2c39..ec2701d8b 100644 --- a/pkg/sentry/fsimpl/tmpfs/pipe_test.go +++ b/pkg/sentry/fsimpl/tmpfs/pipe_test.go @@ -32,7 +32,7 @@ const fileName = "mypipe" func TestSeparateFDs(t *testing.T) { ctx, creds, vfsObj, root := setup(t) - defer root.DecRef() + defer root.DecRef(ctx) // Open the read side. This is done in a concurrently because opening // One end the pipe blocks until the other end is opened. @@ -55,13 +55,13 @@ func TestSeparateFDs(t *testing.T) { if err != nil { t.Fatalf("failed to open pipe for writing %q: %v", fileName, err) } - defer wfd.DecRef() + defer wfd.DecRef(ctx) rfd, ok := <-rfdchan if !ok { t.Fatalf("failed to open pipe for reading %q", fileName) } - defer rfd.DecRef() + defer rfd.DecRef(ctx) const msg = "vamos azul" checkEmpty(ctx, t, rfd) @@ -71,7 +71,7 @@ func TestSeparateFDs(t *testing.T) { func TestNonblockingRead(t *testing.T) { ctx, creds, vfsObj, root := setup(t) - defer root.DecRef() + defer root.DecRef(ctx) // Open the read side as nonblocking. pop := vfs.PathOperation{ @@ -85,7 +85,7 @@ func TestNonblockingRead(t *testing.T) { if err != nil { t.Fatalf("failed to open pipe for reading %q: %v", fileName, err) } - defer rfd.DecRef() + defer rfd.DecRef(ctx) // Open the write side. openOpts = vfs.OpenOptions{Flags: linux.O_WRONLY} @@ -93,7 +93,7 @@ func TestNonblockingRead(t *testing.T) { if err != nil { t.Fatalf("failed to open pipe for writing %q: %v", fileName, err) } - defer wfd.DecRef() + defer wfd.DecRef(ctx) const msg = "geh blau" checkEmpty(ctx, t, rfd) @@ -103,7 +103,7 @@ func TestNonblockingRead(t *testing.T) { func TestNonblockingWriteError(t *testing.T) { ctx, creds, vfsObj, root := setup(t) - defer root.DecRef() + defer root.DecRef(ctx) // Open the write side as nonblocking, which should return ENXIO. pop := vfs.PathOperation{ @@ -121,7 +121,7 @@ func TestNonblockingWriteError(t *testing.T) { func TestSingleFD(t *testing.T) { ctx, creds, vfsObj, root := setup(t) - defer root.DecRef() + defer root.DecRef(ctx) // Open the pipe as readable and writable. pop := vfs.PathOperation{ @@ -135,7 +135,7 @@ func TestSingleFD(t *testing.T) { if err != nil { t.Fatalf("failed to open pipe for writing %q: %v", fileName, err) } - defer fd.DecRef() + defer fd.DecRef(ctx) const msg = "forza blu" checkEmpty(ctx, t, fd) @@ -152,7 +152,7 @@ func setup(t *testing.T) (context.Context, *auth.Credentials, *vfs.VirtualFilesy // Create VFS. vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } vfsObj.MustRegisterFilesystemType("tmpfs", FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{ diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go index 3f433d666..0710b65db 100644 --- a/pkg/sentry/fsimpl/tmpfs/regular_file.go +++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go @@ -25,7 +25,6 @@ import ( "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" - "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" @@ -85,12 +84,12 @@ type regularFile struct { size uint64 } -func (fs *filesystem) newRegularFile(creds *auth.Credentials, mode linux.FileMode) *inode { +func (fs *filesystem) newRegularFile(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode) *inode { file := ®ularFile{ memFile: fs.memFile, seals: linux.F_SEAL_SEAL, } - file.inode.init(file, fs, creds, linux.S_IFREG|mode) + file.inode.init(file, fs, kuid, kgid, linux.S_IFREG|mode) file.inode.nlink = 1 // from parent directory return &file.inode } @@ -271,15 +270,39 @@ type regularFileFD struct { } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *regularFileFD) Release() { +func (fd *regularFileFD) Release(context.Context) { // noop } +// Allocate implements vfs.FileDescriptionImpl.Allocate. +func (fd *regularFileFD) Allocate(ctx context.Context, mode, offset, length uint64) error { + f := fd.inode().impl.(*regularFile) + + f.inode.mu.Lock() + defer f.inode.mu.Unlock() + oldSize := f.size + size := offset + length + if oldSize >= size { + return nil + } + _, err := f.truncateLocked(size) + return err +} + // PRead implements vfs.FileDescriptionImpl.PRead. func (fd *regularFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { if offset < 0 { return 0, syserror.EINVAL } + + // Check that flags are supported. RWF_DSYNC/RWF_SYNC can be ignored since + // all state is in-memory. + // + // TODO(gvisor.dev/issue/2601): Support select preadv2 flags. + if opts.Flags&^(linux.RWF_HIPRI|linux.RWF_DSYNC|linux.RWF_SYNC) != 0 { + return 0, syserror.EOPNOTSUPP + } + if dst.NumBytes() == 0 { return 0, nil } @@ -302,40 +325,60 @@ func (fd *regularFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts // PWrite implements vfs.FileDescriptionImpl.PWrite. func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { + n, _, err := fd.pwrite(ctx, src, offset, opts) + return n, err +} + +// pwrite returns the number of bytes written, final offset and error. The +// final offset should be ignored by PWrite. +func (fd *regularFileFD) pwrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (written, finalOff int64, err error) { if offset < 0 { - return 0, syserror.EINVAL + return 0, offset, syserror.EINVAL } + + // Check that flags are supported. RWF_DSYNC/RWF_SYNC can be ignored since + // all state is in-memory. + // + // TODO(gvisor.dev/issue/2601): Support select preadv2 flags. + if opts.Flags&^(linux.RWF_HIPRI|linux.RWF_DSYNC|linux.RWF_SYNC) != 0 { + return 0, offset, syserror.EOPNOTSUPP + } + srclen := src.NumBytes() if srclen == 0 { - return 0, nil + return 0, offset, nil } f := fd.inode().impl.(*regularFile) + f.inode.mu.Lock() + defer f.inode.mu.Unlock() + // If the file is opened with O_APPEND, update offset to file size. + if fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 { + // Locking f.inode.mu is sufficient for reading f.size. + offset = int64(f.size) + } if end := offset + srclen; end < offset { // Overflow. - return 0, syserror.EFBIG + return 0, offset, syserror.EINVAL } - var err error srclen, err = vfs.CheckLimit(ctx, offset, srclen) if err != nil { - return 0, err + return 0, offset, err } src = src.TakeFirst64(srclen) - f.inode.mu.Lock() rw := getRegularFileReadWriter(f, offset) n, err := src.CopyInTo(ctx, rw) - fd.inode().touchCMtimeLocked() - f.inode.mu.Unlock() + f.inode.touchCMtimeLocked() putRegularFileReadWriter(rw) - return n, err + return n, n + offset, err } // Write implements vfs.FileDescriptionImpl.Write. func (fd *regularFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { fd.offMu.Lock() - n, err := fd.PWrite(ctx, src, fd.off, opts) - fd.off += n + n, off, err := fd.pwrite(ctx, src, fd.off, opts) + fd.off = off fd.offMu.Unlock() return n, err } @@ -361,33 +404,6 @@ func (fd *regularFileFD) Seek(ctx context.Context, offset int64, whence int32) ( return offset, nil } -// Sync implements vfs.FileDescriptionImpl.Sync. -func (fd *regularFileFD) Sync(ctx context.Context) error { - return nil -} - -// LockBSD implements vfs.FileDescriptionImpl.LockBSD. -func (fd *regularFileFD) LockBSD(ctx context.Context, uid lock.UniqueID, t lock.LockType, block lock.Blocker) error { - return fd.inode().lockBSD(uid, t, block) -} - -// UnlockBSD implements vfs.FileDescriptionImpl.UnlockBSD. -func (fd *regularFileFD) UnlockBSD(ctx context.Context, uid lock.UniqueID) error { - fd.inode().unlockBSD(uid) - return nil -} - -// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. -func (fd *regularFileFD) LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, rng lock.LockRange, block lock.Blocker) error { - return fd.inode().lockPOSIX(uid, t, rng, block) -} - -// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. -func (fd *regularFileFD) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, rng lock.LockRange) error { - fd.inode().unlockPOSIX(uid, rng) - return nil -} - // ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap. func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error { file := fd.inode().impl.(*regularFile) diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file_test.go b/pkg/sentry/fsimpl/tmpfs/regular_file_test.go index 64e1c40ad..146c7fdfe 100644 --- a/pkg/sentry/fsimpl/tmpfs/regular_file_test.go +++ b/pkg/sentry/fsimpl/tmpfs/regular_file_test.go @@ -138,48 +138,37 @@ func TestLocks(t *testing.T) { } defer cleanup() - var ( - uid1 lock.UniqueID - uid2 lock.UniqueID - // Non-blocking. - block lock.Blocker - ) - - uid1 = 123 - uid2 = 456 - - if err := fd.Impl().LockBSD(ctx, uid1, lock.ReadLock, block); err != nil { + uid1 := 123 + uid2 := 456 + if err := fd.Impl().LockBSD(ctx, uid1, lock.ReadLock, nil); err != nil { t.Fatalf("fd.Impl().LockBSD failed: err = %v", err) } - if err := fd.Impl().LockBSD(ctx, uid2, lock.ReadLock, block); err != nil { + if err := fd.Impl().LockBSD(ctx, uid2, lock.ReadLock, nil); err != nil { t.Fatalf("fd.Impl().LockBSD failed: err = %v", err) } - if got, want := fd.Impl().LockBSD(ctx, uid2, lock.WriteLock, block), syserror.ErrWouldBlock; got != want { + if got, want := fd.Impl().LockBSD(ctx, uid2, lock.WriteLock, nil), syserror.ErrWouldBlock; got != want { t.Fatalf("fd.Impl().LockBSD failed: got = %v, want = %v", got, want) } if err := fd.Impl().UnlockBSD(ctx, uid1); err != nil { t.Fatalf("fd.Impl().UnlockBSD failed: err = %v", err) } - if err := fd.Impl().LockBSD(ctx, uid2, lock.WriteLock, block); err != nil { + if err := fd.Impl().LockBSD(ctx, uid2, lock.WriteLock, nil); err != nil { t.Fatalf("fd.Impl().LockBSD failed: err = %v", err) } - rng1 := lock.LockRange{0, 1} - rng2 := lock.LockRange{1, 2} - - if err := fd.Impl().LockPOSIX(ctx, uid1, lock.ReadLock, rng1, block); err != nil { + if err := fd.Impl().LockPOSIX(ctx, uid1, lock.ReadLock, 0, 1, linux.SEEK_SET, nil); err != nil { t.Fatalf("fd.Impl().LockPOSIX failed: err = %v", err) } - if err := fd.Impl().LockPOSIX(ctx, uid2, lock.ReadLock, rng2, block); err != nil { + if err := fd.Impl().LockPOSIX(ctx, uid2, lock.ReadLock, 1, 2, linux.SEEK_SET, nil); err != nil { t.Fatalf("fd.Impl().LockPOSIX failed: err = %v", err) } - if err := fd.Impl().LockPOSIX(ctx, uid1, lock.WriteLock, rng1, block); err != nil { + if err := fd.Impl().LockPOSIX(ctx, uid1, lock.WriteLock, 0, 1, linux.SEEK_SET, nil); err != nil { t.Fatalf("fd.Impl().LockPOSIX failed: err = %v", err) } - if got, want := fd.Impl().LockPOSIX(ctx, uid2, lock.ReadLock, rng1, block), syserror.ErrWouldBlock; got != want { + if got, want := fd.Impl().LockPOSIX(ctx, uid2, lock.ReadLock, 0, 1, linux.SEEK_SET, nil), syserror.ErrWouldBlock; got != want { t.Fatalf("fd.Impl().LockPOSIX failed: got = %v, want = %v", got, want) } - if err := fd.Impl().UnlockPOSIX(ctx, uid1, rng1); err != nil { + if err := fd.Impl().UnlockPOSIX(ctx, uid1, 0, 1, linux.SEEK_SET); err != nil { t.Fatalf("fd.Impl().UnlockPOSIX failed: err = %v", err) } } diff --git a/pkg/sentry/fsimpl/tmpfs/socket_file.go b/pkg/sentry/fsimpl/tmpfs/socket_file.go index 25c2321af..3ed650474 100644 --- a/pkg/sentry/fsimpl/tmpfs/socket_file.go +++ b/pkg/sentry/fsimpl/tmpfs/socket_file.go @@ -26,9 +26,9 @@ type socketFile struct { ep transport.BoundEndpoint } -func (fs *filesystem) newSocketFile(creds *auth.Credentials, mode linux.FileMode, ep transport.BoundEndpoint) *inode { +func (fs *filesystem) newSocketFile(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode, ep transport.BoundEndpoint) *inode { file := &socketFile{ep: ep} - file.inode.init(file, fs, creds, mode) + file.inode.init(file, fs, kuid, kgid, mode) file.inode.nlink = 1 // from parent directory return &file.inode } diff --git a/pkg/sentry/fsimpl/tmpfs/symlink.go b/pkg/sentry/fsimpl/tmpfs/symlink.go index 47e075ed4..b0de5fabe 100644 --- a/pkg/sentry/fsimpl/tmpfs/symlink.go +++ b/pkg/sentry/fsimpl/tmpfs/symlink.go @@ -24,11 +24,11 @@ type symlink struct { target string // immutable } -func (fs *filesystem) newSymlink(creds *auth.Credentials, target string) *inode { +func (fs *filesystem) newSymlink(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode, target string) *inode { link := &symlink{ target: target, } - link.inode.init(link, fs, creds, linux.S_IFLNK|0777) + link.inode.init(link, fs, kuid, kgid, linux.S_IFLNK|mode) link.inode.nlink = 1 // from parent directory return &link.inode } diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go index 1e781aecd..de2af6d01 100644 --- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go +++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go @@ -30,6 +30,7 @@ package tmpfs import ( "fmt" "math" + "strconv" "strings" "sync/atomic" @@ -40,7 +41,6 @@ import ( "gvisor.dev/gvisor/pkg/sentry/kernel/time" "gvisor.dev/gvisor/pkg/sentry/pgalloc" "gvisor.dev/gvisor/pkg/sentry/vfs" - "gvisor.dev/gvisor/pkg/sentry/vfs/lock" "gvisor.dev/gvisor/pkg/sentry/vfs/memxattr" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" @@ -112,6 +112,58 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt } } + mopts := vfs.GenericParseMountOptions(opts.Data) + rootMode := linux.FileMode(0777) + if rootFileType == linux.S_IFDIR { + rootMode = 01777 + } + modeStr, ok := mopts["mode"] + if ok { + delete(mopts, "mode") + mode, err := strconv.ParseUint(modeStr, 8, 32) + if err != nil { + ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: invalid mode: %q", modeStr) + return nil, nil, syserror.EINVAL + } + rootMode = linux.FileMode(mode & 07777) + } + rootKUID := creds.EffectiveKUID + uidStr, ok := mopts["uid"] + if ok { + delete(mopts, "uid") + uid, err := strconv.ParseUint(uidStr, 10, 32) + if err != nil { + ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: invalid uid: %q", uidStr) + return nil, nil, syserror.EINVAL + } + kuid := creds.UserNamespace.MapToKUID(auth.UID(uid)) + if !kuid.Ok() { + ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: unmapped uid: %d", uid) + return nil, nil, syserror.EINVAL + } + rootKUID = kuid + } + rootKGID := creds.EffectiveKGID + gidStr, ok := mopts["gid"] + if ok { + delete(mopts, "gid") + gid, err := strconv.ParseUint(gidStr, 10, 32) + if err != nil { + ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: invalid gid: %q", gidStr) + return nil, nil, syserror.EINVAL + } + kgid := creds.UserNamespace.MapToKGID(auth.GID(gid)) + if !kgid.Ok() { + ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: unmapped gid: %d", gid) + return nil, nil, syserror.EINVAL + } + rootKGID = kgid + } + if len(mopts) != 0 { + ctx.Warningf("tmpfs.FilesystemType.GetFilesystem: unknown options: %v", mopts) + return nil, nil, syserror.EINVAL + } + devMinor, err := vfsObj.GetAnonBlockDevMinor() if err != nil { return nil, nil, err @@ -127,13 +179,13 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt var root *dentry switch rootFileType { case linux.S_IFREG: - root = fs.newDentry(fs.newRegularFile(creds, 0777)) + root = fs.newDentry(fs.newRegularFile(rootKUID, rootKGID, rootMode)) case linux.S_IFLNK: - root = fs.newDentry(fs.newSymlink(creds, tmpfsOpts.RootSymlinkTarget)) + root = fs.newDentry(fs.newSymlink(rootKUID, rootKGID, rootMode, tmpfsOpts.RootSymlinkTarget)) case linux.S_IFDIR: - root = &fs.newDirectory(creds, 01777).dentry + root = &fs.newDirectory(rootKUID, rootKGID, rootMode).dentry default: - fs.vfsfs.DecRef() + fs.vfsfs.DecRef(ctx) return nil, nil, fmt.Errorf("invalid tmpfs root file type: %#o", rootFileType) } return &fs.vfsfs, &root.vfsd, nil @@ -145,7 +197,7 @@ func NewFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *au } // Release implements vfs.FilesystemImpl.Release. -func (fs *filesystem) Release() { +func (fs *filesystem) Release(ctx context.Context) { fs.vfsfs.VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor) } @@ -197,24 +249,46 @@ func (d *dentry) TryIncRef() bool { } // DecRef implements vfs.DentryImpl.DecRef. -func (d *dentry) DecRef() { - d.inode.decRef() +func (d *dentry) DecRef(ctx context.Context) { + d.inode.decRef(ctx) } +// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent. +func (d *dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et vfs.EventType) { + if d.inode.isDir() { + events |= linux.IN_ISDIR + } + + // tmpfs never calls VFS.InvalidateDentry(), so d.vfsd.IsDead() indicates + // that d was deleted. + deleted := d.vfsd.IsDead() + + d.inode.fs.mu.RLock() + // The ordering below is important, Linux always notifies the parent first. + if d.parent != nil { + d.parent.inode.watches.Notify(ctx, d.name, events, cookie, et, deleted) + } + d.inode.watches.Notify(ctx, "", events, cookie, et, deleted) + d.inode.fs.mu.RUnlock() +} + +// Watches implements vfs.DentryImpl.Watches. +func (d *dentry) Watches() *vfs.Watches { + return &d.inode.watches +} + +// OnZeroWatches implements vfs.Dentry.OnZeroWatches. +func (d *dentry) OnZeroWatches(context.Context) {} + // inode represents a filesystem object. type inode struct { // fs is the owning filesystem. fs is immutable. fs *filesystem - // refs is a reference count. refs is accessed using atomic memory - // operations. - // - // A reference is held on all inodes that are reachable in the filesystem - // tree. For non-directories (which may have multiple hard links), this - // means that a reference is dropped when nlink reaches 0. For directories, - // nlink never reaches 0 due to the "." entry; instead, - // filesystem.RmdirAt() drops the reference. - refs int64 + // A reference is held on all inodes as long as they are reachable in the + // filesystem tree, i.e. nlink is nonzero. This reference is dropped when + // nlink reaches 0. + refs inodeRefs // xattrs implements extended attributes. // @@ -235,23 +309,24 @@ type inode struct { ctime int64 // nanoseconds mtime int64 // nanoseconds - // Advisory file locks, which lock at the inode level. - locks lock.FileLocks + locks vfs.FileLocks + + // Inotify watches for this inode. + watches vfs.Watches impl interface{} // immutable } const maxLinks = math.MaxUint32 -func (i *inode) init(impl interface{}, fs *filesystem, creds *auth.Credentials, mode linux.FileMode) { +func (i *inode) init(impl interface{}, fs *filesystem, kuid auth.KUID, kgid auth.KGID, mode linux.FileMode) { if mode.FileType() == 0 { panic("file type is required in FileMode") } i.fs = fs - i.refs = 1 i.mode = uint32(mode) - i.uid = uint32(creds.EffectiveKUID) - i.gid = uint32(creds.EffectiveKGID) + i.uid = uint32(kuid) + i.gid = uint32(kgid) i.ino = atomic.AddUint64(&fs.nextInoMinusOne, 1) // Tmpfs creation sets atime, ctime, and mtime to current time. now := fs.clock.Now().Nanoseconds() @@ -260,6 +335,7 @@ func (i *inode) init(impl interface{}, fs *filesystem, creds *auth.Credentials, i.mtime = now // i.nlink initialized by caller i.impl = impl + i.refs.EnableLeakCheck() } // incLinksLocked increments i's link count. @@ -276,45 +352,37 @@ func (i *inode) incLinksLocked() { atomic.AddUint32(&i.nlink, 1) } -// decLinksLocked decrements i's link count. +// decLinksLocked decrements i's link count. If the link count reaches 0, we +// remove a reference on i as well. // // Preconditions: filesystem.mu must be locked for writing. i.nlink != 0. -func (i *inode) decLinksLocked() { +func (i *inode) decLinksLocked(ctx context.Context) { if i.nlink == 0 { panic("tmpfs.inode.decLinksLocked() called with no existing links") } - atomic.AddUint32(&i.nlink, ^uint32(0)) + if atomic.AddUint32(&i.nlink, ^uint32(0)) == 0 { + i.decRef(ctx) + } } func (i *inode) incRef() { - if atomic.AddInt64(&i.refs, 1) <= 1 { - panic("tmpfs.inode.incRef() called without holding a reference") - } + i.refs.IncRef() } func (i *inode) tryIncRef() bool { - for { - refs := atomic.LoadInt64(&i.refs) - if refs == 0 { - return false - } - if atomic.CompareAndSwapInt64(&i.refs, refs, refs+1) { - return true - } - } + return i.refs.TryIncRef() } -func (i *inode) decRef() { - if refs := atomic.AddInt64(&i.refs, -1); refs == 0 { +func (i *inode) decRef(ctx context.Context) { + i.refs.DecRef(func() { + i.watches.HandleDeletion(ctx) if regFile, ok := i.impl.(*regularFile); ok { // Release memory used by regFile to store data. Since regFile is // no longer usable, we don't need to grab any locks or update any // metadata. regFile.data.DropAll(regFile.memFile) } - } else if refs < 0 { - panic("tmpfs.inode.decRef() called without holding a reference") - } + }) } func (i *inode) checkPermissions(creds *auth.Credentials, ats vfs.AccessTypes) error { @@ -369,7 +437,8 @@ func (i *inode) statTo(stat *linux.Statx) { } } -func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, stat *linux.Statx) error { +func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, opts *vfs.SetStatOptions) error { + stat := &opts.Stat if stat.Mask == 0 { return nil } @@ -377,7 +446,7 @@ func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, stat *linu return syserror.EPERM } mode := linux.FileMode(atomic.LoadUint32(&i.mode)) - if err := vfs.CheckSetStat(ctx, creds, stat, mode, auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil { + if err := vfs.CheckSetStat(ctx, creds, opts, mode, auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid))); err != nil { return err } i.mu.Lock() @@ -455,44 +524,6 @@ func (i *inode) setStat(ctx context.Context, creds *auth.Credentials, stat *linu return nil } -// TODO(gvisor.dev/issue/1480): support file locking for file types other than regular. -func (i *inode) lockBSD(uid fslock.UniqueID, t fslock.LockType, block fslock.Blocker) error { - switch i.impl.(type) { - case *regularFile: - return i.locks.LockBSD(uid, t, block) - } - return syserror.EBADF -} - -// TODO(gvisor.dev/issue/1480): support file locking for file types other than regular. -func (i *inode) unlockBSD(uid fslock.UniqueID) error { - switch i.impl.(type) { - case *regularFile: - i.locks.UnlockBSD(uid) - return nil - } - return syserror.EBADF -} - -// TODO(gvisor.dev/issue/1480): support file locking for file types other than regular. -func (i *inode) lockPOSIX(uid fslock.UniqueID, t fslock.LockType, rng fslock.LockRange, block fslock.Blocker) error { - switch i.impl.(type) { - case *regularFile: - return i.locks.LockPOSIX(uid, t, rng, block) - } - return syserror.EBADF -} - -// TODO(gvisor.dev/issue/1480): support file locking for file types other than regular. -func (i *inode) unlockPOSIX(uid fslock.UniqueID, rng fslock.LockRange) error { - switch i.impl.(type) { - case *regularFile: - i.locks.UnlockPOSIX(uid, rng) - return nil - } - return syserror.EBADF -} - // allocatedBlocksForSize returns the number of 512B blocks needed to // accommodate the given size in bytes, as appropriate for struct // stat::st_blocks and struct statx::stx_blocks. (Note that this 512B block @@ -512,6 +543,8 @@ func (i *inode) direntType() uint8 { return linux.DT_LNK case *socketFile: return linux.DT_SOCK + case *namedPipe: + return linux.DT_FIFO case *deviceFile: switch impl.kind { case vfs.BlockDevice: @@ -531,6 +564,9 @@ func (i *inode) isDir() bool { } func (i *inode) touchAtime(mnt *vfs.Mount) { + if mnt.Flags.NoATime { + return + } if err := mnt.CheckBeginWrite(); err != nil { return } @@ -621,14 +657,19 @@ func (i *inode) userXattrSupported() bool { type fileDescription struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD } func (fd *fileDescription) filesystem() *filesystem { return fd.vfsfd.Mount().Filesystem().Impl().(*filesystem) } +func (fd *fileDescription) dentry() *dentry { + return fd.vfsfd.Dentry().Impl().(*dentry) +} + func (fd *fileDescription) inode() *inode { - return fd.vfsfd.Dentry().Impl().(*dentry).inode + return fd.dentry().inode } // Stat implements vfs.FileDescriptionImpl.Stat. @@ -641,7 +682,15 @@ func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linu // SetStat implements vfs.FileDescriptionImpl.SetStat. func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error { creds := auth.CredentialsFromContext(ctx) - return fd.inode().setStat(ctx, creds, &opts.Stat) + d := fd.dentry() + if err := d.inode.setStat(ctx, creds, &opts); err != nil { + return err + } + + if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 { + d.InotifyWithParent(ctx, ev, 0, vfs.InodeEvent) + } + return nil } // Listxattr implements vfs.FileDescriptionImpl.Listxattr. @@ -656,17 +705,31 @@ func (fd *fileDescription) Getxattr(ctx context.Context, opts vfs.GetxattrOption // Setxattr implements vfs.FileDescriptionImpl.Setxattr. func (fd *fileDescription) Setxattr(ctx context.Context, opts vfs.SetxattrOptions) error { - return fd.inode().setxattr(auth.CredentialsFromContext(ctx), &opts) + d := fd.dentry() + if err := d.inode.setxattr(auth.CredentialsFromContext(ctx), &opts); err != nil { + return err + } + + // Generate inotify events. + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // Removexattr implements vfs.FileDescriptionImpl.Removexattr. func (fd *fileDescription) Removexattr(ctx context.Context, name string) error { - return fd.inode().removexattr(auth.CredentialsFromContext(ctx), name) + d := fd.dentry() + if err := d.inode.removexattr(auth.CredentialsFromContext(ctx), name); err != nil { + return err + } + + // Generate inotify events. + d.InotifyWithParent(ctx, linux.IN_ATTRIB, 0, vfs.InodeEvent) + return nil } // NewMemfd creates a new tmpfs regular file and file description that can back // an anonymous fd created by memfd_create. -func NewMemfd(mount *vfs.Mount, creds *auth.Credentials, allowSeals bool, name string) (*vfs.FileDescription, error) { +func NewMemfd(ctx context.Context, creds *auth.Credentials, mount *vfs.Mount, allowSeals bool, name string) (*vfs.FileDescription, error) { fs, ok := mount.Filesystem().Impl().(*filesystem) if !ok { panic("NewMemfd() called with non-tmpfs mount") @@ -674,23 +737,39 @@ func NewMemfd(mount *vfs.Mount, creds *auth.Credentials, allowSeals bool, name s // Per Linux, mm/shmem.c:__shmem_file_setup(), memfd inodes are set up with // S_IRWXUGO. - mode := linux.FileMode(0777) - inode := fs.newRegularFile(creds, mode) + inode := fs.newRegularFile(creds.EffectiveKUID, creds.EffectiveKGID, 0777) rf := inode.impl.(*regularFile) if allowSeals { rf.seals = 0 } d := fs.newDentry(inode) - defer d.DecRef() + defer d.DecRef(ctx) d.name = name // Per Linux, mm/shmem.c:__shmem_file_setup(), memfd files are set up with // FMODE_READ | FMODE_WRITE. var fd regularFileFD + fd.Init(&inode.locks) flags := uint32(linux.O_RDWR) if err := fd.vfsfd.Init(&fd, flags, mount, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil { return nil, err } return &fd.vfsfd, nil } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *fileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} + +// Sync implements vfs.FileDescriptionImpl.Sync. It does nothing because all +// filesystem state is in-memory. +func (*fileDescription) Sync(context.Context) error { + return nil +} diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs_test.go b/pkg/sentry/fsimpl/tmpfs/tmpfs_test.go index a240fb276..6f3e3ae6f 100644 --- a/pkg/sentry/fsimpl/tmpfs/tmpfs_test.go +++ b/pkg/sentry/fsimpl/tmpfs/tmpfs_test.go @@ -34,7 +34,7 @@ func newTmpfsRoot(ctx context.Context) (*vfs.VirtualFilesystem, vfs.VirtualDentr creds := auth.CredentialsFromContext(ctx) vfsObj := &vfs.VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { return nil, vfs.VirtualDentry{}, nil, fmt.Errorf("VFS init: %v", err) } @@ -47,8 +47,8 @@ func newTmpfsRoot(ctx context.Context) (*vfs.VirtualFilesystem, vfs.VirtualDentr } root := mntns.Root() return vfsObj, root, func() { - root.DecRef() - mntns.DecRef() + root.DecRef(ctx) + mntns.DecRef(ctx) }, nil } diff --git a/pkg/sentry/inet/inet.go b/pkg/sentry/inet/inet.go index 2916a0644..c0b4831d1 100644 --- a/pkg/sentry/inet/inet.go +++ b/pkg/sentry/inet/inet.go @@ -56,6 +56,12 @@ type Stack interface { // settings. SetTCPSACKEnabled(enabled bool) error + // TCPRecovery returns the TCP loss detection algorithm. + TCPRecovery() (TCPLossRecovery, error) + + // SetTCPRecovery attempts to change TCP loss detection algorithm. + SetTCPRecovery(recovery TCPLossRecovery) error + // Statistics reports stack statistics. Statistics(stat interface{}, arg string) error @@ -189,3 +195,14 @@ type StatSNMPUDP [8]uint64 // StatSNMPUDPLite describes UdpLite line of /proc/net/snmp. type StatSNMPUDPLite [8]uint64 + +// TCPLossRecovery indicates TCP loss detection and recovery methods to use. +type TCPLossRecovery int32 + +// Loss recovery constants from include/net/tcp.h which are used to set +// /proc/sys/net/ipv4/tcp_recovery. +const ( + TCP_RACK_LOSS_DETECTION TCPLossRecovery = 1 << iota + TCP_RACK_STATIC_REO_WND + TCP_RACK_NO_DUPTHRESH +) diff --git a/pkg/sentry/inet/test_stack.go b/pkg/sentry/inet/test_stack.go index d8961fc94..9771f01fc 100644 --- a/pkg/sentry/inet/test_stack.go +++ b/pkg/sentry/inet/test_stack.go @@ -25,6 +25,7 @@ type TestStack struct { TCPRecvBufSize TCPBufferSize TCPSendBufSize TCPBufferSize TCPSACKFlag bool + Recovery TCPLossRecovery } // NewTestStack returns a TestStack with no network interfaces. The value of @@ -91,6 +92,17 @@ func (s *TestStack) SetTCPSACKEnabled(enabled bool) error { return nil } +// TCPRecovery implements Stack.TCPRecovery. +func (s *TestStack) TCPRecovery() (TCPLossRecovery, error) { + return s.Recovery, nil +} + +// SetTCPRecovery implements Stack.SetTCPRecovery. +func (s *TestStack) SetTCPRecovery(recovery TCPLossRecovery) error { + s.Recovery = recovery + return nil +} + // Statistics implements inet.Stack.Statistics. func (s *TestStack) Statistics(stat interface{}, arg string) error { return nil diff --git a/pkg/sentry/kernel/BUILD b/pkg/sentry/kernel/BUILD index a28eab8b8..f6886a758 100644 --- a/pkg/sentry/kernel/BUILD +++ b/pkg/sentry/kernel/BUILD @@ -85,6 +85,7 @@ go_library( name = "kernel", srcs = [ "abstract_socket_namespace.go", + "aio.go", "context.go", "fd_table.go", "fd_table_unsafe.go", @@ -131,6 +132,7 @@ go_library( "task_stop.go", "task_syscall.go", "task_usermem.go", + "task_work.go", "thread_group.go", "threads.go", "timekeeper.go", @@ -199,6 +201,7 @@ go_library( "//pkg/sentry/vfs", "//pkg/state", "//pkg/state/statefile", + "//pkg/state/wire", "//pkg/sync", "//pkg/syserr", "//pkg/syserror", diff --git a/pkg/sentry/kernel/abstract_socket_namespace.go b/pkg/sentry/kernel/abstract_socket_namespace.go index 920fe4329..52ed5cea2 100644 --- a/pkg/sentry/kernel/abstract_socket_namespace.go +++ b/pkg/sentry/kernel/abstract_socket_namespace.go @@ -17,6 +17,7 @@ package kernel import ( "syscall" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" "gvisor.dev/gvisor/pkg/sync" @@ -31,7 +32,7 @@ type abstractEndpoint struct { } // WeakRefGone implements refs.WeakRefUser.WeakRefGone. -func (e *abstractEndpoint) WeakRefGone() { +func (e *abstractEndpoint) WeakRefGone(context.Context) { e.ns.mu.Lock() if e.ns.endpoints[e.name].ep == e.ep { delete(e.ns.endpoints, e.name) @@ -64,9 +65,9 @@ type boundEndpoint struct { } // Release implements transport.BoundEndpoint.Release. -func (e *boundEndpoint) Release() { - e.rc.DecRef() - e.BoundEndpoint.Release() +func (e *boundEndpoint) Release(ctx context.Context) { + e.rc.DecRef(ctx) + e.BoundEndpoint.Release(ctx) } // BoundEndpoint retrieves the endpoint bound to the given name. The return @@ -93,13 +94,13 @@ func (a *AbstractSocketNamespace) BoundEndpoint(name string) transport.BoundEndp // // When the last reference managed by rc is dropped, ep may be removed from the // namespace. -func (a *AbstractSocketNamespace) Bind(name string, ep transport.BoundEndpoint, rc refs.RefCounter) error { +func (a *AbstractSocketNamespace) Bind(ctx context.Context, name string, ep transport.BoundEndpoint, rc refs.RefCounter) error { a.mu.Lock() defer a.mu.Unlock() if ep, ok := a.endpoints[name]; ok { if rc := ep.wr.Get(); rc != nil { - rc.DecRef() + rc.DecRef(ctx) return syscall.EADDRINUSE } } diff --git a/pkg/sentry/kernel/aio.go b/pkg/sentry/kernel/aio.go new file mode 100644 index 000000000..0ac78c0b8 --- /dev/null +++ b/pkg/sentry/kernel/aio.go @@ -0,0 +1,81 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package kernel + +import ( + "time" + + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/log" +) + +// AIOCallback is an function that does asynchronous I/O on behalf of a task. +type AIOCallback func(context.Context) + +// QueueAIO queues an AIOCallback which will be run asynchronously. +func (t *Task) QueueAIO(cb AIOCallback) { + ctx := taskAsyncContext{t: t} + wg := &t.TaskSet().aioGoroutines + wg.Add(1) + go func() { + cb(ctx) + wg.Done() + }() +} + +type taskAsyncContext struct { + context.NoopSleeper + t *Task +} + +// Debugf implements log.Logger.Debugf. +func (ctx taskAsyncContext) Debugf(format string, v ...interface{}) { + ctx.t.Debugf(format, v...) +} + +// Infof implements log.Logger.Infof. +func (ctx taskAsyncContext) Infof(format string, v ...interface{}) { + ctx.t.Infof(format, v...) +} + +// Warningf implements log.Logger.Warningf. +func (ctx taskAsyncContext) Warningf(format string, v ...interface{}) { + ctx.t.Warningf(format, v...) +} + +// IsLogging implements log.Logger.IsLogging. +func (ctx taskAsyncContext) IsLogging(level log.Level) bool { + return ctx.t.IsLogging(level) +} + +// Deadline implements context.Context.Deadline. +func (ctx taskAsyncContext) Deadline() (time.Time, bool) { + return ctx.t.Deadline() +} + +// Done implements context.Context.Done. +func (ctx taskAsyncContext) Done() <-chan struct{} { + return ctx.t.Done() +} + +// Err implements context.Context.Err. +func (ctx taskAsyncContext) Err() error { + return ctx.t.Err() +} + +// Value implements context.Context.Value. +func (ctx taskAsyncContext) Value(key interface{}) interface{} { + return ctx.t.Value(key) +} diff --git a/pkg/sentry/kernel/auth/credentials.go b/pkg/sentry/kernel/auth/credentials.go index e057d2c6d..6862f2ef5 100644 --- a/pkg/sentry/kernel/auth/credentials.go +++ b/pkg/sentry/kernel/auth/credentials.go @@ -232,3 +232,31 @@ func (c *Credentials) UseGID(gid GID) (KGID, error) { } return NoID, syserror.EPERM } + +// SetUID translates the provided uid to the root user namespace and updates c's +// uids to it. This performs no permissions or capabilities checks, the caller +// is responsible for ensuring the calling context is permitted to modify c. +func (c *Credentials) SetUID(uid UID) error { + kuid := c.UserNamespace.MapToKUID(uid) + if !kuid.Ok() { + return syserror.EINVAL + } + c.RealKUID = kuid + c.EffectiveKUID = kuid + c.SavedKUID = kuid + return nil +} + +// SetGID translates the provided gid to the root user namespace and updates c's +// gids to it. This performs no permissions or capabilities checks, the caller +// is responsible for ensuring the calling context is permitted to modify c. +func (c *Credentials) SetGID(gid GID) error { + kgid := c.UserNamespace.MapToKGID(gid) + if !kgid.Ok() { + return syserror.EINVAL + } + c.RealKGID = kgid + c.EffectiveKGID = kgid + c.SavedKGID = kgid + return nil +} diff --git a/pkg/sentry/kernel/context.go b/pkg/sentry/kernel/context.go index 0c40bf315..dd5f0f5fa 100644 --- a/pkg/sentry/kernel/context.go +++ b/pkg/sentry/kernel/context.go @@ -18,7 +18,6 @@ import ( "time" "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/log" ) // contextID is the kernel package's type for context.Context.Value keys. @@ -113,55 +112,3 @@ func (*Task) Done() <-chan struct{} { func (*Task) Err() error { return nil } - -// AsyncContext returns a context.Context that may be used by goroutines that -// do work on behalf of t and therefore share its contextual values, but are -// not t's task goroutine (e.g. asynchronous I/O). -func (t *Task) AsyncContext() context.Context { - return taskAsyncContext{t: t} -} - -type taskAsyncContext struct { - context.NoopSleeper - t *Task -} - -// Debugf implements log.Logger.Debugf. -func (ctx taskAsyncContext) Debugf(format string, v ...interface{}) { - ctx.t.Debugf(format, v...) -} - -// Infof implements log.Logger.Infof. -func (ctx taskAsyncContext) Infof(format string, v ...interface{}) { - ctx.t.Infof(format, v...) -} - -// Warningf implements log.Logger.Warningf. -func (ctx taskAsyncContext) Warningf(format string, v ...interface{}) { - ctx.t.Warningf(format, v...) -} - -// IsLogging implements log.Logger.IsLogging. -func (ctx taskAsyncContext) IsLogging(level log.Level) bool { - return ctx.t.IsLogging(level) -} - -// Deadline implements context.Context.Deadline. -func (ctx taskAsyncContext) Deadline() (time.Time, bool) { - return ctx.t.Deadline() -} - -// Done implements context.Context.Done. -func (ctx taskAsyncContext) Done() <-chan struct{} { - return ctx.t.Done() -} - -// Err implements context.Context.Err. -func (ctx taskAsyncContext) Err() error { - return ctx.t.Err() -} - -// Value implements context.Context.Value. -func (ctx taskAsyncContext) Value(key interface{}) interface{} { - return ctx.t.Value(key) -} diff --git a/pkg/sentry/kernel/epoll/epoll.go b/pkg/sentry/kernel/epoll/epoll.go index 3d78cd48f..15519f0df 100644 --- a/pkg/sentry/kernel/epoll/epoll.go +++ b/pkg/sentry/kernel/epoll/epoll.go @@ -76,8 +76,8 @@ type pollEntry struct { // WeakRefGone implements refs.WeakRefUser.WeakRefGone. // weakReferenceGone is called when the file in the weak reference is destroyed. // The poll entry is removed in response to this. -func (p *pollEntry) WeakRefGone() { - p.epoll.RemoveEntry(p.id) +func (p *pollEntry) WeakRefGone(ctx context.Context) { + p.epoll.RemoveEntry(ctx, p.id) } // EventPoll holds all the state associated with an event poll object, that is, @@ -107,7 +107,7 @@ type EventPoll struct { // different lock to avoid circular lock acquisition order involving // the wait queue mutexes and mu. The full order is mu, observed file // wait queue mutex, then listsMu; this allows listsMu to be acquired - // when readyCallback is called. + // when (*pollEntry).Callback is called. // // An entry is always in one of the following lists: // readyList -- when there's a chance that it's ready to have @@ -116,7 +116,7 @@ type EventPoll struct { // readEvents() functions always call the entry's file // Readiness() function to confirm it's ready. // waitingList -- when there's no chance that the entry is ready, - // so it's waiting for the readyCallback to be called + // so it's waiting for the (*pollEntry).Callback to be called // on it before it gets moved to the readyList. // disabledList -- when the entry is disabled. This happens when // a one-shot entry gets delivered via readEvents(). @@ -144,14 +144,14 @@ func NewEventPoll(ctx context.Context) *fs.File { // name matches fs/eventpoll.c:epoll_create1. dirent := fs.NewDirent(ctx, anon.NewInode(ctx), fmt.Sprintf("anon_inode:[eventpoll]")) // Release the initial dirent reference after NewFile takes a reference. - defer dirent.DecRef() + defer dirent.DecRef(ctx) return fs.NewFile(ctx, dirent, fs.FileFlags{}, &EventPoll{ files: make(map[FileIdentifier]*pollEntry), }) } // Release implements fs.FileOperations.Release. -func (e *EventPoll) Release() { +func (e *EventPoll) Release(ctx context.Context) { // We need to take the lock now because files may be attempting to // remove entries in parallel if they get destroyed. e.mu.Lock() @@ -160,7 +160,7 @@ func (e *EventPoll) Release() { // Go through all entries and clean up. for _, entry := range e.files { entry.id.File.EventUnregister(&entry.waiter) - entry.file.Drop() + entry.file.Drop(ctx) } e.files = nil } @@ -269,21 +269,19 @@ func (e *EventPoll) ReadEvents(max int) []linux.EpollEvent { return ret } -// readyCallback is called when one of the files we're polling becomes ready. It -// moves said file to the readyList if it's currently in the waiting list. -type readyCallback struct{} - // Callback implements waiter.EntryCallback.Callback. -func (*readyCallback) Callback(w *waiter.Entry) { - entry := w.Context.(*pollEntry) - e := entry.epoll +// +// Callback is called when one of the files we're polling becomes ready. It +// moves said file to the readyList if it's currently in the waiting list. +func (p *pollEntry) Callback(*waiter.Entry) { + e := p.epoll e.listsMu.Lock() - if entry.curList == &e.waitingList { - e.waitingList.Remove(entry) - e.readyList.PushBack(entry) - entry.curList = &e.readyList + if p.curList == &e.waitingList { + e.waitingList.Remove(p) + e.readyList.PushBack(p) + p.curList = &e.readyList e.listsMu.Unlock() e.Notify(waiter.EventIn) @@ -310,7 +308,7 @@ func (e *EventPoll) initEntryReadiness(entry *pollEntry) { // Check if the file happens to already be in a ready state. ready := f.Readiness(entry.mask) & entry.mask if ready != 0 { - (*readyCallback).Callback(nil, &entry.waiter) + entry.Callback(&entry.waiter) } } @@ -380,10 +378,9 @@ func (e *EventPoll) AddEntry(id FileIdentifier, flags EntryFlags, mask waiter.Ev userData: data, epoll: e, flags: flags, - waiter: waiter.Entry{Callback: &readyCallback{}}, mask: mask, } - entry.waiter.Context = entry + entry.waiter.Callback = entry e.files[id] = entry entry.file = refs.NewWeakRef(id.File, entry) @@ -406,7 +403,7 @@ func (e *EventPoll) UpdateEntry(id FileIdentifier, flags EntryFlags, mask waiter } // Unregister the old mask and remove entry from the list it's in, so - // readyCallback is guaranteed to not be called on this entry anymore. + // (*pollEntry).Callback is guaranteed to not be called on this entry anymore. entry.id.File.EventUnregister(&entry.waiter) // Remove entry from whatever list it's in. This ensure that no other @@ -426,7 +423,7 @@ func (e *EventPoll) UpdateEntry(id FileIdentifier, flags EntryFlags, mask waiter } // RemoveEntry a files from the collection of observed files. -func (e *EventPoll) RemoveEntry(id FileIdentifier) error { +func (e *EventPoll) RemoveEntry(ctx context.Context, id FileIdentifier) error { e.mu.Lock() defer e.mu.Unlock() @@ -448,7 +445,7 @@ func (e *EventPoll) RemoveEntry(id FileIdentifier) error { // Remove file from map, and drop weak reference. delete(e.files, id) - entry.file.Drop() + entry.file.Drop(ctx) return nil } diff --git a/pkg/sentry/kernel/epoll/epoll_state.go b/pkg/sentry/kernel/epoll/epoll_state.go index 8e9f200d0..7c61e0258 100644 --- a/pkg/sentry/kernel/epoll/epoll_state.go +++ b/pkg/sentry/kernel/epoll/epoll_state.go @@ -21,8 +21,7 @@ import ( // afterLoad is invoked by stateify. func (p *pollEntry) afterLoad() { - p.waiter = waiter.Entry{Callback: &readyCallback{}} - p.waiter.Context = p + p.waiter.Callback = p p.file = refs.NewWeakRef(p.id.File, p) p.id.File.EventRegister(&p.waiter, p.mask) } diff --git a/pkg/sentry/kernel/epoll/epoll_test.go b/pkg/sentry/kernel/epoll/epoll_test.go index 22630e9c5..55b505593 100644 --- a/pkg/sentry/kernel/epoll/epoll_test.go +++ b/pkg/sentry/kernel/epoll/epoll_test.go @@ -26,7 +26,8 @@ func TestFileDestroyed(t *testing.T) { f := filetest.NewTestFile(t) id := FileIdentifier{f, 12} - efile := NewEventPoll(contexttest.Context(t)) + ctx := contexttest.Context(t) + efile := NewEventPoll(ctx) e := efile.FileOperations.(*EventPoll) if err := e.AddEntry(id, 0, waiter.EventIn, [2]int32{}); err != nil { t.Fatalf("addEntry failed: %v", err) @@ -44,7 +45,7 @@ func TestFileDestroyed(t *testing.T) { } // Destroy the file. Check that we get no more events. - f.DecRef() + f.DecRef(ctx) evt = e.ReadEvents(1) if len(evt) != 0 { diff --git a/pkg/sentry/kernel/eventfd/eventfd.go b/pkg/sentry/kernel/eventfd/eventfd.go index 87951adeb..bbf568dfc 100644 --- a/pkg/sentry/kernel/eventfd/eventfd.go +++ b/pkg/sentry/kernel/eventfd/eventfd.go @@ -70,7 +70,7 @@ func New(ctx context.Context, initVal uint64, semMode bool) *fs.File { // name matches fs/eventfd.c:eventfd_file_create. dirent := fs.NewDirent(ctx, anon.NewInode(ctx), "anon_inode:[eventfd]") // Release the initial dirent reference after NewFile takes a reference. - defer dirent.DecRef() + defer dirent.DecRef(ctx) return fs.NewFile(ctx, dirent, fs.FileFlags{Read: true, Write: true}, &EventOperations{ val: initVal, semMode: semMode, @@ -106,7 +106,7 @@ func (e *EventOperations) HostFD() (int, error) { } // Release implements fs.FileOperations.Release. -func (e *EventOperations) Release() { +func (e *EventOperations) Release(context.Context) { e.mu.Lock() defer e.mu.Unlock() if e.hostfd >= 0 { diff --git a/pkg/sentry/kernel/fasync/BUILD b/pkg/sentry/kernel/fasync/BUILD index b9126e946..2b3955598 100644 --- a/pkg/sentry/kernel/fasync/BUILD +++ b/pkg/sentry/kernel/fasync/BUILD @@ -11,6 +11,7 @@ go_library( "//pkg/sentry/fs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", + "//pkg/sentry/vfs", "//pkg/sync", "//pkg/waiter", ], diff --git a/pkg/sentry/kernel/fasync/fasync.go b/pkg/sentry/kernel/fasync/fasync.go index d32c3e90a..153d2cd9b 100644 --- a/pkg/sentry/kernel/fasync/fasync.go +++ b/pkg/sentry/kernel/fasync/fasync.go @@ -20,15 +20,21 @@ import ( "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/waiter" ) -// New creates a new FileAsync. +// New creates a new fs.FileAsync. func New() fs.FileAsync { return &FileAsync{} } +// NewVFS2 creates a new vfs.FileAsync. +func NewVFS2() vfs.FileAsync { + return &FileAsync{} +} + // FileAsync sends signals when the registered file is ready for IO. // // +stateify savable @@ -170,3 +176,13 @@ func (a *FileAsync) SetOwnerProcessGroup(requester *kernel.Task, recipient *kern a.recipientTG = nil a.recipientPG = recipient } + +// ClearOwner unsets the current signal recipient. +func (a *FileAsync) ClearOwner() { + a.mu.Lock() + defer a.mu.Unlock() + a.requester = nil + a.recipientT = nil + a.recipientTG = nil + a.recipientPG = nil +} diff --git a/pkg/sentry/kernel/fd_table.go b/pkg/sentry/kernel/fd_table.go index ed40b5303..ce53af69b 100644 --- a/pkg/sentry/kernel/fd_table.go +++ b/pkg/sentry/kernel/fd_table.go @@ -29,6 +29,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/limits" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/syserror" ) // FDFlags define flags for an individual descriptor. @@ -80,9 +81,6 @@ type FDTable struct { refs.AtomicRefCount k *Kernel - // uid is a unique identifier. - uid uint64 - // mu protects below. mu sync.Mutex `state:"nosave"` @@ -100,7 +98,7 @@ type FDTable struct { func (f *FDTable) saveDescriptorTable() map[int32]descriptor { m := make(map[int32]descriptor) - f.forEach(func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { + f.forEach(context.Background(), func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { m[fd] = descriptor{ file: file, fileVFS2: fileVFS2, @@ -111,6 +109,7 @@ func (f *FDTable) saveDescriptorTable() map[int32]descriptor { } func (f *FDTable) loadDescriptorTable(m map[int32]descriptor) { + ctx := context.Background() f.init() // Initialize table. for fd, d := range m { f.setAll(fd, d.file, d.fileVFS2, d.flags) @@ -120,9 +119,9 @@ func (f *FDTable) loadDescriptorTable(m map[int32]descriptor) { // reference taken by set above. switch { case d.file != nil: - d.file.DecRef() + d.file.DecRef(ctx) case d.fileVFS2 != nil: - d.fileVFS2.DecRef() + d.fileVFS2.DecRef(ctx) } } } @@ -130,7 +129,7 @@ func (f *FDTable) loadDescriptorTable(m map[int32]descriptor) { // drop drops the table reference. func (f *FDTable) drop(file *fs.File) { // Release locks. - file.Dirent.Inode.LockCtx.Posix.UnlockRegion(lock.UniqueID(f.uid), lock.LockRange{0, lock.LockEOF}) + file.Dirent.Inode.LockCtx.Posix.UnlockRegion(f, lock.LockRange{0, lock.LockEOF}) // Send inotify events. d := file.Dirent @@ -146,43 +145,47 @@ func (f *FDTable) drop(file *fs.File) { d.InotifyEvent(ev, 0) // Drop the table reference. - file.DecRef() + file.DecRef(context.Background()) } // dropVFS2 drops the table reference. func (f *FDTable) dropVFS2(file *vfs.FileDescription) { - // TODO(gvisor.dev/issue/1480): Release locks. - // TODO(gvisor.dev/issue/1479): Send inotify events. + // Release any POSIX lock possibly held by the FDTable. Range {0, 0} means the + // entire file. + ctx := context.Background() + err := file.UnlockPOSIX(ctx, f, 0, 0, linux.SEEK_SET) + if err != nil && err != syserror.ENOLCK { + panic(fmt.Sprintf("UnlockPOSIX failed: %v", err)) + } - // Drop the table reference. - file.DecRef() -} + // Generate inotify events. + ev := uint32(linux.IN_CLOSE_NOWRITE) + if file.IsWritable() { + ev = linux.IN_CLOSE_WRITE + } + file.Dentry().InotifyWithParent(ctx, ev, 0, vfs.PathEvent) -// ID returns a unique identifier for this FDTable. -func (f *FDTable) ID() uint64 { - return f.uid + // Drop the table's reference. + file.DecRef(ctx) } // NewFDTable allocates a new FDTable that may be used by tasks in k. func (k *Kernel) NewFDTable() *FDTable { - f := &FDTable{ - k: k, - uid: atomic.AddUint64(&k.fdMapUids, 1), - } + f := &FDTable{k: k} f.init() return f } // destroy removes all of the file descriptors from the map. -func (f *FDTable) destroy() { - f.RemoveIf(func(*fs.File, *vfs.FileDescription, FDFlags) bool { +func (f *FDTable) destroy(ctx context.Context) { + f.RemoveIf(ctx, func(*fs.File, *vfs.FileDescription, FDFlags) bool { return true }) } // DecRef implements RefCounter.DecRef with destructor f.destroy. -func (f *FDTable) DecRef() { - f.DecRefWithDestructor(f.destroy) +func (f *FDTable) DecRef(ctx context.Context) { + f.DecRefWithDestructor(ctx, f.destroy) } // Size returns the number of file descriptor slots currently allocated. @@ -194,7 +197,7 @@ func (f *FDTable) Size() int { // forEach iterates over all non-nil files in sorted order. // // It is the caller's responsibility to acquire an appropriate lock. -func (f *FDTable) forEach(fn func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags)) { +func (f *FDTable) forEach(ctx context.Context, fn func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags)) { // retries tracks the number of failed TryIncRef attempts for the same FD. retries := 0 fd := int32(0) @@ -213,7 +216,7 @@ func (f *FDTable) forEach(fn func(fd int32, file *fs.File, fileVFS2 *vfs.FileDes continue // Race caught. } fn(fd, file, nil, flags) - file.DecRef() + file.DecRef(ctx) case fileVFS2 != nil: if !fileVFS2.TryIncRef() { retries++ @@ -223,7 +226,7 @@ func (f *FDTable) forEach(fn func(fd int32, file *fs.File, fileVFS2 *vfs.FileDes continue // Race caught. } fn(fd, nil, fileVFS2, flags) - fileVFS2.DecRef() + fileVFS2.DecRef(ctx) } retries = 0 fd++ @@ -233,7 +236,8 @@ func (f *FDTable) forEach(fn func(fd int32, file *fs.File, fileVFS2 *vfs.FileDes // String is a stringer for FDTable. func (f *FDTable) String() string { var buf strings.Builder - f.forEach(func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { + ctx := context.Background() + f.forEach(ctx, func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { switch { case file != nil: n, _ := file.Dirent.FullName(nil /* root */) @@ -241,7 +245,7 @@ func (f *FDTable) String() string { case fileVFS2 != nil: vfsObj := fileVFS2.Mount().Filesystem().VirtualFilesystem() - name, err := vfsObj.PathnameWithDeleted(context.Background(), vfs.VirtualDentry{}, fileVFS2.VirtualDentry()) + name, err := vfsObj.PathnameWithDeleted(ctx, vfs.VirtualDentry{}, fileVFS2.VirtualDentry()) if err != nil { fmt.Fprintf(&buf, "<err: %v>\n", err) return @@ -463,6 +467,29 @@ func (f *FDTable) SetFlags(fd int32, flags FDFlags) error { return nil } +// SetFlagsVFS2 sets the flags for the given file descriptor. +// +// True is returned iff flags were changed. +func (f *FDTable) SetFlagsVFS2(fd int32, flags FDFlags) error { + if fd < 0 { + // Don't accept negative FDs. + return syscall.EBADF + } + + f.mu.Lock() + defer f.mu.Unlock() + + file, _, _ := f.getVFS2(fd) + if file == nil { + // No file found. + return syscall.EBADF + } + + // Update the flags. + f.setVFS2(fd, file, flags) + return nil +} + // Get returns a reference to the file and the flags for the FD or nil if no // file is defined for the given fd. // @@ -517,9 +544,9 @@ func (f *FDTable) GetVFS2(fd int32) (*vfs.FileDescription, FDFlags) { // // Precondition: The caller must be running on the task goroutine, or Task.mu // must be locked. -func (f *FDTable) GetFDs() []int32 { +func (f *FDTable) GetFDs(ctx context.Context) []int32 { fds := make([]int32, 0, int(atomic.LoadInt32(&f.used))) - f.forEach(func(fd int32, _ *fs.File, _ *vfs.FileDescription, _ FDFlags) { + f.forEach(ctx, func(fd int32, _ *fs.File, _ *vfs.FileDescription, _ FDFlags) { fds = append(fds, fd) }) return fds @@ -528,9 +555,9 @@ func (f *FDTable) GetFDs() []int32 { // GetRefs returns a stable slice of references to all files and bumps the // reference count on each. The caller must use DecRef on each reference when // they're done using the slice. -func (f *FDTable) GetRefs() []*fs.File { +func (f *FDTable) GetRefs(ctx context.Context) []*fs.File { files := make([]*fs.File, 0, f.Size()) - f.forEach(func(_ int32, file *fs.File, _ *vfs.FileDescription, _ FDFlags) { + f.forEach(ctx, func(_ int32, file *fs.File, _ *vfs.FileDescription, _ FDFlags) { file.IncRef() // Acquire a reference for caller. files = append(files, file) }) @@ -540,9 +567,9 @@ func (f *FDTable) GetRefs() []*fs.File { // GetRefsVFS2 returns a stable slice of references to all files and bumps the // reference count on each. The caller must use DecRef on each reference when // they're done using the slice. -func (f *FDTable) GetRefsVFS2() []*vfs.FileDescription { +func (f *FDTable) GetRefsVFS2(ctx context.Context) []*vfs.FileDescription { files := make([]*vfs.FileDescription, 0, f.Size()) - f.forEach(func(_ int32, _ *fs.File, file *vfs.FileDescription, _ FDFlags) { + f.forEach(ctx, func(_ int32, _ *fs.File, file *vfs.FileDescription, _ FDFlags) { file.IncRef() // Acquire a reference for caller. files = append(files, file) }) @@ -550,10 +577,10 @@ func (f *FDTable) GetRefsVFS2() []*vfs.FileDescription { } // Fork returns an independent FDTable. -func (f *FDTable) Fork() *FDTable { +func (f *FDTable) Fork(ctx context.Context) *FDTable { clone := f.k.NewFDTable() - f.forEach(func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { + f.forEach(ctx, func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { // The set function here will acquire an appropriate table // reference for the clone. We don't need anything else. switch { @@ -598,11 +625,11 @@ func (f *FDTable) Remove(fd int32) (*fs.File, *vfs.FileDescription) { } // RemoveIf removes all FDs where cond is true. -func (f *FDTable) RemoveIf(cond func(*fs.File, *vfs.FileDescription, FDFlags) bool) { +func (f *FDTable) RemoveIf(ctx context.Context, cond func(*fs.File, *vfs.FileDescription, FDFlags) bool) { f.mu.Lock() defer f.mu.Unlock() - f.forEach(func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { + f.forEach(ctx, func(fd int32, file *fs.File, fileVFS2 *vfs.FileDescription, flags FDFlags) { if cond(file, fileVFS2, flags) { f.set(fd, nil, FDFlags{}) // Clear from table. // Update current available position. diff --git a/pkg/sentry/kernel/fd_table_test.go b/pkg/sentry/kernel/fd_table_test.go index 29f95a2c4..e3f30ba2a 100644 --- a/pkg/sentry/kernel/fd_table_test.go +++ b/pkg/sentry/kernel/fd_table_test.go @@ -154,7 +154,7 @@ func TestFDTable(t *testing.T) { if ref == nil { t.Fatalf("fdTable.Remove(1) for an existing FD: failed, want success") } - ref.DecRef() + ref.DecRef(ctx) if ref, _ := fdTable.Remove(1); ref != nil { t.Fatalf("r.Remove(1) for a removed FD: got success, want failure") @@ -191,7 +191,7 @@ func BenchmarkFDLookupAndDecRef(b *testing.B) { b.StartTimer() // Benchmark. for i := 0; i < b.N; i++ { tf, _ := fdTable.Get(fds[i%len(fds)]) - tf.DecRef() + tf.DecRef(ctx) } }) } @@ -219,7 +219,7 @@ func BenchmarkFDLookupAndDecRefConcurrent(b *testing.B) { defer wg.Done() for i := 0; i < each; i++ { tf, _ := fdTable.Get(fds[i%len(fds)]) - tf.DecRef() + tf.DecRef(ctx) } }() } diff --git a/pkg/sentry/kernel/fs_context.go b/pkg/sentry/kernel/fs_context.go index 47f78df9a..8f2d36d5a 100644 --- a/pkg/sentry/kernel/fs_context.go +++ b/pkg/sentry/kernel/fs_context.go @@ -17,6 +17,7 @@ package kernel import ( "fmt" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/vfs" @@ -89,28 +90,28 @@ func NewFSContextVFS2(root, cwd vfs.VirtualDentry, umask uint) *FSContext { // Note that there may still be calls to WorkingDirectory() or RootDirectory() // (that return nil). This is because valid references may still be held via // proc files or other mechanisms. -func (f *FSContext) destroy() { +func (f *FSContext) destroy(ctx context.Context) { // Hold f.mu so that we don't race with RootDirectory() and // WorkingDirectory(). f.mu.Lock() defer f.mu.Unlock() if VFS2Enabled { - f.rootVFS2.DecRef() + f.rootVFS2.DecRef(ctx) f.rootVFS2 = vfs.VirtualDentry{} - f.cwdVFS2.DecRef() + f.cwdVFS2.DecRef(ctx) f.cwdVFS2 = vfs.VirtualDentry{} } else { - f.root.DecRef() + f.root.DecRef(ctx) f.root = nil - f.cwd.DecRef() + f.cwd.DecRef(ctx) f.cwd = nil } } // DecRef implements RefCounter.DecRef with destructor f.destroy. -func (f *FSContext) DecRef() { - f.DecRefWithDestructor(f.destroy) +func (f *FSContext) DecRef(ctx context.Context) { + f.DecRefWithDestructor(ctx, f.destroy) } // Fork forks this FSContext. @@ -165,7 +166,7 @@ func (f *FSContext) WorkingDirectoryVFS2() vfs.VirtualDentry { // This will take an extra reference on the Dirent. // // This is not a valid call after destroy. -func (f *FSContext) SetWorkingDirectory(d *fs.Dirent) { +func (f *FSContext) SetWorkingDirectory(ctx context.Context, d *fs.Dirent) { if d == nil { panic("FSContext.SetWorkingDirectory called with nil dirent") } @@ -180,21 +181,21 @@ func (f *FSContext) SetWorkingDirectory(d *fs.Dirent) { old := f.cwd f.cwd = d d.IncRef() - old.DecRef() + old.DecRef(ctx) } // SetWorkingDirectoryVFS2 sets the current working directory. // This will take an extra reference on the VirtualDentry. // // This is not a valid call after destroy. -func (f *FSContext) SetWorkingDirectoryVFS2(d vfs.VirtualDentry) { +func (f *FSContext) SetWorkingDirectoryVFS2(ctx context.Context, d vfs.VirtualDentry) { f.mu.Lock() defer f.mu.Unlock() old := f.cwdVFS2 f.cwdVFS2 = d d.IncRef() - old.DecRef() + old.DecRef(ctx) } // RootDirectory returns the current filesystem root. @@ -226,7 +227,7 @@ func (f *FSContext) RootDirectoryVFS2() vfs.VirtualDentry { // This will take an extra reference on the Dirent. // // This is not a valid call after free. -func (f *FSContext) SetRootDirectory(d *fs.Dirent) { +func (f *FSContext) SetRootDirectory(ctx context.Context, d *fs.Dirent) { if d == nil { panic("FSContext.SetRootDirectory called with nil dirent") } @@ -241,13 +242,13 @@ func (f *FSContext) SetRootDirectory(d *fs.Dirent) { old := f.root f.root = d d.IncRef() - old.DecRef() + old.DecRef(ctx) } // SetRootDirectoryVFS2 sets the root directory. It takes a reference on vd. // // This is not a valid call after free. -func (f *FSContext) SetRootDirectoryVFS2(vd vfs.VirtualDentry) { +func (f *FSContext) SetRootDirectoryVFS2(ctx context.Context, vd vfs.VirtualDentry) { if !vd.Ok() { panic("FSContext.SetRootDirectoryVFS2 called with zero-value VirtualDentry") } @@ -263,7 +264,7 @@ func (f *FSContext) SetRootDirectoryVFS2(vd vfs.VirtualDentry) { vd.IncRef() f.rootVFS2 = vd f.mu.Unlock() - old.DecRef() + old.DecRef(ctx) } // Umask returns the current umask. diff --git a/pkg/sentry/kernel/futex/BUILD b/pkg/sentry/kernel/futex/BUILD index c5021f2db..daa2dae76 100644 --- a/pkg/sentry/kernel/futex/BUILD +++ b/pkg/sentry/kernel/futex/BUILD @@ -51,6 +51,7 @@ go_test( srcs = ["futex_test.go"], library = ":futex", deps = [ + "//pkg/context", "//pkg/sync", "//pkg/usermem", ], diff --git a/pkg/sentry/kernel/futex/futex.go b/pkg/sentry/kernel/futex/futex.go index 732e66da4..e4dcc4d40 100644 --- a/pkg/sentry/kernel/futex/futex.go +++ b/pkg/sentry/kernel/futex/futex.go @@ -19,6 +19,7 @@ package futex import ( "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" @@ -66,9 +67,9 @@ type Key struct { Offset uint64 } -func (k *Key) release() { +func (k *Key) release(t Target) { if k.MappingIdentity != nil { - k.MappingIdentity.DecRef() + k.MappingIdentity.DecRef(t) } k.Mappable = nil k.MappingIdentity = nil @@ -94,6 +95,8 @@ func (k *Key) matches(k2 *Key) bool { // Target abstracts memory accesses and keys. type Target interface { + context.Context + // SwapUint32 gives access to usermem.IO.SwapUint32. SwapUint32(addr usermem.Addr, new uint32) (uint32, error) @@ -296,7 +299,7 @@ func (b *bucket) wakeWaiterLocked(w *Waiter) { // bucket "to". // // Preconditions: b and to must be locked. -func (b *bucket) requeueLocked(to *bucket, key, nkey *Key, n int) int { +func (b *bucket) requeueLocked(t Target, to *bucket, key, nkey *Key, n int) int { done := 0 for w := b.waiters.Front(); done < n && w != nil; { if !w.key.matches(key) { @@ -308,7 +311,7 @@ func (b *bucket) requeueLocked(to *bucket, key, nkey *Key, n int) int { requeued := w w = w.Next() // Next iteration. b.waiters.Remove(requeued) - requeued.key.release() + requeued.key.release(t) requeued.key = nkey.clone() to.waiters.PushBack(requeued) requeued.bucket.Store(to) @@ -456,7 +459,7 @@ func (m *Manager) Wake(t Target, addr usermem.Addr, private bool, bitmask uint32 r := b.wakeLocked(&k, bitmask, n) b.mu.Unlock() - k.release() + k.release(t) return r, nil } @@ -465,12 +468,12 @@ func (m *Manager) doRequeue(t Target, addr, naddr usermem.Addr, private bool, ch if err != nil { return 0, err } - defer k1.release() + defer k1.release(t) k2, err := getKey(t, naddr, private) if err != nil { return 0, err } - defer k2.release() + defer k2.release(t) b1, b2 := m.lockBuckets(&k1, &k2) defer b1.mu.Unlock() @@ -488,7 +491,7 @@ func (m *Manager) doRequeue(t Target, addr, naddr usermem.Addr, private bool, ch done := b1.wakeLocked(&k1, ^uint32(0), nwake) // Requeue the number required. - b1.requeueLocked(b2, &k1, &k2, nreq) + b1.requeueLocked(t, b2, &k1, &k2, nreq) return done, nil } @@ -515,12 +518,12 @@ func (m *Manager) WakeOp(t Target, addr1, addr2 usermem.Addr, private bool, nwak if err != nil { return 0, err } - defer k1.release() + defer k1.release(t) k2, err := getKey(t, addr2, private) if err != nil { return 0, err } - defer k2.release() + defer k2.release(t) b1, b2 := m.lockBuckets(&k1, &k2) defer b1.mu.Unlock() @@ -571,7 +574,7 @@ func (m *Manager) WaitPrepare(w *Waiter, t Target, addr usermem.Addr, private bo // Perform our atomic check. if err := check(t, addr, val); err != nil { b.mu.Unlock() - w.key.release() + w.key.release(t) return err } @@ -585,7 +588,7 @@ func (m *Manager) WaitPrepare(w *Waiter, t Target, addr usermem.Addr, private bo // WaitComplete must be called when a Waiter previously added by WaitPrepare is // no longer eligible to be woken. -func (m *Manager) WaitComplete(w *Waiter) { +func (m *Manager) WaitComplete(w *Waiter, t Target) { // Remove w from the bucket it's in. for { b := w.bucket.Load() @@ -617,7 +620,7 @@ func (m *Manager) WaitComplete(w *Waiter) { } // Release references held by the waiter. - w.key.release() + w.key.release(t) } // LockPI attempts to lock the futex following the Priority-inheritance futex @@ -648,13 +651,13 @@ func (m *Manager) LockPI(w *Waiter, t Target, addr usermem.Addr, tid uint32, pri success, err := m.lockPILocked(w, t, addr, tid, b, try) if err != nil { - w.key.release() + w.key.release(t) b.mu.Unlock() return false, err } if success || try { // Release waiter if it's not going to be a wait. - w.key.release() + w.key.release(t) } b.mu.Unlock() return success, nil @@ -717,10 +720,10 @@ func (m *Manager) lockPILocked(w *Waiter, t Target, addr usermem.Addr, tid uint3 } } -// UnlockPI unlock the futex following the Priority-inheritance futex -// rules. The address provided must contain the caller's TID. If there are -// waiters, TID of the next waiter (FIFO) is set to the given address, and the -// waiter woken up. If there are no waiters, 0 is set to the address. +// UnlockPI unlocks the futex following the Priority-inheritance futex rules. +// The address provided must contain the caller's TID. If there are waiters, +// TID of the next waiter (FIFO) is set to the given address, and the waiter +// woken up. If there are no waiters, 0 is set to the address. func (m *Manager) UnlockPI(t Target, addr usermem.Addr, tid uint32, private bool) error { k, err := getKey(t, addr, private) if err != nil { @@ -730,7 +733,7 @@ func (m *Manager) UnlockPI(t Target, addr usermem.Addr, tid uint32, private bool err = m.unlockPILocked(t, addr, tid, b, &k) - k.release() + k.release(t) b.mu.Unlock() return err } diff --git a/pkg/sentry/kernel/futex/futex_test.go b/pkg/sentry/kernel/futex/futex_test.go index 7c5c7665b..d0128c548 100644 --- a/pkg/sentry/kernel/futex/futex_test.go +++ b/pkg/sentry/kernel/futex/futex_test.go @@ -22,6 +22,7 @@ import ( "testing" "unsafe" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/usermem" ) @@ -29,28 +30,33 @@ import ( // testData implements the Target interface, and allows us to // treat the address passed for futex operations as an index in // a byte slice for testing simplicity. -type testData []byte +type testData struct { + context.Context + data []byte +} const sizeofInt32 = 4 func newTestData(size uint) testData { - return make([]byte, size) + return testData{ + data: make([]byte, size), + } } func (t testData) SwapUint32(addr usermem.Addr, new uint32) (uint32, error) { - val := atomic.SwapUint32((*uint32)(unsafe.Pointer(&t[addr])), new) + val := atomic.SwapUint32((*uint32)(unsafe.Pointer(&t.data[addr])), new) return val, nil } func (t testData) CompareAndSwapUint32(addr usermem.Addr, old, new uint32) (uint32, error) { - if atomic.CompareAndSwapUint32((*uint32)(unsafe.Pointer(&t[addr])), old, new) { + if atomic.CompareAndSwapUint32((*uint32)(unsafe.Pointer(&t.data[addr])), old, new) { return old, nil } - return atomic.LoadUint32((*uint32)(unsafe.Pointer(&t[addr]))), nil + return atomic.LoadUint32((*uint32)(unsafe.Pointer(&t.data[addr]))), nil } func (t testData) LoadUint32(addr usermem.Addr) (uint32, error) { - return atomic.LoadUint32((*uint32)(unsafe.Pointer(&t[addr]))), nil + return atomic.LoadUint32((*uint32)(unsafe.Pointer(&t.data[addr]))), nil } func (t testData) GetSharedKey(addr usermem.Addr) (Key, error) { @@ -83,7 +89,7 @@ func TestFutexWake(t *testing.T) { // Start waiting for wakeup. w := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w) + defer m.WaitComplete(w, d) // Perform a wakeup. if n, err := m.Wake(d, 0, private, ^uint32(0), 1); err != nil || n != 1 { @@ -106,7 +112,7 @@ func TestFutexWakeBitmask(t *testing.T) { // Start waiting for wakeup. w := newPreparedTestWaiter(t, m, d, 0, private, 0, 0x0000ffff) - defer m.WaitComplete(w) + defer m.WaitComplete(w, d) // Perform a wakeup using the wrong bitmask. if n, err := m.Wake(d, 0, private, 0xffff0000, 1); err != nil || n != 0 { @@ -141,7 +147,7 @@ func TestFutexWakeTwo(t *testing.T) { var ws [3]*Waiter for i := range ws { ws[i] = newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(ws[i]) + defer m.WaitComplete(ws[i], d) } // Perform two wakeups. @@ -174,9 +180,9 @@ func TestFutexWakeUnrelated(t *testing.T) { // Start two waiters waiting for wakeup on different addresses. w1 := newPreparedTestWaiter(t, m, d, 0*sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w1) + defer m.WaitComplete(w1, d) w2 := newPreparedTestWaiter(t, m, d, 1*sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w2) + defer m.WaitComplete(w2, d) // Perform two wakeups on the second address. if n, err := m.Wake(d, 1*sizeofInt32, private, ^uint32(0), 2); err != nil || n != 1 { @@ -216,9 +222,9 @@ func TestWakeOpFirstNonEmpty(t *testing.T) { // Add two waiters on address 0. w1 := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w1) + defer m.WaitComplete(w1, d) w2 := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w2) + defer m.WaitComplete(w2, d) // Perform 10 wakeups on address 0. if n, err := m.WakeOp(d, 0, sizeofInt32, private, 10, 0, 0); err != nil || n != 2 { @@ -244,9 +250,9 @@ func TestWakeOpSecondNonEmpty(t *testing.T) { // Add two waiters on address sizeofInt32. w1 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w1) + defer m.WaitComplete(w1, d) w2 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w2) + defer m.WaitComplete(w2, d) // Perform 10 wakeups on address sizeofInt32 (contingent on // d.Op(0), which should succeed). @@ -273,9 +279,9 @@ func TestWakeOpSecondNonEmptyFailingOp(t *testing.T) { // Add two waiters on address sizeofInt32. w1 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w1) + defer m.WaitComplete(w1, d) w2 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w2) + defer m.WaitComplete(w2, d) // Perform 10 wakeups on address sizeofInt32 (contingent on // d.Op(1), which should fail). @@ -302,15 +308,15 @@ func TestWakeOpAllNonEmpty(t *testing.T) { // Add two waiters on address 0. w1 := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w1) + defer m.WaitComplete(w1, d) w2 := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w2) + defer m.WaitComplete(w2, d) // Add two waiters on address sizeofInt32. w3 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w3) + defer m.WaitComplete(w3, d) w4 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w4) + defer m.WaitComplete(w4, d) // Perform 10 wakeups on address 0 (unconditionally), and 10 // wakeups on address sizeofInt32 (contingent on d.Op(0), which @@ -344,15 +350,15 @@ func TestWakeOpAllNonEmptyFailingOp(t *testing.T) { // Add two waiters on address 0. w1 := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w1) + defer m.WaitComplete(w1, d) w2 := newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(w2) + defer m.WaitComplete(w2, d) // Add two waiters on address sizeofInt32. w3 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w3) + defer m.WaitComplete(w3, d) w4 := newPreparedTestWaiter(t, m, d, sizeofInt32, private, 0, ^uint32(0)) - defer m.WaitComplete(w4) + defer m.WaitComplete(w4, d) // Perform 10 wakeups on address 0 (unconditionally), and 10 // wakeups on address sizeofInt32 (contingent on d.Op(1), which @@ -388,7 +394,7 @@ func TestWakeOpSameAddress(t *testing.T) { var ws [4]*Waiter for i := range ws { ws[i] = newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(ws[i]) + defer m.WaitComplete(ws[i], d) } // Perform 1 wakeup on address 0 (unconditionally), and 1 wakeup @@ -422,7 +428,7 @@ func TestWakeOpSameAddressFailingOp(t *testing.T) { var ws [4]*Waiter for i := range ws { ws[i] = newPreparedTestWaiter(t, m, d, 0, private, 0, ^uint32(0)) - defer m.WaitComplete(ws[i]) + defer m.WaitComplete(ws[i], d) } // Perform 1 wakeup on address 0 (unconditionally), and 1 wakeup @@ -472,7 +478,7 @@ func (t *testMutex) Lock() { for { // Attempt to grab the lock. if atomic.CompareAndSwapUint32( - (*uint32)(unsafe.Pointer(&t.d[t.a])), + (*uint32)(unsafe.Pointer(&t.d.data[t.a])), testMutexUnlocked, testMutexLocked) { // Lock held. @@ -490,7 +496,7 @@ func (t *testMutex) Lock() { panic("WaitPrepare returned unexpected error: " + err.Error()) } <-w.C - t.m.WaitComplete(w) + t.m.WaitComplete(w, t.d) } } @@ -498,7 +504,7 @@ func (t *testMutex) Lock() { // This will notify any waiters via the futex manager. func (t *testMutex) Unlock() { // Unlock. - atomic.StoreUint32((*uint32)(unsafe.Pointer(&t.d[t.a])), testMutexUnlocked) + atomic.StoreUint32((*uint32)(unsafe.Pointer(&t.d.data[t.a])), testMutexUnlocked) // Notify all waiters. t.m.Wake(t.d, t.a, true, ^uint32(0), math.MaxInt32) diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go index 5efeb3767..1028d13c6 100644 --- a/pkg/sentry/kernel/kernel.go +++ b/pkg/sentry/kernel/kernel.go @@ -34,7 +34,6 @@ package kernel import ( "errors" "fmt" - "io" "path/filepath" "sync/atomic" "time" @@ -73,6 +72,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/uniqueid" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/state" + "gvisor.dev/gvisor/pkg/state/wire" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/tcpip" ) @@ -81,6 +81,10 @@ import ( // easy access everywhere. To be removed once VFS2 becomes the default. var VFS2Enabled = false +// FUSEEnabled is set to true when FUSE is enabled. Added as a global for allow +// easy access everywhere. To be removed once FUSE is completed. +var FUSEEnabled = false + // Kernel represents an emulated Linux kernel. It must be initialized by calling // Init() or LoadFrom(). // @@ -194,11 +198,6 @@ type Kernel struct { // cpuClockTickerSetting is protected by runningTasksMu. cpuClockTickerSetting ktime.Setting - // fdMapUids is an ever-increasing counter for generating FDTable uids. - // - // fdMapUids is mutable, and is accessed using atomic memory operations. - fdMapUids uint64 - // uniqueID is used to generate unique identifiers. // // uniqueID is mutable, and is accessed using atomic memory operations. @@ -377,7 +376,8 @@ func (k *Kernel) Init(args InitKernelArgs) error { k.netlinkPorts = port.New() if VFS2Enabled { - if err := k.vfs.Init(); err != nil { + ctx := k.SupervisorContext() + if err := k.vfs.Init(ctx); err != nil { return fmt.Errorf("failed to initialize VFS: %v", err) } @@ -385,19 +385,19 @@ func (k *Kernel) Init(args InitKernelArgs) error { if err != nil { return fmt.Errorf("failed to create pipefs filesystem: %v", err) } - defer pipeFilesystem.DecRef() + defer pipeFilesystem.DecRef(ctx) pipeMount, err := k.vfs.NewDisconnectedMount(pipeFilesystem, nil, &vfs.MountOptions{}) if err != nil { return fmt.Errorf("failed to create pipefs mount: %v", err) } k.pipeMount = pipeMount - tmpfsFilesystem, tmpfsRoot, err := tmpfs.NewFilesystem(k.SupervisorContext(), &k.vfs, auth.NewRootCredentials(k.rootUserNamespace)) + tmpfsFilesystem, tmpfsRoot, err := tmpfs.NewFilesystem(ctx, &k.vfs, auth.NewRootCredentials(k.rootUserNamespace)) if err != nil { return fmt.Errorf("failed to create tmpfs filesystem: %v", err) } - defer tmpfsFilesystem.DecRef() - defer tmpfsRoot.DecRef() + defer tmpfsFilesystem.DecRef(ctx) + defer tmpfsRoot.DecRef(ctx) shmMount, err := k.vfs.NewDisconnectedMount(tmpfsFilesystem, tmpfsRoot, &vfs.MountOptions{}) if err != nil { return fmt.Errorf("failed to create tmpfs mount: %v", err) @@ -408,7 +408,7 @@ func (k *Kernel) Init(args InitKernelArgs) error { if err != nil { return fmt.Errorf("failed to create sockfs filesystem: %v", err) } - defer socketFilesystem.DecRef() + defer socketFilesystem.DecRef(ctx) socketMount, err := k.vfs.NewDisconnectedMount(socketFilesystem, nil, &vfs.MountOptions{}) if err != nil { return fmt.Errorf("failed to create sockfs mount: %v", err) @@ -422,7 +422,7 @@ func (k *Kernel) Init(args InitKernelArgs) error { // SaveTo saves the state of k to w. // // Preconditions: The kernel must be paused throughout the call to SaveTo. -func (k *Kernel) SaveTo(w io.Writer) error { +func (k *Kernel) SaveTo(w wire.Writer) error { saveStart := time.Now() ctx := k.SupervisorContext() @@ -431,8 +431,8 @@ func (k *Kernel) SaveTo(w io.Writer) error { defer k.extMu.Unlock() // Stop time. - k.pauseTimeLocked() - defer k.resumeTimeLocked() + k.pauseTimeLocked(ctx) + defer k.resumeTimeLocked(ctx) // Evict all evictable MemoryFile allocations. k.mf.StartEvictions() @@ -448,18 +448,16 @@ func (k *Kernel) SaveTo(w io.Writer) error { // Remove all epoll waiter objects from underlying wait queues. // NOTE: for programs to resume execution in future snapshot scenarios, // we will need to re-establish these waiter objects after saving. - k.tasks.unregisterEpollWaiters() + k.tasks.unregisterEpollWaiters(ctx) // Clear the dirent cache before saving because Dirents must be Loaded in a // particular order (parents before children), and Loading dirents from a cache // breaks that order. - if err := k.flushMountSourceRefs(); err != nil { + if err := k.flushMountSourceRefs(ctx); err != nil { return err } - // Ensure that all pending asynchronous work is complete: - // - inode and mount release - // - asynchronuous IO + // Ensure that all inode and mount release operations have completed. fs.AsyncBarrier() // Once all fs work has completed (flushed references have all been released), @@ -480,18 +478,18 @@ func (k *Kernel) SaveTo(w io.Writer) error { // // N.B. This will also be saved along with the full kernel save below. cpuidStart := time.Now() - if err := state.Save(k.SupervisorContext(), w, k.FeatureSet(), nil); err != nil { + if _, err := state.Save(k.SupervisorContext(), w, k.FeatureSet()); err != nil { return err } log.Infof("CPUID save took [%s].", time.Since(cpuidStart)) // Save the kernel state. kernelStart := time.Now() - var stats state.Stats - if err := state.Save(k.SupervisorContext(), w, k, &stats); err != nil { + stats, err := state.Save(k.SupervisorContext(), w, k) + if err != nil { return err } - log.Infof("Kernel save stats: %s", &stats) + log.Infof("Kernel save stats: %s", stats.String()) log.Infof("Kernel save took [%s].", time.Since(kernelStart)) // Save the memory file's state. @@ -508,7 +506,7 @@ func (k *Kernel) SaveTo(w io.Writer) error { // flushMountSourceRefs flushes the MountSources for all mounted filesystems // and open FDs. -func (k *Kernel) flushMountSourceRefs() error { +func (k *Kernel) flushMountSourceRefs(ctx context.Context) error { // Flush all mount sources for currently mounted filesystems in each task. flushed := make(map[*fs.MountNamespace]struct{}) k.tasks.mu.RLock() @@ -524,7 +522,7 @@ func (k *Kernel) flushMountSourceRefs() error { // There may be some open FDs whose filesystems have been unmounted. We // must flush those as well. - return k.tasks.forEachFDPaused(func(file *fs.File, _ *vfs.FileDescription) error { + return k.tasks.forEachFDPaused(ctx, func(file *fs.File, _ *vfs.FileDescription) error { file.Dirent.Inode.MountSource.FlushDirentRefs() return nil }) @@ -534,7 +532,7 @@ func (k *Kernel) flushMountSourceRefs() error { // each task. // // Precondition: Must be called with the kernel paused. -func (ts *TaskSet) forEachFDPaused(f func(*fs.File, *vfs.FileDescription) error) (err error) { +func (ts *TaskSet) forEachFDPaused(ctx context.Context, f func(*fs.File, *vfs.FileDescription) error) (err error) { // TODO(gvisor.dev/issue/1663): Add save support for VFS2. if VFS2Enabled { return nil @@ -547,7 +545,7 @@ func (ts *TaskSet) forEachFDPaused(f func(*fs.File, *vfs.FileDescription) error) if t.fdTable == nil { continue } - t.fdTable.forEach(func(_ int32, file *fs.File, fileVFS2 *vfs.FileDescription, _ FDFlags) { + t.fdTable.forEach(ctx, func(_ int32, file *fs.File, fileVFS2 *vfs.FileDescription, _ FDFlags) { if lastErr := f(file, fileVFS2); lastErr != nil && err == nil { err = lastErr } @@ -558,7 +556,7 @@ func (ts *TaskSet) forEachFDPaused(f func(*fs.File, *vfs.FileDescription) error) func (ts *TaskSet) flushWritesToFiles(ctx context.Context) error { // TODO(gvisor.dev/issue/1663): Add save support for VFS2. - return ts.forEachFDPaused(func(file *fs.File, _ *vfs.FileDescription) error { + return ts.forEachFDPaused(ctx, func(file *fs.File, _ *vfs.FileDescription) error { if flags := file.Flags(); !flags.Write { return nil } @@ -605,7 +603,7 @@ func (k *Kernel) invalidateUnsavableMappings(ctx context.Context) error { return nil } -func (ts *TaskSet) unregisterEpollWaiters() { +func (ts *TaskSet) unregisterEpollWaiters(ctx context.Context) { // TODO(gvisor.dev/issue/1663): Add save support for VFS2. if VFS2Enabled { return @@ -626,7 +624,7 @@ func (ts *TaskSet) unregisterEpollWaiters() { if _, ok := processed[t.fdTable]; ok { continue } - t.fdTable.forEach(func(_ int32, file *fs.File, _ *vfs.FileDescription, _ FDFlags) { + t.fdTable.forEach(ctx, func(_ int32, file *fs.File, _ *vfs.FileDescription, _ FDFlags) { if e, ok := file.FileOperations.(*epoll.EventPoll); ok { e.UnregisterEpollWaiters() } @@ -636,7 +634,7 @@ func (ts *TaskSet) unregisterEpollWaiters() { } // LoadFrom returns a new Kernel loaded from args. -func (k *Kernel) LoadFrom(r io.Reader, net inet.Stack, clocks sentrytime.Clocks) error { +func (k *Kernel) LoadFrom(r wire.Reader, net inet.Stack, clocks sentrytime.Clocks) error { loadStart := time.Now() initAppCores := k.applicationCores @@ -647,7 +645,7 @@ func (k *Kernel) LoadFrom(r io.Reader, net inet.Stack, clocks sentrytime.Clocks) // don't need to explicitly install it in the Kernel. cpuidStart := time.Now() var features cpuid.FeatureSet - if err := state.Load(k.SupervisorContext(), r, &features, nil); err != nil { + if _, err := state.Load(k.SupervisorContext(), r, &features); err != nil { return err } log.Infof("CPUID load took [%s].", time.Since(cpuidStart)) @@ -662,11 +660,11 @@ func (k *Kernel) LoadFrom(r io.Reader, net inet.Stack, clocks sentrytime.Clocks) // Load the kernel state. kernelStart := time.Now() - var stats state.Stats - if err := state.Load(k.SupervisorContext(), r, k, &stats); err != nil { + stats, err := state.Load(k.SupervisorContext(), r, k) + if err != nil { return err } - log.Infof("Kernel load stats: %s", &stats) + log.Infof("Kernel load stats: %s", stats.String()) log.Infof("Kernel load took [%s].", time.Since(kernelStart)) // rootNetworkNamespace should be populated after loading the state file. @@ -897,13 +895,13 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID, if mntnsVFS2 == nil { // MountNamespaceVFS2 adds a reference to the namespace, which is // transferred to the new process. - mntnsVFS2 = k.GlobalInit().Leader().MountNamespaceVFS2() + mntnsVFS2 = k.globalInit.Leader().MountNamespaceVFS2() } // Get the root directory from the MountNamespace. root := args.MountNamespaceVFS2.Root() // The call to newFSContext below will take a reference on root, so we // don't need to hold this one. - defer root.DecRef() + defer root.DecRef(ctx) // Grab the working directory. wd := root // Default. @@ -921,7 +919,7 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID, if err != nil { return nil, 0, fmt.Errorf("failed to find initial working directory %q: %v", args.WorkingDirectory, err) } - defer wd.DecRef() + defer wd.DecRef(ctx) } opener = fsbridge.NewVFSLookup(mntnsVFS2, root, wd) fsContext = NewFSContextVFS2(root, wd, args.Umask) @@ -936,7 +934,7 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID, root := mntns.Root() // The call to newFSContext below will take a reference on root, so we // don't need to hold this one. - defer root.DecRef() + defer root.DecRef(ctx) // Grab the working directory. remainingTraversals := args.MaxSymlinkTraversals @@ -947,7 +945,7 @@ func (k *Kernel) CreateProcess(args CreateProcessArgs) (*ThreadGroup, ThreadID, if err != nil { return nil, 0, fmt.Errorf("failed to find initial working directory %q: %v", args.WorkingDirectory, err) } - defer wd.DecRef() + defer wd.DecRef(ctx) } opener = fsbridge.NewFSLookup(mntns, root, wd) fsContext = newFSContext(root, wd, args.Umask) @@ -1057,7 +1055,7 @@ func (k *Kernel) Start() error { // If k was created by LoadKernelFrom, timers were stopped during // Kernel.SaveTo and need to be resumed. If k was created by NewKernel, // this is a no-op. - k.resumeTimeLocked() + k.resumeTimeLocked(k.SupervisorContext()) // Start task goroutines. k.tasks.mu.RLock() defer k.tasks.mu.RUnlock() @@ -1071,7 +1069,7 @@ func (k *Kernel) Start() error { // // Preconditions: Any task goroutines running in k must be stopped. k.extMu // must be locked. -func (k *Kernel) pauseTimeLocked() { +func (k *Kernel) pauseTimeLocked(ctx context.Context) { // k.cpuClockTicker may be nil since Kernel.SaveTo() may be called before // Kernel.Start(). if k.cpuClockTicker != nil { @@ -1093,7 +1091,7 @@ func (k *Kernel) pauseTimeLocked() { // This means we'll iterate FDTables shared by multiple tasks repeatedly, // but ktime.Timer.Pause is idempotent so this is harmless. if t.fdTable != nil { - t.fdTable.forEach(func(_ int32, file *fs.File, fd *vfs.FileDescription, _ FDFlags) { + t.fdTable.forEach(ctx, func(_ int32, file *fs.File, fd *vfs.FileDescription, _ FDFlags) { if VFS2Enabled { if tfd, ok := fd.Impl().(*timerfd.TimerFileDescription); ok { tfd.PauseTimer() @@ -1115,7 +1113,7 @@ func (k *Kernel) pauseTimeLocked() { // // Preconditions: Any task goroutines running in k must be stopped. k.extMu // must be locked. -func (k *Kernel) resumeTimeLocked() { +func (k *Kernel) resumeTimeLocked(ctx context.Context) { if k.cpuClockTicker != nil { k.cpuClockTicker.Resume() } @@ -1129,7 +1127,7 @@ func (k *Kernel) resumeTimeLocked() { } } if t.fdTable != nil { - t.fdTable.forEach(func(_ int32, file *fs.File, fd *vfs.FileDescription, _ FDFlags) { + t.fdTable.forEach(ctx, func(_ int32, file *fs.File, fd *vfs.FileDescription, _ FDFlags) { if VFS2Enabled { if tfd, ok := fd.Impl().(*timerfd.TimerFileDescription); ok { tfd.ResumeTimer() @@ -1254,13 +1252,22 @@ func (k *Kernel) Kill(es ExitStatus) { } // Pause requests that all tasks in k temporarily stop executing, and blocks -// until all tasks in k have stopped. Multiple calls to Pause nest and require -// an equal number of calls to Unpause to resume execution. +// until all tasks and asynchronous I/O operations in k have stopped. Multiple +// calls to Pause nest and require an equal number of calls to Unpause to +// resume execution. func (k *Kernel) Pause() { k.extMu.Lock() k.tasks.BeginExternalStop() k.extMu.Unlock() k.tasks.runningGoroutines.Wait() + k.tasks.aioGoroutines.Wait() +} + +// ReceiveTaskStates receives full states for all tasks. +func (k *Kernel) ReceiveTaskStates() { + k.extMu.Lock() + k.tasks.PullFullState() + k.extMu.Unlock() } // Unpause ends the effect of a previous call to Pause. If Unpause is called @@ -1470,6 +1477,11 @@ func (k *Kernel) NowMonotonic() int64 { return now } +// AfterFunc implements tcpip.Clock.AfterFunc. +func (k *Kernel) AfterFunc(d time.Duration, f func()) tcpip.Timer { + return ktime.TcpipAfterFunc(k.realtimeClock, d, f) +} + // SetMemoryFile sets Kernel.mf. SetMemoryFile must be called before Init or // LoadFrom. func (k *Kernel) SetMemoryFile(mf *pgalloc.MemoryFile) { @@ -1507,7 +1519,7 @@ type SocketEntry struct { } // WeakRefGone implements refs.WeakRefUser.WeakRefGone. -func (s *SocketEntry) WeakRefGone() { +func (s *SocketEntry) WeakRefGone(context.Context) { s.k.extMu.Lock() s.k.sockets.Remove(s) s.k.extMu.Unlock() @@ -1596,7 +1608,7 @@ func (ctx supervisorContext) Value(key interface{}) interface{} { return vfs.VirtualDentry{} } mntns := ctx.k.GlobalInit().Leader().MountNamespaceVFS2() - defer mntns.DecRef() + defer mntns.DecRef(ctx) // Root() takes a reference on the root dirent for us. return mntns.Root() case vfs.CtxMountNamespace: diff --git a/pkg/sentry/kernel/pipe/BUILD b/pkg/sentry/kernel/pipe/BUILD index f29dc0472..449643118 100644 --- a/pkg/sentry/kernel/pipe/BUILD +++ b/pkg/sentry/kernel/pipe/BUILD @@ -8,6 +8,7 @@ go_library( "device.go", "node.go", "pipe.go", + "pipe_unsafe.go", "pipe_util.go", "reader.go", "reader_writer.go", @@ -20,10 +21,12 @@ go_library( "//pkg/amutex", "//pkg/buffer", "//pkg/context", + "//pkg/safemem", "//pkg/sentry/arch", "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/vfs", "//pkg/sync", "//pkg/syserror", diff --git a/pkg/sentry/kernel/pipe/node.go b/pkg/sentry/kernel/pipe/node.go index 4b688c627..6497dc4ba 100644 --- a/pkg/sentry/kernel/pipe/node.go +++ b/pkg/sentry/kernel/pipe/node.go @@ -93,7 +93,7 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi if i.p.isNamed && !flags.NonBlocking && !i.p.HasWriters() { if !waitFor(&i.mu, &i.wWakeup, ctx) { - r.DecRef() + r.DecRef(ctx) return nil, syserror.ErrInterrupted } } @@ -111,12 +111,12 @@ func (i *inodeOperations) GetFile(ctx context.Context, d *fs.Dirent, flags fs.Fi // On a nonblocking, write-only open, the open fails with ENXIO if the // read side isn't open yet. if flags.NonBlocking { - w.DecRef() + w.DecRef(ctx) return nil, syserror.ENXIO } if !waitFor(&i.mu, &i.rWakeup, ctx) { - w.DecRef() + w.DecRef(ctx) return nil, syserror.ErrInterrupted } } diff --git a/pkg/sentry/kernel/pipe/node_test.go b/pkg/sentry/kernel/pipe/node_test.go index ab75a87ff..ce0db5583 100644 --- a/pkg/sentry/kernel/pipe/node_test.go +++ b/pkg/sentry/kernel/pipe/node_test.go @@ -167,7 +167,7 @@ func TestClosedReaderBlocksWriteOpen(t *testing.T) { f := NewInodeOperations(ctx, perms, newNamedPipe(t)) rFile, _ := testOpenOrDie(ctx, t, f, fs.FileFlags{Read: true, NonBlocking: true}, nil) - rFile.DecRef() + rFile.DecRef(ctx) wDone := make(chan struct{}) // This open for write should block because the reader is now gone. diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go index 62c8691f1..297e8f28f 100644 --- a/pkg/sentry/kernel/pipe/pipe.go +++ b/pkg/sentry/kernel/pipe/pipe.go @@ -152,7 +152,7 @@ func NewConnectedPipe(ctx context.Context, sizeBytes, atomicIOBytes int64) (*fs. d := fs.NewDirent(ctx, fs.NewInode(ctx, iops, ms, sattr), fmt.Sprintf("pipe:[%d]", ino)) // The p.Open calls below will each take a reference on the Dirent. We // must drop the one we already have. - defer d.DecRef() + defer d.DecRef(ctx) return p.Open(ctx, d, fs.FileFlags{Read: true}), p.Open(ctx, d, fs.FileFlags{Write: true}) } @@ -207,7 +207,10 @@ func (p *Pipe) read(ctx context.Context, ops readOps) (int64, error) { p.mu.Lock() defer p.mu.Unlock() + return p.readLocked(ctx, ops) +} +func (p *Pipe) readLocked(ctx context.Context, ops readOps) (int64, error) { // Is the pipe empty? if p.view.Size() == 0 { if !p.HasWriters() { @@ -246,7 +249,10 @@ type writeOps struct { func (p *Pipe) write(ctx context.Context, ops writeOps) (int64, error) { p.mu.Lock() defer p.mu.Unlock() + return p.writeLocked(ctx, ops) +} +func (p *Pipe) writeLocked(ctx context.Context, ops writeOps) (int64, error) { // Can't write to a pipe with no readers. if !p.HasReaders() { return 0, syscall.EPIPE diff --git a/pkg/sentry/kernel/pipe/pipe_test.go b/pkg/sentry/kernel/pipe/pipe_test.go index bda739dbe..fe97e9800 100644 --- a/pkg/sentry/kernel/pipe/pipe_test.go +++ b/pkg/sentry/kernel/pipe/pipe_test.go @@ -27,8 +27,8 @@ import ( func TestPipeRW(t *testing.T) { ctx := contexttest.Context(t) r, w := NewConnectedPipe(ctx, 65536, 4096) - defer r.DecRef() - defer w.DecRef() + defer r.DecRef(ctx) + defer w.DecRef(ctx) msg := []byte("here's some bytes") wantN := int64(len(msg)) @@ -47,8 +47,8 @@ func TestPipeRW(t *testing.T) { func TestPipeReadBlock(t *testing.T) { ctx := contexttest.Context(t) r, w := NewConnectedPipe(ctx, 65536, 4096) - defer r.DecRef() - defer w.DecRef() + defer r.DecRef(ctx) + defer w.DecRef(ctx) n, err := r.Readv(ctx, usermem.BytesIOSequence(make([]byte, 1))) if n != 0 || err != syserror.ErrWouldBlock { @@ -62,8 +62,8 @@ func TestPipeWriteBlock(t *testing.T) { ctx := contexttest.Context(t) r, w := NewConnectedPipe(ctx, capacity, atomicIOBytes) - defer r.DecRef() - defer w.DecRef() + defer r.DecRef(ctx) + defer w.DecRef(ctx) msg := make([]byte, capacity+1) n, err := w.Writev(ctx, usermem.BytesIOSequence(msg)) @@ -77,8 +77,8 @@ func TestPipeWriteUntilEnd(t *testing.T) { ctx := contexttest.Context(t) r, w := NewConnectedPipe(ctx, atomicIOBytes, atomicIOBytes) - defer r.DecRef() - defer w.DecRef() + defer r.DecRef(ctx) + defer w.DecRef(ctx) msg := []byte("here's some bytes") diff --git a/pkg/sentry/kernel/pipe/pipe_unsafe.go b/pkg/sentry/kernel/pipe/pipe_unsafe.go new file mode 100644 index 000000000..dd60cba24 --- /dev/null +++ b/pkg/sentry/kernel/pipe/pipe_unsafe.go @@ -0,0 +1,35 @@ +// Copyright 2019 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package pipe + +import ( + "unsafe" +) + +// lockTwoPipes locks both x.mu and y.mu in an order that is guaranteed to be +// consistent for both lockTwoPipes(x, y) and lockTwoPipes(y, x), such that +// concurrent calls cannot deadlock. +// +// Preconditions: x != y. +func lockTwoPipes(x, y *Pipe) { + // Lock the two pipes in order of increasing address. + if uintptr(unsafe.Pointer(x)) < uintptr(unsafe.Pointer(y)) { + x.mu.Lock() + y.mu.Lock() + } else { + y.mu.Lock() + x.mu.Lock() + } +} diff --git a/pkg/sentry/kernel/pipe/pipe_util.go b/pkg/sentry/kernel/pipe/pipe_util.go index aacf28da2..6d58b682f 100644 --- a/pkg/sentry/kernel/pipe/pipe_util.go +++ b/pkg/sentry/kernel/pipe/pipe_util.go @@ -33,7 +33,7 @@ import ( // the old fs architecture. // Release cleans up the pipe's state. -func (p *Pipe) Release() { +func (p *Pipe) Release(context.Context) { p.rClose() p.wClose() diff --git a/pkg/sentry/kernel/pipe/reader.go b/pkg/sentry/kernel/pipe/reader.go index 7724b4452..ac18785c0 100644 --- a/pkg/sentry/kernel/pipe/reader.go +++ b/pkg/sentry/kernel/pipe/reader.go @@ -15,6 +15,7 @@ package pipe import ( + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/waiter" ) @@ -29,7 +30,7 @@ type Reader struct { // Release implements fs.FileOperations.Release. // // This overrides ReaderWriter.Release. -func (r *Reader) Release() { +func (r *Reader) Release(context.Context) { r.Pipe.rClose() // Wake up writers. diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go index b54f08a30..28f998e45 100644 --- a/pkg/sentry/kernel/pipe/vfs.go +++ b/pkg/sentry/kernel/pipe/vfs.go @@ -16,8 +16,11 @@ package pipe import ( "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/buffer" "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" @@ -59,11 +62,13 @@ func NewVFSPipe(isNamed bool, sizeBytes, atomicIOBytes int64) *VFSPipe { // // Preconditions: statusFlags should not contain an open access mode. func (vp *VFSPipe) ReaderWriterPair(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) (*vfs.FileDescription, *vfs.FileDescription) { - return vp.newFD(mnt, vfsd, linux.O_RDONLY|statusFlags), vp.newFD(mnt, vfsd, linux.O_WRONLY|statusFlags) + // Connected pipes share the same locks. + locks := &vfs.FileLocks{} + return vp.newFD(mnt, vfsd, linux.O_RDONLY|statusFlags, locks), vp.newFD(mnt, vfsd, linux.O_WRONLY|statusFlags, locks) } // Open opens the pipe represented by vp. -func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) (*vfs.FileDescription, error) { +func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32, locks *vfs.FileLocks) (*vfs.FileDescription, error) { vp.mu.Lock() defer vp.mu.Unlock() @@ -73,7 +78,7 @@ func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, s return nil, syserror.EINVAL } - fd := vp.newFD(mnt, vfsd, statusFlags) + fd := vp.newFD(mnt, vfsd, statusFlags, locks) // Named pipes have special blocking semantics during open: // @@ -96,7 +101,7 @@ func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, s // If this pipe is being opened as blocking and there's no // writer, we have to wait for a writer to open the other end. if vp.pipe.isNamed && statusFlags&linux.O_NONBLOCK == 0 && !vp.pipe.HasWriters() && !waitFor(&vp.mu, &vp.wWakeup, ctx) { - fd.DecRef() + fd.DecRef(ctx) return nil, syserror.EINTR } @@ -107,12 +112,12 @@ func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, s // Non-blocking, write-only opens fail with ENXIO when the read // side isn't open yet. if statusFlags&linux.O_NONBLOCK != 0 { - fd.DecRef() + fd.DecRef(ctx) return nil, syserror.ENXIO } // Wait for a reader to open the other end. if !waitFor(&vp.mu, &vp.rWakeup, ctx) { - fd.DecRef() + fd.DecRef(ctx) return nil, syserror.EINTR } } @@ -125,10 +130,11 @@ func (vp *VFSPipe) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, s } // Preconditions: vp.mu must be held. -func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) *vfs.FileDescription { +func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32, locks *vfs.FileLocks) *vfs.FileDescription { fd := &VFSPipeFD{ pipe: &vp.pipe, } + fd.LockFD.Init(locks) fd.vfsfd.Init(fd, statusFlags, mnt, vfsd, &vfs.FileDescriptionOptions{ DenyPRead: true, DenyPWrite: true, @@ -150,17 +156,20 @@ func (vp *VFSPipe) newFD(mnt *vfs.Mount, vfsd *vfs.Dentry, statusFlags uint32) * return &fd.vfsfd } -// VFSPipeFD implements vfs.FileDescriptionImpl for pipes. +// VFSPipeFD implements vfs.FileDescriptionImpl for pipes. It also implements +// non-atomic usermem.IO methods, allowing it to be passed as usermem.IO to +// other FileDescriptions for splice(2) and tee(2). type VFSPipeFD struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.LockFD pipe *Pipe } // Release implements vfs.FileDescriptionImpl.Release. -func (fd *VFSPipeFD) Release() { +func (fd *VFSPipeFD) Release(context.Context) { var event waiter.EventMask if fd.vfsfd.IsReadable() { fd.pipe.rClose() @@ -191,6 +200,11 @@ func (fd *VFSPipeFD) Readiness(mask waiter.EventMask) waiter.EventMask { } } +// Allocate implements vfs.FileDescriptionImpl.Allocate. +func (fd *VFSPipeFD) Allocate(ctx context.Context, mode, offset, length uint64) error { + return syserror.ESPIPE +} + // EventRegister implements waiter.Waitable.EventRegister. func (fd *VFSPipeFD) EventRegister(e *waiter.Entry, mask waiter.EventMask) { fd.pipe.EventRegister(e, mask) @@ -229,3 +243,226 @@ func (fd *VFSPipeFD) PipeSize() int64 { func (fd *VFSPipeFD) SetPipeSize(size int64) (int64, error) { return fd.pipe.SetFifoSize(size) } + +// IOSequence returns a useremm.IOSequence that reads up to count bytes from, +// or writes up to count bytes to, fd. +func (fd *VFSPipeFD) IOSequence(count int64) usermem.IOSequence { + return usermem.IOSequence{ + IO: fd, + Addrs: usermem.AddrRangeSeqOf(usermem.AddrRange{0, usermem.Addr(count)}), + } +} + +// CopyIn implements usermem.IO.CopyIn. +func (fd *VFSPipeFD) CopyIn(ctx context.Context, addr usermem.Addr, dst []byte, opts usermem.IOOpts) (int, error) { + origCount := int64(len(dst)) + n, err := fd.pipe.read(ctx, readOps{ + left: func() int64 { + return int64(len(dst)) + }, + limit: func(l int64) { + dst = dst[:l] + }, + read: func(view *buffer.View) (int64, error) { + n, err := view.ReadAt(dst, 0) + view.TrimFront(int64(n)) + return int64(n), err + }, + }) + if n > 0 { + fd.pipe.Notify(waiter.EventOut) + } + if err == nil && n != origCount { + return int(n), syserror.ErrWouldBlock + } + return int(n), err +} + +// CopyOut implements usermem.IO.CopyOut. +func (fd *VFSPipeFD) CopyOut(ctx context.Context, addr usermem.Addr, src []byte, opts usermem.IOOpts) (int, error) { + origCount := int64(len(src)) + n, err := fd.pipe.write(ctx, writeOps{ + left: func() int64 { + return int64(len(src)) + }, + limit: func(l int64) { + src = src[:l] + }, + write: func(view *buffer.View) (int64, error) { + view.Append(src) + return int64(len(src)), nil + }, + }) + if n > 0 { + fd.pipe.Notify(waiter.EventIn) + } + if err == nil && n != origCount { + return int(n), syserror.ErrWouldBlock + } + return int(n), err +} + +// ZeroOut implements usermem.IO.ZeroOut. +func (fd *VFSPipeFD) ZeroOut(ctx context.Context, addr usermem.Addr, toZero int64, opts usermem.IOOpts) (int64, error) { + origCount := toZero + n, err := fd.pipe.write(ctx, writeOps{ + left: func() int64 { + return toZero + }, + limit: func(l int64) { + toZero = l + }, + write: func(view *buffer.View) (int64, error) { + view.Grow(view.Size()+toZero, true /* zero */) + return toZero, nil + }, + }) + if n > 0 { + fd.pipe.Notify(waiter.EventIn) + } + if err == nil && n != origCount { + return n, syserror.ErrWouldBlock + } + return n, err +} + +// CopyInTo implements usermem.IO.CopyInTo. +func (fd *VFSPipeFD) CopyInTo(ctx context.Context, ars usermem.AddrRangeSeq, dst safemem.Writer, opts usermem.IOOpts) (int64, error) { + count := ars.NumBytes() + if count == 0 { + return 0, nil + } + origCount := count + n, err := fd.pipe.read(ctx, readOps{ + left: func() int64 { + return count + }, + limit: func(l int64) { + count = l + }, + read: func(view *buffer.View) (int64, error) { + n, err := view.ReadToSafememWriter(dst, uint64(count)) + view.TrimFront(int64(n)) + return int64(n), err + }, + }) + if n > 0 { + fd.pipe.Notify(waiter.EventOut) + } + if err == nil && n != origCount { + return n, syserror.ErrWouldBlock + } + return n, err +} + +// CopyOutFrom implements usermem.IO.CopyOutFrom. +func (fd *VFSPipeFD) CopyOutFrom(ctx context.Context, ars usermem.AddrRangeSeq, src safemem.Reader, opts usermem.IOOpts) (int64, error) { + count := ars.NumBytes() + if count == 0 { + return 0, nil + } + origCount := count + n, err := fd.pipe.write(ctx, writeOps{ + left: func() int64 { + return count + }, + limit: func(l int64) { + count = l + }, + write: func(view *buffer.View) (int64, error) { + n, err := view.WriteFromSafememReader(src, uint64(count)) + return int64(n), err + }, + }) + if n > 0 { + fd.pipe.Notify(waiter.EventIn) + } + if err == nil && n != origCount { + return n, syserror.ErrWouldBlock + } + return n, err +} + +// SwapUint32 implements usermem.IO.SwapUint32. +func (fd *VFSPipeFD) SwapUint32(ctx context.Context, addr usermem.Addr, new uint32, opts usermem.IOOpts) (uint32, error) { + // How did a pipe get passed as the virtual address space to futex(2)? + panic("VFSPipeFD.SwapUint32 called unexpectedly") +} + +// CompareAndSwapUint32 implements usermem.IO.CompareAndSwapUint32. +func (fd *VFSPipeFD) CompareAndSwapUint32(ctx context.Context, addr usermem.Addr, old, new uint32, opts usermem.IOOpts) (uint32, error) { + panic("VFSPipeFD.CompareAndSwapUint32 called unexpectedly") +} + +// LoadUint32 implements usermem.IO.LoadUint32. +func (fd *VFSPipeFD) LoadUint32(ctx context.Context, addr usermem.Addr, opts usermem.IOOpts) (uint32, error) { + panic("VFSPipeFD.LoadUint32 called unexpectedly") +} + +// Splice reads up to count bytes from src and writes them to dst. It returns +// the number of bytes moved. +// +// Preconditions: count > 0. +func Splice(ctx context.Context, dst, src *VFSPipeFD, count int64) (int64, error) { + return spliceOrTee(ctx, dst, src, count, true /* removeFromSrc */) +} + +// Tee reads up to count bytes from src and writes them to dst, without +// removing the read bytes from src. It returns the number of bytes copied. +// +// Preconditions: count > 0. +func Tee(ctx context.Context, dst, src *VFSPipeFD, count int64) (int64, error) { + return spliceOrTee(ctx, dst, src, count, false /* removeFromSrc */) +} + +// Preconditions: count > 0. +func spliceOrTee(ctx context.Context, dst, src *VFSPipeFD, count int64, removeFromSrc bool) (int64, error) { + if dst.pipe == src.pipe { + return 0, syserror.EINVAL + } + + lockTwoPipes(dst.pipe, src.pipe) + defer dst.pipe.mu.Unlock() + defer src.pipe.mu.Unlock() + + n, err := dst.pipe.writeLocked(ctx, writeOps{ + left: func() int64 { + return count + }, + limit: func(l int64) { + count = l + }, + write: func(dstView *buffer.View) (int64, error) { + return src.pipe.readLocked(ctx, readOps{ + left: func() int64 { + return count + }, + limit: func(l int64) { + count = l + }, + read: func(srcView *buffer.View) (int64, error) { + n, err := srcView.ReadToSafememWriter(dstView, uint64(count)) + if n > 0 && removeFromSrc { + srcView.TrimFront(int64(n)) + } + return int64(n), err + }, + }) + }, + }) + if n > 0 { + dst.pipe.Notify(waiter.EventIn) + src.pipe.Notify(waiter.EventOut) + } + return n, err +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (fd *VFSPipeFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return fd.Locks().LockPOSIX(ctx, &fd.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (fd *VFSPipeFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/kernel/pipe/writer.go b/pkg/sentry/kernel/pipe/writer.go index 5bc6aa931..ef4b70ca3 100644 --- a/pkg/sentry/kernel/pipe/writer.go +++ b/pkg/sentry/kernel/pipe/writer.go @@ -15,6 +15,7 @@ package pipe import ( + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/waiter" ) @@ -29,7 +30,7 @@ type Writer struct { // Release implements fs.FileOperations.Release. // // This overrides ReaderWriter.Release. -func (w *Writer) Release() { +func (w *Writer) Release(context.Context) { w.Pipe.wClose() // Wake up readers. diff --git a/pkg/sentry/kernel/ptrace.go b/pkg/sentry/kernel/ptrace.go index e23e796ef..619b0cb7c 100644 --- a/pkg/sentry/kernel/ptrace.go +++ b/pkg/sentry/kernel/ptrace.go @@ -1018,6 +1018,9 @@ func (t *Task) Ptrace(req int64, pid ThreadID, addr, data usermem.Addr) error { if err != nil { return err } + + t.p.PullFullState(t.MemoryManager().AddressSpace(), t.Arch()) + ar := ars.Head() n, err := target.Arch().PtraceGetRegSet(uintptr(addr), &usermem.IOReadWriter{ Ctx: t, @@ -1044,10 +1047,14 @@ func (t *Task) Ptrace(req int64, pid ThreadID, addr, data usermem.Addr) error { if err != nil { return err } + + mm := t.MemoryManager() + t.p.PullFullState(mm.AddressSpace(), t.Arch()) + ar := ars.Head() n, err := target.Arch().PtraceSetRegSet(uintptr(addr), &usermem.IOReadWriter{ Ctx: t, - IO: t.MemoryManager(), + IO: mm, Addr: ar.Start, Opts: usermem.IOOpts{ AddressSpaceActive: true, @@ -1056,6 +1063,7 @@ func (t *Task) Ptrace(req int64, pid ThreadID, addr, data usermem.Addr) error { if err != nil { return err } + t.p.FullStateChanged() ar.End -= usermem.Addr(n) return t.CopyOutIovecs(data, usermem.AddrRangeSeqOf(ar)) diff --git a/pkg/sentry/kernel/sessions.go b/pkg/sentry/kernel/sessions.go index 0e19286de..5c4c622c2 100644 --- a/pkg/sentry/kernel/sessions.go +++ b/pkg/sentry/kernel/sessions.go @@ -16,6 +16,7 @@ package kernel import ( "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/syserror" @@ -70,7 +71,7 @@ func (s *Session) incRef() { // // Precondition: callers must hold TaskSet.mu for writing. func (s *Session) decRef() { - s.refs.DecRefWithDestructor(func() { + s.refs.DecRefWithDestructor(nil, func(context.Context) { // Remove translations from the leader. for ns := s.leader.pidns; ns != nil; ns = ns.parent { id := ns.sids[s] @@ -162,7 +163,7 @@ func (pg *ProcessGroup) decRefWithParent(parentPG *ProcessGroup) { } alive := true - pg.refs.DecRefWithDestructor(func() { + pg.refs.DecRefWithDestructor(nil, func(context.Context) { alive = false // don't bother with handleOrphan. // Remove translations from the originator. diff --git a/pkg/sentry/kernel/shm/BUILD b/pkg/sentry/kernel/shm/BUILD index bfd779837..c211fc8d0 100644 --- a/pkg/sentry/kernel/shm/BUILD +++ b/pkg/sentry/kernel/shm/BUILD @@ -20,7 +20,6 @@ go_library( "//pkg/sentry/kernel/time", "//pkg/sentry/memmap", "//pkg/sentry/pgalloc", - "//pkg/sentry/platform", "//pkg/sentry/usage", "//pkg/sync", "//pkg/syserror", diff --git a/pkg/sentry/kernel/shm/shm.go b/pkg/sentry/kernel/shm/shm.go index f66cfcc7f..13ec7afe0 100644 --- a/pkg/sentry/kernel/shm/shm.go +++ b/pkg/sentry/kernel/shm/shm.go @@ -45,7 +45,6 @@ import ( ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" @@ -370,7 +369,7 @@ type Shm struct { // fr is the offset into mfp.MemoryFile() that backs this contents of this // segment. Immutable. - fr platform.FileRange + fr memmap.FileRange // mu protects all fields below. mu sync.Mutex `state:"nosave"` @@ -432,8 +431,8 @@ func (s *Shm) InodeID() uint64 { // DecRef overrides refs.RefCount.DecRef with a destructor. // // Precondition: Caller must not hold s.mu. -func (s *Shm) DecRef() { - s.DecRefWithDestructor(s.destroy) +func (s *Shm) DecRef(ctx context.Context) { + s.DecRefWithDestructor(ctx, s.destroy) } // Msync implements memmap.MappingIdentity.Msync. Msync is a no-op for shm @@ -643,7 +642,7 @@ func (s *Shm) Set(ctx context.Context, ds *linux.ShmidDS) error { return nil } -func (s *Shm) destroy() { +func (s *Shm) destroy(context.Context) { s.mfp.MemoryFile().DecRef(s.fr) s.registry.remove(s) } @@ -652,7 +651,7 @@ func (s *Shm) destroy() { // destroyed once it has no references. MarkDestroyed may be called multiple // times, and is safe to call after a segment has already been destroyed. See // shmctl(IPC_RMID). -func (s *Shm) MarkDestroyed() { +func (s *Shm) MarkDestroyed(ctx context.Context) { s.registry.dissociateKey(s) s.mu.Lock() @@ -664,7 +663,7 @@ func (s *Shm) MarkDestroyed() { // // N.B. This cannot be the final DecRef, as the caller also // holds a reference. - s.DecRef() + s.DecRef(ctx) return } } diff --git a/pkg/sentry/kernel/signalfd/signalfd.go b/pkg/sentry/kernel/signalfd/signalfd.go index 8243bb93e..b07e1c1bd 100644 --- a/pkg/sentry/kernel/signalfd/signalfd.go +++ b/pkg/sentry/kernel/signalfd/signalfd.go @@ -76,7 +76,7 @@ func New(ctx context.Context, mask linux.SignalSet) (*fs.File, error) { } // Release implements fs.FileOperations.Release. -func (s *SignalOperations) Release() {} +func (s *SignalOperations) Release(context.Context) {} // Mask returns the signal mask. func (s *SignalOperations) Mask() linux.SignalSet { diff --git a/pkg/sentry/kernel/syslog.go b/pkg/sentry/kernel/syslog.go index 4607cde2f..a83ce219c 100644 --- a/pkg/sentry/kernel/syslog.go +++ b/pkg/sentry/kernel/syslog.go @@ -98,6 +98,15 @@ func (s *syslog) Log() []byte { s.msg = append(s.msg, []byte(fmt.Sprintf(format, time, selectMessage()))...) } + if VFS2Enabled { + time += rand.Float64() / 2 + s.msg = append(s.msg, []byte(fmt.Sprintf(format, time, "Setting up VFS2..."))...) + if FUSEEnabled { + time += rand.Float64() / 2 + s.msg = append(s.msg, []byte(fmt.Sprintf(format, time, "Setting up FUSE..."))...) + } + } + time += rand.Float64() / 2 s.msg = append(s.msg, []byte(fmt.Sprintf(format, time, "Ready!"))...) diff --git a/pkg/sentry/kernel/task.go b/pkg/sentry/kernel/task.go index f48247c94..5aee699e7 100644 --- a/pkg/sentry/kernel/task.go +++ b/pkg/sentry/kernel/task.go @@ -68,6 +68,21 @@ type Task struct { // runState is exclusive to the task goroutine. runState taskRunState + // taskWorkCount represents the current size of the task work queue. It is + // used to avoid acquiring taskWorkMu when the queue is empty. + // + // Must accessed with atomic memory operations. + taskWorkCount int32 + + // taskWorkMu protects taskWork. + taskWorkMu sync.Mutex `state:"nosave"` + + // taskWork is a queue of work to be executed before resuming user execution. + // It is similar to the task_work mechanism in Linux. + // + // taskWork is exclusive to the task goroutine. + taskWork []TaskWorker + // haveSyscallReturn is true if tc.Arch().Return() represents a value // returned by a syscall (or set by ptrace after a syscall). // @@ -550,6 +565,10 @@ type Task struct { // futexWaiter is exclusive to the task goroutine. futexWaiter *futex.Waiter `state:"nosave"` + // robustList is a pointer to the head of the tasks's robust futex + // list. + robustList usermem.Addr + // startTime is the real time at which the task started. It is set when // a Task is created or invokes execve(2). // @@ -711,17 +730,17 @@ func (t *Task) SyscallRestartBlock() SyscallRestartBlock { func (t *Task) IsChrooted() bool { if VFS2Enabled { realRoot := t.mountNamespaceVFS2.Root() - defer realRoot.DecRef() + defer realRoot.DecRef(t) root := t.fsContext.RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) return root != realRoot } realRoot := t.tg.mounts.Root() - defer realRoot.DecRef() + defer realRoot.DecRef(t) root := t.fsContext.RootDirectory() if root != nil { - defer root.DecRef() + defer root.DecRef(t) } return root != realRoot } diff --git a/pkg/sentry/kernel/task_clone.go b/pkg/sentry/kernel/task_clone.go index e1ecca99e..9d7a9128f 100644 --- a/pkg/sentry/kernel/task_clone.go +++ b/pkg/sentry/kernel/task_clone.go @@ -161,6 +161,10 @@ func (t *Task) Clone(opts *CloneOptions) (ThreadID, *SyscallControl, error) { return 0, nil, syserror.EINVAL } + // Pull task registers and FPU state, a cloned task will inherit the + // state of the current task. + t.p.PullFullState(t.MemoryManager().AddressSpace(), t.Arch()) + // "If CLONE_NEWUSER is specified along with other CLONE_NEW* flags in a // single clone(2) or unshare(2) call, the user namespace is guaranteed to // be created first, giving the child (clone(2)) or caller (unshare(2)) @@ -237,7 +241,7 @@ func (t *Task) Clone(opts *CloneOptions) (ThreadID, *SyscallControl, error) { var fdTable *FDTable if opts.NewFiles { - fdTable = t.fdTable.Fork() + fdTable = t.fdTable.Fork(t) } else { fdTable = t.fdTable fdTable.IncRef() @@ -294,7 +298,7 @@ func (t *Task) Clone(opts *CloneOptions) (ThreadID, *SyscallControl, error) { nt, err := t.tg.pidns.owner.NewTask(cfg) if err != nil { if opts.NewThreadGroup { - tg.release() + tg.release(t) } return 0, nil, err } @@ -510,7 +514,7 @@ func (t *Task) Unshare(opts *SharingOptions) error { var oldFDTable *FDTable if opts.NewFiles { oldFDTable = t.fdTable - t.fdTable = oldFDTable.Fork() + t.fdTable = oldFDTable.Fork(t) } var oldFSContext *FSContext if opts.NewFSContext { @@ -519,10 +523,10 @@ func (t *Task) Unshare(opts *SharingOptions) error { } t.mu.Unlock() if oldFDTable != nil { - oldFDTable.DecRef() + oldFDTable.DecRef(t) } if oldFSContext != nil { - oldFSContext.DecRef() + oldFSContext.DecRef(t) } return nil } diff --git a/pkg/sentry/kernel/task_exec.go b/pkg/sentry/kernel/task_exec.go index 00c425cca..5e4fb3e3a 100644 --- a/pkg/sentry/kernel/task_exec.go +++ b/pkg/sentry/kernel/task_exec.go @@ -198,11 +198,18 @@ func (r *runSyscallAfterExecStop) execute(t *Task) taskRunState { t.tg.oldRSeqCritical.Store(&OldRSeqCriticalRegion{}) t.tg.pidns.owner.mu.Unlock() + oldFDTable := t.fdTable + t.fdTable = t.fdTable.Fork(t) + oldFDTable.DecRef(t) + // Remove FDs with the CloseOnExec flag set. - t.fdTable.RemoveIf(func(_ *fs.File, _ *vfs.FileDescription, flags FDFlags) bool { + t.fdTable.RemoveIf(t, func(_ *fs.File, _ *vfs.FileDescription, flags FDFlags) bool { return flags.CloseOnExec }) + // Handle the robust futex list. + t.exitRobustList() + // NOTE(b/30815691): We currently do not implement privileged // executables (set-user/group-ID bits and file capabilities). This // allows us to unconditionally enable user dumpability on the new mm. @@ -219,6 +226,7 @@ func (r *runSyscallAfterExecStop) execute(t *Task) taskRunState { t.tc = *r.tc t.mu.Unlock() t.unstopVforkParent() + t.p.FullStateChanged() // NOTE(b/30316266): All locks must be dropped prior to calling Activate. t.MemoryManager().Activate(t) diff --git a/pkg/sentry/kernel/task_exit.go b/pkg/sentry/kernel/task_exit.go index c4ade6e8e..c165d6cb1 100644 --- a/pkg/sentry/kernel/task_exit.go +++ b/pkg/sentry/kernel/task_exit.go @@ -253,6 +253,9 @@ func (*runExitMain) execute(t *Task) taskRunState { } } + // Handle the robust futex list. + t.exitRobustList() + // Deactivate the address space and update max RSS before releasing the // task's MM. t.Deactivate() @@ -266,12 +269,12 @@ func (*runExitMain) execute(t *Task) taskRunState { // Releasing the MM unblocks a blocked CLONE_VFORK parent. t.unstopVforkParent() - t.fsContext.DecRef() - t.fdTable.DecRef() + t.fsContext.DecRef(t) + t.fdTable.DecRef(t) t.mu.Lock() if t.mountNamespaceVFS2 != nil { - t.mountNamespaceVFS2.DecRef() + t.mountNamespaceVFS2.DecRef(t) t.mountNamespaceVFS2 = nil } t.mu.Unlock() @@ -279,7 +282,7 @@ func (*runExitMain) execute(t *Task) taskRunState { // If this is the last task to exit from the thread group, release the // thread group's resources. if lastExiter { - t.tg.release() + t.tg.release(t) } // Detach tracees. diff --git a/pkg/sentry/kernel/task_futex.go b/pkg/sentry/kernel/task_futex.go index a53e77c9f..4b535c949 100644 --- a/pkg/sentry/kernel/task_futex.go +++ b/pkg/sentry/kernel/task_futex.go @@ -15,6 +15,7 @@ package kernel import ( + "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/sentry/kernel/futex" "gvisor.dev/gvisor/pkg/usermem" ) @@ -52,3 +53,127 @@ func (t *Task) LoadUint32(addr usermem.Addr) (uint32, error) { func (t *Task) GetSharedKey(addr usermem.Addr) (futex.Key, error) { return t.MemoryManager().GetSharedFutexKey(t, addr) } + +// GetRobustList sets the robust futex list for the task. +func (t *Task) GetRobustList() usermem.Addr { + t.mu.Lock() + addr := t.robustList + t.mu.Unlock() + return addr +} + +// SetRobustList sets the robust futex list for the task. +func (t *Task) SetRobustList(addr usermem.Addr) { + t.mu.Lock() + t.robustList = addr + t.mu.Unlock() +} + +// exitRobustList walks the robust futex list, marking locks dead and notifying +// wakers. It corresponds to Linux's exit_robust_list(). Following Linux, +// errors are silently ignored. +func (t *Task) exitRobustList() { + t.mu.Lock() + addr := t.robustList + t.robustList = 0 + t.mu.Unlock() + + if addr == 0 { + return + } + + var rl linux.RobustListHead + if _, err := rl.CopyIn(t, usermem.Addr(addr)); err != nil { + return + } + + next := rl.List + done := 0 + var pendingLockAddr usermem.Addr + if rl.ListOpPending != 0 { + pendingLockAddr = usermem.Addr(rl.ListOpPending + rl.FutexOffset) + } + + // Wake up normal elements. + for usermem.Addr(next) != addr { + // We traverse to the next element of the list before we + // actually wake anything. This prevents the race where waking + // this futex causes a modification of the list. + thisLockAddr := usermem.Addr(next + rl.FutexOffset) + + // Try to decode the next element in the list before waking the + // current futex. But don't check the error until after we've + // woken the current futex. Linux does it in this order too + _, nextErr := t.CopyIn(usermem.Addr(next), &next) + + // Wakeup the current futex if it's not pending. + if thisLockAddr != pendingLockAddr { + t.wakeRobustListOne(thisLockAddr) + } + + // If there was an error copying the next futex, we must bail. + if nextErr != nil { + break + } + + // This is a user structure, so it could be a massive list, or + // even contain a loop if they are trying to mess with us. We + // cap traversal to prevent that. + done++ + if done >= linux.ROBUST_LIST_LIMIT { + break + } + } + + // Is there a pending entry to wake? + if pendingLockAddr != 0 { + t.wakeRobustListOne(pendingLockAddr) + } +} + +// wakeRobustListOne wakes a single futex from the robust list. +func (t *Task) wakeRobustListOne(addr usermem.Addr) { + // Bit 0 in address signals PI futex. + pi := addr&1 == 1 + addr = addr &^ 1 + + // Load the futex. + f, err := t.LoadUint32(addr) + if err != nil { + // Can't read this single value? Ignore the problem. + // We can wake the other futexes in the list. + return + } + + tid := uint32(t.ThreadID()) + for { + // Is this held by someone else? + if f&linux.FUTEX_TID_MASK != tid { + return + } + + // This thread is dying and it's holding this futex. We need to + // set the owner died bit and wake up any waiters. + newF := (f & linux.FUTEX_WAITERS) | linux.FUTEX_OWNER_DIED + if curF, err := t.CompareAndSwapUint32(addr, f, newF); err != nil { + return + } else if curF != f { + // Futex changed out from under us. Try again... + f = curF + continue + } + + // Wake waiters if there are any. + if f&linux.FUTEX_WAITERS != 0 { + private := f&linux.FUTEX_PRIVATE_FLAG != 0 + if pi { + t.Futex().UnlockPI(t, addr, tid, private) + return + } + t.Futex().Wake(t, addr, private, linux.FUTEX_BITSET_MATCH_ANY, 1) + } + + // Done. + return + } +} diff --git a/pkg/sentry/kernel/task_log.go b/pkg/sentry/kernel/task_log.go index eeccaa197..d23cea802 100644 --- a/pkg/sentry/kernel/task_log.go +++ b/pkg/sentry/kernel/task_log.go @@ -27,6 +27,9 @@ const ( // maxStackDebugBytes is the maximum number of user stack bytes that may be // printed by debugDumpStack. maxStackDebugBytes = 1024 + // maxCodeDebugBytes is the maximum number of user code bytes that may be + // printed by debugDumpCode. + maxCodeDebugBytes = 128 ) // Infof logs an formatted info message by calling log.Infof. @@ -61,6 +64,7 @@ func (t *Task) IsLogging(level log.Level) bool { func (t *Task) DebugDumpState() { t.debugDumpRegisters() t.debugDumpStack() + t.debugDumpCode() if mm := t.MemoryManager(); mm != nil { t.Debugf("Mappings:\n%s", mm) } @@ -128,6 +132,45 @@ func (t *Task) debugDumpStack() { } } +// debugDumpCode logs user code contents at log level debug. +// +// Preconditions: The caller must be running on the task goroutine. +func (t *Task) debugDumpCode() { + if !t.IsLogging(log.Debug) { + return + } + m := t.MemoryManager() + if m == nil { + t.Debugf("Memory manager for task is gone, skipping application code dump.") + return + } + t.Debugf("Code:") + // Print code on both sides of the instruction register. + start := usermem.Addr(t.Arch().IP()) - maxCodeDebugBytes/2 + // Round addr down to a 16-byte boundary. + start &= ^usermem.Addr(15) + // Print 16 bytes per line, one byte at a time. + for offset := uint64(0); offset < maxCodeDebugBytes; offset += 16 { + addr, ok := start.AddLength(offset) + if !ok { + break + } + var data [16]byte + n, err := m.CopyIn(t, addr, data[:], usermem.IOOpts{ + IgnorePermissions: true, + }) + // Print as much of the line as we can, even if an error was + // encountered. + if n > 0 { + t.Debugf("%x: % x", addr, data[:n]) + } + if err != nil { + t.Debugf("Error reading stack at address %x: %v", addr+usermem.Addr(n), err) + break + } + } +} + // trace definitions. // // Note that all region names are prefixed by ':' in order to ensure that they @@ -203,6 +246,6 @@ func (t *Task) traceExecEvent(tc *TaskContext) { trace.Logf(t.traceContext, traceCategory, "exec: << unknown >>") return } - defer file.DecRef() + defer file.DecRef(t) trace.Logf(t.traceContext, traceCategory, "exec: %s", file.PathnameWithDeleted(t)) } diff --git a/pkg/sentry/kernel/task_run.go b/pkg/sentry/kernel/task_run.go index d654dd997..abaf29216 100644 --- a/pkg/sentry/kernel/task_run.go +++ b/pkg/sentry/kernel/task_run.go @@ -167,7 +167,22 @@ func (app *runApp) execute(t *Task) taskRunState { return (*runInterrupt)(nil) } - // We're about to switch to the application again. If there's still a + // Execute any task work callbacks before returning to user space. + if atomic.LoadInt32(&t.taskWorkCount) > 0 { + t.taskWorkMu.Lock() + queue := t.taskWork + t.taskWork = nil + atomic.StoreInt32(&t.taskWorkCount, 0) + t.taskWorkMu.Unlock() + + // Do not hold taskWorkMu while executing task work, which may register + // more work. + for _, work := range queue { + work.TaskWork(t) + } + } + + // We're about to switch to the application again. If there's still an // unhandled SyscallRestartErrno that wasn't translated to an EINTR, // restart the syscall that was interrupted. If there's a saved signal // mask, restore it. (Note that restoring the saved signal mask may unblock @@ -245,7 +260,7 @@ func (app *runApp) execute(t *Task) taskRunState { region := trace.StartRegion(t.traceContext, runRegion) t.accountTaskGoroutineEnter(TaskGoroutineRunningApp) - info, at, err := t.p.Switch(t.MemoryManager().AddressSpace(), t.Arch(), t.rseqCPU) + info, at, err := t.p.Switch(t, t.MemoryManager(), t.Arch(), t.rseqCPU) t.accountTaskGoroutineLeave(TaskGoroutineRunningApp) region.End() diff --git a/pkg/sentry/kernel/task_signals.go b/pkg/sentry/kernel/task_signals.go index 79766cafe..cff2a8365 100644 --- a/pkg/sentry/kernel/task_signals.go +++ b/pkg/sentry/kernel/task_signals.go @@ -255,10 +255,11 @@ func (t *Task) deliverSignalToHandler(info *arch.SignalInfo, act arch.SignalAct) } } + mm := t.MemoryManager() // Set up the signal handler. If we have a saved signal mask, the signal // handler should run with the current mask, but sigreturn should restore // the saved one. - st := &arch.Stack{t.Arch(), t.MemoryManager(), sp} + st := &arch.Stack{t.Arch(), mm, sp} mask := t.signalMask if t.haveSavedSignalMask { mask = t.savedSignalMask @@ -273,12 +274,13 @@ func (t *Task) deliverSignalToHandler(info *arch.SignalInfo, act arch.SignalAct) // Please see the linux code as reference: // linux/arch/arm64/kernel/signal.c:setup_return() if act.Flags&linux.SA_RESTORER == 0 { - act.Restorer = t.MemoryManager().VDSOSigReturn() + act.Restorer = mm.VDSOSigReturn() } if err := t.Arch().SignalSetup(st, &act, info, &alt, mask); err != nil { return err } + t.p.FullStateChanged() t.haveSavedSignalMask = false // Add our signal mask. @@ -310,6 +312,7 @@ func (t *Task) SignalReturn(rt bool) (*SyscallControl, error) { // Restore our signal mask. SIGKILL and SIGSTOP should not be blocked. t.SetSignalMask(sigset &^ UnblockableSignals) + t.p.FullStateChanged() return ctrlResume, nil } @@ -636,6 +639,7 @@ func (t *Task) SetSavedSignalMask(mask linux.SignalSet) { // SignalStack returns the task-private signal stack. func (t *Task) SignalStack() arch.SignalStack { + t.p.PullFullState(t.MemoryManager().AddressSpace(), t.Arch()) alt := t.signalStack if t.onSignalStack(alt) { alt.Flags |= arch.SignalStackFlagOnStack @@ -1050,6 +1054,8 @@ func (*runInterrupt) execute(t *Task) taskRunState { // Are there signals pending? if info := t.dequeueSignalLocked(t.signalMask); info != nil { + t.p.PullFullState(t.MemoryManager().AddressSpace(), t.Arch()) + if linux.SignalSetOf(linux.Signal(info.Signo))&StopSignals != 0 { // Indicate that we've dequeued a stop signal before unlocking the // signal mutex; initiateGroupStop will check for races with diff --git a/pkg/sentry/kernel/task_start.go b/pkg/sentry/kernel/task_start.go index 8485fb4b6..64c1e120a 100644 --- a/pkg/sentry/kernel/task_start.go +++ b/pkg/sentry/kernel/task_start.go @@ -102,10 +102,10 @@ func (ts *TaskSet) NewTask(cfg *TaskConfig) (*Task, error) { t, err := ts.newTask(cfg) if err != nil { cfg.TaskContext.release() - cfg.FSContext.DecRef() - cfg.FDTable.DecRef() + cfg.FSContext.DecRef(t) + cfg.FDTable.DecRef(t) if cfg.MountNamespaceVFS2 != nil { - cfg.MountNamespaceVFS2.DecRef() + cfg.MountNamespaceVFS2.DecRef(t) } return nil, err } diff --git a/pkg/sentry/kernel/task_stop.go b/pkg/sentry/kernel/task_stop.go index 10c6e455c..296735d32 100644 --- a/pkg/sentry/kernel/task_stop.go +++ b/pkg/sentry/kernel/task_stop.go @@ -205,6 +205,22 @@ func (ts *TaskSet) BeginExternalStop() { } } +// PullFullState receives full states for all tasks. +func (ts *TaskSet) PullFullState() { + ts.mu.Lock() + defer ts.mu.Unlock() + if ts.Root == nil { + return + } + for t := range ts.Root.tids { + t.Activate() + if mm := t.MemoryManager(); mm != nil { + t.p.PullFullState(t.MemoryManager().AddressSpace(), t.Arch()) + } + t.Deactivate() + } +} + // EndExternalStop indicates the end of an external stop started by a previous // call to TaskSet.BeginExternalStop. EndExternalStop does not wait for task // goroutines to resume. diff --git a/pkg/sentry/kernel/task_work.go b/pkg/sentry/kernel/task_work.go new file mode 100644 index 000000000..dda5a433a --- /dev/null +++ b/pkg/sentry/kernel/task_work.go @@ -0,0 +1,38 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package kernel + +import "sync/atomic" + +// TaskWorker is a deferred task. +// +// This must be savable. +type TaskWorker interface { + // TaskWork will be executed prior to returning to user space. Note that + // TaskWork may call RegisterWork again, but this will not be executed until + // the next return to user space, unlike in Linux. This effectively allows + // registration of indefinite user return hooks, but not by default. + TaskWork(t *Task) +} + +// RegisterWork can be used to register additional task work that will be +// performed prior to returning to user space. See TaskWorker.TaskWork for +// semantics regarding registration. +func (t *Task) RegisterWork(work TaskWorker) { + t.taskWorkMu.Lock() + defer t.taskWorkMu.Unlock() + atomic.AddInt32(&t.taskWorkCount, 1) + t.taskWork = append(t.taskWork, work) +} diff --git a/pkg/sentry/kernel/thread_group.go b/pkg/sentry/kernel/thread_group.go index 52849f5b3..0b34c0099 100644 --- a/pkg/sentry/kernel/thread_group.go +++ b/pkg/sentry/kernel/thread_group.go @@ -308,7 +308,7 @@ func (tg *ThreadGroup) Limits() *limits.LimitSet { } // release releases the thread group's resources. -func (tg *ThreadGroup) release() { +func (tg *ThreadGroup) release(t *Task) { // Timers must be destroyed without holding the TaskSet or signal mutexes // since timers send signals with Timer.mu locked. tg.itimerRealTimer.Destroy() @@ -325,7 +325,7 @@ func (tg *ThreadGroup) release() { it.DestroyTimer() } if tg.mounts != nil { - tg.mounts.DecRef() + tg.mounts.DecRef(t) } } @@ -366,7 +366,8 @@ func (tg *ThreadGroup) SetControllingTTY(tty *TTY, arg int32) error { // terminal is stolen, and all processes that had it as controlling // terminal lose it." - tty_ioctl(4) if tty.tg != nil && tg.processGroup.session != tty.tg.processGroup.session { - if !auth.CredentialsFromContext(tg.leader).HasCapability(linux.CAP_SYS_ADMIN) || arg != 1 { + // Stealing requires CAP_SYS_ADMIN in the root user namespace. + if creds := auth.CredentialsFromContext(tg.leader); !creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, creds.UserNamespace.Root()) || arg != 1 { return syserror.EPERM } // Steal the TTY away. Unlike TIOCNOTTY, don't send signals. diff --git a/pkg/sentry/kernel/threads.go b/pkg/sentry/kernel/threads.go index bf2dabb6e..872e1a82d 100644 --- a/pkg/sentry/kernel/threads.go +++ b/pkg/sentry/kernel/threads.go @@ -87,6 +87,13 @@ type TaskSet struct { // at time of save (but note that this is not necessarily the same thing as // sync.WaitGroup's zero value). runningGoroutines sync.WaitGroup `state:"nosave"` + + // aioGoroutines is the number of goroutines running async I/O + // callbacks. + // + // aioGoroutines is not saved but is required to be zero at the time of + // save. + aioGoroutines sync.WaitGroup `state:"nosave"` } // newTaskSet returns a new, empty TaskSet. diff --git a/pkg/sentry/kernel/time/BUILD b/pkg/sentry/kernel/time/BUILD index 7ba7dc50c..2817aa3ba 100644 --- a/pkg/sentry/kernel/time/BUILD +++ b/pkg/sentry/kernel/time/BUILD @@ -6,6 +6,7 @@ go_library( name = "time", srcs = [ "context.go", + "tcpip.go", "time.go", ], visibility = ["//pkg/sentry:internal"], diff --git a/pkg/sentry/kernel/time/tcpip.go b/pkg/sentry/kernel/time/tcpip.go new file mode 100644 index 000000000..c4474c0cf --- /dev/null +++ b/pkg/sentry/kernel/time/tcpip.go @@ -0,0 +1,131 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package time + +import ( + "sync" + "time" +) + +// TcpipAfterFunc waits for duration to elapse according to clock then runs fn. +// The timer is started immediately and will fire exactly once. +func TcpipAfterFunc(clock Clock, duration time.Duration, fn func()) *TcpipTimer { + timer := &TcpipTimer{ + clock: clock, + } + timer.notifier = functionNotifier{ + fn: func() { + // tcpip.Timer.Stop() explicitly states that the function is called in a + // separate goroutine that Stop() does not synchronize with. + // Timer.Destroy() synchronizes with calls to TimerListener.Notify(). + // This is semantically meaningful because, in the former case, it's + // legal to call tcpip.Timer.Stop() while holding locks that may also be + // taken by the function, but this isn't so in the latter case. Most + // immediately, Timer calls TimerListener.Notify() while holding + // Timer.mu. A deadlock occurs without spawning a goroutine: + // T1: (Timer expires) + // => Timer.Tick() <- Timer.mu.Lock() called + // => TimerListener.Notify() + // => Timer.Stop() + // => Timer.Destroy() <- Timer.mu.Lock() called, deadlock! + // + // Spawning a goroutine avoids the deadlock: + // T1: (Timer expires) + // => Timer.Tick() <- Timer.mu.Lock() called + // => TimerListener.Notify() <- Launches T2 + // T2: + // => Timer.Stop() + // => Timer.Destroy() <- Timer.mu.Lock() called, blocks + // T1: + // => (returns) <- Timer.mu.Unlock() called + // T2: + // => (continues) <- No deadlock! + go func() { + timer.Stop() + fn() + }() + }, + } + timer.Reset(duration) + return timer +} + +// TcpipTimer is a resettable timer with variable duration expirations. +// Implements tcpip.Timer, which does not define a Destroy method; instead, all +// resources are released after timer expiration and calls to Timer.Stop. +// +// Must be created by AfterFunc. +type TcpipTimer struct { + // clock is the time source. clock is immutable. + clock Clock + + // notifier is called when the Timer expires. notifier is immutable. + notifier functionNotifier + + // mu protects t. + mu sync.Mutex + + // t stores the latest running Timer. This is replaced whenever Reset is + // called since Timer cannot be restarted once it has been Destroyed by Stop. + // + // This field is nil iff Stop has been called. + t *Timer +} + +// Stop implements tcpip.Timer.Stop. +func (r *TcpipTimer) Stop() bool { + r.mu.Lock() + defer r.mu.Unlock() + + if r.t == nil { + return false + } + _, lastSetting := r.t.Swap(Setting{}) + r.t.Destroy() + r.t = nil + return lastSetting.Enabled +} + +// Reset implements tcpip.Timer.Reset. +func (r *TcpipTimer) Reset(d time.Duration) { + r.mu.Lock() + defer r.mu.Unlock() + + if r.t == nil { + r.t = NewTimer(r.clock, &r.notifier) + } + + r.t.Swap(Setting{ + Enabled: true, + Period: 0, + Next: r.clock.Now().Add(d), + }) +} + +// functionNotifier is a TimerListener that runs a function. +// +// functionNotifier cannot be saved or loaded. +type functionNotifier struct { + fn func() +} + +// Notify implements ktime.TimerListener.Notify. +func (f *functionNotifier) Notify(uint64, Setting) (Setting, bool) { + f.fn() + return Setting{}, false +} + +// Destroy implements ktime.TimerListener.Destroy. +func (f *functionNotifier) Destroy() {} diff --git a/pkg/sentry/kernel/timekeeper.go b/pkg/sentry/kernel/timekeeper.go index da0ea7bb5..7c4fefb16 100644 --- a/pkg/sentry/kernel/timekeeper.go +++ b/pkg/sentry/kernel/timekeeper.go @@ -21,8 +21,8 @@ import ( "gvisor.dev/gvisor/pkg/log" ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" sentrytime "gvisor.dev/gvisor/pkg/sentry/time" "gvisor.dev/gvisor/pkg/sync" ) @@ -90,7 +90,7 @@ type Timekeeper struct { // NewTimekeeper does not take ownership of paramPage. // // SetClocks must be called on the returned Timekeeper before it is usable. -func NewTimekeeper(mfp pgalloc.MemoryFileProvider, paramPage platform.FileRange) (*Timekeeper, error) { +func NewTimekeeper(mfp pgalloc.MemoryFileProvider, paramPage memmap.FileRange) (*Timekeeper, error) { return &Timekeeper{ params: NewVDSOParamPage(mfp, paramPage), }, nil @@ -186,6 +186,7 @@ func (t *Timekeeper) startUpdater() { timer := time.NewTicker(sentrytime.ApproxUpdateInterval) t.wg.Add(1) go func() { // S/R-SAFE: stopped during save. + defer t.wg.Done() for { // Start with an update immediately, so the clocks are // ready ASAP. @@ -209,9 +210,6 @@ func (t *Timekeeper) startUpdater() { p.realtimeBaseRef = int64(realtimeParams.BaseRef) p.realtimeFrequency = realtimeParams.Frequency } - - log.Debugf("Updating VDSO parameters: %+v", p) - return p }); err != nil { log.Warningf("Unable to update VDSO parameter page: %v", err) @@ -220,7 +218,6 @@ func (t *Timekeeper) startUpdater() { select { case <-timer.C: case <-t.stop: - t.wg.Done() return } } diff --git a/pkg/sentry/kernel/vdso.go b/pkg/sentry/kernel/vdso.go index f1b3c212c..290c32466 100644 --- a/pkg/sentry/kernel/vdso.go +++ b/pkg/sentry/kernel/vdso.go @@ -19,8 +19,8 @@ import ( "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/safemem" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/usermem" ) @@ -58,7 +58,7 @@ type vdsoParams struct { type VDSOParamPage struct { // The parameter page is fr, allocated from mfp.MemoryFile(). mfp pgalloc.MemoryFileProvider - fr platform.FileRange + fr memmap.FileRange // seq is the current sequence count written to the page. // @@ -81,7 +81,7 @@ type VDSOParamPage struct { // * VDSOParamPage must be the only writer to fr. // // * mfp.MemoryFile().MapInternal(fr) must return a single safemem.Block. -func NewVDSOParamPage(mfp pgalloc.MemoryFileProvider, fr platform.FileRange) *VDSOParamPage { +func NewVDSOParamPage(mfp pgalloc.MemoryFileProvider, fr memmap.FileRange) *VDSOParamPage { return &VDSOParamPage{mfp: mfp, fr: fr} } diff --git a/pkg/sentry/loader/BUILD b/pkg/sentry/loader/BUILD index c6aa65f28..34bdb0b69 100644 --- a/pkg/sentry/loader/BUILD +++ b/pkg/sentry/loader/BUILD @@ -30,9 +30,6 @@ go_library( "//pkg/rand", "//pkg/safemem", "//pkg/sentry/arch", - "//pkg/sentry/fs", - "//pkg/sentry/fs/anon", - "//pkg/sentry/fs/fsutil", "//pkg/sentry/fsbridge", "//pkg/sentry/kernel/auth", "//pkg/sentry/limits", @@ -45,6 +42,5 @@ go_library( "//pkg/syserr", "//pkg/syserror", "//pkg/usermem", - "//pkg/waiter", ], ) diff --git a/pkg/sentry/loader/elf.go b/pkg/sentry/loader/elf.go index 616fafa2c..20dd1cc21 100644 --- a/pkg/sentry/loader/elf.go +++ b/pkg/sentry/loader/elf.go @@ -90,14 +90,23 @@ type elfInfo struct { sharedObject bool } +// fullReader interface extracts the ReadFull method from fsbridge.File so that +// client code does not need to define an entire fsbridge.File when only read +// functionality is needed. +// +// TODO(gvisor.dev/issue/1035): Once VFS2 ships, rewrite this to wrap +// vfs.FileDescription's PRead/Read instead. +type fullReader interface { + // ReadFull is the same as fsbridge.File.ReadFull. + ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) +} + // parseHeader parse the ELF header, verifying that this is a supported ELF // file and returning the ELF program headers. // // This is similar to elf.NewFile, except that it is more strict about what it // accepts from the ELF, and it doesn't parse unnecessary parts of the file. -// -// ctx may be nil if f does not need it. -func parseHeader(ctx context.Context, f fsbridge.File) (elfInfo, error) { +func parseHeader(ctx context.Context, f fullReader) (elfInfo, error) { // Check ident first; it will tell us the endianness of the rest of the // structs. var ident [elf.EI_NIDENT]byte @@ -272,7 +281,7 @@ func mapSegment(ctx context.Context, m *mm.MemoryManager, f fsbridge.File, phdr } defer func() { if mopts.MappingIdentity != nil { - mopts.MappingIdentity.DecRef() + mopts.MappingIdentity.DecRef(ctx) } }() if err := f.ConfigureMMap(ctx, &mopts); err != nil { @@ -654,7 +663,7 @@ func loadELF(ctx context.Context, args LoadArgs) (loadedELF, arch.Context, error ctx.Infof("Error opening interpreter %s: %v", bin.interpreter, err) return loadedELF{}, nil, err } - defer intFile.DecRef() + defer intFile.DecRef(ctx) interp, err = loadInterpreterELF(ctx, args.MemoryManager, intFile, bin) if err != nil { diff --git a/pkg/sentry/loader/loader.go b/pkg/sentry/loader/loader.go index 88449fe95..8d6802ea3 100644 --- a/pkg/sentry/loader/loader.go +++ b/pkg/sentry/loader/loader.go @@ -27,7 +27,6 @@ import ( "gvisor.dev/gvisor/pkg/cpuid" "gvisor.dev/gvisor/pkg/rand" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sentry/mm" @@ -80,22 +79,6 @@ type LoadArgs struct { Features *cpuid.FeatureSet } -// readFull behaves like io.ReadFull for an *fs.File. -func readFull(ctx context.Context, f *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { - var total int64 - for dst.NumBytes() > 0 { - n, err := f.Preadv(ctx, dst, offset+total) - total += n - if err == io.EOF && total != 0 { - return total, io.ErrUnexpectedEOF - } else if err != nil { - return total, err - } - dst = dst.DropFirst64(n) - } - return total, nil -} - // openPath opens args.Filename and checks that it is valid for loading. // // openPath returns an *fs.Dirent and *fs.File for args.Filename, which is not @@ -171,7 +154,7 @@ func loadExecutable(ctx context.Context, args LoadArgs) (loadedELF, arch.Context return loadedELF{}, nil, nil, nil, err } // Ensure file is release in case the code loops or errors out. - defer args.File.DecRef() + defer args.File.DecRef(ctx) } else { if err := checkIsRegularFile(ctx, args.File, args.Filename); err != nil { return loadedELF{}, nil, nil, nil, err @@ -238,14 +221,14 @@ func Load(ctx context.Context, args LoadArgs, extraAuxv []arch.AuxEntry, vdso *V // Load the executable itself. loaded, ac, file, newArgv, err := loadExecutable(ctx, args) if err != nil { - return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("Failed to load %s: %v", args.Filename, err), syserr.FromError(err).ToLinux()) + return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("failed to load %s: %v", args.Filename, err), syserr.FromError(err).ToLinux()) } - defer file.DecRef() + defer file.DecRef(ctx) // Load the VDSO. vdsoAddr, err := loadVDSO(ctx, args.MemoryManager, vdso, loaded) if err != nil { - return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("Error loading VDSO: %v", err), syserr.FromError(err).ToLinux()) + return 0, nil, "", syserr.NewDynamic(fmt.Sprintf("error loading VDSO: %v", err), syserr.FromError(err).ToLinux()) } // Setup the heap. brk starts at the next page after the end of the @@ -309,7 +292,7 @@ func Load(ctx context.Context, args LoadArgs, extraAuxv []arch.AuxEntry, vdso *V m.SetEnvvStart(sl.EnvvStart) m.SetEnvvEnd(sl.EnvvEnd) m.SetAuxv(auxv) - m.SetExecutable(file) + m.SetExecutable(ctx, file) symbolValue, err := getSymbolValueFromVDSO("rt_sigreturn") if err != nil { diff --git a/pkg/sentry/loader/vdso.go b/pkg/sentry/loader/vdso.go index 00977fc08..05a294fe6 100644 --- a/pkg/sentry/loader/vdso.go +++ b/pkg/sentry/loader/vdso.go @@ -26,10 +26,6 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/fs" - "gvisor.dev/gvisor/pkg/sentry/fs/anon" - "gvisor.dev/gvisor/pkg/sentry/fs/fsutil" - "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/mm" "gvisor.dev/gvisor/pkg/sentry/pgalloc" @@ -37,7 +33,6 @@ import ( "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" - "gvisor.dev/gvisor/pkg/waiter" ) const vdsoPrelink = 0xffffffffff700000 @@ -55,52 +50,11 @@ func (f *fileContext) Value(key interface{}) interface{} { } } -// byteReader implements fs.FileOperations for reading from a []byte source. -type byteReader struct { - fsutil.FileNoFsync `state:"nosave"` - fsutil.FileNoIoctl `state:"nosave"` - fsutil.FileNoMMap `state:"nosave"` - fsutil.FileNoSplice `state:"nosave"` - fsutil.FileNoopFlush `state:"nosave"` - fsutil.FileNoopRelease `state:"nosave"` - fsutil.FileNotDirReaddir `state:"nosave"` - fsutil.FilePipeSeek `state:"nosave"` - fsutil.FileUseInodeUnstableAttr `state:"nosave"` - waiter.AlwaysReady `state:"nosave"` - +type byteFullReader struct { data []byte } -var _ fs.FileOperations = (*byteReader)(nil) - -// newByteReaderFile creates a fake file to read data from. -// -// TODO(gvisor.dev/issue/1623): Convert to VFS2. -func newByteReaderFile(ctx context.Context, data []byte) *fs.File { - // Create a fake inode. - inode := fs.NewInode( - ctx, - &fsutil.SimpleFileInode{}, - fs.NewPseudoMountSource(ctx), - fs.StableAttr{ - Type: fs.Anonymous, - DeviceID: anon.PseudoDevice.DeviceID(), - InodeID: anon.PseudoDevice.NextIno(), - BlockSize: usermem.PageSize, - }) - - // Use the fake inode to create a fake dirent. - dirent := fs.NewTransientDirent(inode) - defer dirent.DecRef() - - // Use the fake dirent to make a fake file. - flags := fs.FileFlags{Read: true, Pread: true} - return fs.NewFile(&fileContext{Context: context.Background()}, dirent, flags, &byteReader{ - data: data, - }) -} - -func (b *byteReader) Read(ctx context.Context, file *fs.File, dst usermem.IOSequence, offset int64) (int64, error) { +func (b *byteFullReader) ReadFull(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) { if offset < 0 { return 0, syserror.EINVAL } @@ -111,10 +65,6 @@ func (b *byteReader) Read(ctx context.Context, file *fs.File, dst usermem.IOSequ return int64(n), err } -func (b *byteReader) Write(ctx context.Context, file *fs.File, src usermem.IOSequence, offset int64) (int64, error) { - panic("Write not supported") -} - // validateVDSO checks that the VDSO can be loaded by loadVDSO. // // VDSOs are special (see below). Since we are going to map the VDSO directly @@ -130,7 +80,7 @@ func (b *byteReader) Write(ctx context.Context, file *fs.File, src usermem.IOSeq // * PT_LOAD segments don't extend beyond the end of the file. // // ctx may be nil if f does not need it. -func validateVDSO(ctx context.Context, f fsbridge.File, size uint64) (elfInfo, error) { +func validateVDSO(ctx context.Context, f fullReader, size uint64) (elfInfo, error) { info, err := parseHeader(ctx, f) if err != nil { log.Infof("Unable to parse VDSO header: %v", err) @@ -248,13 +198,12 @@ func getSymbolValueFromVDSO(symbol string) (uint64, error) { // PrepareVDSO validates the system VDSO and returns a VDSO, containing the // param page for updating by the kernel. -func PrepareVDSO(ctx context.Context, mfp pgalloc.MemoryFileProvider) (*VDSO, error) { - vdsoFile := fsbridge.NewFSFile(newByteReaderFile(ctx, vdsoBin)) +func PrepareVDSO(mfp pgalloc.MemoryFileProvider) (*VDSO, error) { + vdsoFile := &byteFullReader{data: vdsoBin} // First make sure the VDSO is valid. vdsoFile does not use ctx, so a // nil context can be passed. info, err := validateVDSO(nil, vdsoFile, uint64(len(vdsoBin))) - vdsoFile.DecRef() if err != nil { return nil, err } diff --git a/pkg/sentry/memmap/BUILD b/pkg/sentry/memmap/BUILD index a98b66de1..2c95669cd 100644 --- a/pkg/sentry/memmap/BUILD +++ b/pkg/sentry/memmap/BUILD @@ -28,9 +28,21 @@ go_template_instance( }, ) +go_template_instance( + name = "file_range", + out = "file_range.go", + package = "memmap", + prefix = "File", + template = "//pkg/segment:generic_range", + types = { + "T": "uint64", + }, +) + go_library( name = "memmap", srcs = [ + "file_range.go", "mappable_range.go", "mapping_set.go", "mapping_set_impl.go", @@ -40,7 +52,7 @@ go_library( deps = [ "//pkg/context", "//pkg/log", - "//pkg/sentry/platform", + "//pkg/safemem", "//pkg/syserror", "//pkg/usermem", ], diff --git a/pkg/sentry/memmap/memmap.go b/pkg/sentry/memmap/memmap.go index c6db9fc8f..65d83096f 100644 --- a/pkg/sentry/memmap/memmap.go +++ b/pkg/sentry/memmap/memmap.go @@ -19,12 +19,12 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/sentry/platform" + "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/usermem" ) // Mappable represents a memory-mappable object, a mutable mapping from uint64 -// offsets to (platform.File, uint64 File offset) pairs. +// offsets to (File, uint64 File offset) pairs. // // See mm/mm.go for Mappable's place in the lock order. // @@ -74,7 +74,7 @@ type Mappable interface { // Translations are valid until invalidated by a callback to // MappingSpace.Invalidate or until the caller removes its mapping of the // translated range. Mappable implementations must ensure that at least one - // reference is held on all pages in a platform.File that may be the result + // reference is held on all pages in a File that may be the result // of a valid Translation. // // Preconditions: required.Length() > 0. optional.IsSupersetOf(required). @@ -100,7 +100,7 @@ type Translation struct { Source MappableRange // File is the mapped file. - File platform.File + File File // Offset is the offset into File at which this Translation begins. Offset uint64 @@ -110,9 +110,9 @@ type Translation struct { Perms usermem.AccessType } -// FileRange returns the platform.FileRange represented by t. -func (t Translation) FileRange() platform.FileRange { - return platform.FileRange{t.Offset, t.Offset + t.Source.Length()} +// FileRange returns the FileRange represented by t. +func (t Translation) FileRange() FileRange { + return FileRange{t.Offset, t.Offset + t.Source.Length()} } // CheckTranslateResult returns an error if (ts, terr) does not satisfy all @@ -238,7 +238,7 @@ type MappingIdentity interface { IncRef() // DecRef decrements the MappingIdentity's reference count. - DecRef() + DecRef(ctx context.Context) // MappedName returns the application-visible name shown in // /proc/[pid]/maps. @@ -360,4 +360,57 @@ type MMapOpts struct { // // TODO(jamieliu): Replace entirely with MappingIdentity? Hint string + + // Force means to skip validation checks of Addr and Length. It can be + // used to create special mappings below mm.layout.MinAddr and + // mm.layout.MaxAddr. It has to be used with caution. + // + // If Force is true, Unmap and Fixed must be true. + Force bool +} + +// File represents a host file that may be mapped into an platform.AddressSpace. +type File interface { + // All pages in a File are reference-counted. + + // IncRef increments the reference count on all pages in fr. + // + // Preconditions: fr.Start and fr.End must be page-aligned. fr.Length() > + // 0. At least one reference must be held on all pages in fr. (The File + // interface does not provide a way to acquire an initial reference; + // implementors may define mechanisms for doing so.) + IncRef(fr FileRange) + + // DecRef decrements the reference count on all pages in fr. + // + // Preconditions: fr.Start and fr.End must be page-aligned. fr.Length() > + // 0. At least one reference must be held on all pages in fr. + DecRef(fr FileRange) + + // MapInternal returns a mapping of the given file offsets in the invoking + // process' address space for reading and writing. + // + // Note that fr.Start and fr.End need not be page-aligned. + // + // Preconditions: fr.Length() > 0. At least one reference must be held on + // all pages in fr. + // + // Postconditions: The returned mapping is valid as long as at least one + // reference is held on the mapped pages. + MapInternal(fr FileRange, at usermem.AccessType) (safemem.BlockSeq, error) + + // FD returns the file descriptor represented by the File. + // + // The only permitted operation on the returned file descriptor is to map + // pages from it consistent with the requirements of AddressSpace.MapFile. + FD() int +} + +// FileRange represents a range of uint64 offsets into a File. +// +// type FileRange <generated using go_generics> + +// String implements fmt.Stringer.String. +func (fr FileRange) String() string { + return fmt.Sprintf("[%#x, %#x)", fr.Start, fr.End) } diff --git a/pkg/sentry/mm/BUILD b/pkg/sentry/mm/BUILD index a036ce53c..f9d0837a1 100644 --- a/pkg/sentry/mm/BUILD +++ b/pkg/sentry/mm/BUILD @@ -7,14 +7,14 @@ go_template_instance( name = "file_refcount_set", out = "file_refcount_set.go", imports = { - "platform": "gvisor.dev/gvisor/pkg/sentry/platform", + "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap", }, package = "mm", prefix = "fileRefcount", template = "//pkg/segment:generic_set", types = { "Key": "uint64", - "Range": "platform.FileRange", + "Range": "memmap.FileRange", "Value": "int32", "Functions": "fileRefcountSetFunctions", }, diff --git a/pkg/sentry/mm/aio_context.go b/pkg/sentry/mm/aio_context.go index 379148903..16fea53c4 100644 --- a/pkg/sentry/mm/aio_context.go +++ b/pkg/sentry/mm/aio_context.go @@ -20,7 +20,6 @@ import ( "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" @@ -243,7 +242,7 @@ type aioMappable struct { refs.AtomicRefCount mfp pgalloc.MemoryFileProvider - fr platform.FileRange + fr memmap.FileRange } var aioRingBufferSize = uint64(usermem.Addr(linux.AIORingSize).MustRoundUp()) @@ -259,8 +258,8 @@ func newAIOMappable(mfp pgalloc.MemoryFileProvider) (*aioMappable, error) { } // DecRef implements refs.RefCounter.DecRef. -func (m *aioMappable) DecRef() { - m.AtomicRefCount.DecRefWithDestructor(func() { +func (m *aioMappable) DecRef(ctx context.Context) { + m.AtomicRefCount.DecRefWithDestructor(ctx, func(context.Context) { m.mfp.MemoryFile().DecRef(m.fr) }) } @@ -368,7 +367,7 @@ func (mm *MemoryManager) NewAIOContext(ctx context.Context, events uint32) (uint if err != nil { return 0, err } - defer m.DecRef() + defer m.DecRef(ctx) addr, err := mm.MMap(ctx, memmap.MMapOpts{ Length: aioRingBufferSize, MappingIdentity: m, diff --git a/pkg/sentry/mm/lifecycle.go b/pkg/sentry/mm/lifecycle.go index aac56679b..09dbc06a4 100644 --- a/pkg/sentry/mm/lifecycle.go +++ b/pkg/sentry/mm/lifecycle.go @@ -57,6 +57,8 @@ func (mm *MemoryManager) SetMmapLayout(ac arch.Context, r *limits.LimitSet) (arc // Fork creates a copy of mm with 1 user, as for Linux syscalls fork() or // clone() (without CLONE_VM). func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error) { + mm.AddressSpace().PreFork() + defer mm.AddressSpace().PostFork() mm.metadataMu.Lock() defer mm.metadataMu.Unlock() mm.mappingMu.RLock() @@ -258,7 +260,7 @@ func (mm *MemoryManager) DecUsers(ctx context.Context) { mm.executable = nil mm.metadataMu.Unlock() if exe != nil { - exe.DecRef() + exe.DecRef(ctx) } mm.activeMu.Lock() diff --git a/pkg/sentry/mm/metadata.go b/pkg/sentry/mm/metadata.go index 28e5057f7..0cfd60f6c 100644 --- a/pkg/sentry/mm/metadata.go +++ b/pkg/sentry/mm/metadata.go @@ -15,6 +15,7 @@ package mm import ( + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/fsbridge" "gvisor.dev/gvisor/pkg/usermem" @@ -147,7 +148,7 @@ func (mm *MemoryManager) Executable() fsbridge.File { // SetExecutable sets the executable. // // This takes a reference on d. -func (mm *MemoryManager) SetExecutable(file fsbridge.File) { +func (mm *MemoryManager) SetExecutable(ctx context.Context, file fsbridge.File) { mm.metadataMu.Lock() // Grab a new reference. @@ -164,7 +165,7 @@ func (mm *MemoryManager) SetExecutable(file fsbridge.File) { // Do this without holding the lock, since it may wind up doing some // I/O to sync the dirent, etc. if orig != nil { - orig.DecRef() + orig.DecRef(ctx) } } diff --git a/pkg/sentry/mm/mm.go b/pkg/sentry/mm/mm.go index 6db7c3d40..3e85964e4 100644 --- a/pkg/sentry/mm/mm.go +++ b/pkg/sentry/mm/mm.go @@ -25,7 +25,7 @@ // Locks taken by memmap.Mappable.Translate // mm.privateRefs.mu // platform.AddressSpace locks -// platform.File locks +// memmap.File locks // mm.aioManager.mu // mm.AIOContext.mu // @@ -396,7 +396,7 @@ type pma struct { // file is the file mapped by this pma. Only pmas for which file == // MemoryManager.mfp.MemoryFile() may be saved. pmas hold a reference to // the corresponding file range while they exist. - file platform.File `state:"nosave"` + file memmap.File `state:"nosave"` // off is the offset into file at which this pma begins. // @@ -436,7 +436,7 @@ type pma struct { private bool // If internalMappings is not empty, it is the cached return value of - // file.MapInternal for the platform.FileRange mapped by this pma. + // file.MapInternal for the memmap.FileRange mapped by this pma. internalMappings safemem.BlockSeq `state:"nosave"` } @@ -469,10 +469,10 @@ func (fileRefcountSetFunctions) MaxKey() uint64 { func (fileRefcountSetFunctions) ClearValue(_ *int32) { } -func (fileRefcountSetFunctions) Merge(_ platform.FileRange, rc1 int32, _ platform.FileRange, rc2 int32) (int32, bool) { +func (fileRefcountSetFunctions) Merge(_ memmap.FileRange, rc1 int32, _ memmap.FileRange, rc2 int32) (int32, bool) { return rc1, rc1 == rc2 } -func (fileRefcountSetFunctions) Split(_ platform.FileRange, rc int32, _ uint64) (int32, int32) { +func (fileRefcountSetFunctions) Split(_ memmap.FileRange, rc int32, _ uint64) (int32, int32) { return rc, rc } diff --git a/pkg/sentry/mm/pma.go b/pkg/sentry/mm/pma.go index 62e4c20af..930ec895f 100644 --- a/pkg/sentry/mm/pma.go +++ b/pkg/sentry/mm/pma.go @@ -21,7 +21,6 @@ import ( "gvisor.dev/gvisor/pkg/safecopy" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/memmap" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" @@ -604,7 +603,7 @@ func (mm *MemoryManager) invalidateLocked(ar usermem.AddrRange, invalidatePrivat } } -// Pin returns the platform.File ranges currently mapped by addresses in ar in +// Pin returns the memmap.File ranges currently mapped by addresses in ar in // mm, acquiring a reference on the returned ranges which the caller must // release by calling Unpin. If not all addresses are mapped, Pin returns a // non-nil error. Note that Pin may return both a non-empty slice of @@ -674,15 +673,15 @@ type PinnedRange struct { Source usermem.AddrRange // File is the mapped file. - File platform.File + File memmap.File // Offset is the offset into File at which this PinnedRange begins. Offset uint64 } -// FileRange returns the platform.File offsets mapped by pr. -func (pr PinnedRange) FileRange() platform.FileRange { - return platform.FileRange{pr.Offset, pr.Offset + uint64(pr.Source.Length())} +// FileRange returns the memmap.File offsets mapped by pr. +func (pr PinnedRange) FileRange() memmap.FileRange { + return memmap.FileRange{pr.Offset, pr.Offset + uint64(pr.Source.Length())} } // Unpin releases the reference held by prs. @@ -857,7 +856,7 @@ func (mm *MemoryManager) vecInternalMappingsLocked(ars usermem.AddrRangeSeq) saf } // incPrivateRef acquires a reference on private pages in fr. -func (mm *MemoryManager) incPrivateRef(fr platform.FileRange) { +func (mm *MemoryManager) incPrivateRef(fr memmap.FileRange) { mm.privateRefs.mu.Lock() defer mm.privateRefs.mu.Unlock() refSet := &mm.privateRefs.refs @@ -878,8 +877,8 @@ func (mm *MemoryManager) incPrivateRef(fr platform.FileRange) { } // decPrivateRef releases a reference on private pages in fr. -func (mm *MemoryManager) decPrivateRef(fr platform.FileRange) { - var freed []platform.FileRange +func (mm *MemoryManager) decPrivateRef(fr memmap.FileRange) { + var freed []memmap.FileRange mm.privateRefs.mu.Lock() refSet := &mm.privateRefs.refs @@ -951,7 +950,7 @@ func (pmaSetFunctions) Merge(ar1 usermem.AddrRange, pma1 pma, ar2 usermem.AddrRa // Discard internal mappings instead of trying to merge them, since merging // them requires an allocation and getting them again from the - // platform.File might not. + // memmap.File might not. pma1.internalMappings = safemem.BlockSeq{} return pma1, true } @@ -1012,12 +1011,12 @@ func (pseg pmaIterator) getInternalMappingsLocked() error { return nil } -func (pseg pmaIterator) fileRange() platform.FileRange { +func (pseg pmaIterator) fileRange() memmap.FileRange { return pseg.fileRangeOf(pseg.Range()) } // Preconditions: pseg.Range().IsSupersetOf(ar). ar.Length != 0. -func (pseg pmaIterator) fileRangeOf(ar usermem.AddrRange) platform.FileRange { +func (pseg pmaIterator) fileRangeOf(ar usermem.AddrRange) memmap.FileRange { if checkInvariants { if !pseg.Ok() { panic("terminal pma iterator") @@ -1032,5 +1031,5 @@ func (pseg pmaIterator) fileRangeOf(ar usermem.AddrRange) platform.FileRange { pma := pseg.ValuePtr() pstart := pseg.Start() - return platform.FileRange{pma.off + uint64(ar.Start-pstart), pma.off + uint64(ar.End-pstart)} + return memmap.FileRange{pma.off + uint64(ar.Start-pstart), pma.off + uint64(ar.End-pstart)} } diff --git a/pkg/sentry/mm/special_mappable.go b/pkg/sentry/mm/special_mappable.go index 9ad52082d..4cdb52eb6 100644 --- a/pkg/sentry/mm/special_mappable.go +++ b/pkg/sentry/mm/special_mappable.go @@ -19,7 +19,6 @@ import ( "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/pgalloc" - "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" @@ -35,7 +34,7 @@ type SpecialMappable struct { refs.AtomicRefCount mfp pgalloc.MemoryFileProvider - fr platform.FileRange + fr memmap.FileRange name string } @@ -44,15 +43,15 @@ type SpecialMappable struct { // SpecialMappable will use the given name in /proc/[pid]/maps. // // Preconditions: fr.Length() != 0. -func NewSpecialMappable(name string, mfp pgalloc.MemoryFileProvider, fr platform.FileRange) *SpecialMappable { +func NewSpecialMappable(name string, mfp pgalloc.MemoryFileProvider, fr memmap.FileRange) *SpecialMappable { m := SpecialMappable{mfp: mfp, fr: fr, name: name} m.EnableLeakCheck("mm.SpecialMappable") return &m } // DecRef implements refs.RefCounter.DecRef. -func (m *SpecialMappable) DecRef() { - m.AtomicRefCount.DecRefWithDestructor(func() { +func (m *SpecialMappable) DecRef(ctx context.Context) { + m.AtomicRefCount.DecRefWithDestructor(ctx, func(context.Context) { m.mfp.MemoryFile().DecRef(m.fr) }) } @@ -126,7 +125,7 @@ func (m *SpecialMappable) MemoryFileProvider() pgalloc.MemoryFileProvider { // FileRange returns the offsets into MemoryFileProvider().MemoryFile() that // store the SpecialMappable's contents. -func (m *SpecialMappable) FileRange() platform.FileRange { +func (m *SpecialMappable) FileRange() memmap.FileRange { return m.fr } diff --git a/pkg/sentry/mm/syscalls.go b/pkg/sentry/mm/syscalls.go index 3f496aa9f..e74d4e1c1 100644 --- a/pkg/sentry/mm/syscalls.go +++ b/pkg/sentry/mm/syscalls.go @@ -101,7 +101,7 @@ func (mm *MemoryManager) MMap(ctx context.Context, opts memmap.MMapOpts) (userme if err != nil { return 0, err } - defer m.DecRef() + defer m.DecRef(ctx) opts.MappingIdentity = m opts.Mappable = m } @@ -1191,7 +1191,7 @@ func (mm *MemoryManager) MSync(ctx context.Context, addr usermem.Addr, length ui mr := vseg.mappableRangeOf(vseg.Range().Intersect(ar)) mm.mappingMu.RUnlock() err := id.Msync(ctx, mr) - id.DecRef() + id.DecRef(ctx) if err != nil { return err } diff --git a/pkg/sentry/mm/vma.go b/pkg/sentry/mm/vma.go index 16d8207e9..c4e1989ed 100644 --- a/pkg/sentry/mm/vma.go +++ b/pkg/sentry/mm/vma.go @@ -42,7 +42,12 @@ func (mm *MemoryManager) createVMALocked(ctx context.Context, opts memmap.MMapOp Map32Bit: opts.Map32Bit, }) if err != nil { - return vmaIterator{}, usermem.AddrRange{}, err + // Can't force without opts.Unmap and opts.Fixed. + if opts.Force && opts.Unmap && opts.Fixed { + addr = opts.Addr + } else { + return vmaIterator{}, usermem.AddrRange{}, err + } } ar, _ := addr.ToRange(opts.Length) @@ -377,7 +382,7 @@ func (mm *MemoryManager) removeVMAsLocked(ctx context.Context, ar usermem.AddrRa vma.mappable.RemoveMapping(ctx, mm, vmaAR, vma.off, vma.canWriteMappableLocked()) } if vma.id != nil { - vma.id.DecRef() + vma.id.DecRef(ctx) } mm.usageAS -= uint64(vmaAR.Length()) if vma.isPrivateDataLocked() { @@ -446,7 +451,7 @@ func (vmaSetFunctions) Merge(ar1 usermem.AddrRange, vma1 vma, ar2 usermem.AddrRa } if vma2.id != nil { - vma2.id.DecRef() + vma2.id.DecRef(context.Background()) } return vma1, true } diff --git a/pkg/sentry/pgalloc/BUILD b/pkg/sentry/pgalloc/BUILD index 1eeb9f317..7a3311a70 100644 --- a/pkg/sentry/pgalloc/BUILD +++ b/pkg/sentry/pgalloc/BUILD @@ -33,21 +33,42 @@ go_template_instance( out = "usage_set.go", consts = { "minDegree": "10", + "trackGaps": "1", }, imports = { - "platform": "gvisor.dev/gvisor/pkg/sentry/platform", + "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap", }, package = "pgalloc", prefix = "usage", template = "//pkg/segment:generic_set", types = { "Key": "uint64", - "Range": "platform.FileRange", + "Range": "memmap.FileRange", "Value": "usageInfo", "Functions": "usageSetFunctions", }, ) +go_template_instance( + name = "reclaim_set", + out = "reclaim_set.go", + consts = { + "minDegree": "10", + }, + imports = { + "memmap": "gvisor.dev/gvisor/pkg/sentry/memmap", + }, + package = "pgalloc", + prefix = "reclaim", + template = "//pkg/segment:generic_set", + types = { + "Key": "uint64", + "Range": "memmap.FileRange", + "Value": "reclaimSetValue", + "Functions": "reclaimSetFunctions", + }, +) + go_library( name = "pgalloc", srcs = [ @@ -56,6 +77,7 @@ go_library( "evictable_range_set.go", "pgalloc.go", "pgalloc_unsafe.go", + "reclaim_set.go", "save_restore.go", "usage_set.go", ], @@ -67,9 +89,10 @@ go_library( "//pkg/safemem", "//pkg/sentry/arch", "//pkg/sentry/hostmm", - "//pkg/sentry/platform", + "//pkg/sentry/memmap", "//pkg/sentry/usage", "//pkg/state", + "//pkg/state/wire", "//pkg/sync", "//pkg/syserror", "//pkg/usermem", diff --git a/pkg/sentry/pgalloc/pgalloc.go b/pkg/sentry/pgalloc/pgalloc.go index 2b11ea4ae..46d3be58c 100644 --- a/pkg/sentry/pgalloc/pgalloc.go +++ b/pkg/sentry/pgalloc/pgalloc.go @@ -33,14 +33,14 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/sentry/hostmm" - "gvisor.dev/gvisor/pkg/sentry/platform" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" ) -// MemoryFile is a platform.File whose pages may be allocated to arbitrary +// MemoryFile is a memmap.File whose pages may be allocated to arbitrary // users. type MemoryFile struct { // opts holds options passed to NewMemoryFile. opts is immutable. @@ -108,12 +108,6 @@ type MemoryFile struct { usageSwapped uint64 usageLast time.Time - // minUnallocatedPage is the minimum page that may be unallocated. - // i.e., there are no unallocated pages below minUnallocatedPage. - // - // minUnallocatedPage is protected by mu. - minUnallocatedPage uint64 - // fileSize is the size of the backing memory file in bytes. fileSize is // always a power-of-two multiple of chunkSize. // @@ -146,11 +140,9 @@ type MemoryFile struct { // is protected by mu. reclaimable bool - // minReclaimablePage is the minimum page that may be reclaimable. - // i.e., all reclaimable pages are >= minReclaimablePage. - // - // minReclaimablePage is protected by mu. - minReclaimablePage uint64 + // relcaim is the collection of regions for reclaim. relcaim is protected + // by mu. + reclaim reclaimSet // reclaimCond is signaled (with mu locked) when reclaimable or destroyed // transitions from false to true. @@ -273,12 +265,10 @@ type evictableMemoryUserInfo struct { } const ( - chunkShift = 24 - chunkSize = 1 << chunkShift // 16 MB + chunkShift = 30 + chunkSize = 1 << chunkShift // 1 GB chunkMask = chunkSize - 1 - initialSize = chunkSize - // maxPage is the highest 64-bit page. maxPage = math.MaxUint64 &^ (usermem.PageSize - 1) ) @@ -302,19 +292,12 @@ func NewMemoryFile(file *os.File, opts MemoryFileOpts) (*MemoryFile, error) { if err := file.Truncate(0); err != nil { return nil, err } - if err := file.Truncate(initialSize); err != nil { - return nil, err - } f := &MemoryFile{ - opts: opts, - fileSize: initialSize, - file: file, - // No pages are reclaimable. DecRef will always be able to - // decrease minReclaimablePage from this point. - minReclaimablePage: maxPage, - evictable: make(map[EvictableMemoryUser]*evictableMemoryUserInfo), + opts: opts, + file: file, + evictable: make(map[EvictableMemoryUser]*evictableMemoryUserInfo), } - f.mappings.Store(make([]uintptr, initialSize/chunkSize)) + f.mappings.Store(make([]uintptr, 0)) f.reclaimCond.L = &f.mu if f.opts.DelayedEviction == DelayedEvictionEnabled && f.opts.UseHostMemcgPressure { @@ -389,7 +372,7 @@ func (f *MemoryFile) Destroy() { // to Allocate. // // Preconditions: length must be page-aligned and non-zero. -func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.FileRange, error) { +func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (memmap.FileRange, error) { if length == 0 || length%usermem.PageSize != 0 { panic(fmt.Sprintf("invalid allocation length: %#x", length)) } @@ -404,48 +387,38 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi alignment = usermem.HugePageSize } - start, minUnallocatedPage := findUnallocatedRange(&f.usage, f.minUnallocatedPage, length, alignment) - end := start + length - // File offsets are int64s. Since length must be strictly positive, end - // cannot legitimately be 0. - if end < start || int64(end) <= 0 { - return platform.FileRange{}, syserror.ENOMEM + // Find a range in the underlying file. + fr, ok := findAvailableRange(&f.usage, f.fileSize, length, alignment) + if !ok { + return memmap.FileRange{}, syserror.ENOMEM } - // Expand the file if needed. Double the file size on each expansion; - // uncommitted pages have effectively no cost. - fileSize := f.fileSize - for int64(end) > fileSize { - if fileSize >= 2*fileSize { - // fileSize overflow. - return platform.FileRange{}, syserror.ENOMEM + // Expand the file if needed. + if int64(fr.End) > f.fileSize { + // Round the new file size up to be chunk-aligned. + newFileSize := (int64(fr.End) + chunkMask) &^ chunkMask + if err := f.file.Truncate(newFileSize); err != nil { + return memmap.FileRange{}, err } - fileSize *= 2 - } - if fileSize > f.fileSize { - if err := f.file.Truncate(fileSize); err != nil { - return platform.FileRange{}, err - } - f.fileSize = fileSize + f.fileSize = newFileSize f.mappingsMu.Lock() oldMappings := f.mappings.Load().([]uintptr) - newMappings := make([]uintptr, fileSize>>chunkShift) + newMappings := make([]uintptr, newFileSize>>chunkShift) copy(newMappings, oldMappings) f.mappings.Store(newMappings) f.mappingsMu.Unlock() } - // Mark selected pages as in use. - fr := platform.FileRange{start, end} if f.opts.ManualZeroing { if err := f.forEachMappingSlice(fr, func(bs []byte) { for i := range bs { bs[i] = 0 } }); err != nil { - return platform.FileRange{}, err + return memmap.FileRange{}, err } } + // Mark selected pages as in use. if !f.usage.Add(fr, usageInfo{ kind: kind, refs: 1, @@ -453,49 +426,79 @@ func (f *MemoryFile) Allocate(length uint64, kind usage.MemoryKind) (platform.Fi panic(fmt.Sprintf("allocating %v: failed to insert into usage set:\n%v", fr, &f.usage)) } - if minUnallocatedPage < start { - f.minUnallocatedPage = minUnallocatedPage - } else { - // start was the first unallocated page. The next must be - // somewhere beyond end. - f.minUnallocatedPage = end - } - return fr, nil } -// findUnallocatedRange returns the first unallocated page in usage of the -// specified length and alignment beginning at page start and the first single -// unallocated page. -func findUnallocatedRange(usage *usageSet, start, length, alignment uint64) (uint64, uint64) { - // Only searched until the first page is found. - firstPage := start - foundFirstPage := false - alignMask := alignment - 1 - for seg := usage.LowerBoundSegment(start); seg.Ok(); seg = seg.NextSegment() { - r := seg.Range() - - if !foundFirstPage && r.Start > firstPage { - foundFirstPage = true +// findAvailableRange returns an available range in the usageSet. +// +// Note that scanning for available slots takes place from end first backwards, +// then forwards. This heuristic has important consequence for how sequential +// mappings can be merged in the host VMAs, given that addresses for both +// application and sentry mappings are allocated top-down (from higher to +// lower addresses). The file is also grown expoentially in order to create +// space for mappings to be allocated downwards. +// +// Precondition: alignment must be a power of 2. +func findAvailableRange(usage *usageSet, fileSize int64, length, alignment uint64) (memmap.FileRange, bool) { + alignmentMask := alignment - 1 + + // Search for space in existing gaps, starting at the current end of the + // file and working backward. + lastGap := usage.LastGap() + gap := lastGap + for { + end := gap.End() + if end > uint64(fileSize) { + end = uint64(fileSize) } - if start >= r.End { - // start was rounded up to an alignment boundary from the end - // of a previous segment and is now beyond r.End. - continue + // Try to allocate from the end of this gap, with the start of the + // allocated range aligned down to alignment. + unalignedStart := end - length + if unalignedStart > end { + // Negative overflow: this and all preceding gaps are too small to + // accommodate length. + break + } + if start := unalignedStart &^ alignmentMask; start >= gap.Start() { + return memmap.FileRange{start, start + length}, true } - // This segment represents allocated or reclaimable pages; only the - // range from start to the segment's beginning is allocatable, and the - // next allocatable range begins after the segment. - if r.Start > start && r.Start-start >= length { + + gap = gap.PrevLargeEnoughGap(length) + if !gap.Ok() { break } - start = (r.End + alignMask) &^ alignMask - if !foundFirstPage { - firstPage = r.End + } + + // Check that it's possible to fit this allocation at the end of a file of any size. + min := lastGap.Start() + min = (min + alignmentMask) &^ alignmentMask + if min+length < min { + // Overflow: allocation would exceed the range of uint64. + return memmap.FileRange{}, false + } + + // Determine the minimum file size required to fit this allocation at its end. + for { + newFileSize := 2 * fileSize + if newFileSize <= fileSize { + if fileSize != 0 { + // Overflow: allocation would exceed the range of int64. + return memmap.FileRange{}, false + } + newFileSize = chunkSize + } + fileSize = newFileSize + + unalignedStart := uint64(fileSize) - length + if unalignedStart > uint64(fileSize) { + // Negative overflow: fileSize is still inadequate. + continue + } + if start := unalignedStart &^ alignmentMask; start >= min { + return memmap.FileRange{start, start + length}, true } } - return start, firstPage } // AllocateAndFill allocates memory of the given kind and fills it by calling @@ -505,22 +508,22 @@ func findUnallocatedRange(usage *usageSet, start, length, alignment uint64) (uin // by r.ReadToBlocks(), it returns that error. // // Preconditions: length > 0. length must be page-aligned. -func (f *MemoryFile) AllocateAndFill(length uint64, kind usage.MemoryKind, r safemem.Reader) (platform.FileRange, error) { +func (f *MemoryFile) AllocateAndFill(length uint64, kind usage.MemoryKind, r safemem.Reader) (memmap.FileRange, error) { fr, err := f.Allocate(length, kind) if err != nil { - return platform.FileRange{}, err + return memmap.FileRange{}, err } dsts, err := f.MapInternal(fr, usermem.Write) if err != nil { f.DecRef(fr) - return platform.FileRange{}, err + return memmap.FileRange{}, err } n, err := safemem.ReadFullToBlocks(r, dsts) un := uint64(usermem.Addr(n).RoundDown()) if un < length { // Free unused memory and update fr to contain only the memory that is // still allocated. - f.DecRef(platform.FileRange{fr.Start + un, fr.End}) + f.DecRef(memmap.FileRange{fr.Start + un, fr.End}) fr.End = fr.Start + un } return fr, err @@ -537,7 +540,7 @@ const ( // will read zeroes. // // Preconditions: fr.Length() > 0. -func (f *MemoryFile) Decommit(fr platform.FileRange) error { +func (f *MemoryFile) Decommit(fr memmap.FileRange) error { if !fr.WellFormed() || fr.Length() == 0 || fr.Start%usermem.PageSize != 0 || fr.End%usermem.PageSize != 0 { panic(fmt.Sprintf("invalid range: %v", fr)) } @@ -557,7 +560,7 @@ func (f *MemoryFile) Decommit(fr platform.FileRange) error { return nil } -func (f *MemoryFile) markDecommitted(fr platform.FileRange) { +func (f *MemoryFile) markDecommitted(fr memmap.FileRange) { f.mu.Lock() defer f.mu.Unlock() // Since we're changing the knownCommitted attribute, we need to merge @@ -578,8 +581,8 @@ func (f *MemoryFile) markDecommitted(fr platform.FileRange) { f.usage.MergeRange(fr) } -// IncRef implements platform.File.IncRef. -func (f *MemoryFile) IncRef(fr platform.FileRange) { +// IncRef implements memmap.File.IncRef. +func (f *MemoryFile) IncRef(fr memmap.FileRange) { if !fr.WellFormed() || fr.Length() == 0 || fr.Start%usermem.PageSize != 0 || fr.End%usermem.PageSize != 0 { panic(fmt.Sprintf("invalid range: %v", fr)) } @@ -597,8 +600,8 @@ func (f *MemoryFile) IncRef(fr platform.FileRange) { f.usage.MergeAdjacent(fr) } -// DecRef implements platform.File.DecRef. -func (f *MemoryFile) DecRef(fr platform.FileRange) { +// DecRef implements memmap.File.DecRef. +func (f *MemoryFile) DecRef(fr memmap.FileRange) { if !fr.WellFormed() || fr.Length() == 0 || fr.Start%usermem.PageSize != 0 || fr.End%usermem.PageSize != 0 { panic(fmt.Sprintf("invalid range: %v", fr)) } @@ -616,6 +619,7 @@ func (f *MemoryFile) DecRef(fr platform.FileRange) { } val.refs-- if val.refs == 0 { + f.reclaim.Add(seg.Range(), reclaimSetValue{}) freed = true // Reclassify memory as System, until it's freed by the reclaim // goroutine. @@ -628,17 +632,13 @@ func (f *MemoryFile) DecRef(fr platform.FileRange) { f.usage.MergeAdjacent(fr) if freed { - if fr.Start < f.minReclaimablePage { - // We've freed at least one lower page. - f.minReclaimablePage = fr.Start - } f.reclaimable = true f.reclaimCond.Signal() } } -// MapInternal implements platform.File.MapInternal. -func (f *MemoryFile) MapInternal(fr platform.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { +// MapInternal implements memmap.File.MapInternal. +func (f *MemoryFile) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) { if !fr.WellFormed() || fr.Length() == 0 { panic(fmt.Sprintf("invalid range: %v", fr)) } @@ -664,7 +664,7 @@ func (f *MemoryFile) MapInternal(fr platform.FileRange, at usermem.AccessType) ( // forEachMappingSlice invokes fn on a sequence of byte slices that // collectively map all bytes in fr. -func (f *MemoryFile) forEachMappingSlice(fr platform.FileRange, fn func([]byte)) error { +func (f *MemoryFile) forEachMappingSlice(fr memmap.FileRange, fn func([]byte)) error { mappings := f.mappings.Load().([]uintptr) for chunkStart := fr.Start &^ chunkMask; chunkStart < fr.End; chunkStart += chunkSize { chunk := int(chunkStart >> chunkShift) @@ -944,7 +944,7 @@ func (f *MemoryFile) updateUsageLocked(currentUsage uint64, checkCommitted func( continue case !populated && populatedRun: // Finish the run by changing this segment. - runRange := platform.FileRange{ + runRange := memmap.FileRange{ Start: r.Start + uint64(populatedRunStart*usermem.PageSize), End: r.Start + uint64(i*usermem.PageSize), } @@ -1009,7 +1009,7 @@ func (f *MemoryFile) File() *os.File { return f.file } -// FD implements platform.File.FD. +// FD implements memmap.File.FD. func (f *MemoryFile) FD() int { return int(f.file.Fd()) } @@ -1030,6 +1030,7 @@ func (f *MemoryFile) String() string { // for allocation. func (f *MemoryFile) runReclaim() { for { + // N.B. We must call f.markReclaimed on the returned FrameRange. fr, ok := f.findReclaimable() if !ok { break @@ -1085,13 +1086,17 @@ func (f *MemoryFile) runReclaim() { } } -func (f *MemoryFile) findReclaimable() (platform.FileRange, bool) { +// findReclaimable finds memory that has been marked for reclaim. +// +// Note that there returned range will be removed from tracking. It +// must be reclaimed (removed from f.usage) at this point. +func (f *MemoryFile) findReclaimable() (memmap.FileRange, bool) { f.mu.Lock() defer f.mu.Unlock() for { for { if f.destroyed { - return platform.FileRange{}, false + return memmap.FileRange{}, false } if f.reclaimable { break @@ -1103,27 +1108,24 @@ func (f *MemoryFile) findReclaimable() (platform.FileRange, bool) { } f.reclaimCond.Wait() } - // Allocate returns the first usable range in offset order and is - // currently a linear scan, so reclaiming from the beginning of the - // file minimizes the expected latency of Allocate. - for seg := f.usage.LowerBoundSegment(f.minReclaimablePage); seg.Ok(); seg = seg.NextSegment() { - if seg.ValuePtr().refs == 0 { - f.minReclaimablePage = seg.End() - return seg.Range(), true - } + // Allocate works from the back of the file inwards, so reclaim + // preserves this order to minimize the cost of the search. + if seg := f.reclaim.LastSegment(); seg.Ok() { + fr := seg.Range() + f.reclaim.Remove(seg) + return fr, true } - // No pages are reclaimable. + // Nothing is reclaimable. f.reclaimable = false - f.minReclaimablePage = maxPage } } -func (f *MemoryFile) markReclaimed(fr platform.FileRange) { +func (f *MemoryFile) markReclaimed(fr memmap.FileRange) { f.mu.Lock() defer f.mu.Unlock() seg := f.usage.FindSegment(fr.Start) - // All of fr should be mapped to a single uncommitted reclaimable segment - // accounted to System. + // All of fr should be mapped to a single uncommitted reclaimable + // segment accounted to System. if !seg.Ok() { panic(fmt.Sprintf("reclaimed pages %v include unreferenced pages:\n%v", fr, &f.usage)) } @@ -1137,14 +1139,10 @@ func (f *MemoryFile) markReclaimed(fr platform.FileRange) { }); got != want { panic(fmt.Sprintf("reclaimed pages %v in segment %v has incorrect state %v, wanted %v:\n%v", fr, seg.Range(), got, want, &f.usage)) } - // Deallocate reclaimed pages. Even though all of seg is reclaimable, the - // caller of markReclaimed may not have decommitted it, so we can only mark - // fr as reclaimed. + // Deallocate reclaimed pages. Even though all of seg is reclaimable, + // the caller of markReclaimed may not have decommitted it, so we can + // only mark fr as reclaimed. f.usage.Remove(f.usage.Isolate(seg, fr)) - if fr.Start < f.minUnallocatedPage { - // We've deallocated at least one lower page. - f.minUnallocatedPage = fr.Start - } } // StartEvictions requests that f evict all evictable allocations. It does not @@ -1224,11 +1222,11 @@ func (usageSetFunctions) MaxKey() uint64 { func (usageSetFunctions) ClearValue(val *usageInfo) { } -func (usageSetFunctions) Merge(_ platform.FileRange, val1 usageInfo, _ platform.FileRange, val2 usageInfo) (usageInfo, bool) { +func (usageSetFunctions) Merge(_ memmap.FileRange, val1 usageInfo, _ memmap.FileRange, val2 usageInfo) (usageInfo, bool) { return val1, val1 == val2 } -func (usageSetFunctions) Split(_ platform.FileRange, val usageInfo, _ uint64) (usageInfo, usageInfo) { +func (usageSetFunctions) Split(_ memmap.FileRange, val usageInfo, _ uint64) (usageInfo, usageInfo) { return val, val } @@ -1255,3 +1253,27 @@ func (evictableRangeSetFunctions) Merge(_ EvictableRange, _ evictableRangeSetVal func (evictableRangeSetFunctions) Split(_ EvictableRange, _ evictableRangeSetValue, _ uint64) (evictableRangeSetValue, evictableRangeSetValue) { return evictableRangeSetValue{}, evictableRangeSetValue{} } + +// reclaimSetValue is the value type of reclaimSet. +type reclaimSetValue struct{} + +type reclaimSetFunctions struct{} + +func (reclaimSetFunctions) MinKey() uint64 { + return 0 +} + +func (reclaimSetFunctions) MaxKey() uint64 { + return math.MaxUint64 +} + +func (reclaimSetFunctions) ClearValue(val *reclaimSetValue) { +} + +func (reclaimSetFunctions) Merge(_ memmap.FileRange, _ reclaimSetValue, _ memmap.FileRange, _ reclaimSetValue) (reclaimSetValue, bool) { + return reclaimSetValue{}, true +} + +func (reclaimSetFunctions) Split(_ memmap.FileRange, _ reclaimSetValue, _ uint64) (reclaimSetValue, reclaimSetValue) { + return reclaimSetValue{}, reclaimSetValue{} +} diff --git a/pkg/sentry/pgalloc/pgalloc_test.go b/pkg/sentry/pgalloc/pgalloc_test.go index 293f22c6b..405db141f 100644 --- a/pkg/sentry/pgalloc/pgalloc_test.go +++ b/pkg/sentry/pgalloc/pgalloc_test.go @@ -23,39 +23,49 @@ import ( const ( page = usermem.PageSize hugepage = usermem.HugePageSize + topPage = (1 << 63) - page ) func TestFindUnallocatedRange(t *testing.T) { for _, test := range []struct { - desc string - usage *usageSegmentDataSlices - start uint64 - length uint64 - alignment uint64 - unallocated uint64 - minUnallocated uint64 + desc string + usage *usageSegmentDataSlices + fileSize int64 + length uint64 + alignment uint64 + start uint64 + expectFail bool }{ { - desc: "Initial allocation succeeds", - usage: &usageSegmentDataSlices{}, - start: 0, - length: page, - alignment: page, - unallocated: 0, - minUnallocated: 0, + desc: "Initial allocation succeeds", + usage: &usageSegmentDataSlices{}, + length: page, + alignment: page, + start: chunkSize - page, // Grows by chunkSize, allocate down. }, { - desc: "Allocation begins at start of file", + desc: "Allocation finds empty space at start of file", usage: &usageSegmentDataSlices{ Start: []uint64{page}, End: []uint64{2 * page}, Values: []usageInfo{{refs: 1}}, }, - start: 0, - length: page, - alignment: page, - unallocated: 0, - minUnallocated: 0, + fileSize: 2 * page, + length: page, + alignment: page, + start: 0, + }, + { + desc: "Allocation finds empty space at end of file", + usage: &usageSegmentDataSlices{ + Start: []uint64{0}, + End: []uint64{page}, + Values: []usageInfo{{refs: 1}}, + }, + fileSize: 2 * page, + length: page, + alignment: page, + start: page, }, { desc: "In-use frames are not allocatable", @@ -64,11 +74,10 @@ func TestFindUnallocatedRange(t *testing.T) { End: []uint64{page, 2 * page}, Values: []usageInfo{{refs: 1}, {refs: 2}}, }, - start: 0, - length: page, - alignment: page, - unallocated: 2 * page, - minUnallocated: 2 * page, + fileSize: 2 * page, + length: page, + alignment: page, + start: 3 * page, // Double fileSize, allocate top-down. }, { desc: "Reclaimable frames are not allocatable", @@ -77,11 +86,10 @@ func TestFindUnallocatedRange(t *testing.T) { End: []uint64{page, 2 * page, 3 * page}, Values: []usageInfo{{refs: 1}, {refs: 0}, {refs: 1}}, }, - start: 0, - length: page, - alignment: page, - unallocated: 3 * page, - minUnallocated: 3 * page, + fileSize: 3 * page, + length: page, + alignment: page, + start: 5 * page, // Double fileSize, grow down. }, { desc: "Gaps between in-use frames are allocatable", @@ -90,11 +98,10 @@ func TestFindUnallocatedRange(t *testing.T) { End: []uint64{page, 3 * page}, Values: []usageInfo{{refs: 1}, {refs: 1}}, }, - start: 0, - length: page, - alignment: page, - unallocated: page, - minUnallocated: page, + fileSize: 3 * page, + length: page, + alignment: page, + start: page, }, { desc: "Inadequately-sized gaps are rejected", @@ -103,14 +110,13 @@ func TestFindUnallocatedRange(t *testing.T) { End: []uint64{page, 3 * page}, Values: []usageInfo{{refs: 1}, {refs: 1}}, }, - start: 0, - length: 2 * page, - alignment: page, - unallocated: 3 * page, - minUnallocated: page, + fileSize: 3 * page, + length: 2 * page, + alignment: page, + start: 4 * page, // Double fileSize, grow down. }, { - desc: "Hugepage alignment is honored", + desc: "Alignment is honored at end of file", usage: &usageSegmentDataSlices{ Start: []uint64{0, hugepage + page}, // Hugepage-sized gap here that shouldn't be allocated from @@ -118,37 +124,103 @@ func TestFindUnallocatedRange(t *testing.T) { End: []uint64{page, hugepage + 2*page}, Values: []usageInfo{{refs: 1}, {refs: 1}}, }, - start: 0, - length: hugepage, - alignment: hugepage, - unallocated: 2 * hugepage, - minUnallocated: page, + fileSize: hugepage + 2*page, + length: hugepage, + alignment: hugepage, + start: 3 * hugepage, // Double fileSize until alignment is satisfied, grow down. }, { - desc: "Pages before start ignored", + desc: "Alignment is honored before end of file", + usage: &usageSegmentDataSlices{ + Start: []uint64{0, 2*hugepage + page}, + // Page will need to be shifted down from top. + End: []uint64{page, 2*hugepage + 2*page}, + Values: []usageInfo{{refs: 1}, {refs: 1}}, + }, + fileSize: 2*hugepage + 2*page, + length: hugepage, + alignment: hugepage, + start: hugepage, + }, + { + desc: "Allocation doubles file size more than once if necessary", + usage: &usageSegmentDataSlices{}, + fileSize: page, + length: 4 * page, + alignment: page, + start: 0, + }, + { + desc: "Allocations are compact if possible", usage: &usageSegmentDataSlices{ Start: []uint64{page, 3 * page}, End: []uint64{2 * page, 4 * page}, Values: []usageInfo{{refs: 1}, {refs: 2}}, }, - start: page, - length: page, - alignment: page, - unallocated: 2 * page, - minUnallocated: 2 * page, + fileSize: 4 * page, + length: page, + alignment: page, + start: 2 * page, + }, + { + desc: "Top-down allocation within one gap", + usage: &usageSegmentDataSlices{ + Start: []uint64{page, 4 * page, 7 * page}, + End: []uint64{2 * page, 5 * page, 8 * page}, + Values: []usageInfo{{refs: 1}, {refs: 2}, {refs: 1}}, + }, + fileSize: 8 * page, + length: page, + alignment: page, + start: 6 * page, + }, + { + desc: "Top-down allocation between multiple gaps", + usage: &usageSegmentDataSlices{ + Start: []uint64{page, 3 * page, 5 * page}, + End: []uint64{2 * page, 4 * page, 6 * page}, + Values: []usageInfo{{refs: 1}, {refs: 2}, {refs: 1}}, + }, + fileSize: 6 * page, + length: page, + alignment: page, + start: 4 * page, }, { - desc: "start may be in the middle of segment", + desc: "Top-down allocation with large top gap", usage: &usageSegmentDataSlices{ - Start: []uint64{0, 3 * page}, + Start: []uint64{page, 3 * page}, End: []uint64{2 * page, 4 * page}, Values: []usageInfo{{refs: 1}, {refs: 2}}, }, - start: page, - length: page, - alignment: page, - unallocated: 2 * page, - minUnallocated: 2 * page, + fileSize: 8 * page, + length: page, + alignment: page, + start: 7 * page, + }, + { + desc: "Gaps found with possible overflow", + usage: &usageSegmentDataSlices{ + Start: []uint64{page, topPage - page}, + End: []uint64{2 * page, topPage}, + Values: []usageInfo{{refs: 1}, {refs: 1}}, + }, + fileSize: topPage, + length: page, + alignment: page, + start: topPage - 2*page, + }, + { + desc: "Overflow detected", + usage: &usageSegmentDataSlices{ + Start: []uint64{page}, + End: []uint64{topPage}, + Values: []usageInfo{{refs: 1}}, + }, + fileSize: topPage, + length: 2 * page, + alignment: page, + expectFail: true, }, } { t.Run(test.desc, func(t *testing.T) { @@ -156,12 +228,18 @@ func TestFindUnallocatedRange(t *testing.T) { if err := usage.ImportSortedSlices(test.usage); err != nil { t.Fatalf("Failed to initialize usage from %v: %v", test.usage, err) } - unallocated, minUnallocated := findUnallocatedRange(&usage, test.start, test.length, test.alignment) - if unallocated != test.unallocated { - t.Errorf("findUnallocatedRange(%v, %x, %x, %x): got unallocated %x, wanted %x", test.usage, test.start, test.length, test.alignment, unallocated, test.unallocated) + fr, ok := findAvailableRange(&usage, test.fileSize, test.length, test.alignment) + if !test.expectFail && !ok { + t.Fatalf("findAvailableRange(%v, %x, %x, %x): got %x, false wanted %x, true", test.usage, test.fileSize, test.length, test.alignment, fr.Start, test.start) + } + if test.expectFail && ok { + t.Fatalf("findAvailableRange(%v, %x, %x, %x): got %x, true wanted %x, false", test.usage, test.fileSize, test.length, test.alignment, fr.Start, test.start) + } + if ok && fr.Start != test.start { + t.Errorf("findAvailableRange(%v, %x, %x, %x): got start=%x, wanted %x", test.usage, test.fileSize, test.length, test.alignment, fr.Start, test.start) } - if minUnallocated != test.minUnallocated { - t.Errorf("findUnallocatedRange(%v, %x, %x, %x): got minUnallocated %x, wanted %x", test.usage, test.start, test.length, test.alignment, minUnallocated, test.minUnallocated) + if ok && fr.End != test.start+test.length { + t.Errorf("findAvailableRange(%v, %x, %x, %x): got end=%x, wanted %x", test.usage, test.fileSize, test.length, test.alignment, fr.End, test.start+test.length) } }) } diff --git a/pkg/sentry/pgalloc/save_restore.go b/pkg/sentry/pgalloc/save_restore.go index f8385c146..78317fa35 100644 --- a/pkg/sentry/pgalloc/save_restore.go +++ b/pkg/sentry/pgalloc/save_restore.go @@ -26,11 +26,12 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/usage" "gvisor.dev/gvisor/pkg/state" + "gvisor.dev/gvisor/pkg/state/wire" "gvisor.dev/gvisor/pkg/usermem" ) // SaveTo writes f's state to the given stream. -func (f *MemoryFile) SaveTo(ctx context.Context, w io.Writer) error { +func (f *MemoryFile) SaveTo(ctx context.Context, w wire.Writer) error { // Wait for reclaim. f.mu.Lock() defer f.mu.Unlock() @@ -79,10 +80,10 @@ func (f *MemoryFile) SaveTo(ctx context.Context, w io.Writer) error { } // Save metadata. - if err := state.Save(ctx, w, &f.fileSize, nil); err != nil { + if _, err := state.Save(ctx, w, &f.fileSize); err != nil { return err } - if err := state.Save(ctx, w, &f.usage, nil); err != nil { + if _, err := state.Save(ctx, w, &f.usage); err != nil { return err } @@ -115,9 +116,9 @@ func (f *MemoryFile) SaveTo(ctx context.Context, w io.Writer) error { } // LoadFrom loads MemoryFile state from the given stream. -func (f *MemoryFile) LoadFrom(ctx context.Context, r io.Reader) error { +func (f *MemoryFile) LoadFrom(ctx context.Context, r wire.Reader) error { // Load metadata. - if err := state.Load(ctx, r, &f.fileSize, nil); err != nil { + if _, err := state.Load(ctx, r, &f.fileSize); err != nil { return err } if err := f.file.Truncate(f.fileSize); err != nil { @@ -125,7 +126,7 @@ func (f *MemoryFile) LoadFrom(ctx context.Context, r io.Reader) error { } newMappings := make([]uintptr, f.fileSize>>chunkShift) f.mappings.Store(newMappings) - if err := state.Load(ctx, r, &f.usage, nil); err != nil { + if _, err := state.Load(ctx, r, &f.usage); err != nil { return err } diff --git a/pkg/sentry/platform/BUILD b/pkg/sentry/platform/BUILD index 453241eca..209b28053 100644 --- a/pkg/sentry/platform/BUILD +++ b/pkg/sentry/platform/BUILD @@ -1,39 +1,21 @@ load("//tools:defs.bzl", "go_library") -load("//tools/go_generics:defs.bzl", "go_template_instance") package(licenses = ["notice"]) -go_template_instance( - name = "file_range", - out = "file_range.go", - package = "platform", - prefix = "File", - template = "//pkg/segment:generic_range", - types = { - "T": "uint64", - }, -) - go_library( name = "platform", srcs = [ "context.go", - "file_range.go", "mmap_min_addr.go", "platform.go", ], visibility = ["//pkg/sentry:internal"], deps = [ "//pkg/abi/linux", - "//pkg/atomicbitops", "//pkg/context", - "//pkg/log", - "//pkg/safecopy", - "//pkg/safemem", "//pkg/seccomp", "//pkg/sentry/arch", - "//pkg/sentry/usage", - "//pkg/syserror", + "//pkg/sentry/memmap", "//pkg/usermem", ], ) diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD index 159f7eafd..3970dd81d 100644 --- a/pkg/sentry/platform/kvm/BUILD +++ b/pkg/sentry/platform/kvm/BUILD @@ -6,8 +6,8 @@ go_library( name = "kvm", srcs = [ "address_space.go", - "allocator.go", "bluepill.go", + "bluepill_allocator.go", "bluepill_amd64.go", "bluepill_amd64.s", "bluepill_amd64_unsafe.go", @@ -41,12 +41,14 @@ go_library( deps = [ "//pkg/abi/linux", "//pkg/atomicbitops", + "//pkg/context", "//pkg/cpuid", "//pkg/log", "//pkg/procid", "//pkg/safecopy", "//pkg/seccomp", "//pkg/sentry/arch", + "//pkg/sentry/memmap", "//pkg/sentry/platform", "//pkg/sentry/platform/interrupt", "//pkg/sentry/platform/ring0", @@ -60,6 +62,7 @@ go_library( go_test( name = "kvm_test", srcs = [ + "kvm_amd64_test.go", "kvm_test.go", "virtual_map_test.go", ], diff --git a/pkg/sentry/platform/kvm/address_space.go b/pkg/sentry/platform/kvm/address_space.go index be213bfe8..af5c5e191 100644 --- a/pkg/sentry/platform/kvm/address_space.go +++ b/pkg/sentry/platform/kvm/address_space.go @@ -18,6 +18,7 @@ import ( "sync/atomic" "gvisor.dev/gvisor/pkg/atomicbitops" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables" "gvisor.dev/gvisor/pkg/sync" @@ -26,16 +27,15 @@ import ( // dirtySet tracks vCPUs for invalidation. type dirtySet struct { - vCPUs []uint64 + vCPUMasks []uint64 } // forEach iterates over all CPUs in the dirty set. +// +//go:nosplit func (ds *dirtySet) forEach(m *machine, fn func(c *vCPU)) { - m.mu.RLock() - defer m.mu.RUnlock() - - for index := range ds.vCPUs { - mask := atomic.SwapUint64(&ds.vCPUs[index], 0) + for index := range ds.vCPUMasks { + mask := atomic.SwapUint64(&ds.vCPUMasks[index], 0) if mask != 0 { for bit := 0; bit < 64; bit++ { if mask&(1<<uint64(bit)) == 0 { @@ -54,7 +54,7 @@ func (ds *dirtySet) mark(c *vCPU) bool { index := uint64(c.id) / 64 bit := uint64(1) << uint(c.id%64) - oldValue := atomic.LoadUint64(&ds.vCPUs[index]) + oldValue := atomic.LoadUint64(&ds.vCPUMasks[index]) if oldValue&bit != 0 { return false // Not clean. } @@ -62,7 +62,7 @@ func (ds *dirtySet) mark(c *vCPU) bool { // Set the bit unilaterally, and ensure that a flush takes place. Note // that it's possible for races to occur here, but since the flush is // taking place long after these lines there's no race in practice. - atomicbitops.OrUint64(&ds.vCPUs[index], bit) + atomicbitops.OrUint64(&ds.vCPUMasks[index], bit) return true // Previously clean. } @@ -113,7 +113,12 @@ type hostMapEntry struct { length uintptr } -func (as *addressSpace) mapHost(addr usermem.Addr, m hostMapEntry, at usermem.AccessType) (inv bool) { +// mapLocked maps the given host entry. +// +// +checkescape:hard,stack +// +//go:nosplit +func (as *addressSpace) mapLocked(addr usermem.Addr, m hostMapEntry, at usermem.AccessType) (inv bool) { for m.length > 0 { physical, length, ok := translateToPhysical(m.addr) if !ok { @@ -133,18 +138,10 @@ func (as *addressSpace) mapHost(addr usermem.Addr, m hostMapEntry, at usermem.Ac // important; if the pagetable mappings were installed before // ensuring the physical pages were available, then some other // thread could theoretically access them. - // - // Due to the way KVM's shadow paging implementation works, - // modifications to the page tables while in host mode may not - // be trapped, leading to the shadow pages being out of sync. - // Therefore, we need to ensure that we are in guest mode for - // page table modifications. See the call to bluepill, below. - as.machine.retryInGuest(func() { - inv = as.pageTables.Map(addr, length, pagetables.MapOpts{ - AccessType: at, - User: true, - }, physical) || inv - }) + inv = as.pageTables.Map(addr, length, pagetables.MapOpts{ + AccessType: at, + User: true, + }, physical) || inv m.addr += length m.length -= length addr += usermem.Addr(length) @@ -154,7 +151,7 @@ func (as *addressSpace) mapHost(addr usermem.Addr, m hostMapEntry, at usermem.Ac } // MapFile implements platform.AddressSpace.MapFile. -func (as *addressSpace) MapFile(addr usermem.Addr, f platform.File, fr platform.FileRange, at usermem.AccessType, precommit bool) error { +func (as *addressSpace) MapFile(addr usermem.Addr, f memmap.File, fr memmap.FileRange, at usermem.AccessType, precommit bool) error { as.mu.Lock() defer as.mu.Unlock() @@ -176,6 +173,10 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f platform.File, fr platform. return err } + // See block in mapLocked. + as.pageTables.Allocator.(*allocator).cpu = as.machine.Get() + defer as.machine.Put(as.pageTables.Allocator.(*allocator).cpu) + // Map the mappings in the sentry's address space (guest physical memory) // into the application's address space (guest virtual memory). inv := false @@ -190,7 +191,12 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f platform.File, fr platform. _ = s[i] // Touch to commit. } } - prev := as.mapHost(addr, hostMapEntry{ + + // See bluepill_allocator.go. + bluepill(as.pageTables.Allocator.(*allocator).cpu) + + // Perform the mapping. + prev := as.mapLocked(addr, hostMapEntry{ addr: b.Addr(), length: uintptr(b.Len()), }, at) @@ -204,17 +210,27 @@ func (as *addressSpace) MapFile(addr usermem.Addr, f platform.File, fr platform. return nil } +// unmapLocked is an escape-checked wrapped around Unmap. +// +// +checkescape:hard,stack +// +//go:nosplit +func (as *addressSpace) unmapLocked(addr usermem.Addr, length uint64) bool { + return as.pageTables.Unmap(addr, uintptr(length)) +} + // Unmap unmaps the given range by calling pagetables.PageTables.Unmap. func (as *addressSpace) Unmap(addr usermem.Addr, length uint64) { as.mu.Lock() defer as.mu.Unlock() - // See above re: retryInGuest. - var prev bool - as.machine.retryInGuest(func() { - prev = as.pageTables.Unmap(addr, uintptr(length)) || prev - }) - if prev { + // See above & bluepill_allocator.go. + as.pageTables.Allocator.(*allocator).cpu = as.machine.Get() + defer as.machine.Put(as.pageTables.Allocator.(*allocator).cpu) + bluepill(as.pageTables.Allocator.(*allocator).cpu) + + if prev := as.unmapLocked(addr, length); prev { + // Invalidate all active vCPUs. as.invalidate() // Recycle any freed intermediate pages. @@ -227,8 +243,14 @@ func (as *addressSpace) Release() { as.Unmap(0, ^uint64(0)) // Free all pages from the allocator. - as.pageTables.Allocator.(allocator).base.Drain() + as.pageTables.Allocator.(*allocator).base.Drain() // Drop all cached machine references. as.machine.dropPageTables(as.pageTables) } + +// PreFork implements platform.AddressSpace.PreFork. +func (as *addressSpace) PreFork() {} + +// PostFork implements platform.AddressSpace.PostFork. +func (as *addressSpace) PostFork() {} diff --git a/pkg/sentry/platform/kvm/allocator.go b/pkg/sentry/platform/kvm/bluepill_allocator.go index 3f35414bb..9485e1301 100644 --- a/pkg/sentry/platform/kvm/allocator.go +++ b/pkg/sentry/platform/kvm/bluepill_allocator.go @@ -21,56 +21,80 @@ import ( ) type allocator struct { - base *pagetables.RuntimeAllocator + base pagetables.RuntimeAllocator + + // cpu must be set prior to any pagetable operation. + // + // Due to the way KVM's shadow paging implementation works, + // modifications to the page tables while in host mode may not be + // trapped, leading to the shadow pages being out of sync. Therefore, + // we need to ensure that we are in guest mode for page table + // modifications. See the call to bluepill, below. + cpu *vCPU } // newAllocator is used to define the allocator. -func newAllocator() allocator { - return allocator{ - base: pagetables.NewRuntimeAllocator(), - } +func newAllocator() *allocator { + a := new(allocator) + a.base.Init() + return a } // NewPTEs implements pagetables.Allocator.NewPTEs. // +// +checkescape:all +// //go:nosplit -func (a allocator) NewPTEs() *pagetables.PTEs { - return a.base.NewPTEs() +func (a *allocator) NewPTEs() *pagetables.PTEs { + ptes := a.base.NewPTEs() // escapes: bluepill below. + if a.cpu != nil { + bluepill(a.cpu) + } + return ptes } // PhysicalFor returns the physical address for a set of PTEs. // +// +checkescape:all +// //go:nosplit -func (a allocator) PhysicalFor(ptes *pagetables.PTEs) uintptr { +func (a *allocator) PhysicalFor(ptes *pagetables.PTEs) uintptr { virtual := a.base.PhysicalFor(ptes) physical, _, ok := translateToPhysical(virtual) if !ok { - panic(fmt.Sprintf("PhysicalFor failed for %p", ptes)) + panic(fmt.Sprintf("PhysicalFor failed for %p", ptes)) // escapes: panic. } return physical } // LookupPTEs implements pagetables.Allocator.LookupPTEs. // +// +checkescape:all +// //go:nosplit -func (a allocator) LookupPTEs(physical uintptr) *pagetables.PTEs { +func (a *allocator) LookupPTEs(physical uintptr) *pagetables.PTEs { virtualStart, physicalStart, _, ok := calculateBluepillFault(physical, physicalRegions) if !ok { - panic(fmt.Sprintf("LookupPTEs failed for 0x%x", physical)) + panic(fmt.Sprintf("LookupPTEs failed for 0x%x", physical)) // escapes: panic. } return a.base.LookupPTEs(virtualStart + (physical - physicalStart)) } // FreePTEs implements pagetables.Allocator.FreePTEs. // +// +checkescape:all +// //go:nosplit -func (a allocator) FreePTEs(ptes *pagetables.PTEs) { - a.base.FreePTEs(ptes) +func (a *allocator) FreePTEs(ptes *pagetables.PTEs) { + a.base.FreePTEs(ptes) // escapes: bluepill below. + if a.cpu != nil { + bluepill(a.cpu) + } } // Recycle implements pagetables.Allocator.Recycle. // //go:nosplit -func (a allocator) Recycle() { +func (a *allocator) Recycle() { a.base.Recycle() } diff --git a/pkg/sentry/platform/kvm/bluepill_amd64.go b/pkg/sentry/platform/kvm/bluepill_amd64.go index 133c2203d..ddc1554d5 100644 --- a/pkg/sentry/platform/kvm/bluepill_amd64.go +++ b/pkg/sentry/platform/kvm/bluepill_amd64.go @@ -63,6 +63,8 @@ func bluepillArchEnter(context *arch.SignalContext64) *vCPU { // KernelSyscall handles kernel syscalls. // +// +checkescape:all +// //go:nosplit func (c *vCPU) KernelSyscall() { regs := c.Registers() @@ -72,13 +74,15 @@ func (c *vCPU) KernelSyscall() { // We only trigger a bluepill entry in the bluepill function, and can // therefore be guaranteed that there is no floating point state to be // loaded on resuming from halt. We only worry about saving on exit. - ring0.SaveFloatingPoint((*byte)(c.floatingPointState)) + ring0.SaveFloatingPoint((*byte)(c.floatingPointState)) // escapes: no. ring0.Halt() - ring0.WriteFS(uintptr(regs.Fs_base)) // Reload host segment. + ring0.WriteFS(uintptr(regs.Fs_base)) // escapes: no, reload host segment. } // KernelException handles kernel exceptions. // +// +checkescape:all +// //go:nosplit func (c *vCPU) KernelException(vector ring0.Vector) { regs := c.Registers() @@ -89,9 +93,9 @@ func (c *vCPU) KernelException(vector ring0.Vector) { regs.Rip = 0 } // See above. - ring0.SaveFloatingPoint((*byte)(c.floatingPointState)) + ring0.SaveFloatingPoint((*byte)(c.floatingPointState)) // escapes: no. ring0.Halt() - ring0.WriteFS(uintptr(regs.Fs_base)) // Reload host segment. + ring0.WriteFS(uintptr(regs.Fs_base)) // escapes: no; reload host segment. } // bluepillArchExit is called during bluepillEnter. diff --git a/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go b/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go index 99cac665d..03a98512e 100644 --- a/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go +++ b/pkg/sentry/platform/kvm/bluepill_amd64_unsafe.go @@ -17,6 +17,7 @@ package kvm import ( + "syscall" "unsafe" "gvisor.dev/gvisor/pkg/sentry/arch" @@ -53,3 +54,34 @@ func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) { context.Rbx = uint64(uintptr(unsafe.Pointer(c))) context.Rip = uint64(dieTrampolineAddr) } + +// getHypercallID returns hypercall ID. +// +//go:nosplit +func getHypercallID(addr uintptr) int { + return _KVM_HYPERCALL_MAX +} + +// bluepillStopGuest is reponsible for injecting interrupt. +// +//go:nosplit +func bluepillStopGuest(c *vCPU) { + // Interrupt: we must have requested an interrupt + // window; set the interrupt line. + if _, _, errno := syscall.RawSyscall( + syscall.SYS_IOCTL, + uintptr(c.fd), + _KVM_INTERRUPT, + uintptr(unsafe.Pointer(&bounce))); errno != 0 { + throw("interrupt injection failed") + } + // Clear previous injection request. + c.runData.requestInterruptWindow = 0 +} + +// bluepillReadyStopGuest checks whether the current vCPU is ready for interrupt injection. +// +//go:nosplit +func bluepillReadyStopGuest(c *vCPU) bool { + return c.runData.readyForInterruptInjection != 0 +} diff --git a/pkg/sentry/platform/kvm/bluepill_arm64.go b/pkg/sentry/platform/kvm/bluepill_arm64.go index c215d443c..ed5ae03d3 100644 --- a/pkg/sentry/platform/kvm/bluepill_arm64.go +++ b/pkg/sentry/platform/kvm/bluepill_arm64.go @@ -26,6 +26,17 @@ import ( var ( // The action for bluepillSignal is changed by sigaction(). bluepillSignal = syscall.SIGILL + + // vcpuSErr is the event of system error. + vcpuSErr = kvmVcpuEvents{ + exception: exception{ + sErrPending: 1, + sErrHasEsr: 0, + pad: [6]uint8{0, 0, 0, 0, 0, 0}, + sErrEsr: 1, + }, + rsvd: [12]uint32{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, + } ) // bluepillArchEnter is called during bluepillEnter. @@ -38,7 +49,7 @@ func bluepillArchEnter(context *arch.SignalContext64) (c *vCPU) { regs.Sp = context.Sp regs.Pc = context.Pc regs.Pstate = context.Pstate - regs.Pstate &^= uint64(ring0.KernelFlagsClear) + regs.Pstate &^= uint64(ring0.PsrFlagsClear) regs.Pstate |= ring0.KernelFlagsSet return } @@ -52,7 +63,7 @@ func bluepillArchExit(c *vCPU, context *arch.SignalContext64) { context.Sp = regs.Sp context.Pc = regs.Pc context.Pstate = regs.Pstate - context.Pstate &^= uint64(ring0.UserFlagsClear) + context.Pstate &^= uint64(ring0.PsrFlagsClear) context.Pstate |= ring0.UserFlagsSet lazyVfp := c.GetLazyVFP() @@ -66,6 +77,8 @@ func bluepillArchExit(c *vCPU, context *arch.SignalContext64) { // KernelSyscall handles kernel syscalls. // +// +checkescape:all +// //go:nosplit func (c *vCPU) KernelSyscall() { regs := c.Registers() @@ -88,6 +101,8 @@ func (c *vCPU) KernelSyscall() { // KernelException handles kernel exceptions. // +// +checkescape:all +// //go:nosplit func (c *vCPU) KernelException(vector ring0.Vector) { regs := c.Registers() diff --git a/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go b/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go index 4ca2b7717..b35c930e2 100644 --- a/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go +++ b/pkg/sentry/platform/kvm/bluepill_arm64_unsafe.go @@ -17,6 +17,7 @@ package kvm import ( + "syscall" "unsafe" "gvisor.dev/gvisor/pkg/sentry/arch" @@ -40,7 +41,7 @@ func fpsimdPtr(addr *byte) *arch.FpsimdContext { func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) { // If the vCPU is in user mode, we set the stack to the stored stack // value in the vCPU itself. We don't want to unwind the user stack. - if guestRegs.Regs.Pstate&ring0.PSR_MODE_MASK == ring0.PSR_MODE_EL0t { + if guestRegs.Regs.Pstate&ring0.PsrModeMask == ring0.UserFlagsSet { regs := c.CPU.Registers() context.Regs[0] = regs.Regs[0] context.Sp = regs.Sp @@ -61,3 +62,36 @@ func dieArchSetup(c *vCPU, context *arch.SignalContext64, guestRegs *userRegs) { func bluepillArchFpContext(context unsafe.Pointer) *arch.FpsimdContext { return &((*arch.SignalContext64)(context).Fpsimd64) } + +// getHypercallID returns hypercall ID. +// +// On Arm64, the MMIO address should be 64-bit aligned. +// +//go:nosplit +func getHypercallID(addr uintptr) int { + if addr < arm64HypercallMMIOBase || addr >= (arm64HypercallMMIOBase+_AARCH64_HYPERCALL_MMIO_SIZE) { + return _KVM_HYPERCALL_MAX + } else { + return int(((addr) - arm64HypercallMMIOBase) >> 3) + } +} + +// bluepillStopGuest is reponsible for injecting sError. +// +//go:nosplit +func bluepillStopGuest(c *vCPU) { + if _, _, errno := syscall.RawSyscall( + syscall.SYS_IOCTL, + uintptr(c.fd), + _KVM_SET_VCPU_EVENTS, + uintptr(unsafe.Pointer(&vcpuSErr))); errno != 0 { + throw("sErr injection failed") + } +} + +// bluepillReadyStopGuest checks whether the current vCPU is ready for sError injection. +// +//go:nosplit +func bluepillReadyStopGuest(c *vCPU) bool { + return true +} diff --git a/pkg/sentry/platform/kvm/bluepill_unsafe.go b/pkg/sentry/platform/kvm/bluepill_unsafe.go index 9add7c944..bf357de1a 100644 --- a/pkg/sentry/platform/kvm/bluepill_unsafe.go +++ b/pkg/sentry/platform/kvm/bluepill_unsafe.go @@ -13,7 +13,7 @@ // limitations under the License. // +build go1.12 -// +build !go1.15 +// +build !go1.16 // Check go:linkname function signatures when updating Go version. @@ -58,12 +58,32 @@ func bluepillArchContext(context unsafe.Pointer) *arch.SignalContext64 { return &((*arch.UContext64)(context).MContext) } +// bluepillHandleHlt is reponsible for handling VM-Exit. +// +//go:nosplit +func bluepillGuestExit(c *vCPU, context unsafe.Pointer) { + // Copy out registers. + bluepillArchExit(c, bluepillArchContext(context)) + + // Return to the vCPUReady state; notify any waiters. + user := atomic.LoadUint32(&c.state) & vCPUUser + switch atomic.SwapUint32(&c.state, user) { + case user | vCPUGuest: // Expected case. + case user | vCPUGuest | vCPUWaiter: + c.notify() + default: + throw("invalid state") + } +} + // bluepillHandler is called from the signal stub. // // The world may be stopped while this is executing, and it executes on the // signal stack. It should only execute raw system calls and functions that are // explicitly marked go:nosplit. // +// +checkescape:all +// //go:nosplit func bluepillHandler(context unsafe.Pointer) { // Sanitize the registers; interrupts must always be disabled. @@ -82,7 +102,8 @@ func bluepillHandler(context unsafe.Pointer) { } for { - switch _, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(c.fd), _KVM_RUN, 0); errno { + _, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(c.fd), _KVM_RUN, 0) // escapes: no. + switch errno { case 0: // Expected case. case syscall.EINTR: // First, we process whatever pending signal @@ -90,7 +111,7 @@ func bluepillHandler(context unsafe.Pointer) { // currently, all signals are masked and the signal // must have been delivered directly to this thread. timeout := syscall.Timespec{} - sig, _, errno := syscall.RawSyscall6( + sig, _, errno := syscall.RawSyscall6( // escapes: no. syscall.SYS_RT_SIGTIMEDWAIT, uintptr(unsafe.Pointer(&bounceSignalMask)), 0, // siginfo. @@ -112,12 +133,12 @@ func bluepillHandler(context unsafe.Pointer) { // PIC, we can't inject an interrupt while they are // masked. We need to request a window if it's not // ready. - if c.runData.readyForInterruptInjection == 0 { - c.runData.requestInterruptWindow = 1 - continue // Rerun vCPU. - } else { + if bluepillReadyStopGuest(c) { // Force injection below; the vCPU is ready. c.runData.exitReason = _KVM_EXIT_IRQ_WINDOW_OPEN + } else { + c.runData.requestInterruptWindow = 1 + continue // Rerun vCPU. } case syscall.EFAULT: // If a fault is not serviceable due to the host @@ -125,7 +146,7 @@ func bluepillHandler(context unsafe.Pointer) { // MMIO exit we receive EFAULT from the run ioctl. We // always inject an NMI here since we may be in kernel // mode and have interrupts disabled. - if _, _, errno := syscall.RawSyscall( + if _, _, errno := syscall.RawSyscall( // escapes: no. syscall.SYS_IOCTL, uintptr(c.fd), _KVM_NMI, 0); errno != 0 { @@ -156,25 +177,20 @@ func bluepillHandler(context unsafe.Pointer) { c.die(bluepillArchContext(context), "debug") return case _KVM_EXIT_HLT: - // Copy out registers. - bluepillArchExit(c, bluepillArchContext(context)) - - // Return to the vCPUReady state; notify any waiters. - user := atomic.LoadUint32(&c.state) & vCPUUser - switch atomic.SwapUint32(&c.state, user) { - case user | vCPUGuest: // Expected case. - case user | vCPUGuest | vCPUWaiter: - c.notify() - default: - throw("invalid state") - } + bluepillGuestExit(c, context) return case _KVM_EXIT_MMIO: + physical := uintptr(c.runData.data[0]) + if getHypercallID(physical) == _KVM_HYPERCALL_VMEXIT { + bluepillGuestExit(c, context) + return + } + // Increment the fault count. atomic.AddUint32(&c.faults, 1) // For MMIO, the physical address is the first data item. - physical := uintptr(c.runData.data[0]) + physical = uintptr(c.runData.data[0]) virtual, ok := handleBluepillFault(c.machine, physical, physicalRegions, _KVM_MEM_FLAGS_NONE) if !ok { c.die(bluepillArchContext(context), "invalid physical address") @@ -201,17 +217,7 @@ func bluepillHandler(context unsafe.Pointer) { } } case _KVM_EXIT_IRQ_WINDOW_OPEN: - // Interrupt: we must have requested an interrupt - // window; set the interrupt line. - if _, _, errno := syscall.RawSyscall( - syscall.SYS_IOCTL, - uintptr(c.fd), - _KVM_INTERRUPT, - uintptr(unsafe.Pointer(&bounce))); errno != 0 { - throw("interrupt injection failed") - } - // Clear previous injection request. - c.runData.requestInterruptWindow = 0 + bluepillStopGuest(c) case _KVM_EXIT_SHUTDOWN: c.die(bluepillArchContext(context), "shutdown") return diff --git a/pkg/sentry/platform/kvm/context.go b/pkg/sentry/platform/kvm/context.go index 6507121ea..6e6b76416 100644 --- a/pkg/sentry/platform/kvm/context.go +++ b/pkg/sentry/platform/kvm/context.go @@ -15,6 +15,7 @@ package kvm import ( + pkgcontext "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/platform/interrupt" @@ -37,7 +38,8 @@ type context struct { } // Switch runs the provided context in the given address space. -func (c *context) Switch(as platform.AddressSpace, ac arch.Context, _ int32) (*arch.SignalInfo, usermem.AccessType, error) { +func (c *context) Switch(ctx pkgcontext.Context, mm platform.MemoryManager, ac arch.Context, _ int32) (*arch.SignalInfo, usermem.AccessType, error) { + as := mm.AddressSpace() localAS := as.(*addressSpace) // Grab a vCPU. @@ -88,3 +90,9 @@ func (c *context) Interrupt() { // Release implements platform.Context.Release(). func (c *context) Release() {} + +// FullStateChanged implements platform.Context.FullStateChanged. +func (c *context) FullStateChanged() {} + +// PullFullState implements platform.Context.PullFullState. +func (c *context) PullFullState(as platform.AddressSpace, ac arch.Context) {} diff --git a/pkg/sentry/platform/kvm/kvm_amd64_test.go b/pkg/sentry/platform/kvm/kvm_amd64_test.go new file mode 100644 index 000000000..c0b4fd374 --- /dev/null +++ b/pkg/sentry/platform/kvm/kvm_amd64_test.go @@ -0,0 +1,51 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// +build amd64 + +package kvm + +import ( + "testing" + + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/platform" + "gvisor.dev/gvisor/pkg/sentry/platform/kvm/testutil" + "gvisor.dev/gvisor/pkg/sentry/platform/ring0" + "gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables" +) + +func TestSegments(t *testing.T) { + applicationTest(t, true, testutil.TwiddleSegments, func(c *vCPU, regs *arch.Registers, pt *pagetables.PageTables) bool { + testutil.SetTestSegments(regs) + for { + var si arch.SignalInfo + if _, err := c.SwitchToUser(ring0.SwitchOpts{ + Registers: regs, + FloatingPointState: dummyFPState, + PageTables: pt, + FullRestore: true, + }, &si); err == platform.ErrContextInterrupt { + continue // Retry. + } else if err != nil { + t.Errorf("application segment check with full restore got unexpected error: %v", err) + } + if err := testutil.CheckTestSegments(regs); err != nil { + t.Errorf("application segment check with full restore failed: %v", err) + } + break // Done. + } + return false + }) +} diff --git a/pkg/sentry/platform/kvm/kvm_arm64.go b/pkg/sentry/platform/kvm/kvm_arm64.go index 29d457a7e..0b06a923a 100644 --- a/pkg/sentry/platform/kvm/kvm_arm64.go +++ b/pkg/sentry/platform/kvm/kvm_arm64.go @@ -26,6 +26,9 @@ type kvmOneReg struct { addr uint64 } +// arm64HypercallMMIOBase is MMIO base address used to dispatch hypercalls. +var arm64HypercallMMIOBase uintptr + const KVM_NR_SPSR = 5 type userFpsimdState struct { @@ -43,6 +46,18 @@ type userRegs struct { fpRegs userFpsimdState } +type exception struct { + sErrPending uint8 + sErrHasEsr uint8 + pad [6]uint8 + sErrEsr uint64 +} + +type kvmVcpuEvents struct { + exception + rsvd [12]uint32 +} + // updateGlobalOnce does global initialization. It has to be called only once. func updateGlobalOnce(fd int) error { physicalInit() diff --git a/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go b/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go index 6531bae1d..48ccf8474 100644 --- a/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go +++ b/pkg/sentry/platform/kvm/kvm_arm64_unsafe.go @@ -22,7 +22,8 @@ import ( ) var ( - runDataSize int + runDataSize int + hasGuestPCID bool ) func updateSystemValues(fd int) error { @@ -33,6 +34,7 @@ func updateSystemValues(fd int) error { } // Save the data. runDataSize = int(sz) + hasGuestPCID = true // Success. return nil diff --git a/pkg/sentry/platform/kvm/kvm_const.go b/pkg/sentry/platform/kvm/kvm_const.go index 1d5c77ff4..3bf918446 100644 --- a/pkg/sentry/platform/kvm/kvm_const.go +++ b/pkg/sentry/platform/kvm/kvm_const.go @@ -35,6 +35,8 @@ const ( _KVM_GET_SUPPORTED_CPUID = 0xc008ae05 _KVM_SET_CPUID2 = 0x4008ae90 _KVM_SET_SIGNAL_MASK = 0x4004ae8b + _KVM_GET_VCPU_EVENTS = 0x8040ae9f + _KVM_SET_VCPU_EVENTS = 0x4040aea0 ) // KVM exit reasons. @@ -54,8 +56,10 @@ const ( // KVM capability options. const ( - _KVM_CAP_MAX_VCPUS = 0x42 - _KVM_CAP_ARM_VM_IPA_SIZE = 0xa5 + _KVM_CAP_MAX_VCPUS = 0x42 + _KVM_CAP_ARM_VM_IPA_SIZE = 0xa5 + _KVM_CAP_VCPU_EVENTS = 0x29 + _KVM_CAP_ARM_INJECT_SERROR_ESR = 0x9e ) // KVM limits. @@ -71,3 +75,13 @@ const ( _KVM_MEM_READONLY = uint32(1) << 1 _KVM_MEM_FLAGS_NONE = 0 ) + +// KVM hypercall list. +// Canonical list of hypercalls supported. +const ( + // On amd64, it uses 'HLT' to leave the guest. + // Unlike amd64, arm64 can only uses mmio_exit/psci to leave the guest. + // _KVM_HYPERCALL_VMEXIT is only used on Arm64 for now. + _KVM_HYPERCALL_VMEXIT int = iota + _KVM_HYPERCALL_MAX +) diff --git a/pkg/sentry/platform/kvm/kvm_const_arm64.go b/pkg/sentry/platform/kvm/kvm_const_arm64.go index 531ae8b1e..9a7be3655 100644 --- a/pkg/sentry/platform/kvm/kvm_const_arm64.go +++ b/pkg/sentry/platform/kvm/kvm_const_arm64.go @@ -72,6 +72,7 @@ const ( _TCR_T0SZ_VA48 = 64 - 48 // VA=48 _TCR_T1SZ_VA48 = 64 - 48 // VA=48 + _TCR_A1 = 1 << 22 _TCR_ASID16 = 1 << 36 _TCR_TBI0 = 1 << 37 @@ -116,6 +117,17 @@ const ( // Arm64: Exception Syndrome Register EL1. const ( + _ESR_ELx_EC_SHIFT = 26 + _ESR_ELx_EC_MASK = 0x3F << _ESR_ELx_EC_SHIFT + + _ESR_ELx_EC_IMP_DEF = 0x1f + _ESR_ELx_EC_IABT_LOW = 0x20 + _ESR_ELx_EC_IABT_CUR = 0x21 + _ESR_ELx_EC_PC_ALIGN = 0x22 + + _ESR_ELx_CM = 1 << 8 + _ESR_ELx_WNR = 1 << 6 + _ESR_ELx_FSC = 0x3F _ESR_SEGV_MAPERR_L0 = 0x4 @@ -131,3 +143,10 @@ const ( _ESR_SEGV_PEMERR_L2 = 0xe _ESR_SEGV_PEMERR_L3 = 0xf ) + +// Arm64: MMIO base address used to dispatch hypercalls. +const ( + // on Arm64, the MMIO address must be 64-bit aligned. + // Currently, we only need 1 hypercall: hypercall_vmexit. + _AARCH64_HYPERCALL_MMIO_SIZE = 1 << 3 +) diff --git a/pkg/sentry/platform/kvm/kvm_test.go b/pkg/sentry/platform/kvm/kvm_test.go index 6c8f4fa28..45b3180f1 100644 --- a/pkg/sentry/platform/kvm/kvm_test.go +++ b/pkg/sentry/platform/kvm/kvm_test.go @@ -262,30 +262,6 @@ func TestRegistersFault(t *testing.T) { }) } -func TestSegments(t *testing.T) { - applicationTest(t, true, testutil.TwiddleSegments, func(c *vCPU, regs *arch.Registers, pt *pagetables.PageTables) bool { - testutil.SetTestSegments(regs) - for { - var si arch.SignalInfo - if _, err := c.SwitchToUser(ring0.SwitchOpts{ - Registers: regs, - FloatingPointState: dummyFPState, - PageTables: pt, - FullRestore: true, - }, &si); err == platform.ErrContextInterrupt { - continue // Retry. - } else if err != nil { - t.Errorf("application segment check with full restore got unexpected error: %v", err) - } - if err := testutil.CheckTestSegments(regs); err != nil { - t.Errorf("application segment check with full restore failed: %v", err) - } - break // Done. - } - return false - }) -} - func TestBounce(t *testing.T) { applicationTest(t, true, testutil.SpinLoop, func(c *vCPU, regs *arch.Registers, pt *pagetables.PageTables) bool { go func() { diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go index f1afc74dc..6c54712d1 100644 --- a/pkg/sentry/platform/kvm/machine.go +++ b/pkg/sentry/platform/kvm/machine.go @@ -52,16 +52,19 @@ type machine struct { // available is notified when vCPUs are available. available sync.Cond - // vCPUs are the machine vCPUs. + // vCPUsByTID are the machine vCPUs. // // These are populated dynamically. - vCPUs map[uint64]*vCPU + vCPUsByTID map[uint64]*vCPU // vCPUsByID are the machine vCPUs, can be indexed by the vCPU's ID. - vCPUsByID map[int]*vCPU + vCPUsByID []*vCPU // maxVCPUs is the maximum number of vCPUs supported by the machine. maxVCPUs int + + // nextID is the next vCPU ID. + nextID uint32 } const ( @@ -137,9 +140,8 @@ type dieState struct { // // Precondition: mu must be held. func (m *machine) newVCPU() *vCPU { - id := len(m.vCPUs) - // Create the vCPU. + id := int(atomic.AddUint32(&m.nextID, 1) - 1) fd, _, errno := syscall.RawSyscall(syscall.SYS_IOCTL, uintptr(m.fd), _KVM_CREATE_VCPU, uintptr(id)) if errno != 0 { panic(fmt.Sprintf("error creating new vCPU: %v", errno)) @@ -176,11 +178,7 @@ func (m *machine) newVCPU() *vCPU { // newMachine returns a new VM context. func newMachine(vm int) (*machine, error) { // Create the machine. - m := &machine{ - fd: vm, - vCPUs: make(map[uint64]*vCPU), - vCPUsByID: make(map[int]*vCPU), - } + m := &machine{fd: vm} m.available.L = &m.mu m.kernel.Init(ring0.KernelOpts{ PageTables: pagetables.New(newAllocator()), @@ -194,6 +192,10 @@ func newMachine(vm int) (*machine, error) { } log.Debugf("The maximum number of vCPUs is %d.", m.maxVCPUs) + // Create the vCPUs map/slices. + m.vCPUsByTID = make(map[uint64]*vCPU) + m.vCPUsByID = make([]*vCPU, m.maxVCPUs) + // Apply the physical mappings. Note that these mappings may point to // guest physical addresses that are not actually available. These // physical pages are mapped on demand, see kernel_unsafe.go. @@ -274,6 +276,8 @@ func newMachine(vm int) (*machine, error) { // not available. This attempts to be efficient for calls in the hot path. // // This panics on error. +// +//go:nosplit func (m *machine) mapPhysical(physical, length uintptr, phyRegions []physicalRegion, flags uint32) { for end := physical + length; physical < end; { _, physicalStart, length, ok := calculateBluepillFault(physical, phyRegions) @@ -304,7 +308,11 @@ func (m *machine) Destroy() { runtime.SetFinalizer(m, nil) // Destroy vCPUs. - for _, c := range m.vCPUs { + for _, c := range m.vCPUsByID { + if c == nil { + continue + } + // Ensure the vCPU is not still running in guest mode. This is // possible iff teardown has been done by other threads, and // somehow a single thread has not executed any system calls. @@ -337,7 +345,7 @@ func (m *machine) Get() *vCPU { tid := procid.Current() // Check for an exact match. - if c := m.vCPUs[tid]; c != nil { + if c := m.vCPUsByTID[tid]; c != nil { c.lock() m.mu.RUnlock() return c @@ -356,7 +364,7 @@ func (m *machine) Get() *vCPU { tid = procid.Current() // Recheck for an exact match. - if c := m.vCPUs[tid]; c != nil { + if c := m.vCPUsByTID[tid]; c != nil { c.lock() m.mu.Unlock() return c @@ -364,10 +372,10 @@ func (m *machine) Get() *vCPU { for { // Scan for an available vCPU. - for origTID, c := range m.vCPUs { + for origTID, c := range m.vCPUsByTID { if atomic.CompareAndSwapUint32(&c.state, vCPUReady, vCPUUser) { - delete(m.vCPUs, origTID) - m.vCPUs[tid] = c + delete(m.vCPUsByTID, origTID) + m.vCPUsByTID[tid] = c m.mu.Unlock() c.loadSegments(tid) return c @@ -375,17 +383,17 @@ func (m *machine) Get() *vCPU { } // Create a new vCPU (maybe). - if len(m.vCPUs) < m.maxVCPUs { + if int(m.nextID) < m.maxVCPUs { c := m.newVCPU() c.lock() - m.vCPUs[tid] = c + m.vCPUsByTID[tid] = c m.mu.Unlock() c.loadSegments(tid) return c } // Scan for something not in user mode. - for origTID, c := range m.vCPUs { + for origTID, c := range m.vCPUsByTID { if !atomic.CompareAndSwapUint32(&c.state, vCPUGuest, vCPUGuest|vCPUWaiter) { continue } @@ -403,8 +411,8 @@ func (m *machine) Get() *vCPU { } // Steal the vCPU. - delete(m.vCPUs, origTID) - m.vCPUs[tid] = c + delete(m.vCPUsByTID, origTID) + m.vCPUsByTID[tid] = c m.mu.Unlock() c.loadSegments(tid) return c @@ -431,7 +439,7 @@ func (m *machine) Put(c *vCPU) { // newDirtySet returns a new dirty set. func (m *machine) newDirtySet() *dirtySet { return &dirtySet{ - vCPUs: make([]uint64, (m.maxVCPUs+63)/64, (m.maxVCPUs+63)/64), + vCPUMasks: make([]uint64, (m.maxVCPUs+63)/64, (m.maxVCPUs+63)/64), } } diff --git a/pkg/sentry/platform/kvm/machine_amd64.go b/pkg/sentry/platform/kvm/machine_amd64.go index 923ce3909..acc823ba6 100644 --- a/pkg/sentry/platform/kvm/machine_amd64.go +++ b/pkg/sentry/platform/kvm/machine_amd64.go @@ -51,9 +51,10 @@ func (m *machine) initArchState() error { recover() debug.SetPanicOnFault(old) }() - m.retryInGuest(func() { - ring0.SetCPUIDFaulting(true) - }) + c := m.Get() + defer m.Put(c) + bluepill(c) + ring0.SetCPUIDFaulting(true) return nil } @@ -89,8 +90,8 @@ func (m *machine) dropPageTables(pt *pagetables.PageTables) { defer m.mu.Unlock() // Clear from all PCIDs. - for _, c := range m.vCPUs { - if c.PCIDs != nil { + for _, c := range m.vCPUsByID { + if c != nil && c.PCIDs != nil { c.PCIDs.Drop(pt) } } @@ -335,29 +336,6 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) } } -// retryInGuest runs the given function in guest mode. -// -// If the function does not complete in guest mode (due to execution of a -// system call due to a GC stall, for example), then it will be retried. The -// given function must be idempotent as a result of the retry mechanism. -func (m *machine) retryInGuest(fn func()) { - c := m.Get() - defer m.Put(c) - for { - c.ClearErrorCode() // See below. - bluepill(c) // Force guest mode. - fn() // Execute the given function. - _, user := c.ErrorCode() - if user { - // If user is set, then we haven't bailed back to host - // mode via a kernel exception or system call. We - // consider the full function to have executed in guest - // mode and we can return. - break - } - } -} - // On x86 platform, the flags for "setMemoryRegion" can always be set as 0. // There is no need to return read-only physicalRegions. func rdonlyRegionsForSetMem() (phyRegions []physicalRegion) { diff --git a/pkg/sentry/platform/kvm/machine_amd64_unsafe.go b/pkg/sentry/platform/kvm/machine_amd64_unsafe.go index 7156c245f..290f035dd 100644 --- a/pkg/sentry/platform/kvm/machine_amd64_unsafe.go +++ b/pkg/sentry/platform/kvm/machine_amd64_unsafe.go @@ -154,7 +154,7 @@ func (c *vCPU) setUserRegisters(uregs *userRegs) error { // //go:nosplit func (c *vCPU) getUserRegisters(uregs *userRegs) syscall.Errno { - if _, _, errno := syscall.RawSyscall( + if _, _, errno := syscall.RawSyscall( // escapes: no. syscall.SYS_IOCTL, uintptr(c.fd), _KVM_GET_REGS, diff --git a/pkg/sentry/platform/kvm/machine_arm64.go b/pkg/sentry/platform/kvm/machine_arm64.go index e42505542..9db171af9 100644 --- a/pkg/sentry/platform/kvm/machine_arm64.go +++ b/pkg/sentry/platform/kvm/machine_arm64.go @@ -60,6 +60,12 @@ func rdonlyRegionsForSetMem() (phyRegions []physicalRegion) { if !vr.accessType.Write && vr.accessType.Read { rdonlyRegions = append(rdonlyRegions, vr.region) } + + // TODO(gvisor.dev/issue/2686): PROT_NONE should be specially treated. + // Workaround: treated as rdonly temporarily. + if !vr.accessType.Write && !vr.accessType.Read && !vr.accessType.Execute { + rdonlyRegions = append(rdonlyRegions, vr.region) + } }) for _, r := range rdonlyRegions { @@ -100,7 +106,7 @@ func (m *machine) dropPageTables(pt *pagetables.PageTables) { defer m.mu.Unlock() // Clear from all PCIDs. - for _, c := range m.vCPUs { + for _, c := range m.vCPUsByID { if c.PCIDs != nil { c.PCIDs.Drop(pt) } @@ -119,71 +125,59 @@ func nonCanonical(addr uint64, signal int32, info *arch.SignalInfo) (usermem.Acc return usermem.NoAccess, platform.ErrContextSignal } +// isInstructionAbort returns true if it is an instruction abort. +// +//go:nosplit +func isInstructionAbort(code uint64) bool { + value := (code & _ESR_ELx_EC_MASK) >> _ESR_ELx_EC_SHIFT + return value == _ESR_ELx_EC_IABT_LOW +} + +// isWriteFault returns whether it is a write fault. +// +//go:nosplit +func isWriteFault(code uint64) bool { + if isInstructionAbort(code) { + return false + } + + return (code & _ESR_ELx_WNR) != 0 +} + // fault generates an appropriate fault return. // //go:nosplit func (c *vCPU) fault(signal int32, info *arch.SignalInfo) (usermem.AccessType, error) { + bluepill(c) // Probably no-op, but may not be. faultAddr := c.GetFaultAddr() code, user := c.ErrorCode() + if !user { + // The last fault serviced by this CPU was not a user + // fault, so we can't reliably trust the faultAddr or + // the code provided here. We need to re-execute. + return usermem.NoAccess, platform.ErrContextInterrupt + } + // Reset the pointed SignalInfo. *info = arch.SignalInfo{Signo: signal} info.SetAddr(uint64(faultAddr)) - read := true - write := false - execute := true - ret := code & _ESR_ELx_FSC switch ret { case _ESR_SEGV_MAPERR_L0, _ESR_SEGV_MAPERR_L1, _ESR_SEGV_MAPERR_L2, _ESR_SEGV_MAPERR_L3: info.Code = 1 //SEGV_MAPERR - read = false - write = true - execute = false case _ESR_SEGV_ACCERR_L1, _ESR_SEGV_ACCERR_L2, _ESR_SEGV_ACCERR_L3, _ESR_SEGV_PEMERR_L1, _ESR_SEGV_PEMERR_L2, _ESR_SEGV_PEMERR_L3: info.Code = 2 // SEGV_ACCERR. - read = true - write = false - execute = false default: info.Code = 2 } - if !user { - read = true - write = false - execute = true - - } accessType := usermem.AccessType{ - Read: read, - Write: write, - Execute: execute, + Read: !isWriteFault(uint64(code)), + Write: isWriteFault(uint64(code)), + Execute: isInstructionAbort(uint64(code)), } return accessType, platform.ErrContextSignal } - -// retryInGuest runs the given function in guest mode. -// -// If the function does not complete in guest mode (due to execution of a -// system call due to a GC stall, for example), then it will be retried. The -// given function must be idempotent as a result of the retry mechanism. -func (m *machine) retryInGuest(fn func()) { - c := m.Get() - defer m.Put(c) - for { - c.ClearErrorCode() // See below. - bluepill(c) // Force guest mode. - fn() // Execute the given function. - _, user := c.ErrorCode() - if user { - // If user is set, then we haven't bailed back to host - // mode via a kernel exception or system call. We - // consider the full function to have executed in guest - // mode and we can return. - break - } - } -} diff --git a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go index 3c02cef7c..905712076 100644 --- a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go +++ b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go @@ -26,6 +26,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/platform/ring0" + "gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables" "gvisor.dev/gvisor/pkg/usermem" ) @@ -60,7 +61,6 @@ func (c *vCPU) initArchState() error { reg.addr = uint64(reflect.ValueOf(&data).Pointer()) regGet.addr = uint64(reflect.ValueOf(&dataGet).Pointer()) - vcpuInit.target = _KVM_ARM_TARGET_GENERIC_V8 vcpuInit.features[0] |= (1 << _KVM_ARM_VCPU_PSCI_0_2) if _, _, errno := syscall.RawSyscall( syscall.SYS_IOCTL, @@ -78,19 +78,6 @@ func (c *vCPU) initArchState() error { return err } - // sctlr_el1 - regGet.id = _KVM_ARM64_REGS_SCTLR_EL1 - if err := c.getOneRegister(®Get); err != nil { - return err - } - - dataGet |= (_SCTLR_M | _SCTLR_C | _SCTLR_I) - data = dataGet - reg.id = _KVM_ARM64_REGS_SCTLR_EL1 - if err := c.setOneRegister(®); err != nil { - return err - } - // tcr_el1 data = _TCR_TXSZ_VA48 | _TCR_CACHE_FLAGS | _TCR_SHARED | _TCR_TG_FLAGS | _TCR_ASID16 | _TCR_IPS_40BITS reg.id = _KVM_ARM64_REGS_TCR_EL1 @@ -159,10 +146,16 @@ func (c *vCPU) initArchState() error { return err } - data = ring0.PsrDefaultSet | ring0.KernelFlagsSet - reg.id = _KVM_ARM64_REGS_PSTATE - if err := c.setOneRegister(®); err != nil { - return err + // Use the address of the exception vector table as + // the MMIO address base. + arm64HypercallMMIOBase = toLocation + + // Initialize the PCID database. + if hasGuestPCID { + // Note that NewPCIDs may return a nil table here, in which + // case we simply don't use PCID support (see below). In + // practice, this should not happen, however. + c.PCIDs = pagetables.NewPCIDs(fixedKernelPCID+1, poolPCIDs) } c.floatingPointState = arch.NewFloatingPointData() @@ -243,6 +236,13 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) return nonCanonical(regs.Sp, int32(syscall.SIGBUS), info) } + // Assign PCIDs. + if c.PCIDs != nil { + var requireFlushPCID bool // Force a flush? + switchOpts.UserASID, requireFlushPCID = c.PCIDs.Assign(switchOpts.PageTables) + switchOpts.Flush = switchOpts.Flush || requireFlushPCID + } + var vector ring0.Vector ttbr0App := switchOpts.PageTables.TTBR0_EL1(false, 0) c.SetTtbr0App(uintptr(ttbr0App)) @@ -269,10 +269,18 @@ func (c *vCPU) SwitchToUser(switchOpts ring0.SwitchOpts, info *arch.SignalInfo) case ring0.PageFault: return c.fault(int32(syscall.SIGSEGV), info) - case 0xaa: - return usermem.NoAccess, nil + case ring0.Vector(bounce): // ring0.VirtualizationException + return usermem.NoAccess, platform.ErrContextInterrupt + case ring0.El0Sync_undef, + ring0.El1Sync_undef: + *info = arch.SignalInfo{ + Signo: int32(syscall.SIGILL), + Code: 1, // ILL_ILLOPC (illegal opcode). + } + info.SetAddr(switchOpts.Registers.Pc) // Include address. + return usermem.AccessType{}, platform.ErrContextSignal default: - return usermem.NoAccess, platform.ErrContextSignal + panic(fmt.Sprintf("unexpected vector: 0x%x", vector)) } } diff --git a/pkg/sentry/platform/kvm/machine_unsafe.go b/pkg/sentry/platform/kvm/machine_unsafe.go index f04be2ab5..9f86f6a7a 100644 --- a/pkg/sentry/platform/kvm/machine_unsafe.go +++ b/pkg/sentry/platform/kvm/machine_unsafe.go @@ -13,7 +13,7 @@ // limitations under the License. // +build go1.12 -// +build !go1.15 +// +build !go1.16 // Check go:linkname function signatures when updating Go version. @@ -115,7 +115,7 @@ func (a *atomicAddressSpace) get() *addressSpace { // //go:nosplit func (c *vCPU) notify() { - _, _, errno := syscall.RawSyscall6( + _, _, errno := syscall.RawSyscall6( // escapes: no. syscall.SYS_FUTEX, uintptr(unsafe.Pointer(&c.state)), linux.FUTEX_WAKE|linux.FUTEX_PRIVATE_FLAG, diff --git a/pkg/sentry/platform/kvm/testutil/testutil_arm64.go b/pkg/sentry/platform/kvm/testutil/testutil_arm64.go index ca902c8c1..4dad877ba 100644 --- a/pkg/sentry/platform/kvm/testutil/testutil_arm64.go +++ b/pkg/sentry/platform/kvm/testutil/testutil_arm64.go @@ -56,5 +56,9 @@ func CheckTestRegs(regs *arch.Registers, full bool) (err error) { err = addRegisterMismatch(err, fmt.Sprintf("R%d", i), regs.Regs[i], need) } } + // Check tls. + if need := ^uint64(11); regs.TPIDR_EL0 != need { + err = addRegisterMismatch(err, "tpdir_el0", regs.TPIDR_EL0, need) + } return } diff --git a/pkg/sentry/platform/kvm/testutil/testutil_arm64.s b/pkg/sentry/platform/kvm/testutil/testutil_arm64.s index 0bebee852..6caf7282d 100644 --- a/pkg/sentry/platform/kvm/testutil/testutil_arm64.s +++ b/pkg/sentry/platform/kvm/testutil/testutil_arm64.s @@ -52,6 +52,8 @@ start: TEXT ·FloatingPointWorks(SB),NOSPLIT,$0-8 NO_LOCAL_POINTERS + // gc will touch fpsimd, so we should test it. + // such as in <runtime.deductSweepCredit>. FMOVD $(9.9), F0 MOVD $SYS_GETPID, R8 // getpid SVC @@ -102,5 +104,15 @@ isNaN: TEXT ·TwiddleRegsSyscall(SB),NOSPLIT,$0 TWIDDLE_REGS() + MSR R10, TPIDR_EL0 + // Trapped in el0_svc. SVC RET // never reached + +TEXT ·TwiddleRegsFault(SB),NOSPLIT,$0 + TWIDDLE_REGS() + MSR R10, TPIDR_EL0 + // Trapped in el0_ia. + // Branch to Register branches unconditionally to an address in <Rn>. + JMP (R6) // <=> br x6, must fault + RET // never reached diff --git a/pkg/sentry/platform/platform.go b/pkg/sentry/platform/platform.go index 171513f3f..ba031516a 100644 --- a/pkg/sentry/platform/platform.go +++ b/pkg/sentry/platform/platform.go @@ -22,9 +22,10 @@ import ( "os" "gvisor.dev/gvisor/pkg/abi/linux" - "gvisor.dev/gvisor/pkg/safemem" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/seccomp" "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/usermem" ) @@ -114,6 +115,17 @@ func (NoCPUPreemptionDetection) PreemptAllCPUs() error { panic("This platform does not support CPU preemption detection") } +// MemoryManager represents an abstraction above the platform address space +// which manages memory mappings and their contents. +type MemoryManager interface { + //usermem.IO provides access to the contents of a virtual memory space. + usermem.IO + // MMap establishes a memory mapping. + MMap(ctx context.Context, opts memmap.MMapOpts) (usermem.Addr, error) + // AddressSpace returns the AddressSpace bound to mm. + AddressSpace() AddressSpace +} + // Context represents the execution context for a single thread. type Context interface { // Switch resumes execution of the thread specified by the arch.Context @@ -143,7 +155,36 @@ type Context interface { // concurrent call to Switch(). // // - ErrContextCPUPreempted: See the definition of that error for details. - Switch(as AddressSpace, ac arch.Context, cpu int32) (*arch.SignalInfo, usermem.AccessType, error) + Switch(ctx context.Context, mm MemoryManager, ac arch.Context, cpu int32) (*arch.SignalInfo, usermem.AccessType, error) + + // PullFullState() pulls a full state of the application thread. + // + // A platform can support lazy loading/restoring of a thread state + // which includes registers and a floating point state. + // + // For example, when the Sentry handles a system call, it may have only + // syscall arguments without other registers and a floating point + // state. And in this case, if the Sentry will need to construct a + // signal frame to call a signal handler, it will need to call + // PullFullState() to load all registers and FPU state. + // + // Preconditions: The caller must be running on the task goroutine. + PullFullState(as AddressSpace, ac arch.Context) + + // FullStateChanged() indicates that a thread state has been changed by + // the Sentry. This happens in case of the rt_sigreturn, execve, etc. + // + // First, it indicates that the Sentry has the full state of the thread + // and PullFullState() has to do nothing if it is called after + // FullStateChanged(). + // + // Second, it forces restoring the full state of the application + // thread. A platform can support lazy loading/restoring of a thread + // state. This means that if the Sentry has not changed a thread state, + // the platform may not restore it. + // + // Preconditions: The caller must be running on the task goroutine. + FullStateChanged() // Interrupt interrupts a concurrent call to Switch(), causing it to return // ErrContextInterrupt. @@ -207,7 +248,7 @@ type AddressSpace interface { // Preconditions: addr and fr must be page-aligned. fr.Length() > 0. // at.Any() == true. At least one reference must be held on all pages in // fr, and must continue to be held as long as pages are mapped. - MapFile(addr usermem.Addr, f File, fr FileRange, at usermem.AccessType, precommit bool) error + MapFile(addr usermem.Addr, f memmap.File, fr memmap.FileRange, at usermem.AccessType, precommit bool) error // Unmap unmaps the given range. // @@ -218,6 +259,13 @@ type AddressSpace interface { // must be acquired via platform.NewAddressSpace(). Release() + // PreFork() is called before creating a copy of AddressSpace. This + // guarantees that this address space will be in a consistent state. + PreFork() + + // PostFork() is called after creating a copy of AddressSpace. + PostFork() + // AddressSpaceIO methods are supported iff the associated platform's // Platform.SupportsAddressSpaceIO() == true. AddressSpaces for which this // does not hold may panic if AddressSpaceIO methods are invoked. @@ -310,52 +358,6 @@ func (f SegmentationFault) Error() string { return fmt.Sprintf("segmentation fault at %#x", f.Addr) } -// File represents a host file that may be mapped into an AddressSpace. -type File interface { - // All pages in a File are reference-counted. - - // IncRef increments the reference count on all pages in fr. - // - // Preconditions: fr.Start and fr.End must be page-aligned. fr.Length() > - // 0. At least one reference must be held on all pages in fr. (The File - // interface does not provide a way to acquire an initial reference; - // implementors may define mechanisms for doing so.) - IncRef(fr FileRange) - - // DecRef decrements the reference count on all pages in fr. - // - // Preconditions: fr.Start and fr.End must be page-aligned. fr.Length() > - // 0. At least one reference must be held on all pages in fr. - DecRef(fr FileRange) - - // MapInternal returns a mapping of the given file offsets in the invoking - // process' address space for reading and writing. - // - // Note that fr.Start and fr.End need not be page-aligned. - // - // Preconditions: fr.Length() > 0. At least one reference must be held on - // all pages in fr. - // - // Postconditions: The returned mapping is valid as long as at least one - // reference is held on the mapped pages. - MapInternal(fr FileRange, at usermem.AccessType) (safemem.BlockSeq, error) - - // FD returns the file descriptor represented by the File. - // - // The only permitted operation on the returned file descriptor is to map - // pages from it consistent with the requirements of AddressSpace.MapFile. - FD() int -} - -// FileRange represents a range of uint64 offsets into a File. -// -// type FileRange <generated using go_generics> - -// String implements fmt.Stringer.String. -func (fr FileRange) String() string { - return fmt.Sprintf("[%#x, %#x)", fr.Start, fr.End) -} - // Requirements is used to specify platform specific requirements. type Requirements struct { // RequiresCurrentPIDNS indicates that the sandbox has to be started in the diff --git a/pkg/sentry/platform/ptrace/BUILD b/pkg/sentry/platform/ptrace/BUILD index 30402c2df..e04165fbf 100644 --- a/pkg/sentry/platform/ptrace/BUILD +++ b/pkg/sentry/platform/ptrace/BUILD @@ -24,12 +24,14 @@ go_library( visibility = ["//:sandbox"], deps = [ "//pkg/abi/linux", + "//pkg/context", "//pkg/log", "//pkg/procid", "//pkg/safecopy", "//pkg/seccomp", "//pkg/sentry/arch", "//pkg/sentry/hostcpu", + "//pkg/sentry/memmap", "//pkg/sentry/platform", "//pkg/sentry/platform/interrupt", "//pkg/sync", diff --git a/pkg/sentry/platform/ptrace/ptrace.go b/pkg/sentry/platform/ptrace/ptrace.go index 08d055e05..b52d0fbd8 100644 --- a/pkg/sentry/platform/ptrace/ptrace.go +++ b/pkg/sentry/platform/ptrace/ptrace.go @@ -48,6 +48,7 @@ import ( "os" "gvisor.dev/gvisor/pkg/abi/linux" + pkgcontext "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sentry/platform/interrupt" @@ -95,7 +96,8 @@ type context struct { } // Switch runs the provided context in the given address space. -func (c *context) Switch(as platform.AddressSpace, ac arch.Context, cpu int32) (*arch.SignalInfo, usermem.AccessType, error) { +func (c *context) Switch(ctx pkgcontext.Context, mm platform.MemoryManager, ac arch.Context, cpu int32) (*arch.SignalInfo, usermem.AccessType, error) { + as := mm.AddressSpace() s := as.(*subprocess) isSyscall := s.switchToApp(c, ac) @@ -180,6 +182,12 @@ func (c *context) Interrupt() { // Release implements platform.Context.Release(). func (c *context) Release() {} +// FullStateChanged implements platform.Context.FullStateChanged. +func (c *context) FullStateChanged() {} + +// PullFullState implements platform.Context.PullFullState. +func (c *context) PullFullState(as platform.AddressSpace, ac arch.Context) {} + // PTrace represents a collection of ptrace subprocesses. type PTrace struct { platform.MMapMinAddr diff --git a/pkg/sentry/platform/ptrace/subprocess.go b/pkg/sentry/platform/ptrace/subprocess.go index 2389423b0..e1d54d8a2 100644 --- a/pkg/sentry/platform/ptrace/subprocess.go +++ b/pkg/sentry/platform/ptrace/subprocess.go @@ -24,6 +24,7 @@ import ( "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/procid" "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/platform" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/usermem" @@ -616,7 +617,7 @@ func (s *subprocess) syscall(sysno uintptr, args ...arch.SyscallArgument) (uintp } // MapFile implements platform.AddressSpace.MapFile. -func (s *subprocess) MapFile(addr usermem.Addr, f platform.File, fr platform.FileRange, at usermem.AccessType, precommit bool) error { +func (s *subprocess) MapFile(addr usermem.Addr, f memmap.File, fr memmap.FileRange, at usermem.AccessType, precommit bool) error { var flags int if precommit { flags |= syscall.MAP_POPULATE @@ -661,3 +662,9 @@ func (s *subprocess) Unmap(addr usermem.Addr, length uint64) { panic(fmt.Sprintf("munmap(%x, %x)) failed: %v", addr, length, err)) } } + +// PreFork implements platform.AddressSpace.PreFork. +func (s *subprocess) PreFork() {} + +// PostFork implements platform.AddressSpace.PostFork. +func (s *subprocess) PostFork() {} diff --git a/pkg/sentry/platform/ptrace/subprocess_unsafe.go b/pkg/sentry/platform/ptrace/subprocess_unsafe.go index 2ae6b9f9d..0bee995e4 100644 --- a/pkg/sentry/platform/ptrace/subprocess_unsafe.go +++ b/pkg/sentry/platform/ptrace/subprocess_unsafe.go @@ -13,7 +13,7 @@ // limitations under the License. // +build go1.12 -// +build !go1.15 +// +build !go1.16 // Check go:linkname function signatures when updating Go version. diff --git a/pkg/sentry/platform/ring0/aarch64.go b/pkg/sentry/platform/ring0/aarch64.go index 8122ac6e2..87a573cc4 100644 --- a/pkg/sentry/platform/ring0/aarch64.go +++ b/pkg/sentry/platform/ring0/aarch64.go @@ -26,30 +26,31 @@ const ( _PMD_PGT_SIZE = 0x4000 _PTE_PGT_BASE = 0x7000 _PTE_PGT_SIZE = 0x1000 - - _PSR_D_BIT = 0x00000200 - _PSR_A_BIT = 0x00000100 - _PSR_I_BIT = 0x00000080 - _PSR_F_BIT = 0x00000040 ) const ( - // PSR bits - PSR_MODE_EL0t = 0x00000000 - PSR_MODE_EL1t = 0x00000004 - PSR_MODE_EL1h = 0x00000005 - PSR_MODE_MASK = 0x0000000f + // DAIF bits:debug, sError, IRQ, FIQ. + _PSR_D_BIT = 0x00000200 + _PSR_A_BIT = 0x00000100 + _PSR_I_BIT = 0x00000080 + _PSR_F_BIT = 0x00000040 + _PSR_DAIF_SHIFT = 6 + _PSR_DAIF_MASK = 0xf << _PSR_DAIF_SHIFT - // KernelFlagsSet should always be set in the kernel. - KernelFlagsSet = PSR_MODE_EL1h + // PSR bits. + _PSR_MODE_EL0t = 0x00000000 + _PSR_MODE_EL1t = 0x00000004 + _PSR_MODE_EL1h = 0x00000005 + _PSR_MODE_MASK = 0x0000000f - // UserFlagsSet are always set in userspace. - UserFlagsSet = PSR_MODE_EL0t + PsrFlagsClear = _PSR_MODE_MASK | _PSR_DAIF_MASK + PsrModeMask = _PSR_MODE_MASK - KernelFlagsClear = PSR_MODE_MASK - UserFlagsClear = PSR_MODE_MASK + // KernelFlagsSet should always be set in the kernel. + KernelFlagsSet = _PSR_MODE_EL1h | _PSR_D_BIT | _PSR_A_BIT | _PSR_I_BIT | _PSR_F_BIT - PsrDefaultSet = _PSR_D_BIT | _PSR_A_BIT | _PSR_I_BIT | _PSR_F_BIT + // UserFlagsSet are always set in userspace. + UserFlagsSet = _PSR_MODE_EL0t ) // Vector is an exception vector. diff --git a/pkg/sentry/platform/ring0/entry_arm64.s b/pkg/sentry/platform/ring0/entry_arm64.s index db6465663..9d29b7168 100644 --- a/pkg/sentry/platform/ring0/entry_arm64.s +++ b/pkg/sentry/platform/ring0/entry_arm64.s @@ -40,6 +40,20 @@ #define FPEN_ENABLE (FPEN_NOTRAP << FPEN_SHIFT) +// sctlr_el1: system control register el1. +#define SCTLR_M 1 << 0 +#define SCTLR_C 1 << 2 +#define SCTLR_I 1 << 12 +#define SCTLR_UCT 1 << 15 + +#define SCTLR_EL1_DEFAULT (SCTLR_M | SCTLR_C | SCTLR_I | SCTLR_UCT) + +// cntkctl_el1: counter-timer kernel control register el1. +#define CNTKCTL_EL0PCTEN 1 << 0 +#define CNTKCTL_EL0VCTEN 1 << 1 + +#define CNTKCTL_EL1_DEFAULT (CNTKCTL_EL0PCTEN | CNTKCTL_EL0VCTEN) + // Saves a register set. // // This is a macro because it may need to executed in contents where a stack is @@ -298,12 +312,6 @@ ISB $15; \ DSB $15; -#define IRQ_ENABLE \ - MSR $2, DAIFSet; - -#define IRQ_DISABLE \ - MSR $2, DAIFClr; - #define VFP_ENABLE \ MOVD $FPEN_ENABLE, R0; \ WORD $0xd5181040; \ //MSR R0, CPACR_EL1 @@ -356,15 +364,29 @@ TEXT ·Halt(SB),NOSPLIT,$0 CMP RSV_REG, R9 BNE mmio_exit MOVD $0, CPU_REGISTERS+PTRACE_R9(RSV_REG) + + // Flush dcache. + WORD $0xd5087e52 // DC CISW mmio_exit: // Disable fpsimd. WORD $0xd5381041 // MRS CPACR_EL1, R1 MOVD R1, CPU_LAZY_VFP(RSV_REG) VFP_DISABLE - // MMIO_EXIT. - MOVD $0, R9 - MOVD R0, 0xffff000000001000(R9) + // Trigger MMIO_EXIT/_KVM_HYPERCALL_VMEXIT. + // + // To keep it simple, I used the address of exception table as the + // MMIO base address, so that I can trigger a MMIO-EXIT by forcibly writing + // a read-only space. + // Also, the length is engough to match a sufficient number of hypercall ID. + // Then, in host user space, I can calculate this address to find out + // which hypercall. + MRS VBAR_EL1, R9 + MOVD R0, 0x0(R9) + + // Flush dcahce. + WORD $0xd5087e52 // DC CISW + RET // HaltAndResume halts execution and point the pointer to the resume function. @@ -398,6 +420,7 @@ TEXT ·Current(SB),NOSPLIT,$0-8 // Prepare the vcpu environment for container application. TEXT ·kernelExitToEl0(SB),NOSPLIT,$0 // Step1, save sentry context into memory. + MRS TPIDR_EL1, RSV_REG REGISTERS_SAVE(RSV_REG, CPU_REGISTERS) MOVD RSV_REG_APP, CPU_REGISTERS+PTRACE_R9(RSV_REG) @@ -409,34 +432,13 @@ TEXT ·kernelExitToEl0(SB),NOSPLIT,$0 MOVD CPU_REGISTERS+PTRACE_R3(RSV_REG), R3 - // Step2, save SP_EL1, PSTATE into kernel temporary stack. - // switch to temporary stack. + // Step2, switch to temporary stack. LOAD_KERNEL_STACK(RSV_REG) - WORD $0xd538d092 //MRS TPIDR_EL1, R18 - - SUB $STACK_FRAME_SIZE, RSP, RSP - MOVD CPU_REGISTERS+PTRACE_SP(RSV_REG), R11 - MOVD CPU_REGISTERS+PTRACE_PSTATE(RSV_REG), R12 - STP (R11, R12), 16*0(RSP) - - MOVD CPU_REGISTERS+PTRACE_R11(RSV_REG), R11 - MOVD CPU_REGISTERS+PTRACE_R12(RSV_REG), R12 - - // Step3, test user pagetable. - // If user pagetable is empty, trapped in el1_ia. - WORD $0xd538d092 //MRS TPIDR_EL1, R18 - SWITCH_TO_APP_PAGETABLE(RSV_REG) - WORD $0xd538d092 //MRS TPIDR_EL1, R18 - SWITCH_TO_KVM_PAGETABLE(RSV_REG) - WORD $0xd538d092 //MRS TPIDR_EL1, R18 - - // If pagetable is not empty, recovery kernel temporary stack. - ADD $STACK_FRAME_SIZE, RSP, RSP - // Step4, load app context pointer. + // Step3, load app context pointer. MOVD CPU_APP_ADDR(RSV_REG), RSV_REG_APP - // Step5, prepare the environment for container application. + // Step4, prepare the environment for container application. // set sp_el0. MOVD PTRACE_SP(RSV_REG_APP), R1 WORD $0xd5184101 //MSR R1, SP_EL0 @@ -464,13 +466,13 @@ TEXT ·kernelExitToEl0(SB),NOSPLIT,$0 LDP 16*0(RSP), (RSV_REG, RSV_REG_APP) ADD $STACK_FRAME_SIZE, RSP, RSP + ISB $15 ERET() // kernelExitToEl1 is the entrypoint for sentry in guest_el1. // Prepare the vcpu environment for sentry. TEXT ·kernelExitToEl1(SB),NOSPLIT,$0 WORD $0xd538d092 //MRS TPIDR_EL1, R18 - MOVD CPU_REGISTERS+PTRACE_PSTATE(RSV_REG), R1 WORD $0xd5184001 //MSR R1, SPSR_EL1 @@ -487,7 +489,15 @@ TEXT ·kernelExitToEl1(SB),NOSPLIT,$0 // Start is the CPU entrypoint. TEXT ·Start(SB),NOSPLIT,$0 - IRQ_DISABLE + // Flush dcache. + WORD $0xd5087e52 // DC CISW + // Init. + MOVD $SCTLR_EL1_DEFAULT, R1 + MSR R1, SCTLR_EL1 + + MOVD $CNTKCTL_EL1_DEFAULT, R1 + MSR R1, CNTKCTL_EL1 + MOVD R8, RSV_REG ORR $0xffff000000000000, RSV_REG, RSV_REG WORD $0xd518d092 //MSR R18, TPIDR_EL1 @@ -536,6 +546,7 @@ TEXT ·El1_sync(SB),NOSPLIT,$0 B el1_invalid el1_da: +el1_ia: WORD $0xd538d092 //MRS TPIDR_EL1, R18 WORD $0xd538601a //MRS FAR_EL1, R26 @@ -548,9 +559,6 @@ el1_da: B ·HaltAndResume(SB) -el1_ia: - B ·HaltAndResume(SB) - el1_sp_pc: B ·Shutdown(SB) @@ -622,9 +630,10 @@ el0_svc: MOVD $Syscall, R3 MOVD R3, CPU_VECTOR_CODE(RSV_REG) - B ·HaltAndResume(SB) + B ·kernelExitToEl1(SB) el0_da: +el0_ia: WORD $0xd538d092 //MRS TPIDR_EL1, R18 WORD $0xd538601a //MRS FAR_EL1, R26 @@ -636,10 +645,10 @@ el0_da: MOVD $PageFault, R3 MOVD R3, CPU_VECTOR_CODE(RSV_REG) - B ·HaltAndResume(SB) + MRS ESR_EL1, R3 + MOVD R3, CPU_ERROR_CODE(RSV_REG) -el0_ia: - B ·Shutdown(SB) + B ·kernelExitToEl1(SB) el0_fpsimd_acc: B ·Shutdown(SB) @@ -654,7 +663,10 @@ el0_sp_pc: B ·Shutdown(SB) el0_undef: - B ·Shutdown(SB) + MOVD $El0Sync_undef, R3 + MOVD R3, CPU_VECTOR_CODE(RSV_REG) + + B ·kernelExitToEl1(SB) el0_dbg: B ·Shutdown(SB) diff --git a/pkg/sentry/platform/ring0/kernel.go b/pkg/sentry/platform/ring0/kernel.go index 900c0bba7..021693791 100644 --- a/pkg/sentry/platform/ring0/kernel.go +++ b/pkg/sentry/platform/ring0/kernel.go @@ -31,23 +31,39 @@ type defaultHooks struct{} // KernelSyscall implements Hooks.KernelSyscall. // +// +checkescape:all +// //go:nosplit -func (defaultHooks) KernelSyscall() { Halt() } +func (defaultHooks) KernelSyscall() { + Halt() +} // KernelException implements Hooks.KernelException. // +// +checkescape:all +// //go:nosplit -func (defaultHooks) KernelException(Vector) { Halt() } +func (defaultHooks) KernelException(Vector) { + Halt() +} // kernelSyscall is a trampoline. // +// +checkescape:hard,stack +// //go:nosplit -func kernelSyscall(c *CPU) { c.hooks.KernelSyscall() } +func kernelSyscall(c *CPU) { + c.hooks.KernelSyscall() +} // kernelException is a trampoline. // +// +checkescape:hard,stack +// //go:nosplit -func kernelException(c *CPU, vector Vector) { c.hooks.KernelException(vector) } +func kernelException(c *CPU, vector Vector) { + c.hooks.KernelException(vector) +} // Init initializes a new CPU. // diff --git a/pkg/sentry/platform/ring0/kernel_amd64.go b/pkg/sentry/platform/ring0/kernel_amd64.go index 0feff8778..d37981dbf 100644 --- a/pkg/sentry/platform/ring0/kernel_amd64.go +++ b/pkg/sentry/platform/ring0/kernel_amd64.go @@ -178,6 +178,8 @@ func IsCanonical(addr uint64) bool { // // Precondition: the Rip, Rsp, Fs and Gs registers must be canonical. // +// +checkescape:all +// //go:nosplit func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) { userCR3 := switchOpts.PageTables.CR3(!switchOpts.Flush, switchOpts.UserPCID) @@ -192,9 +194,9 @@ func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) { // Perform the switch. swapgs() // GS will be swapped on return. - WriteFS(uintptr(regs.Fs_base)) // Set application FS. - WriteGS(uintptr(regs.Gs_base)) // Set application GS. - LoadFloatingPoint(switchOpts.FloatingPointState) // Copy in floating point. + WriteFS(uintptr(regs.Fs_base)) // escapes: no. Set application FS. + WriteGS(uintptr(regs.Gs_base)) // escapes: no. Set application GS. + LoadFloatingPoint(switchOpts.FloatingPointState) // escapes: no. Copy in floating point. jumpToKernel() // Switch to upper half. writeCR3(uintptr(userCR3)) // Change to user address space. if switchOpts.FullRestore { @@ -204,8 +206,8 @@ func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) { } writeCR3(uintptr(kernelCR3)) // Return to kernel address space. jumpToUser() // Return to lower half. - SaveFloatingPoint(switchOpts.FloatingPointState) // Copy out floating point. - WriteFS(uintptr(c.registers.Fs_base)) // Restore kernel FS. + SaveFloatingPoint(switchOpts.FloatingPointState) // escapes: no. Copy out floating point. + WriteFS(uintptr(c.registers.Fs_base)) // escapes: no. Restore kernel FS. return } diff --git a/pkg/sentry/platform/ring0/kernel_arm64.go b/pkg/sentry/platform/ring0/kernel_arm64.go index ccacaea6b..d0afa1aaa 100644 --- a/pkg/sentry/platform/ring0/kernel_arm64.go +++ b/pkg/sentry/platform/ring0/kernel_arm64.go @@ -53,14 +53,20 @@ func IsCanonical(addr uint64) bool { //go:nosplit func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) { - // Sanitize registers. regs := switchOpts.Registers - regs.Pstate &= ^uint64(UserFlagsClear) + regs.Pstate &= ^uint64(PsrFlagsClear) regs.Pstate |= UserFlagsSet + + LoadFloatingPoint(switchOpts.FloatingPointState) + SetTLS(regs.TPIDR_EL0) + kernelExitToEl0() + + regs.TPIDR_EL0 = GetTLS() + SaveFloatingPoint(switchOpts.FloatingPointState) + vector = c.vecCode - // Perform the switch. return } diff --git a/pkg/sentry/platform/ring0/lib_arm64.go b/pkg/sentry/platform/ring0/lib_arm64.go index a6345010d..00e52c8af 100644 --- a/pkg/sentry/platform/ring0/lib_arm64.go +++ b/pkg/sentry/platform/ring0/lib_arm64.go @@ -38,6 +38,12 @@ func SaveVRegs(*byte) // LoadVRegs loads V0-V31 registers. func LoadVRegs(*byte) +// LoadFloatingPoint loads floating point state. +func LoadFloatingPoint(*byte) + +// SaveFloatingPoint saves floating point state. +func SaveFloatingPoint(*byte) + // GetTLS returns the value of TPIDR_EL0 register. func GetTLS() (value uint64) diff --git a/pkg/sentry/platform/ring0/lib_arm64.s b/pkg/sentry/platform/ring0/lib_arm64.s index b63e14b41..86bfbe46f 100644 --- a/pkg/sentry/platform/ring0/lib_arm64.s +++ b/pkg/sentry/platform/ring0/lib_arm64.s @@ -129,3 +129,89 @@ TEXT ·LoadVRegs(SB),NOSPLIT,$0-8 ISB $15 RET + +TEXT ·LoadFloatingPoint(SB),NOSPLIT,$0-8 + MOVD addr+0(FP), R0 + + MOVD 0(R0), R1 + MOVD R1, FPSR + MOVD 8(R0), R1 + MOVD R1, NZCV + + FMOVD 16*1(R0), F0 + FMOVD 16*2(R0), F1 + FMOVD 16*3(R0), F2 + FMOVD 16*4(R0), F3 + FMOVD 16*5(R0), F4 + FMOVD 16*6(R0), F5 + FMOVD 16*7(R0), F6 + FMOVD 16*8(R0), F7 + FMOVD 16*9(R0), F8 + FMOVD 16*10(R0), F9 + FMOVD 16*11(R0), F10 + FMOVD 16*12(R0), F11 + FMOVD 16*13(R0), F12 + FMOVD 16*14(R0), F13 + FMOVD 16*15(R0), F14 + FMOVD 16*16(R0), F15 + FMOVD 16*17(R0), F16 + FMOVD 16*18(R0), F17 + FMOVD 16*19(R0), F18 + FMOVD 16*20(R0), F19 + FMOVD 16*21(R0), F20 + FMOVD 16*22(R0), F21 + FMOVD 16*23(R0), F22 + FMOVD 16*24(R0), F23 + FMOVD 16*25(R0), F24 + FMOVD 16*26(R0), F25 + FMOVD 16*27(R0), F26 + FMOVD 16*28(R0), F27 + FMOVD 16*29(R0), F28 + FMOVD 16*30(R0), F29 + FMOVD 16*31(R0), F30 + FMOVD 16*32(R0), F31 + + RET + +TEXT ·SaveFloatingPoint(SB),NOSPLIT,$0-8 + MOVD addr+0(FP), R0 + + MOVD FPSR, R1 + MOVD R1, 0(R0) + MOVD NZCV, R1 + MOVD R1, 8(R0) + + FMOVD F0, 16*1(R0) + FMOVD F1, 16*2(R0) + FMOVD F2, 16*3(R0) + FMOVD F3, 16*4(R0) + FMOVD F4, 16*5(R0) + FMOVD F5, 16*6(R0) + FMOVD F6, 16*7(R0) + FMOVD F7, 16*8(R0) + FMOVD F8, 16*9(R0) + FMOVD F9, 16*10(R0) + FMOVD F10, 16*11(R0) + FMOVD F11, 16*12(R0) + FMOVD F12, 16*13(R0) + FMOVD F13, 16*14(R0) + FMOVD F14, 16*15(R0) + FMOVD F15, 16*16(R0) + FMOVD F16, 16*17(R0) + FMOVD F17, 16*18(R0) + FMOVD F18, 16*19(R0) + FMOVD F19, 16*20(R0) + FMOVD F20, 16*21(R0) + FMOVD F21, 16*22(R0) + FMOVD F22, 16*23(R0) + FMOVD F23, 16*24(R0) + FMOVD F24, 16*25(R0) + FMOVD F25, 16*26(R0) + FMOVD F26, 16*27(R0) + FMOVD F27, 16*28(R0) + FMOVD F28, 16*29(R0) + FMOVD F29, 16*30(R0) + FMOVD F30, 16*31(R0) + FMOVD F31, 16*32(R0) + + RET diff --git a/pkg/sentry/platform/ring0/pagetables/allocator.go b/pkg/sentry/platform/ring0/pagetables/allocator.go index 23fd5c352..8d75b7599 100644 --- a/pkg/sentry/platform/ring0/pagetables/allocator.go +++ b/pkg/sentry/platform/ring0/pagetables/allocator.go @@ -53,9 +53,14 @@ type RuntimeAllocator struct { // NewRuntimeAllocator returns an allocator that uses runtime allocation. func NewRuntimeAllocator() *RuntimeAllocator { - return &RuntimeAllocator{ - used: make(map[*PTEs]struct{}), - } + r := new(RuntimeAllocator) + r.Init() + return r +} + +// Init initializes a RuntimeAllocator. +func (r *RuntimeAllocator) Init() { + r.used = make(map[*PTEs]struct{}) } // Recycle returns freed pages to the pool. diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables.go b/pkg/sentry/platform/ring0/pagetables/pagetables.go index 87e88e97d..7f18ac296 100644 --- a/pkg/sentry/platform/ring0/pagetables/pagetables.go +++ b/pkg/sentry/platform/ring0/pagetables/pagetables.go @@ -86,6 +86,8 @@ func (*mapVisitor) requiresSplit() bool { return true } // // Precondition: addr & length must be page-aligned, their sum must not overflow. // +// +checkescape:hard,stack +// //go:nosplit func (p *PageTables) Map(addr usermem.Addr, length uintptr, opts MapOpts, physical uintptr) bool { if !opts.AccessType.Any() { @@ -128,6 +130,8 @@ func (v *unmapVisitor) visit(start uintptr, pte *PTE, align uintptr) { // // Precondition: addr & length must be page-aligned. // +// +checkescape:hard,stack +// //go:nosplit func (p *PageTables) Unmap(addr usermem.Addr, length uintptr) bool { w := unmapWalker{ @@ -162,6 +166,8 @@ func (v *emptyVisitor) visit(start uintptr, pte *PTE, align uintptr) { // // Precondition: addr & length must be page-aligned. // +// +checkescape:hard,stack +// //go:nosplit func (p *PageTables) IsEmpty(addr usermem.Addr, length uintptr) bool { w := emptyWalker{ @@ -197,6 +203,8 @@ func (*lookupVisitor) requiresSplit() bool { return false } // Lookup returns the physical address for the given virtual address. // +// +checkescape:hard,stack +// //go:nosplit func (p *PageTables) Lookup(addr usermem.Addr) (physical uintptr, opts MapOpts) { mask := uintptr(usermem.PageSize - 1) diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go b/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go index 78510ebed..6409d1d91 100644 --- a/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go +++ b/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go @@ -72,13 +72,14 @@ const ( ) const ( - mtNormal = 0x4 << 2 + mtDevicenGnRE = 0x1 << 2 + mtNormal = 0x4 << 2 ) const ( executeDisable = xn optionMask = 0xfff | 0xfff<<48 - protDefault = accessed | shared | mtNormal + protDefault = accessed | shared ) // MapOpts are x86 options. @@ -184,8 +185,10 @@ func (p *PTE) Set(addr uintptr, opts MapOpts) { if opts.User { v |= user + v |= mtNormal } else { v = v &^ user + v |= mtDevicenGnRE // Strong order for the addresses with ring0.KernelStartAddress. } atomic.StoreUintptr((*uintptr)(p), v) } @@ -200,7 +203,7 @@ func (p *PTE) setPageTable(pt *PageTables, ptes *PTEs) { // This should never happen. panic("unaligned physical address!") } - v := addr | typeTable | protDefault + v := addr | typeTable | protDefault | mtNormal atomic.StoreUintptr((*uintptr)(p), v) } diff --git a/pkg/sentry/socket/BUILD b/pkg/sentry/socket/BUILD index c40c6d673..c0fd3425b 100644 --- a/pkg/sentry/socket/BUILD +++ b/pkg/sentry/socket/BUILD @@ -20,5 +20,6 @@ go_library( "//pkg/syserr", "//pkg/tcpip", "//pkg/usermem", + "//tools/go_marshal/marshal", ], ) diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go index 8b439a078..70ccf77a7 100644 --- a/pkg/sentry/socket/control/control.go +++ b/pkg/sentry/socket/control/control.go @@ -68,7 +68,7 @@ func NewSCMRights(t *kernel.Task, fds []int32) (SCMRights, error) { for _, fd := range fds { file := t.GetFile(fd) if file == nil { - files.Release() + files.Release(t) return nil, syserror.EBADF } files = append(files, file) @@ -100,9 +100,9 @@ func (fs *RightsFiles) Clone() transport.RightsControlMessage { } // Release implements transport.RightsControlMessage.Release. -func (fs *RightsFiles) Release() { +func (fs *RightsFiles) Release(ctx context.Context) { for _, f := range *fs { - f.DecRef() + f.DecRef(ctx) } *fs = nil } @@ -115,7 +115,7 @@ func rightsFDs(t *kernel.Task, rights SCMRights, cloexec bool, max int) ([]int32 fd, err := t.NewFDFrom(0, files[0], kernel.FDFlags{ CloseOnExec: cloexec, }) - files[0].DecRef() + files[0].DecRef(t) files = files[1:] if err != nil { t.Warningf("Error inserting FD: %v", err) diff --git a/pkg/sentry/socket/control/control_vfs2.go b/pkg/sentry/socket/control/control_vfs2.go index fd08179be..d9621968c 100644 --- a/pkg/sentry/socket/control/control_vfs2.go +++ b/pkg/sentry/socket/control/control_vfs2.go @@ -46,7 +46,7 @@ func NewSCMRightsVFS2(t *kernel.Task, fds []int32) (SCMRightsVFS2, error) { for _, fd := range fds { file := t.GetFileVFS2(fd) if file == nil { - files.Release() + files.Release(t) return nil, syserror.EBADF } files = append(files, file) @@ -78,9 +78,9 @@ func (fs *RightsFilesVFS2) Clone() transport.RightsControlMessage { } // Release implements transport.RightsControlMessage.Release. -func (fs *RightsFilesVFS2) Release() { +func (fs *RightsFilesVFS2) Release(ctx context.Context) { for _, f := range *fs { - f.DecRef() + f.DecRef(ctx) } *fs = nil } @@ -93,7 +93,7 @@ func rightsFDsVFS2(t *kernel.Task, rights SCMRightsVFS2, cloexec bool, max int) fd, err := t.NewFDFromVFS2(0, files[0], kernel.FDFlags{ CloseOnExec: cloexec, }) - files[0].DecRef() + files[0].DecRef(t) files = files[1:] if err != nil { t.Warningf("Error inserting FD: %v", err) diff --git a/pkg/sentry/socket/hostinet/BUILD b/pkg/sentry/socket/hostinet/BUILD index e82d6cd1e..e76e498de 100644 --- a/pkg/sentry/socket/hostinet/BUILD +++ b/pkg/sentry/socket/hostinet/BUILD @@ -26,6 +26,7 @@ go_library( "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/sockfs", "//pkg/sentry/hostfd", "//pkg/sentry/inet", @@ -39,6 +40,8 @@ go_library( "//pkg/tcpip/stack", "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", "@org_golang_x_sys//unix:go_default_library", ], ) diff --git a/pkg/sentry/socket/hostinet/socket.go b/pkg/sentry/socket/hostinet/socket.go index c11e82c10..242e6bf76 100644 --- a/pkg/sentry/socket/hostinet/socket.go +++ b/pkg/sentry/socket/hostinet/socket.go @@ -36,6 +36,8 @@ import ( "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) const ( @@ -98,12 +100,12 @@ func newSocketFile(ctx context.Context, family int, stype linux.SockType, protoc return nil, syserr.FromError(err) } dirent := socket.NewDirent(ctx, socketDevice) - defer dirent.DecRef() + defer dirent.DecRef(ctx) return fs.NewFile(ctx, dirent, fs.FileFlags{NonBlocking: nonblock, Read: true, Write: true, NonSeekable: true}, s), nil } // Release implements fs.FileOperations.Release. -func (s *socketOpsCommon) Release() { +func (s *socketOpsCommon) Release(context.Context) { fdnotifier.RemoveFD(int32(s.fd)) syscall.Close(s.fd) } @@ -267,7 +269,7 @@ func (s *socketOpsCommon) Accept(t *kernel.Task, peerRequested bool, flags int, syscall.Close(fd) return 0, nil, 0, err } - defer f.DecRef() + defer f.DecRef(t) kfd, kerr = t.NewFDFromVFS2(0, f, kernel.FDFlags{ CloseOnExec: flags&syscall.SOCK_CLOEXEC != 0, @@ -279,7 +281,7 @@ func (s *socketOpsCommon) Accept(t *kernel.Task, peerRequested bool, flags int, syscall.Close(fd) return 0, nil, 0, err } - defer f.DecRef() + defer f.DecRef(t) kfd, kerr = t.NewFDFrom(0, f, kernel.FDFlags{ CloseOnExec: flags&syscall.SOCK_CLOEXEC != 0, @@ -319,12 +321,12 @@ func (s *socketOpsCommon) Shutdown(t *kernel.Task, how int) *syserr.Error { } // GetSockOpt implements socket.Socket.GetSockOpt. -func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { if outLen < 0 { return nil, syserr.ErrInvalidArgument } - // Whitelist options and constrain option length. + // Only allow known and safe options. optlen := getSockOptLen(t, level, name) switch level { case linux.SOL_IP: @@ -364,12 +366,13 @@ func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr if err != nil { return nil, syserr.FromError(err) } - return opt, nil + optP := primitive.ByteSlice(opt) + return &optP, nil } // SetSockOpt implements socket.Socket.SetSockOpt. func (s *socketOpsCommon) SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *syserr.Error { - // Whitelist options and constrain option length. + // Only allow known and safe options. optlen := setSockOptLen(t, level, name) switch level { case linux.SOL_IP: @@ -415,7 +418,7 @@ func (s *socketOpsCommon) SetSockOpt(t *kernel.Task, level int, name int, opt [] // RecvMsg implements socket.Socket.RecvMsg. func (s *socketOpsCommon) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags int, haveDeadline bool, deadline ktime.Time, senderRequested bool, controlLen uint64) (int, int, linux.SockAddr, uint32, socket.ControlMessages, *syserr.Error) { - // Whitelist flags. + // Only allow known and safe flags. // // FIXME(jamieliu): We can't support MSG_ERRQUEUE because it uses ancillary // messages that gvisor/pkg/tcpip/transport/unix doesn't understand. Kill the @@ -537,7 +540,7 @@ func (s *socketOpsCommon) RecvMsg(t *kernel.Task, dst usermem.IOSequence, flags // SendMsg implements socket.Socket.SendMsg. func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []byte, flags int, haveDeadline bool, deadline ktime.Time, controlMessages socket.ControlMessages) (int, *syserr.Error) { - // Whitelist flags. + // Only allow known and safe flags. if flags&^(syscall.MSG_DONTWAIT|syscall.MSG_EOR|syscall.MSG_FASTOPEN|syscall.MSG_MORE|syscall.MSG_NOSIGNAL) != 0 { return 0, syserr.ErrInvalidArgument } @@ -708,6 +711,6 @@ func (p *socketProvider) Pair(t *kernel.Task, stype linux.SockType, protocol int func init() { for _, family := range []int{syscall.AF_INET, syscall.AF_INET6} { socket.RegisterProvider(family, &socketProvider{family}) - socket.RegisterProviderVFS2(family, &socketProviderVFS2{}) + socket.RegisterProviderVFS2(family, &socketProviderVFS2{family}) } } diff --git a/pkg/sentry/socket/hostinet/socket_vfs2.go b/pkg/sentry/socket/hostinet/socket_vfs2.go index 677743113..8a1d52ebf 100644 --- a/pkg/sentry/socket/hostinet/socket_vfs2.go +++ b/pkg/sentry/socket/hostinet/socket_vfs2.go @@ -21,6 +21,7 @@ import ( "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/fdnotifier" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs" "gvisor.dev/gvisor/pkg/sentry/hostfd" "gvisor.dev/gvisor/pkg/sentry/kernel" @@ -35,6 +36,7 @@ import ( type socketVFS2 struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl + vfs.LockFD // We store metadata for hostinet sockets internally. Technically, we should // access metadata (e.g. through stat, chmod) on the host for correctness, @@ -59,6 +61,7 @@ func newVFS2Socket(t *kernel.Task, family int, stype linux.SockType, protocol in fd: fd, }, } + s.LockFD.Init(&vfs.FileLocks{}) if err := fdnotifier.AddFD(int32(fd), &s.queue); err != nil { return nil, syserr.FromError(err) } @@ -68,6 +71,7 @@ func newVFS2Socket(t *kernel.Task, family int, stype linux.SockType, protocol in DenyPWrite: true, UseDentryMetadata: true, }); err != nil { + fdnotifier.RemoveFD(int32(s.fd)) return nil, syserr.FromError(err) } return vfsfd, nil @@ -93,7 +97,12 @@ func (s *socketVFS2) Ioctl(ctx context.Context, uio usermem.IO, args arch.Syscal return ioctl(ctx, s.fd, uio, args) } -// PRead implements vfs.FileDescriptionImpl. +// Allocate implements vfs.FileDescriptionImpl.Allocate. +func (s *socketVFS2) Allocate(ctx context.Context, mode, offset, length uint64) error { + return syserror.ENODEV +} + +// PRead implements vfs.FileDescriptionImpl.PRead. func (s *socketVFS2) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { return 0, syserror.ESPIPE } @@ -131,6 +140,16 @@ func (s *socketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs return int64(n), err } +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (s *socketVFS2) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return s.Locks().LockPOSIX(ctx, &s.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (s *socketVFS2) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return s.Locks().UnlockPOSIX(ctx, &s.vfsfd, uid, start, length, whence) +} + type socketProviderVFS2 struct { family int } diff --git a/pkg/sentry/socket/hostinet/stack.go b/pkg/sentry/socket/hostinet/stack.go index a48082631..fda3dcb35 100644 --- a/pkg/sentry/socket/hostinet/stack.go +++ b/pkg/sentry/socket/hostinet/stack.go @@ -53,6 +53,7 @@ type Stack struct { interfaceAddrs map[int32][]inet.InterfaceAddr routes []inet.Route supportsIPv6 bool + tcpRecovery inet.TCPLossRecovery tcpRecvBufSize inet.TCPBufferSize tcpSendBufSize inet.TCPBufferSize tcpSACKEnabled bool @@ -350,6 +351,16 @@ func (s *Stack) SetTCPSACKEnabled(enabled bool) error { return syserror.EACCES } +// TCPRecovery implements inet.Stack.TCPRecovery. +func (s *Stack) TCPRecovery() (inet.TCPLossRecovery, error) { + return s.tcpRecovery, nil +} + +// SetTCPRecovery implements inet.Stack.SetTCPRecovery. +func (s *Stack) SetTCPRecovery(recovery inet.TCPLossRecovery) error { + return syserror.EACCES +} + // getLine reads one line from proc file, with specified prefix. // The last argument, withHeader, specifies if it contains line header. func getLine(f *os.File, prefix string, withHeader bool) string { diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go index 789bb94c8..e91b0624c 100644 --- a/pkg/sentry/socket/netfilter/netfilter.go +++ b/pkg/sentry/socket/netfilter/netfilter.go @@ -32,28 +32,6 @@ import ( "gvisor.dev/gvisor/pkg/usermem" ) -// errorTargetName is used to mark targets as error targets. Error targets -// shouldn't be reached - an error has occurred if we fall through to one. -const errorTargetName = "ERROR" - -// redirectTargetName is used to mark targets as redirect targets. Redirect -// targets should be reached for only NAT and Mangle tables. These targets will -// change the destination port/destination IP for packets. -const redirectTargetName = "REDIRECT" - -// Metadata is used to verify that we are correctly serializing and -// deserializing iptables into structs consumable by the iptables tool. We save -// a metadata struct when the tables are written, and when they are read out we -// verify that certain fields are the same. -// -// metadata is used by this serialization/deserializing code, not netstack. -type metadata struct { - HookEntry [linux.NF_INET_NUMHOOKS]uint32 - Underflow [linux.NF_INET_NUMHOOKS]uint32 - NumEntries uint32 - Size uint32 -} - // enableLogging controls whether to log the (de)serialization of netfilter // structs between userspace and netstack. These logs are useful when // developing iptables, but can pollute sentry logs otherwise. @@ -64,6 +42,8 @@ const enableLogging = false var emptyFilter = stack.IPHeaderFilter{ Dst: "\x00\x00\x00\x00", DstMask: "\x00\x00\x00\x00", + Src: "\x00\x00\x00\x00", + SrcMask: "\x00\x00\x00\x00", } // nflog logs messages related to the writing and reading of iptables. @@ -77,33 +57,17 @@ func nflog(format string, args ...interface{}) { func GetInfo(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr) (linux.IPTGetinfo, *syserr.Error) { // Read in the struct and table name. var info linux.IPTGetinfo - if _, err := t.CopyIn(outPtr, &info); err != nil { + if _, err := info.CopyIn(t, outPtr); err != nil { return linux.IPTGetinfo{}, syserr.FromError(err) } - // Find the appropriate table. - table, err := findTable(stack, info.Name) + _, info, err := convertNetstackToBinary(stack, info.Name) if err != nil { - nflog("%v", err) + nflog("couldn't convert iptables: %v", err) return linux.IPTGetinfo{}, syserr.ErrInvalidArgument } - // Get the hooks that apply to this table. - info.ValidHooks = table.ValidHooks() - - // Grab the metadata struct, which is used to store information (e.g. - // the number of entries) that applies to the user's encoding of - // iptables, but not netstack's. - metadata := table.Metadata().(metadata) - - // Set values from metadata. - info.HookEntry = metadata.HookEntry - info.Underflow = metadata.Underflow - info.NumEntries = metadata.NumEntries - info.Size = metadata.Size - nflog("returning info: %+v", info) - return info, nil } @@ -111,28 +75,18 @@ func GetInfo(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr) (linux.IPT func GetEntries(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr, outLen int) (linux.KernelIPTGetEntries, *syserr.Error) { // Read in the struct and table name. var userEntries linux.IPTGetEntries - if _, err := t.CopyIn(outPtr, &userEntries); err != nil { + if _, err := userEntries.CopyIn(t, outPtr); err != nil { nflog("couldn't copy in entries %q", userEntries.Name) return linux.KernelIPTGetEntries{}, syserr.FromError(err) } - // Find the appropriate table. - table, err := findTable(stack, userEntries.Name) - if err != nil { - nflog("%v", err) - return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument - } - // Convert netstack's iptables rules to something that the iptables // tool can understand. - entries, meta, err := convertNetstackToBinary(userEntries.Name.String(), table) + entries, _, err := convertNetstackToBinary(stack, userEntries.Name) if err != nil { nflog("couldn't read entries: %v", err) return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument } - if meta != table.Metadata().(metadata) { - panic(fmt.Sprintf("Table %q metadata changed between writing and reading. Was saved as %+v, but is now %+v", userEntries.Name.String(), table.Metadata().(metadata), meta)) - } if binary.Size(entries) > uintptr(outLen) { nflog("insufficient GetEntries output size: %d", uintptr(outLen)) return linux.KernelIPTGetEntries{}, syserr.ErrInvalidArgument @@ -141,48 +95,26 @@ func GetEntries(t *kernel.Task, stack *stack.Stack, outPtr usermem.Addr, outLen return entries, nil } -func findTable(stk *stack.Stack, tablename linux.TableName) (stack.Table, error) { - ipt := stk.IPTables() - table, ok := ipt.Tables[tablename.String()] - if !ok { - return stack.Table{}, fmt.Errorf("couldn't find table %q", tablename) - } - return table, nil -} - -// FillDefaultIPTables sets stack's IPTables to the default tables and -// populates them with metadata. -func FillDefaultIPTables(stk *stack.Stack) { - ipt := stack.DefaultTables() - - // In order to fill in the metadata, we have to translate ipt from its - // netstack format to Linux's giant-binary-blob format. - for name, table := range ipt.Tables { - _, metadata, err := convertNetstackToBinary(name, table) - if err != nil { - panic(fmt.Errorf("Unable to set default IP tables: %v", err)) - } - table.SetMetadata(metadata) - ipt.Tables[name] = table - } - - stk.SetIPTables(ipt) -} - // convertNetstackToBinary converts the iptables as stored in netstack to the // format expected by the iptables tool. Linux stores each table as a binary // blob that can only be traversed by parsing a bit, reading some offsets, // jumping to those offsets, parsing again, etc. -func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelIPTGetEntries, metadata, error) { - // Return values. +func convertNetstackToBinary(stack *stack.Stack, tablename linux.TableName) (linux.KernelIPTGetEntries, linux.IPTGetinfo, error) { + table, ok := stack.IPTables().GetTable(tablename.String()) + if !ok { + return linux.KernelIPTGetEntries{}, linux.IPTGetinfo{}, fmt.Errorf("couldn't find table %q", tablename) + } + var entries linux.KernelIPTGetEntries - var meta metadata + var info linux.IPTGetinfo + info.ValidHooks = table.ValidHooks() // The table name has to fit in the struct. if linux.XT_TABLE_MAXNAMELEN < len(tablename) { - return linux.KernelIPTGetEntries{}, metadata{}, fmt.Errorf("table name %q too long.", tablename) + return linux.KernelIPTGetEntries{}, linux.IPTGetinfo{}, fmt.Errorf("table name %q too long", tablename) } - copy(entries.Name[:], tablename) + copy(info.Name[:], tablename[:]) + copy(entries.Name[:], tablename[:]) for ruleIdx, rule := range table.Rules { nflog("convert to binary: current offset: %d", entries.Size) @@ -191,20 +123,20 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI for hook, hookRuleIdx := range table.BuiltinChains { if hookRuleIdx == ruleIdx { nflog("convert to binary: found hook %d at offset %d", hook, entries.Size) - meta.HookEntry[hook] = entries.Size + info.HookEntry[hook] = entries.Size } } // Is this a chain underflow point? for underflow, underflowRuleIdx := range table.Underflows { if underflowRuleIdx == ruleIdx { nflog("convert to binary: found underflow %d at offset %d", underflow, entries.Size) - meta.Underflow[underflow] = entries.Size + info.Underflow[underflow] = entries.Size } } // Each rule corresponds to an entry. entry := linux.KernelIPTEntry{ - IPTEntry: linux.IPTEntry{ + Entry: linux.IPTEntry{ IP: linux.IPTIP{ Protocol: uint16(rule.Filter.Protocol), }, @@ -212,15 +144,20 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI TargetOffset: linux.SizeOfIPTEntry, }, } - copy(entry.IPTEntry.IP.Dst[:], rule.Filter.Dst) - copy(entry.IPTEntry.IP.DstMask[:], rule.Filter.DstMask) - copy(entry.IPTEntry.IP.OutputInterface[:], rule.Filter.OutputInterface) - copy(entry.IPTEntry.IP.OutputInterfaceMask[:], rule.Filter.OutputInterfaceMask) + copy(entry.Entry.IP.Dst[:], rule.Filter.Dst) + copy(entry.Entry.IP.DstMask[:], rule.Filter.DstMask) + copy(entry.Entry.IP.Src[:], rule.Filter.Src) + copy(entry.Entry.IP.SrcMask[:], rule.Filter.SrcMask) + copy(entry.Entry.IP.OutputInterface[:], rule.Filter.OutputInterface) + copy(entry.Entry.IP.OutputInterfaceMask[:], rule.Filter.OutputInterfaceMask) if rule.Filter.DstInvert { - entry.IPTEntry.IP.InverseFlags |= linux.IPT_INV_DSTIP + entry.Entry.IP.InverseFlags |= linux.IPT_INV_DSTIP + } + if rule.Filter.SrcInvert { + entry.Entry.IP.InverseFlags |= linux.IPT_INV_SRCIP } if rule.Filter.OutputInterfaceInvert { - entry.IPTEntry.IP.InverseFlags |= linux.IPT_INV_VIA_OUT + entry.Entry.IP.InverseFlags |= linux.IPT_INV_VIA_OUT } for _, matcher := range rule.Matchers { @@ -232,8 +169,8 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI panic(fmt.Sprintf("matcher %T is not 64-bit aligned", matcher)) } entry.Elems = append(entry.Elems, serialized...) - entry.NextOffset += uint16(len(serialized)) - entry.TargetOffset += uint16(len(serialized)) + entry.Entry.NextOffset += uint16(len(serialized)) + entry.Entry.TargetOffset += uint16(len(serialized)) } // Serialize and append the target. @@ -242,142 +179,18 @@ func convertNetstackToBinary(tablename string, table stack.Table) (linux.KernelI panic(fmt.Sprintf("target %T is not 64-bit aligned", rule.Target)) } entry.Elems = append(entry.Elems, serialized...) - entry.NextOffset += uint16(len(serialized)) + entry.Entry.NextOffset += uint16(len(serialized)) nflog("convert to binary: adding entry: %+v", entry) - entries.Size += uint32(entry.NextOffset) + entries.Size += uint32(entry.Entry.NextOffset) entries.Entrytable = append(entries.Entrytable, entry) - meta.NumEntries++ - } - - nflog("convert to binary: finished with an marshalled size of %d", meta.Size) - meta.Size = entries.Size - return entries, meta, nil -} - -func marshalTarget(target stack.Target) []byte { - switch tg := target.(type) { - case stack.AcceptTarget: - return marshalStandardTarget(stack.RuleAccept) - case stack.DropTarget: - return marshalStandardTarget(stack.RuleDrop) - case stack.ErrorTarget: - return marshalErrorTarget(errorTargetName) - case stack.UserChainTarget: - return marshalErrorTarget(tg.Name) - case stack.ReturnTarget: - return marshalStandardTarget(stack.RuleReturn) - case stack.RedirectTarget: - return marshalRedirectTarget(tg) - case JumpTarget: - return marshalJumpTarget(tg) - default: - panic(fmt.Errorf("unknown target of type %T", target)) - } -} - -func marshalStandardTarget(verdict stack.RuleVerdict) []byte { - nflog("convert to binary: marshalling standard target") - - // The target's name will be the empty string. - target := linux.XTStandardTarget{ - Target: linux.XTEntryTarget{ - TargetSize: linux.SizeOfXTStandardTarget, - }, - Verdict: translateFromStandardVerdict(verdict), + info.NumEntries++ } - ret := make([]byte, 0, linux.SizeOfXTStandardTarget) - return binary.Marshal(ret, usermem.ByteOrder, target) -} - -func marshalErrorTarget(errorName string) []byte { - // This is an error target named error - target := linux.XTErrorTarget{ - Target: linux.XTEntryTarget{ - TargetSize: linux.SizeOfXTErrorTarget, - }, - } - copy(target.Name[:], errorName) - copy(target.Target.Name[:], errorTargetName) - - ret := make([]byte, 0, linux.SizeOfXTErrorTarget) - return binary.Marshal(ret, usermem.ByteOrder, target) -} - -func marshalRedirectTarget(rt stack.RedirectTarget) []byte { - // This is a redirect target named redirect - target := linux.XTRedirectTarget{ - Target: linux.XTEntryTarget{ - TargetSize: linux.SizeOfXTRedirectTarget, - }, - } - copy(target.Target.Name[:], redirectTargetName) - - ret := make([]byte, 0, linux.SizeOfXTRedirectTarget) - target.NfRange.RangeSize = 1 - if rt.RangeProtoSpecified { - target.NfRange.RangeIPV4.Flags |= linux.NF_NAT_RANGE_PROTO_SPECIFIED - } - // Convert port from little endian to big endian. - port := make([]byte, 2) - binary.LittleEndian.PutUint16(port, rt.MinPort) - target.NfRange.RangeIPV4.MinPort = binary.BigEndian.Uint16(port) - binary.LittleEndian.PutUint16(port, rt.MaxPort) - target.NfRange.RangeIPV4.MaxPort = binary.BigEndian.Uint16(port) - return binary.Marshal(ret, usermem.ByteOrder, target) -} - -func marshalJumpTarget(jt JumpTarget) []byte { - nflog("convert to binary: marshalling jump target") - - // The target's name will be the empty string. - target := linux.XTStandardTarget{ - Target: linux.XTEntryTarget{ - TargetSize: linux.SizeOfXTStandardTarget, - }, - // Verdict is overloaded by the ABI. When positive, it holds - // the jump offset from the start of the table. - Verdict: int32(jt.Offset), - } - - ret := make([]byte, 0, linux.SizeOfXTStandardTarget) - return binary.Marshal(ret, usermem.ByteOrder, target) -} - -// translateFromStandardVerdict translates verdicts the same way as the iptables -// tool. -func translateFromStandardVerdict(verdict stack.RuleVerdict) int32 { - switch verdict { - case stack.RuleAccept: - return -linux.NF_ACCEPT - 1 - case stack.RuleDrop: - return -linux.NF_DROP - 1 - case stack.RuleReturn: - return linux.NF_RETURN - default: - // TODO(gvisor.dev/issue/170): Support Jump. - panic(fmt.Sprintf("unknown standard verdict: %d", verdict)) - } -} - -// translateToStandardTarget translates from the value in a -// linux.XTStandardTarget to an stack.Verdict. -func translateToStandardTarget(val int32) (stack.Target, error) { - // TODO(gvisor.dev/issue/170): Support other verdicts. - switch val { - case -linux.NF_ACCEPT - 1: - return stack.AcceptTarget{}, nil - case -linux.NF_DROP - 1: - return stack.DropTarget{}, nil - case -linux.NF_QUEUE - 1: - return nil, errors.New("unsupported iptables verdict QUEUE") - case linux.NF_RETURN: - return stack.ReturnTarget{}, nil - default: - return nil, fmt.Errorf("unknown iptables verdict %d", val) - } + nflog("convert to binary: finished with an marshalled size of %d", info.Size) + info.Size = entries.Size + return entries, info, nil } // SetEntries sets iptables rules for a single table. See @@ -396,10 +209,10 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { // TODO(gvisor.dev/issue/170): Support other tables. var table stack.Table switch replace.Name.String() { - case stack.TablenameFilter: + case stack.FilterTable: table = stack.EmptyFilterTable() - case stack.TablenameNat: - table = stack.EmptyNatTable() + case stack.NATTable: + table = stack.EmptyNATTable() default: nflog("we don't yet support writing to the %q table (gvisor.dev/issue/170)", replace.Name.String()) return syserr.ErrInvalidArgument @@ -485,6 +298,8 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { for hook, _ := range replace.HookEntry { if table.ValidHooks()&(1<<hook) != 0 { hk := hookFromLinux(hook) + table.BuiltinChains[hk] = stack.HookUnset + table.Underflows[hk] = stack.HookUnset for offset, ruleIdx := range offsets { if offset == replace.HookEntry[hook] { table.BuiltinChains[hk] = ruleIdx @@ -510,8 +325,7 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { // Add the user chains. for ruleIdx, rule := range table.Rules { - target, ok := rule.Target.(stack.UserChainTarget) - if !ok { + if _, ok := rule.Target.(stack.UserChainTarget); !ok { continue } @@ -527,7 +341,6 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { nflog("user chain's first node must have no matchers") return syserr.ErrInvalidArgument } - table.UserChains[target.Name] = ruleIdx + 1 } // Set each jump to point to the appropriate rule. Right now they hold byte @@ -553,7 +366,10 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { // Since we only support modifying the INPUT, PREROUTING and OUTPUT chain right now, // make sure all other chains point to ACCEPT rules. for hook, ruleIdx := range table.BuiltinChains { - if hook == stack.Forward || hook == stack.Postrouting { + if hook := stack.Hook(hook); hook == stack.Forward || hook == stack.Postrouting { + if ruleIdx == stack.HookUnset { + continue + } if !isUnconditionalAccept(table.Rules[ruleIdx]) { nflog("hook %d is unsupported.", hook) return syserr.ErrInvalidArgument @@ -566,17 +382,7 @@ func SetEntries(stk *stack.Stack, optVal []byte) *syserr.Error { // - There are no chains without an unconditional final rule. // - There are no chains without an unconditional underflow rule. - ipt := stk.IPTables() - table.SetMetadata(metadata{ - HookEntry: replace.HookEntry, - Underflow: replace.Underflow, - NumEntries: replace.NumEntries, - Size: replace.Size, - }) - ipt.Tables[replace.Name.String()] = table - stk.SetIPTables(ipt) - - return nil + return syserr.TranslateNetstackError(stk.IPTables().ReplaceTable(replace.Name.String(), table)) } // parseMatchers parses 0 or more matchers from optVal. optVal should contain @@ -623,113 +429,6 @@ func parseMatchers(filter stack.IPHeaderFilter, optVal []byte) ([]stack.Matcher, return matchers, nil } -// parseTarget parses a target from optVal. optVal should contain only the -// target. -func parseTarget(filter stack.IPHeaderFilter, optVal []byte) (stack.Target, error) { - nflog("set entries: parsing target of size %d", len(optVal)) - if len(optVal) < linux.SizeOfXTEntryTarget { - return nil, fmt.Errorf("optVal has insufficient size for entry target %d", len(optVal)) - } - var target linux.XTEntryTarget - buf := optVal[:linux.SizeOfXTEntryTarget] - binary.Unmarshal(buf, usermem.ByteOrder, &target) - switch target.Name.String() { - case "": - // Standard target. - if len(optVal) != linux.SizeOfXTStandardTarget { - return nil, fmt.Errorf("optVal has wrong size for standard target %d", len(optVal)) - } - var standardTarget linux.XTStandardTarget - buf = optVal[:linux.SizeOfXTStandardTarget] - binary.Unmarshal(buf, usermem.ByteOrder, &standardTarget) - - if standardTarget.Verdict < 0 { - // A Verdict < 0 indicates a non-jump verdict. - return translateToStandardTarget(standardTarget.Verdict) - } - // A verdict >= 0 indicates a jump. - return JumpTarget{Offset: uint32(standardTarget.Verdict)}, nil - - case errorTargetName: - // Error target. - if len(optVal) != linux.SizeOfXTErrorTarget { - return nil, fmt.Errorf("optVal has insufficient size for error target %d", len(optVal)) - } - var errorTarget linux.XTErrorTarget - buf = optVal[:linux.SizeOfXTErrorTarget] - binary.Unmarshal(buf, usermem.ByteOrder, &errorTarget) - - // Error targets are used in 2 cases: - // * An actual error case. These rules have an error - // named errorTargetName. The last entry of the table - // is usually an error case to catch any packets that - // somehow fall through every rule. - // * To mark the start of a user defined chain. These - // rules have an error with the name of the chain. - switch name := errorTarget.Name.String(); name { - case errorTargetName: - nflog("set entries: error target") - return stack.ErrorTarget{}, nil - default: - // User defined chain. - nflog("set entries: user-defined target %q", name) - return stack.UserChainTarget{Name: name}, nil - } - - case redirectTargetName: - // Redirect target. - if len(optVal) < linux.SizeOfXTRedirectTarget { - return nil, fmt.Errorf("netfilter.SetEntries: optVal has insufficient size for redirect target %d", len(optVal)) - } - - if filter.Protocol != header.TCPProtocolNumber && filter.Protocol != header.UDPProtocolNumber { - return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") - } - - var redirectTarget linux.XTRedirectTarget - buf = optVal[:linux.SizeOfXTRedirectTarget] - binary.Unmarshal(buf, usermem.ByteOrder, &redirectTarget) - - // Copy linux.XTRedirectTarget to stack.RedirectTarget. - var target stack.RedirectTarget - nfRange := redirectTarget.NfRange - - // RangeSize should be 1. - if nfRange.RangeSize != 1 { - return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") - } - - // TODO(gvisor.dev/issue/170): Check if the flags are valid. - // Also check if we need to map ports or IP. - // For now, redirect target only supports destination port change. - // Port range and IP range are not supported yet. - if nfRange.RangeIPV4.Flags&linux.NF_NAT_RANGE_PROTO_SPECIFIED == 0 { - return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") - } - target.RangeProtoSpecified = true - - target.MinIP = tcpip.Address(nfRange.RangeIPV4.MinIP[:]) - target.MaxIP = tcpip.Address(nfRange.RangeIPV4.MaxIP[:]) - - // TODO(gvisor.dev/issue/170): Port range is not supported yet. - if nfRange.RangeIPV4.MinPort != nfRange.RangeIPV4.MaxPort { - return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") - } - - // Convert port from big endian to little endian. - port := make([]byte, 2) - binary.BigEndian.PutUint16(port, nfRange.RangeIPV4.MinPort) - target.MinPort = binary.LittleEndian.Uint16(port) - - binary.BigEndian.PutUint16(port, nfRange.RangeIPV4.MaxPort) - target.MaxPort = binary.LittleEndian.Uint16(port) - return target, nil - } - - // Unknown target. - return nil, fmt.Errorf("unknown target %q doesn't exist or isn't supported yet.", target.Name.String()) -} - func filterFromIPTIP(iptip linux.IPTIP) (stack.IPHeaderFilter, error) { if containsUnsupportedFields(iptip) { return stack.IPHeaderFilter{}, fmt.Errorf("unsupported fields in struct iptip: %+v", iptip) @@ -737,6 +436,9 @@ func filterFromIPTIP(iptip linux.IPTIP) (stack.IPHeaderFilter, error) { if len(iptip.Dst) != header.IPv4AddressSize || len(iptip.DstMask) != header.IPv4AddressSize { return stack.IPHeaderFilter{}, fmt.Errorf("incorrect length of destination (%d) and/or destination mask (%d) fields", len(iptip.Dst), len(iptip.DstMask)) } + if len(iptip.Src) != header.IPv4AddressSize || len(iptip.SrcMask) != header.IPv4AddressSize { + return stack.IPHeaderFilter{}, fmt.Errorf("incorrect length of source (%d) and/or source mask (%d) fields", len(iptip.Src), len(iptip.SrcMask)) + } n := bytes.IndexByte([]byte(iptip.OutputInterface[:]), 0) if n == -1 { @@ -755,6 +457,9 @@ func filterFromIPTIP(iptip linux.IPTIP) (stack.IPHeaderFilter, error) { Dst: tcpip.Address(iptip.Dst[:]), DstMask: tcpip.Address(iptip.DstMask[:]), DstInvert: iptip.InverseFlags&linux.IPT_INV_DSTIP != 0, + Src: tcpip.Address(iptip.Src[:]), + SrcMask: tcpip.Address(iptip.SrcMask[:]), + SrcInvert: iptip.InverseFlags&linux.IPT_INV_SRCIP != 0, OutputInterface: ifname, OutputInterfaceMask: ifnameMask, OutputInterfaceInvert: iptip.InverseFlags&linux.IPT_INV_VIA_OUT != 0, @@ -765,15 +470,13 @@ func containsUnsupportedFields(iptip linux.IPTIP) bool { // The following features are supported: // - Protocol // - Dst and DstMask + // - Src and SrcMask // - The inverse destination IP check flag // - OutputInterface, OutputInterfaceMask and its inverse. - var emptyInetAddr = linux.InetAddr{} var emptyInterface = [linux.IFNAMSIZ]byte{} // Disable any supported inverse flags. - inverseMask := uint8(linux.IPT_INV_DSTIP) | uint8(linux.IPT_INV_VIA_OUT) - return iptip.Src != emptyInetAddr || - iptip.SrcMask != emptyInetAddr || - iptip.InputInterface != emptyInterface || + inverseMask := uint8(linux.IPT_INV_DSTIP) | uint8(linux.IPT_INV_SRCIP) | uint8(linux.IPT_INV_VIA_OUT) + return iptip.InputInterface != emptyInterface || iptip.InputInterfaceMask != emptyInterface || iptip.Flags != 0 || iptip.InverseFlags&^inverseMask != 0 diff --git a/pkg/sentry/socket/netfilter/owner_matcher.go b/pkg/sentry/socket/netfilter/owner_matcher.go index 3863293c7..1b4e0ad79 100644 --- a/pkg/sentry/socket/netfilter/owner_matcher.go +++ b/pkg/sentry/socket/netfilter/owner_matcher.go @@ -111,7 +111,7 @@ func (*OwnerMatcher) Name() string { } // Match implements Matcher.Match. -func (om *OwnerMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceName string) (bool, bool) { +func (om *OwnerMatcher) Match(hook stack.Hook, pkt *stack.PacketBuffer, interfaceName string) (bool, bool) { // Support only for OUTPUT chain. // TODO(gvisor.dev/issue/170): Need to support for POSTROUTING chain also. if hook != stack.Output { diff --git a/pkg/sentry/socket/netfilter/targets.go b/pkg/sentry/socket/netfilter/targets.go index 84abe8d29..8ebdaff18 100644 --- a/pkg/sentry/socket/netfilter/targets.go +++ b/pkg/sentry/socket/netfilter/targets.go @@ -15,10 +15,257 @@ package netfilter import ( + "errors" + "fmt" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/binary" "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/header" "gvisor.dev/gvisor/pkg/tcpip/stack" + "gvisor.dev/gvisor/pkg/usermem" ) +// errorTargetName is used to mark targets as error targets. Error targets +// shouldn't be reached - an error has occurred if we fall through to one. +const errorTargetName = "ERROR" + +// redirectTargetName is used to mark targets as redirect targets. Redirect +// targets should be reached for only NAT and Mangle tables. These targets will +// change the destination port/destination IP for packets. +const redirectTargetName = "REDIRECT" + +func marshalTarget(target stack.Target) []byte { + switch tg := target.(type) { + case stack.AcceptTarget: + return marshalStandardTarget(stack.RuleAccept) + case stack.DropTarget: + return marshalStandardTarget(stack.RuleDrop) + case stack.ErrorTarget: + return marshalErrorTarget(errorTargetName) + case stack.UserChainTarget: + return marshalErrorTarget(tg.Name) + case stack.ReturnTarget: + return marshalStandardTarget(stack.RuleReturn) + case stack.RedirectTarget: + return marshalRedirectTarget(tg) + case JumpTarget: + return marshalJumpTarget(tg) + default: + panic(fmt.Errorf("unknown target of type %T", target)) + } +} + +func marshalStandardTarget(verdict stack.RuleVerdict) []byte { + nflog("convert to binary: marshalling standard target") + + // The target's name will be the empty string. + target := linux.XTStandardTarget{ + Target: linux.XTEntryTarget{ + TargetSize: linux.SizeOfXTStandardTarget, + }, + Verdict: translateFromStandardVerdict(verdict), + } + + ret := make([]byte, 0, linux.SizeOfXTStandardTarget) + return binary.Marshal(ret, usermem.ByteOrder, target) +} + +func marshalErrorTarget(errorName string) []byte { + // This is an error target named error + target := linux.XTErrorTarget{ + Target: linux.XTEntryTarget{ + TargetSize: linux.SizeOfXTErrorTarget, + }, + } + copy(target.Name[:], errorName) + copy(target.Target.Name[:], errorTargetName) + + ret := make([]byte, 0, linux.SizeOfXTErrorTarget) + return binary.Marshal(ret, usermem.ByteOrder, target) +} + +func marshalRedirectTarget(rt stack.RedirectTarget) []byte { + // This is a redirect target named redirect + target := linux.XTRedirectTarget{ + Target: linux.XTEntryTarget{ + TargetSize: linux.SizeOfXTRedirectTarget, + }, + } + copy(target.Target.Name[:], redirectTargetName) + + ret := make([]byte, 0, linux.SizeOfXTRedirectTarget) + target.NfRange.RangeSize = 1 + if rt.RangeProtoSpecified { + target.NfRange.RangeIPV4.Flags |= linux.NF_NAT_RANGE_PROTO_SPECIFIED + } + // Convert port from little endian to big endian. + port := make([]byte, 2) + binary.LittleEndian.PutUint16(port, rt.MinPort) + target.NfRange.RangeIPV4.MinPort = binary.BigEndian.Uint16(port) + binary.LittleEndian.PutUint16(port, rt.MaxPort) + target.NfRange.RangeIPV4.MaxPort = binary.BigEndian.Uint16(port) + return binary.Marshal(ret, usermem.ByteOrder, target) +} + +func marshalJumpTarget(jt JumpTarget) []byte { + nflog("convert to binary: marshalling jump target") + + // The target's name will be the empty string. + target := linux.XTStandardTarget{ + Target: linux.XTEntryTarget{ + TargetSize: linux.SizeOfXTStandardTarget, + }, + // Verdict is overloaded by the ABI. When positive, it holds + // the jump offset from the start of the table. + Verdict: int32(jt.Offset), + } + + ret := make([]byte, 0, linux.SizeOfXTStandardTarget) + return binary.Marshal(ret, usermem.ByteOrder, target) +} + +// translateFromStandardVerdict translates verdicts the same way as the iptables +// tool. +func translateFromStandardVerdict(verdict stack.RuleVerdict) int32 { + switch verdict { + case stack.RuleAccept: + return -linux.NF_ACCEPT - 1 + case stack.RuleDrop: + return -linux.NF_DROP - 1 + case stack.RuleReturn: + return linux.NF_RETURN + default: + // TODO(gvisor.dev/issue/170): Support Jump. + panic(fmt.Sprintf("unknown standard verdict: %d", verdict)) + } +} + +// translateToStandardTarget translates from the value in a +// linux.XTStandardTarget to an stack.Verdict. +func translateToStandardTarget(val int32) (stack.Target, error) { + // TODO(gvisor.dev/issue/170): Support other verdicts. + switch val { + case -linux.NF_ACCEPT - 1: + return stack.AcceptTarget{}, nil + case -linux.NF_DROP - 1: + return stack.DropTarget{}, nil + case -linux.NF_QUEUE - 1: + return nil, errors.New("unsupported iptables verdict QUEUE") + case linux.NF_RETURN: + return stack.ReturnTarget{}, nil + default: + return nil, fmt.Errorf("unknown iptables verdict %d", val) + } +} + +// parseTarget parses a target from optVal. optVal should contain only the +// target. +func parseTarget(filter stack.IPHeaderFilter, optVal []byte) (stack.Target, error) { + nflog("set entries: parsing target of size %d", len(optVal)) + if len(optVal) < linux.SizeOfXTEntryTarget { + return nil, fmt.Errorf("optVal has insufficient size for entry target %d", len(optVal)) + } + var target linux.XTEntryTarget + buf := optVal[:linux.SizeOfXTEntryTarget] + binary.Unmarshal(buf, usermem.ByteOrder, &target) + switch target.Name.String() { + case "": + // Standard target. + if len(optVal) != linux.SizeOfXTStandardTarget { + return nil, fmt.Errorf("optVal has wrong size for standard target %d", len(optVal)) + } + var standardTarget linux.XTStandardTarget + buf = optVal[:linux.SizeOfXTStandardTarget] + binary.Unmarshal(buf, usermem.ByteOrder, &standardTarget) + + if standardTarget.Verdict < 0 { + // A Verdict < 0 indicates a non-jump verdict. + return translateToStandardTarget(standardTarget.Verdict) + } + // A verdict >= 0 indicates a jump. + return JumpTarget{Offset: uint32(standardTarget.Verdict)}, nil + + case errorTargetName: + // Error target. + if len(optVal) != linux.SizeOfXTErrorTarget { + return nil, fmt.Errorf("optVal has insufficient size for error target %d", len(optVal)) + } + var errorTarget linux.XTErrorTarget + buf = optVal[:linux.SizeOfXTErrorTarget] + binary.Unmarshal(buf, usermem.ByteOrder, &errorTarget) + + // Error targets are used in 2 cases: + // * An actual error case. These rules have an error + // named errorTargetName. The last entry of the table + // is usually an error case to catch any packets that + // somehow fall through every rule. + // * To mark the start of a user defined chain. These + // rules have an error with the name of the chain. + switch name := errorTarget.Name.String(); name { + case errorTargetName: + nflog("set entries: error target") + return stack.ErrorTarget{}, nil + default: + // User defined chain. + nflog("set entries: user-defined target %q", name) + return stack.UserChainTarget{Name: name}, nil + } + + case redirectTargetName: + // Redirect target. + if len(optVal) < linux.SizeOfXTRedirectTarget { + return nil, fmt.Errorf("netfilter.SetEntries: optVal has insufficient size for redirect target %d", len(optVal)) + } + + if filter.Protocol != header.TCPProtocolNumber && filter.Protocol != header.UDPProtocolNumber { + return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") + } + + var redirectTarget linux.XTRedirectTarget + buf = optVal[:linux.SizeOfXTRedirectTarget] + binary.Unmarshal(buf, usermem.ByteOrder, &redirectTarget) + + // Copy linux.XTRedirectTarget to stack.RedirectTarget. + var target stack.RedirectTarget + nfRange := redirectTarget.NfRange + + // RangeSize should be 1. + if nfRange.RangeSize != 1 { + return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") + } + + // TODO(gvisor.dev/issue/170): Check if the flags are valid. + // Also check if we need to map ports or IP. + // For now, redirect target only supports destination port change. + // Port range and IP range are not supported yet. + if nfRange.RangeIPV4.Flags&linux.NF_NAT_RANGE_PROTO_SPECIFIED == 0 { + return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") + } + target.RangeProtoSpecified = true + + target.MinIP = tcpip.Address(nfRange.RangeIPV4.MinIP[:]) + target.MaxIP = tcpip.Address(nfRange.RangeIPV4.MaxIP[:]) + + // TODO(gvisor.dev/issue/170): Port range is not supported yet. + if nfRange.RangeIPV4.MinPort != nfRange.RangeIPV4.MaxPort { + return nil, fmt.Errorf("netfilter.SetEntries: invalid argument") + } + + // Convert port from big endian to little endian. + port := make([]byte, 2) + binary.BigEndian.PutUint16(port, nfRange.RangeIPV4.MinPort) + target.MinPort = binary.LittleEndian.Uint16(port) + + binary.BigEndian.PutUint16(port, nfRange.RangeIPV4.MaxPort) + target.MaxPort = binary.LittleEndian.Uint16(port) + return target, nil + } + + // Unknown target. + return nil, fmt.Errorf("unknown target %q doesn't exist or isn't supported yet", target.Name.String()) +} + // JumpTarget implements stack.Target. type JumpTarget struct { // Offset is the byte offset of the rule to jump to. It is used for @@ -30,6 +277,6 @@ type JumpTarget struct { } // Action implements stack.Target.Action. -func (jt JumpTarget) Action(*stack.PacketBuffer, *stack.ConnTrackTable, stack.Hook, *stack.GSO, *stack.Route, tcpip.Address) (stack.RuleVerdict, int) { +func (jt JumpTarget) Action(*stack.PacketBuffer, *stack.ConnTrack, stack.Hook, *stack.GSO, *stack.Route, tcpip.Address) (stack.RuleVerdict, int) { return stack.RuleJump, jt.RuleNum } diff --git a/pkg/sentry/socket/netfilter/tcp_matcher.go b/pkg/sentry/socket/netfilter/tcp_matcher.go index 57a1e1c12..0bfd6c1f4 100644 --- a/pkg/sentry/socket/netfilter/tcp_matcher.go +++ b/pkg/sentry/socket/netfilter/tcp_matcher.go @@ -96,8 +96,8 @@ func (*TCPMatcher) Name() string { } // Match implements Matcher.Match. -func (tm *TCPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceName string) (bool, bool) { - netHeader := header.IPv4(pkt.NetworkHeader) +func (tm *TCPMatcher) Match(hook stack.Hook, pkt *stack.PacketBuffer, interfaceName string) (bool, bool) { + netHeader := header.IPv4(pkt.NetworkHeader().View()) if netHeader.TransportProtocol() != header.TCPProtocolNumber { return false, false @@ -111,36 +111,10 @@ func (tm *TCPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceNa return false, false } - // Now we need the transport header. However, this may not have been set - // yet. - // TODO(gvisor.dev/issue/170): Parsing the transport header should - // ultimately be moved into the stack.Check codepath as matchers are - // added. - var tcpHeader header.TCP - if pkt.TransportHeader != nil { - tcpHeader = header.TCP(pkt.TransportHeader) - } else { - var length int - if hook == stack.Prerouting { - // The network header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize) - if !ok { - // There's no valid TCP header here, so we hotdrop the - // packet. - return false, true - } - h := header.IPv4(hdr) - pkt.NetworkHeader = hdr - length = int(h.HeaderLength()) - } - // The TCP header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(length + header.TCPMinimumSize) - if !ok { - // There's no valid TCP header here, so we hotdrop the - // packet. - return false, true - } - tcpHeader = header.TCP(hdr[length:]) + tcpHeader := header.TCP(pkt.TransportHeader().View()) + if len(tcpHeader) < header.TCPMinimumSize { + // There's no valid TCP header here, so we drop the packet immediately. + return false, true } // Check whether the source and destination ports are within the diff --git a/pkg/sentry/socket/netfilter/udp_matcher.go b/pkg/sentry/socket/netfilter/udp_matcher.go index cfa9e621d..7ed05461d 100644 --- a/pkg/sentry/socket/netfilter/udp_matcher.go +++ b/pkg/sentry/socket/netfilter/udp_matcher.go @@ -93,8 +93,8 @@ func (*UDPMatcher) Name() string { } // Match implements Matcher.Match. -func (um *UDPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceName string) (bool, bool) { - netHeader := header.IPv4(pkt.NetworkHeader) +func (um *UDPMatcher) Match(hook stack.Hook, pkt *stack.PacketBuffer, interfaceName string) (bool, bool) { + netHeader := header.IPv4(pkt.NetworkHeader().View()) // TODO(gvisor.dev/issue/170): Proto checks should ultimately be moved // into the stack.Check codepath as matchers are added. @@ -110,36 +110,10 @@ func (um *UDPMatcher) Match(hook stack.Hook, pkt stack.PacketBuffer, interfaceNa return false, false } - // Now we need the transport header. However, this may not have been set - // yet. - // TODO(gvisor.dev/issue/170): Parsing the transport header should - // ultimately be moved into the stack.Check codepath as matchers are - // added. - var udpHeader header.UDP - if pkt.TransportHeader != nil { - udpHeader = header.UDP(pkt.TransportHeader) - } else { - var length int - if hook == stack.Prerouting { - // The network header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(header.IPv4MinimumSize) - if !ok { - // There's no valid UDP header here, so we hotdrop the - // packet. - return false, true - } - h := header.IPv4(hdr) - pkt.NetworkHeader = hdr - length = int(h.HeaderLength()) - } - // The UDP header hasn't been parsed yet. We have to do it here. - hdr, ok := pkt.Data.PullUp(length + header.UDPMinimumSize) - if !ok { - // There's no valid UDP header here, so we hotdrop the - // packet. - return false, true - } - udpHeader = header.UDP(hdr[length:]) + udpHeader := header.UDP(pkt.TransportHeader().View()) + if len(udpHeader) < header.UDPMinimumSize { + // There's no valid UDP header here, so we drop the packet immediately. + return false, true } // Check whether the source and destination ports are within the diff --git a/pkg/sentry/socket/netlink/BUILD b/pkg/sentry/socket/netlink/BUILD index 7212d8644..0546801bf 100644 --- a/pkg/sentry/socket/netlink/BUILD +++ b/pkg/sentry/socket/netlink/BUILD @@ -20,6 +20,7 @@ go_library( "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/sockfs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", @@ -35,6 +36,8 @@ go_library( "//pkg/tcpip", "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", ], ) diff --git a/pkg/sentry/socket/netlink/provider.go b/pkg/sentry/socket/netlink/provider.go index 0d45e5053..31e374833 100644 --- a/pkg/sentry/socket/netlink/provider.go +++ b/pkg/sentry/socket/netlink/provider.go @@ -97,7 +97,7 @@ func (*socketProvider) Socket(t *kernel.Task, stype linux.SockType, protocol int } d := socket.NewDirent(t, netlinkSocketDevice) - defer d.DecRef() + defer d.DecRef(t) return fs.NewFile(t, d, fs.FileFlags{Read: true, Write: true, NonSeekable: true}, s), nil } diff --git a/pkg/sentry/socket/netlink/socket.go b/pkg/sentry/socket/netlink/socket.go index 81f34c5a2..68a9b9a96 100644 --- a/pkg/sentry/socket/netlink/socket.go +++ b/pkg/sentry/socket/netlink/socket.go @@ -38,6 +38,8 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) const sizeOfInt32 int = 4 @@ -138,14 +140,14 @@ func NewSocket(t *kernel.Task, skType linux.SockType, protocol Protocol) (*Socke // Bind the endpoint for good measure so we can connect to it. The // bound address will never be exposed. if err := ep.Bind(tcpip.FullAddress{Addr: "dummy"}, nil); err != nil { - ep.Close() + ep.Close(t) return nil, err } // Create a connection from which the kernel can write messages. connection, err := ep.(transport.BoundEndpoint).UnidirectionalConnect(t) if err != nil { - ep.Close() + ep.Close(t) return nil, err } @@ -162,9 +164,9 @@ func NewSocket(t *kernel.Task, skType linux.SockType, protocol Protocol) (*Socke } // Release implements fs.FileOperations.Release. -func (s *socketOpsCommon) Release() { - s.connection.Release() - s.ep.Close() +func (s *socketOpsCommon) Release(ctx context.Context) { + s.connection.Release(ctx) + s.ep.Close(ctx) if s.bound { s.ports.Release(s.protocol.Protocol(), s.portID) @@ -330,7 +332,7 @@ func (s *socketOpsCommon) Shutdown(t *kernel.Task, how int) *syserr.Error { } // GetSockOpt implements socket.Socket.GetSockOpt. -func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { switch level { case linux.SOL_SOCKET: switch name { @@ -340,24 +342,26 @@ func (s *socketOpsCommon) GetSockOpt(t *kernel.Task, level int, name int, outPtr } s.mu.Lock() defer s.mu.Unlock() - return int32(s.sendBufferSize), nil + sendBufferSizeP := primitive.Int32(s.sendBufferSize) + return &sendBufferSizeP, nil case linux.SO_RCVBUF: if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } // We don't have limit on receiving size. - return int32(math.MaxInt32), nil + recvBufferSizeP := primitive.Int32(math.MaxInt32) + return &recvBufferSizeP, nil case linux.SO_PASSCRED: if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } - var passcred int32 + var passcred primitive.Int32 if s.Passcred() { passcred = 1 } - return passcred, nil + return &passcred, nil default: socket.GetSockOptEmitUnimplementedEvent(t, name) @@ -617,7 +621,7 @@ func (s *socketOpsCommon) sendResponse(ctx context.Context, ms *MessageSet) *sys if len(bufs) > 0 { // RecvMsg never receives the address, so we don't need to send // one. - _, notify, err := s.connection.Send(bufs, cms, tcpip.FullAddress{}) + _, notify, err := s.connection.Send(ctx, bufs, cms, tcpip.FullAddress{}) // If the buffer is full, we simply drop messages, just like // Linux. if err != nil && err != syserr.ErrWouldBlock { @@ -644,7 +648,7 @@ func (s *socketOpsCommon) sendResponse(ctx context.Context, ms *MessageSet) *sys // Add the dump_done_errno payload. m.Put(int64(0)) - _, notify, err := s.connection.Send([][]byte{m.Finalize()}, cms, tcpip.FullAddress{}) + _, notify, err := s.connection.Send(ctx, [][]byte{m.Finalize()}, cms, tcpip.FullAddress{}) if err != nil && err != syserr.ErrWouldBlock { return err } diff --git a/pkg/sentry/socket/netlink/socket_vfs2.go b/pkg/sentry/socket/netlink/socket_vfs2.go index b854bf990..a38d25da9 100644 --- a/pkg/sentry/socket/netlink/socket_vfs2.go +++ b/pkg/sentry/socket/netlink/socket_vfs2.go @@ -18,6 +18,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/socket" "gvisor.dev/gvisor/pkg/sentry/socket/unix" @@ -40,6 +41,7 @@ type SocketVFS2 struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.LockFD socketOpsCommon } @@ -55,18 +57,18 @@ func NewVFS2(t *kernel.Task, skType linux.SockType, protocol Protocol) (*SocketV // Bind the endpoint for good measure so we can connect to it. The // bound address will never be exposed. if err := ep.Bind(tcpip.FullAddress{Addr: "dummy"}, nil); err != nil { - ep.Close() + ep.Close(t) return nil, err } // Create a connection from which the kernel can write messages. connection, err := ep.(transport.BoundEndpoint).UnidirectionalConnect(t) if err != nil { - ep.Close() + ep.Close(t) return nil, err } - return &SocketVFS2{ + fd := &SocketVFS2{ socketOpsCommon: socketOpsCommon{ ports: t.Kernel().NetlinkPorts(), protocol: protocol, @@ -75,7 +77,9 @@ func NewVFS2(t *kernel.Task, skType linux.SockType, protocol Protocol) (*SocketV connection: connection, sendBufferSize: defaultSendBufferSize, }, - }, nil + } + fd.LockFD.Init(&vfs.FileLocks{}) + return fd, nil } // Readiness implements waiter.Waitable.Readiness. @@ -136,3 +140,13 @@ func (s *SocketVFS2) Write(ctx context.Context, src usermem.IOSequence, opts vfs n, err := s.sendMsg(ctx, src, nil, 0, socket.ControlMessages{}) return int64(n), err.ToError() } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (s *SocketVFS2) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return s.Locks().LockPOSIX(ctx, &s.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (s *SocketVFS2) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return s.Locks().UnlockPOSIX(ctx, &s.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/socket/netstack/BUILD b/pkg/sentry/socket/netstack/BUILD index 333e0042e..1fb777a6c 100644 --- a/pkg/sentry/socket/netstack/BUILD +++ b/pkg/sentry/socket/netstack/BUILD @@ -28,6 +28,7 @@ go_library( "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/sockfs", "//pkg/sentry/inet", "//pkg/sentry/kernel", @@ -50,5 +51,8 @@ go_library( "//pkg/tcpip/transport/udp", "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", + "@org_golang_x_sys//unix:go_default_library", ], ) diff --git a/pkg/sentry/socket/netstack/netstack.go b/pkg/sentry/socket/netstack/netstack.go index 60df51dae..e4846bc0b 100644 --- a/pkg/sentry/socket/netstack/netstack.go +++ b/pkg/sentry/socket/netstack/netstack.go @@ -26,6 +26,7 @@ package netstack import ( "bytes" + "fmt" "io" "math" "reflect" @@ -33,6 +34,7 @@ import ( "syscall" "time" + "golang.org/x/sys/unix" "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/amutex" "gvisor.dev/gvisor/pkg/binary" @@ -60,6 +62,8 @@ import ( "gvisor.dev/gvisor/pkg/tcpip/transport/udp" "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) func mustCreateMetric(name, description string) *tcpip.StatCounter { @@ -190,6 +194,8 @@ var Metrics = tcpip.Stats{ MalformedPacketsReceived: mustCreateMetric("/netstack/udp/malformed_packets_received", "Number of incoming UDP datagrams dropped due to the UDP header being in a malformed state."), PacketsSent: mustCreateMetric("/netstack/udp/packets_sent", "Number of UDP datagrams sent."), PacketSendErrors: mustCreateMetric("/netstack/udp/packet_send_errors", "Number of UDP datagrams failed to be sent."), + ChecksumErrors: mustCreateMetric("/netstack/udp/checksum_errors", "Number of UDP datagrams dropped due to bad checksums."), + InvalidSourceAddress: mustCreateMetric("/netstack/udp/invalid_source", "Number of UDP datagrams dropped due to invalid source address."), }, } @@ -294,8 +300,9 @@ type socketOpsCommon struct { readView buffer.View // readCM holds control message information for the last packet read // from Endpoint. - readCM tcpip.ControlMessages - sender tcpip.FullAddress + readCM tcpip.ControlMessages + sender tcpip.FullAddress + linkPacketInfo tcpip.LinkPacketInfo // sockOptTimestamp corresponds to SO_TIMESTAMP. When true, timestamps // of returned messages can be returned via control messages. When @@ -323,7 +330,7 @@ func New(t *kernel.Task, family int, skType linux.SockType, protocol int, queue } dirent := socket.NewDirent(t, netstackDevice) - defer dirent.DecRef() + defer dirent.DecRef(t) return fs.NewFile(t, dirent, fs.FileFlags{Read: true, Write: true, NonSeekable: true}, &SocketOperations{ socketOpsCommon: socketOpsCommon{ Queue: queue, @@ -416,7 +423,7 @@ func AddressAndFamily(addr []byte) (tcpip.FullAddress, uint16, *syserr.Error) { return tcpip.FullAddress{}, family, syserr.ErrInvalidArgument } - // TODO(b/129292371): Return protocol too. + // TODO(gvisor.dev/issue/173): Return protocol too. return tcpip.FullAddress{ NIC: tcpip.NICID(a.InterfaceIndex), Addr: tcpip.Address(a.HardwareAddr[:header.EthernetAddressSize]), @@ -444,8 +451,21 @@ func (s *socketOpsCommon) fetchReadView() *syserr.Error { } s.readView = nil s.sender = tcpip.FullAddress{} + s.linkPacketInfo = tcpip.LinkPacketInfo{} - v, cms, err := s.Endpoint.Read(&s.sender) + var v buffer.View + var cms tcpip.ControlMessages + var err *tcpip.Error + + switch e := s.Endpoint.(type) { + // The ordering of these interfaces matters. The most specific + // interfaces must be specified before the more generic Endpoint + // interface. + case tcpip.PacketEndpoint: + v, cms, err = e.ReadPacket(&s.sender, &s.linkPacketInfo) + case tcpip.Endpoint: + v, cms, err = e.Read(&s.sender) + } if err != nil { atomic.StoreUint32(&s.readViewHasData, 0) return syserr.TranslateNetstackError(err) @@ -459,7 +479,7 @@ func (s *socketOpsCommon) fetchReadView() *syserr.Error { } // Release implements fs.FileOperations.Release. -func (s *socketOpsCommon) Release() { +func (s *socketOpsCommon) Release(context.Context) { s.Endpoint.Close() } @@ -719,6 +739,14 @@ func (s *socketOpsCommon) Connect(t *kernel.Task, sockaddr []byte, blocking bool defer s.EventUnregister(&e) if err := s.Endpoint.Connect(addr); err != tcpip.ErrConnectStarted && err != tcpip.ErrAlreadyConnecting { + if (s.family == unix.AF_INET || s.family == unix.AF_INET6) && s.skType == linux.SOCK_STREAM { + // TCP unlike UDP returns EADDRNOTAVAIL when it can't + // find an available local ephemeral port. + if err == tcpip.ErrNoPortAvailable { + return syserr.ErrAddressNotAvailable + } + } + return syserr.TranslateNetstackError(err) } @@ -826,7 +854,7 @@ func (s *SocketOperations) Accept(t *kernel.Task, peerRequested bool, flags int, if err != nil { return 0, nil, 0, err } - defer ns.DecRef() + defer ns.DecRef(t) if flags&linux.SOCK_NONBLOCK != 0 { flags := ns.Flags() @@ -884,7 +912,7 @@ func (s *socketOpsCommon) Shutdown(t *kernel.Task, how int) *syserr.Error { // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by // tcpip.Endpoint. -func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { // TODO(b/78348848): Unlike other socket options, SO_TIMESTAMP is // implemented specifically for netstack.SocketOperations rather than // commonEndpoint. commonEndpoint should be extended to support socket @@ -894,25 +922,25 @@ func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr us if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } - val := int32(0) + val := primitive.Int32(0) s.readMu.Lock() defer s.readMu.Unlock() if s.sockOptTimestamp { val = 1 } - return val, nil + return &val, nil } if level == linux.SOL_TCP && name == linux.TCP_INQ { if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } - val := int32(0) + val := primitive.Int32(0) s.readMu.Lock() defer s.readMu.Unlock() if s.sockOptInq { val = 1 } - return val, nil + return &val, nil } if s.skType == linux.SOCK_RAW && level == linux.IPPROTO_IP { @@ -930,7 +958,7 @@ func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr us if err != nil { return nil, err } - return info, nil + return &info, nil case linux.IPT_SO_GET_ENTRIES: if outLen < linux.SizeOfIPTGetEntries { @@ -945,7 +973,7 @@ func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr us if err != nil { return nil, err } - return entries, nil + return &entries, nil } } @@ -955,7 +983,7 @@ func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr us // GetSockOpt can be used to implement the linux syscall getsockopt(2) for // sockets backed by a commonEndpoint. -func GetSockOpt(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, family int, skType linux.SockType, level, name, outLen int) (interface{}, *syserr.Error) { +func GetSockOpt(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, family int, skType linux.SockType, level, name, outLen int) (marshal.Marshallable, *syserr.Error) { switch level { case linux.SOL_SOCKET: return getSockOptSocket(t, s, ep, family, skType, name, outLen) @@ -988,7 +1016,7 @@ func boolToInt32(v bool) int32 { } // getSockOptSocket implements GetSockOpt when level is SOL_SOCKET. -func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, family int, skType linux.SockType, name, outLen int) (interface{}, *syserr.Error) { +func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, family int, skType linux.SockType, name, outLen int) (marshal.Marshallable, *syserr.Error) { // TODO(b/124056281): Stop rejecting short optLen values in getsockopt. switch name { case linux.SO_ERROR: @@ -999,9 +1027,12 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam // Get the last error and convert it. err := ep.GetSockOpt(tcpip.ErrorOption{}) if err == nil { - return int32(0), nil + optP := primitive.Int32(0) + return &optP, nil } - return int32(syserr.TranslateNetstackError(err).ToLinux().Number()), nil + + optP := primitive.Int32(syserr.TranslateNetstackError(err).ToLinux().Number()) + return &optP, nil case linux.SO_PEERCRED: if family != linux.AF_UNIX || outLen < syscall.SizeofUcred { @@ -1009,11 +1040,12 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam } tcred := t.Credentials() - return syscall.Ucred{ - Pid: int32(t.ThreadGroup().ID()), - Uid: uint32(tcred.EffectiveKUID.In(tcred.UserNamespace).OrOverflow()), - Gid: uint32(tcred.EffectiveKGID.In(tcred.UserNamespace).OrOverflow()), - }, nil + creds := linux.ControlMessageCredentials{ + PID: int32(t.ThreadGroup().ID()), + UID: uint32(tcred.EffectiveKUID.In(tcred.UserNamespace).OrOverflow()), + GID: uint32(tcred.EffectiveKGID.In(tcred.UserNamespace).OrOverflow()), + } + return &creds, nil case linux.SO_PASSCRED: if outLen < sizeOfInt32 { @@ -1024,7 +1056,9 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.SO_SNDBUF: if outLen < sizeOfInt32 { @@ -1040,7 +1074,8 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam size = math.MaxInt32 } - return int32(size), nil + sizeP := primitive.Int32(size) + return &sizeP, nil case linux.SO_RCVBUF: if outLen < sizeOfInt32 { @@ -1056,7 +1091,8 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam size = math.MaxInt32 } - return int32(size), nil + sizeP := primitive.Int32(size) + return &sizeP, nil case linux.SO_REUSEADDR: if outLen < sizeOfInt32 { @@ -1067,7 +1103,8 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.SO_REUSEPORT: if outLen < sizeOfInt32 { @@ -1078,7 +1115,9 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.SO_BINDTODEVICE: var v tcpip.BindToDeviceOption @@ -1086,7 +1125,8 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam return nil, syserr.TranslateNetstackError(err) } if v == 0 { - return []byte{}, nil + var b primitive.ByteSlice + return &b, nil } if outLen < linux.IFNAMSIZ { return nil, syserr.ErrInvalidArgument @@ -1101,7 +1141,9 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam // interface was removed. return nil, syserr.ErrUnknownDevice } - return append([]byte(nic.Name), 0), nil + + name := primitive.ByteSlice(append([]byte(nic.Name), 0)) + return &name, nil case linux.SO_BROADCAST: if outLen < sizeOfInt32 { @@ -1112,7 +1154,9 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.SO_KEEPALIVE: if outLen < sizeOfInt32 { @@ -1123,13 +1167,17 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.SO_LINGER: if outLen < linux.SizeOfLinger { return nil, syserr.ErrInvalidArgument } - return linux.Linger{}, nil + + linger := linux.Linger{} + return &linger, nil case linux.SO_SNDTIMEO: // TODO(igudger): Linux allows shorter lengths for partial results. @@ -1137,7 +1185,8 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam return nil, syserr.ErrInvalidArgument } - return linux.NsecToTimeval(s.SendTimeout()), nil + sendTimeout := linux.NsecToTimeval(s.SendTimeout()) + return &sendTimeout, nil case linux.SO_RCVTIMEO: // TODO(igudger): Linux allows shorter lengths for partial results. @@ -1145,7 +1194,8 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam return nil, syserr.ErrInvalidArgument } - return linux.NsecToTimeval(s.RecvTimeout()), nil + recvTimeout := linux.NsecToTimeval(s.RecvTimeout()) + return &recvTimeout, nil case linux.SO_OOBINLINE: if outLen < sizeOfInt32 { @@ -1157,7 +1207,20 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam return nil, syserr.TranslateNetstackError(err) } - return int32(v), nil + vP := primitive.Int32(v) + return &vP, nil + + case linux.SO_NO_CHECK: + if outLen < sizeOfInt32 { + return nil, syserr.ErrInvalidArgument + } + + v, err := ep.GetSockOptBool(tcpip.NoChecksumOption) + if err != nil { + return nil, syserr.TranslateNetstackError(err) + } + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil default: socket.GetSockOptEmitUnimplementedEvent(t, name) @@ -1166,7 +1229,7 @@ func getSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, fam } // getSockOptTCP implements GetSockOpt when level is SOL_TCP. -func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interface{}, *syserr.Error) { +func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (marshal.Marshallable, *syserr.Error) { switch name { case linux.TCP_NODELAY: if outLen < sizeOfInt32 { @@ -1177,7 +1240,9 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(!v), nil + + vP := primitive.Int32(boolToInt32(!v)) + return &vP, nil case linux.TCP_CORK: if outLen < sizeOfInt32 { @@ -1188,7 +1253,9 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.TCP_QUICKACK: if outLen < sizeOfInt32 { @@ -1199,7 +1266,9 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.TCP_MAXSEG: if outLen < sizeOfInt32 { @@ -1210,8 +1279,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err != nil { return nil, syserr.TranslateNetstackError(err) } - - return int32(v), nil + vP := primitive.Int32(v) + return &vP, nil case linux.TCP_KEEPIDLE: if outLen < sizeOfInt32 { @@ -1222,8 +1291,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err := ep.GetSockOpt(&v); err != nil { return nil, syserr.TranslateNetstackError(err) } - - return int32(time.Duration(v) / time.Second), nil + keepAliveIdle := primitive.Int32(time.Duration(v) / time.Second) + return &keepAliveIdle, nil case linux.TCP_KEEPINTVL: if outLen < sizeOfInt32 { @@ -1234,8 +1303,20 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err := ep.GetSockOpt(&v); err != nil { return nil, syserr.TranslateNetstackError(err) } + keepAliveInterval := primitive.Int32(time.Duration(v) / time.Second) + return &keepAliveInterval, nil - return int32(time.Duration(v) / time.Second), nil + case linux.TCP_KEEPCNT: + if outLen < sizeOfInt32 { + return nil, syserr.ErrInvalidArgument + } + + v, err := ep.GetSockOptInt(tcpip.KeepaliveCountOption) + if err != nil { + return nil, syserr.TranslateNetstackError(err) + } + vP := primitive.Int32(v) + return &vP, nil case linux.TCP_USER_TIMEOUT: if outLen < sizeOfInt32 { @@ -1246,8 +1327,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err := ep.GetSockOpt(&v); err != nil { return nil, syserr.TranslateNetstackError(err) } - - return int32(time.Duration(v) / time.Millisecond), nil + tcpUserTimeout := primitive.Int32(time.Duration(v) / time.Millisecond) + return &tcpUserTimeout, nil case linux.TCP_INFO: var v tcpip.TCPInfoOption @@ -1260,12 +1341,13 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa info := linux.TCPInfo{} // Linux truncates the output binary to outLen. - ib := binary.Marshal(nil, usermem.ByteOrder, &info) - if len(ib) > outLen { - ib = ib[:outLen] + buf := t.CopyScratchBuffer(info.SizeBytes()) + info.MarshalUnsafe(buf) + if len(buf) > outLen { + buf = buf[:outLen] } - - return ib, nil + bufP := primitive.ByteSlice(buf) + return &bufP, nil case linux.TCP_CC_INFO, linux.TCP_NOTSENT_LOWAT, @@ -1295,7 +1377,9 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa } b := make([]byte, toCopy) copy(b, v) - return b, nil + + bP := primitive.ByteSlice(b) + return &bP, nil case linux.TCP_LINGER2: if outLen < sizeOfInt32 { @@ -1307,7 +1391,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa return nil, syserr.TranslateNetstackError(err) } - return int32(time.Duration(v) / time.Second), nil + lingerTimeout := primitive.Int32(time.Duration(v) / time.Second) + return &lingerTimeout, nil case linux.TCP_DEFER_ACCEPT: if outLen < sizeOfInt32 { @@ -1319,7 +1404,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa return nil, syserr.TranslateNetstackError(err) } - return int32(time.Duration(v) / time.Second), nil + tcpDeferAccept := primitive.Int32(time.Duration(v) / time.Second) + return &tcpDeferAccept, nil case linux.TCP_SYNCNT: if outLen < sizeOfInt32 { @@ -1330,8 +1416,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err != nil { return nil, syserr.TranslateNetstackError(err) } - - return int32(v), nil + vP := primitive.Int32(v) + return &vP, nil case linux.TCP_WINDOW_CLAMP: if outLen < sizeOfInt32 { @@ -1342,8 +1428,8 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa if err != nil { return nil, syserr.TranslateNetstackError(err) } - - return int32(v), nil + vP := primitive.Int32(v) + return &vP, nil default: emitUnimplementedEventTCP(t, name) } @@ -1351,7 +1437,7 @@ func getSockOptTCP(t *kernel.Task, ep commonEndpoint, name, outLen int) (interfa } // getSockOptIPv6 implements GetSockOpt when level is SOL_IPV6. -func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interface{}, *syserr.Error) { +func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (marshal.Marshallable, *syserr.Error) { switch name { case linux.IPV6_V6ONLY: if outLen < sizeOfInt32 { @@ -1362,7 +1448,9 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.IPV6_PATHMTU: t.Kernel().EmitUnimplementedEvent(t) @@ -1370,21 +1458,24 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf case linux.IPV6_TCLASS: // Length handling for parity with Linux. if outLen == 0 { - return make([]byte, 0), nil + var b primitive.ByteSlice + return &b, nil } v, err := ep.GetSockOptInt(tcpip.IPv6TrafficClassOption) if err != nil { return nil, syserr.TranslateNetstackError(err) } - uintv := uint32(v) + uintv := primitive.Uint32(v) // Linux truncates the output binary to outLen. - ib := binary.Marshal(nil, usermem.ByteOrder, &uintv) + ib := t.CopyScratchBuffer(uintv.SizeBytes()) + uintv.MarshalUnsafe(ib) // Handle cases where outLen is lesser than sizeOfInt32. if len(ib) > outLen { ib = ib[:outLen] } - return ib, nil + ibP := primitive.ByteSlice(ib) + return &ibP, nil case linux.IPV6_RECVTCLASS: if outLen < sizeOfInt32 { @@ -1395,7 +1486,13 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil + + case linux.SO_ORIGINAL_DST: + // TODO(gvisor.dev/issue/170): ip6tables. + return nil, syserr.ErrInvalidArgument default: emitUnimplementedEventIPv6(t, name) @@ -1404,7 +1501,7 @@ func getSockOptIPv6(t *kernel.Task, ep commonEndpoint, name, outLen int) (interf } // getSockOptIP implements GetSockOpt when level is SOL_IP. -func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family int) (interface{}, *syserr.Error) { +func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family int) (marshal.Marshallable, *syserr.Error) { switch name { case linux.IP_TTL: if outLen < sizeOfInt32 { @@ -1417,11 +1514,12 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in } // Fill in the default value, if needed. - if v == 0 { - v = DefaultTTL + vP := primitive.Int32(v) + if vP == 0 { + vP = DefaultTTL } - return int32(v), nil + return &vP, nil case linux.IP_MULTICAST_TTL: if outLen < sizeOfInt32 { @@ -1433,7 +1531,8 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in return nil, syserr.TranslateNetstackError(err) } - return int32(v), nil + vP := primitive.Int32(v) + return &vP, nil case linux.IP_MULTICAST_IF: if outLen < len(linux.InetAddr{}) { @@ -1447,7 +1546,7 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in a, _ := ConvertAddress(linux.AF_INET, tcpip.FullAddress{Addr: v.InterfaceAddr}) - return a.(*linux.SockAddrInet).Addr, nil + return &a.(*linux.SockAddrInet).Addr, nil case linux.IP_MULTICAST_LOOP: if outLen < sizeOfInt32 { @@ -1458,21 +1557,26 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.IP_TOS: // Length handling for parity with Linux. if outLen == 0 { - return []byte(nil), nil + var b primitive.ByteSlice + return &b, nil } v, err := ep.GetSockOptInt(tcpip.IPv4TOSOption) if err != nil { return nil, syserr.TranslateNetstackError(err) } if outLen < sizeOfInt32 { - return uint8(v), nil + vP := primitive.Uint8(v) + return &vP, nil } - return int32(v), nil + vP := primitive.Int32(v) + return &vP, nil case linux.IP_RECVTOS: if outLen < sizeOfInt32 { @@ -1483,7 +1587,9 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil case linux.IP_PKTINFO: if outLen < sizeOfInt32 { @@ -1494,7 +1600,22 @@ func getSockOptIP(t *kernel.Task, ep commonEndpoint, name, outLen int, family in if err != nil { return nil, syserr.TranslateNetstackError(err) } - return boolToInt32(v), nil + + vP := primitive.Int32(boolToInt32(v)) + return &vP, nil + + case linux.SO_ORIGINAL_DST: + if outLen < int(binary.Size(linux.SockAddrInet{})) { + return nil, syserr.ErrInvalidArgument + } + + var v tcpip.OriginalDestinationOption + if err := ep.GetSockOpt(&v); err != nil { + return nil, syserr.TranslateNetstackError(err) + } + + a, _ := ConvertAddress(linux.AF_INET, tcpip.FullAddress(v)) + return a.(*linux.SockAddrInet), nil default: emitUnimplementedEventIP(t, name) @@ -1698,6 +1819,14 @@ func setSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, nam return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.OutOfBandInlineOption(v))) + case linux.SO_NO_CHECK: + if len(optVal) < sizeOfInt32 { + return syserr.ErrInvalidArgument + } + + v := usermem.ByteOrder.Uint32(optVal) + return syserr.TranslateNetstackError(ep.SetSockOptBool(tcpip.NoChecksumOption, v != 0)) + case linux.SO_LINGER: if len(optVal) < linux.SizeOfLinger { return syserr.ErrInvalidArgument @@ -1712,6 +1841,11 @@ func setSockOptSocket(t *kernel.Task, s socket.SocketOps, ep commonEndpoint, nam return nil + case linux.SO_DETACH_FILTER: + // optval is ignored. + var v tcpip.SocketDetachFilterOption + return syserr.TranslateNetstackError(ep.SetSockOpt(v)) + default: socket.SetSockOptEmitUnimplementedEvent(t, name) } @@ -1777,6 +1911,17 @@ func setSockOptTCP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) * } return syserr.TranslateNetstackError(ep.SetSockOpt(tcpip.KeepaliveIntervalOption(time.Second * time.Duration(v)))) + case linux.TCP_KEEPCNT: + if len(optVal) < sizeOfInt32 { + return syserr.ErrInvalidArgument + } + + v := usermem.ByteOrder.Uint32(optVal) + if v < 1 || v > linux.MAX_TCP_KEEPCNT { + return syserr.ErrInvalidArgument + } + return syserr.TranslateNetstackError(ep.SetSockOptInt(tcpip.KeepaliveCountOption, int(v))) + case linux.TCP_USER_TIMEOUT: if len(optVal) < sizeOfInt32 { return syserr.ErrInvalidArgument @@ -2060,13 +2205,22 @@ func setSockOptIP(t *kernel.Task, ep commonEndpoint, name int, optVal []byte) *s } return syserr.TranslateNetstackError(ep.SetSockOptBool(tcpip.ReceiveIPPacketInfoOption, v != 0)) + case linux.IP_HDRINCL: + if len(optVal) == 0 { + return nil + } + v, err := parseIntOrChar(optVal) + if err != nil { + return err + } + return syserr.TranslateNetstackError(ep.SetSockOptBool(tcpip.IPHdrIncludedOption, v != 0)) + case linux.IP_ADD_SOURCE_MEMBERSHIP, linux.IP_BIND_ADDRESS_NO_PORT, linux.IP_BLOCK_SOURCE, linux.IP_CHECKSUM, linux.IP_DROP_SOURCE_MEMBERSHIP, linux.IP_FREEBIND, - linux.IP_HDRINCL, linux.IP_IPSEC_POLICY, linux.IP_MINTTL, linux.IP_MSFILTER, @@ -2106,30 +2260,20 @@ func emitUnimplementedEventTCP(t *kernel.Task, name int) { switch name { case linux.TCP_CONGESTION, linux.TCP_CORK, - linux.TCP_DEFER_ACCEPT, linux.TCP_FASTOPEN, linux.TCP_FASTOPEN_CONNECT, linux.TCP_FASTOPEN_KEY, linux.TCP_FASTOPEN_NO_COOKIE, - linux.TCP_KEEPCNT, - linux.TCP_KEEPIDLE, - linux.TCP_KEEPINTVL, - linux.TCP_LINGER2, - linux.TCP_MAXSEG, linux.TCP_QUEUE_SEQ, - linux.TCP_QUICKACK, linux.TCP_REPAIR, linux.TCP_REPAIR_QUEUE, linux.TCP_REPAIR_WINDOW, linux.TCP_SAVED_SYN, linux.TCP_SAVE_SYN, - linux.TCP_SYNCNT, linux.TCP_THIN_DUPACK, linux.TCP_THIN_LINEAR_TIMEOUTS, linux.TCP_TIMESTAMP, - linux.TCP_ULP, - linux.TCP_USER_TIMEOUT, - linux.TCP_WINDOW_CLAMP: + linux.TCP_ULP: t.Kernel().EmitUnimplementedEvent(t) } @@ -2291,7 +2435,7 @@ func ConvertAddress(family int, addr tcpip.FullAddress) (linux.SockAddr, uint32) return &out, uint32(sockAddrInet6Size) case linux.AF_PACKET: - // TODO(b/129292371): Return protocol too. + // TODO(gvisor.dev/issue/173): Return protocol too. var out linux.SockAddrLink out.Family = linux.AF_PACKET out.InterfaceIndex = int32(addr.NIC) @@ -2397,6 +2541,23 @@ func (s *socketOpsCommon) fillCmsgInq(cmsg *socket.ControlMessages) { cmsg.IP.Inq = int32(len(s.readView) + rcvBufUsed) } +func toLinuxPacketType(pktType tcpip.PacketType) uint8 { + switch pktType { + case tcpip.PacketHost: + return linux.PACKET_HOST + case tcpip.PacketOtherHost: + return linux.PACKET_OTHERHOST + case tcpip.PacketOutgoing: + return linux.PACKET_OUTGOING + case tcpip.PacketBroadcast: + return linux.PACKET_BROADCAST + case tcpip.PacketMulticast: + return linux.PACKET_MULTICAST + default: + panic(fmt.Sprintf("unknown packet type: %d", pktType)) + } +} + // nonBlockingRead issues a non-blocking read. // // TODO(b/78348848): Support timestamps for stream sockets. @@ -2452,6 +2613,11 @@ func (s *socketOpsCommon) nonBlockingRead(ctx context.Context, dst usermem.IOSeq var addrLen uint32 if isPacket && senderRequested { addr, addrLen = ConvertAddress(s.family, s.sender) + switch v := addr.(type) { + case *linux.SockAddrLink: + v.Protocol = htons(uint16(s.linkPacketInfo.Protocol)) + v.PacketType = toLinuxPacketType(s.linkPacketInfo.PktType) + } } if peek { @@ -2686,11 +2852,16 @@ func (s *SocketOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO, } func (s *socketOpsCommon) ioctl(ctx context.Context, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { + t := kernel.TaskFromContext(ctx) + if t == nil { + panic("ioctl(2) may only be called from a task goroutine") + } + // SIOCGSTAMP is implemented by netstack rather than all commonEndpoint // sockets. // TODO(b/78348848): Add a commonEndpoint method to support SIOCGSTAMP. switch args[1].Int() { - case syscall.SIOCGSTAMP: + case linux.SIOCGSTAMP: s.readMu.Lock() defer s.readMu.Unlock() if !s.timestampValid { @@ -2698,9 +2869,7 @@ func (s *socketOpsCommon) ioctl(ctx context.Context, io usermem.IO, args arch.Sy } tv := linux.NsecToTimeval(s.timestampNS) - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), &tv, usermem.IOOpts{ - AddressSpaceActive: true, - }) + _, err := tv.CopyOut(t, args[2].Pointer()) return 0, err case linux.TIOCINQ: @@ -2719,9 +2888,8 @@ func (s *socketOpsCommon) ioctl(ctx context.Context, io usermem.IO, args arch.Sy } // Copy result to userspace. - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{ - AddressSpaceActive: true, - }) + vP := primitive.Int32(v) + _, err := vP.CopyOut(t, args[2].Pointer()) return 0, err } @@ -2730,52 +2898,49 @@ func (s *socketOpsCommon) ioctl(ctx context.Context, io usermem.IO, args arch.Sy // Ioctl performs a socket ioctl. func Ioctl(ctx context.Context, ep commonEndpoint, io usermem.IO, args arch.SyscallArguments) (uintptr, error) { + t := kernel.TaskFromContext(ctx) + if t == nil { + panic("ioctl(2) may only be called from a task goroutine") + } + switch arg := int(args[1].Int()); arg { - case syscall.SIOCGIFFLAGS, - syscall.SIOCGIFADDR, - syscall.SIOCGIFBRDADDR, - syscall.SIOCGIFDSTADDR, - syscall.SIOCGIFHWADDR, - syscall.SIOCGIFINDEX, - syscall.SIOCGIFMAP, - syscall.SIOCGIFMETRIC, - syscall.SIOCGIFMTU, - syscall.SIOCGIFNAME, - syscall.SIOCGIFNETMASK, - syscall.SIOCGIFTXQLEN: + case linux.SIOCGIFFLAGS, + linux.SIOCGIFADDR, + linux.SIOCGIFBRDADDR, + linux.SIOCGIFDSTADDR, + linux.SIOCGIFHWADDR, + linux.SIOCGIFINDEX, + linux.SIOCGIFMAP, + linux.SIOCGIFMETRIC, + linux.SIOCGIFMTU, + linux.SIOCGIFNAME, + linux.SIOCGIFNETMASK, + linux.SIOCGIFTXQLEN, + linux.SIOCETHTOOL: var ifr linux.IFReq - if _, err := usermem.CopyObjectIn(ctx, io, args[2].Pointer(), &ifr, usermem.IOOpts{ - AddressSpaceActive: true, - }); err != nil { + if _, err := ifr.CopyIn(t, args[2].Pointer()); err != nil { return 0, err } if err := interfaceIoctl(ctx, io, arg, &ifr); err != nil { return 0, err.ToError() } - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), &ifr, usermem.IOOpts{ - AddressSpaceActive: true, - }) + _, err := ifr.CopyOut(t, args[2].Pointer()) return 0, err - case syscall.SIOCGIFCONF: + case linux.SIOCGIFCONF: // Return a list of interface addresses or the buffer size // necessary to hold the list. var ifc linux.IFConf - if _, err := usermem.CopyObjectIn(ctx, io, args[2].Pointer(), &ifc, usermem.IOOpts{ - AddressSpaceActive: true, - }); err != nil { + if _, err := ifc.CopyIn(t, args[2].Pointer()); err != nil { return 0, err } - if err := ifconfIoctl(ctx, io, &ifc); err != nil { + if err := ifconfIoctl(ctx, t, io, &ifc); err != nil { return 0, err } - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), ifc, usermem.IOOpts{ - AddressSpaceActive: true, - }) - + _, err := ifc.CopyOut(t, args[2].Pointer()) return 0, err case linux.TIOCINQ: @@ -2788,9 +2953,8 @@ func Ioctl(ctx context.Context, ep commonEndpoint, io usermem.IO, args arch.Sysc v = math.MaxInt32 } // Copy result to userspace. - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{ - AddressSpaceActive: true, - }) + vP := primitive.Int32(v) + _, err := vP.CopyOut(t, args[2].Pointer()) return 0, err case linux.TIOCOUTQ: @@ -2804,9 +2968,8 @@ func Ioctl(ctx context.Context, ep commonEndpoint, io usermem.IO, args arch.Sysc } // Copy result to userspace. - _, err := usermem.CopyObjectOut(ctx, io, args[2].Pointer(), int32(v), usermem.IOOpts{ - AddressSpaceActive: true, - }) + vP := primitive.Int32(v) + _, err := vP.CopyOut(t, args[2].Pointer()) return 0, err case linux.SIOCGIFMEM, linux.SIOCGIFPFLAGS, linux.SIOCGMIIPHY, linux.SIOCGMIIREG: @@ -2832,7 +2995,7 @@ func interfaceIoctl(ctx context.Context, io usermem.IO, arg int, ifr *linux.IFRe // SIOCGIFNAME uses ifr.ifr_ifindex rather than ifr.ifr_name to // identify a device. - if arg == syscall.SIOCGIFNAME { + if arg == linux.SIOCGIFNAME { // Gets the name of the interface given the interface index // stored in ifr_ifindex. index = int32(usermem.ByteOrder.Uint32(ifr.Data[:4])) @@ -2855,21 +3018,28 @@ func interfaceIoctl(ctx context.Context, io usermem.IO, arg int, ifr *linux.IFRe } switch arg { - case syscall.SIOCGIFINDEX: + case linux.SIOCGIFINDEX: // Copy out the index to the data. usermem.ByteOrder.PutUint32(ifr.Data[:], uint32(index)) - case syscall.SIOCGIFHWADDR: + case linux.SIOCGIFHWADDR: // Copy the hardware address out. - ifr.Data[0] = 6 // IEEE802.2 arp type. - ifr.Data[1] = 0 + // + // Refer: https://linux.die.net/man/7/netdevice + // SIOCGIFHWADDR, SIOCSIFHWADDR + // + // Get or set the hardware address of a device using + // ifr_hwaddr. The hardware address is specified in a struct + // sockaddr. sa_family contains the ARPHRD_* device type, + // sa_data the L2 hardware address starting from byte 0. Setting + // the hardware address is a privileged operation. + usermem.ByteOrder.PutUint16(ifr.Data[:], iface.DeviceType) n := copy(ifr.Data[2:], iface.Addr) for i := 2 + n; i < len(ifr.Data); i++ { ifr.Data[i] = 0 // Clear padding. } - usermem.ByteOrder.PutUint16(ifr.Data[:2], uint16(n)) - case syscall.SIOCGIFFLAGS: + case linux.SIOCGIFFLAGS: f, err := interfaceStatusFlags(stack, iface.Name) if err != nil { return err @@ -2878,7 +3048,7 @@ func interfaceIoctl(ctx context.Context, io usermem.IO, arg int, ifr *linux.IFRe // matches Linux behavior. usermem.ByteOrder.PutUint16(ifr.Data[:2], uint16(f)) - case syscall.SIOCGIFADDR: + case linux.SIOCGIFADDR: // Copy the IPv4 address out. for _, addr := range stack.InterfaceAddrs()[index] { // This ioctl is only compatible with AF_INET addresses. @@ -2889,32 +3059,32 @@ func interfaceIoctl(ctx context.Context, io usermem.IO, arg int, ifr *linux.IFRe break } - case syscall.SIOCGIFMETRIC: + case linux.SIOCGIFMETRIC: // Gets the metric of the device. As per netdevice(7), this // always just sets ifr_metric to 0. usermem.ByteOrder.PutUint32(ifr.Data[:4], 0) - case syscall.SIOCGIFMTU: + case linux.SIOCGIFMTU: // Gets the MTU of the device. usermem.ByteOrder.PutUint32(ifr.Data[:4], iface.MTU) - case syscall.SIOCGIFMAP: + case linux.SIOCGIFMAP: // Gets the hardware parameters of the device. // TODO(gvisor.dev/issue/505): Implement. - case syscall.SIOCGIFTXQLEN: + case linux.SIOCGIFTXQLEN: // Gets the transmit queue length of the device. // TODO(gvisor.dev/issue/505): Implement. - case syscall.SIOCGIFDSTADDR: + case linux.SIOCGIFDSTADDR: // Gets the destination address of a point-to-point device. // TODO(gvisor.dev/issue/505): Implement. - case syscall.SIOCGIFBRDADDR: + case linux.SIOCGIFBRDADDR: // Gets the broadcast address of a device. // TODO(gvisor.dev/issue/505): Implement. - case syscall.SIOCGIFNETMASK: + case linux.SIOCGIFNETMASK: // Gets the network mask of a device. for _, addr := range stack.InterfaceAddrs()[index] { // This ioctl is only compatible with AF_INET addresses. @@ -2931,6 +3101,14 @@ func interfaceIoctl(ctx context.Context, io usermem.IO, arg int, ifr *linux.IFRe break } + case linux.SIOCETHTOOL: + // Stubbed out for now, Ideally we should implement the required + // sub-commands for ETHTOOL + // + // See: + // https://github.com/torvalds/linux/blob/aa0c9086b40c17a7ad94425b3b70dd1fdd7497bf/net/core/dev_ioctl.c + return syserr.ErrEndpointOperation + default: // Not a valid call. return syserr.ErrInvalidArgument @@ -2940,7 +3118,7 @@ func interfaceIoctl(ctx context.Context, io usermem.IO, arg int, ifr *linux.IFRe } // ifconfIoctl populates a struct ifconf for the SIOCGIFCONF ioctl. -func ifconfIoctl(ctx context.Context, io usermem.IO, ifc *linux.IFConf) error { +func ifconfIoctl(ctx context.Context, t *kernel.Task, io usermem.IO, ifc *linux.IFConf) error { // If Ptr is NULL, return the necessary buffer size via Len. // Otherwise, write up to Len bytes starting at Ptr containing ifreq // structs. @@ -2977,9 +3155,7 @@ func ifconfIoctl(ctx context.Context, io usermem.IO, ifc *linux.IFConf) error { // Copy the ifr to userspace. dst := uintptr(ifc.Ptr) + uintptr(ifc.Len) ifc.Len += int32(linux.SizeOfIFReq) - if _, err := usermem.CopyObjectOut(ctx, io, usermem.Addr(dst), ifr, usermem.IOOpts{ - AddressSpaceActive: true, - }); err != nil { + if _, err := ifr.CopyOut(t, usermem.Addr(dst)); err != nil { return err } } diff --git a/pkg/sentry/socket/netstack/netstack_vfs2.go b/pkg/sentry/socket/netstack/netstack_vfs2.go index fcd8013c0..3335e7430 100644 --- a/pkg/sentry/socket/netstack/netstack_vfs2.go +++ b/pkg/sentry/socket/netstack/netstack_vfs2.go @@ -19,6 +19,7 @@ import ( "gvisor.dev/gvisor/pkg/amutex" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs" "gvisor.dev/gvisor/pkg/sentry/inet" "gvisor.dev/gvisor/pkg/sentry/kernel" @@ -30,6 +31,8 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) // SocketVFS2 encapsulates all the state needed to represent a network stack @@ -38,6 +41,7 @@ type SocketVFS2 struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.LockFD socketOpsCommon } @@ -64,6 +68,7 @@ func NewVFS2(t *kernel.Task, family int, skType linux.SockType, protocol int, qu protocol: protocol, }, } + s.LockFD.Init(&vfs.FileLocks{}) vfsfd := &s.vfsfd if err := vfsfd.Init(s, linux.O_RDWR, mnt, d, &vfs.FileDescriptionOptions{ DenyPRead: true, @@ -164,7 +169,7 @@ func (s *SocketVFS2) Accept(t *kernel.Task, peerRequested bool, flags int, block if err != nil { return 0, nil, 0, err } - defer ns.DecRef() + defer ns.DecRef(t) if err := ns.SetStatusFlags(t, t.Credentials(), uint32(flags&linux.SOCK_NONBLOCK)); err != nil { return 0, nil, 0, syserr.FromError(err) @@ -197,7 +202,7 @@ func (s *SocketVFS2) Ioctl(ctx context.Context, uio usermem.IO, args arch.Syscal // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by // tcpip.Endpoint. -func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { // TODO(b/78348848): Unlike other socket options, SO_TIMESTAMP is // implemented specifically for netstack.SocketVFS2 rather than // commonEndpoint. commonEndpoint should be extended to support socket @@ -207,25 +212,25 @@ func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem. if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } - val := int32(0) + val := primitive.Int32(0) s.readMu.Lock() defer s.readMu.Unlock() if s.sockOptTimestamp { val = 1 } - return val, nil + return &val, nil } if level == linux.SOL_TCP && name == linux.TCP_INQ { if outLen < sizeOfInt32 { return nil, syserr.ErrInvalidArgument } - val := int32(0) + val := primitive.Int32(0) s.readMu.Lock() defer s.readMu.Unlock() if s.sockOptInq { val = 1 } - return val, nil + return &val, nil } if s.skType == linux.SOCK_RAW && level == linux.IPPROTO_IP { @@ -243,7 +248,7 @@ func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem. if err != nil { return nil, err } - return info, nil + return &info, nil case linux.IPT_SO_GET_ENTRIES: if outLen < linux.SizeOfIPTGetEntries { @@ -258,7 +263,7 @@ func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem. if err != nil { return nil, err } - return entries, nil + return &entries, nil } } @@ -315,3 +320,13 @@ func (s *SocketVFS2) SetSockOpt(t *kernel.Task, level int, name int, optVal []by return SetSockOpt(t, s, s.Endpoint, level, name, optVal) } + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (s *SocketVFS2) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return s.Locks().LockPOSIX(ctx, &s.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (s *SocketVFS2) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return s.Locks().UnlockPOSIX(ctx, &s.vfsfd, uid, start, length, whence) +} diff --git a/pkg/sentry/socket/netstack/stack.go b/pkg/sentry/socket/netstack/stack.go index f5fa18136..f0fe18684 100644 --- a/pkg/sentry/socket/netstack/stack.go +++ b/pkg/sentry/socket/netstack/stack.go @@ -15,10 +15,11 @@ package netstack import ( + "fmt" + "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/inet" - "gvisor.dev/gvisor/pkg/sentry/socket/netfilter" "gvisor.dev/gvisor/pkg/syserr" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/tcpip" @@ -41,19 +42,29 @@ func (s *Stack) SupportsIPv6() bool { return s.Stack.CheckNetworkProtocol(ipv6.ProtocolNumber) } +// Converts Netstack's ARPHardwareType to equivalent linux constants. +func toLinuxARPHardwareType(t header.ARPHardwareType) uint16 { + switch t { + case header.ARPHardwareNone: + return linux.ARPHRD_NONE + case header.ARPHardwareLoopback: + return linux.ARPHRD_LOOPBACK + case header.ARPHardwareEther: + return linux.ARPHRD_ETHER + default: + panic(fmt.Sprintf("unknown ARPHRD type: %d", t)) + } +} + // Interfaces implements inet.Stack.Interfaces. func (s *Stack) Interfaces() map[int32]inet.Interface { is := make(map[int32]inet.Interface) for id, ni := range s.Stack.NICInfo() { - var devType uint16 - if ni.Flags.Loopback { - devType = linux.ARPHRD_LOOPBACK - } is[int32(id)] = inet.Interface{ Name: ni.Name, Addr: []byte(ni.LinkAddress), Flags: uint32(nicStateFlagsToLinux(ni.Flags)), - DeviceType: devType, + DeviceType: toLinuxARPHardwareType(ni.ARPHardwareType), MTU: ni.MTU, } } @@ -196,6 +207,20 @@ func (s *Stack) SetTCPSACKEnabled(enabled bool) error { return syserr.TranslateNetstackError(s.Stack.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.SACKEnabled(enabled))).ToError() } +// TCPRecovery implements inet.Stack.TCPRecovery. +func (s *Stack) TCPRecovery() (inet.TCPLossRecovery, error) { + var recovery tcp.Recovery + if err := s.Stack.TransportProtocolOption(tcp.ProtocolNumber, &recovery); err != nil { + return 0, syserr.TranslateNetstackError(err).ToError() + } + return inet.TCPLossRecovery(recovery), nil +} + +// SetTCPRecovery implements inet.Stack.SetTCPRecovery. +func (s *Stack) SetTCPRecovery(recovery inet.TCPLossRecovery) error { + return syserr.TranslateNetstackError(s.Stack.SetTransportProtocolOption(tcp.ProtocolNumber, tcp.Recovery(recovery))).ToError() +} + // Statistics implements inet.Stack.Statistics. func (s *Stack) Statistics(stat interface{}, arg string) error { switch stats := stat.(type) { @@ -314,7 +339,7 @@ func (s *Stack) Statistics(stat interface{}, arg string) error { udp.PacketsSent.Value(), // OutDatagrams. udp.ReceiveBufferErrors.Value(), // RcvbufErrors. 0, // Udp/SndbufErrors. - 0, // Udp/InCsumErrors. + udp.ChecksumErrors.Value(), // Udp/InCsumErrors. 0, // Udp/IgnoredMulti. } default: @@ -362,16 +387,10 @@ func (s *Stack) RouteTable() []inet.Route { } // IPTables returns the stack's iptables. -func (s *Stack) IPTables() (stack.IPTables, error) { +func (s *Stack) IPTables() (*stack.IPTables, error) { return s.Stack.IPTables(), nil } -// FillDefaultIPTables sets the stack's iptables to the default tables, which -// allow and do not modify all traffic. -func (s *Stack) FillDefaultIPTables() { - netfilter.FillDefaultIPTables(s.Stack) -} - // Resume implements inet.Stack.Resume. func (s *Stack) Resume() { s.Stack.Resume() diff --git a/pkg/sentry/socket/socket.go b/pkg/sentry/socket/socket.go index 6580bd6e9..04b259d27 100644 --- a/pkg/sentry/socket/socket.go +++ b/pkg/sentry/socket/socket.go @@ -35,6 +35,7 @@ import ( "gvisor.dev/gvisor/pkg/syserr" "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/tools/go_marshal/marshal" ) // ControlMessages represents the union of unix control messages and tcpip @@ -45,8 +46,8 @@ type ControlMessages struct { } // Release releases Unix domain socket credentials and rights. -func (c *ControlMessages) Release() { - c.Unix.Release() +func (c *ControlMessages) Release(ctx context.Context) { + c.Unix.Release(ctx) } // Socket is an interface combining fs.FileOperations and SocketOps, @@ -86,7 +87,7 @@ type SocketOps interface { Shutdown(t *kernel.Task, how int) *syserr.Error // GetSockOpt implements the getsockopt(2) linux syscall. - GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) + GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) // SetSockOpt implements the setsockopt(2) linux syscall. SetSockOpt(t *kernel.Task, level int, name int, opt []byte) *syserr.Error @@ -407,7 +408,6 @@ func emitUnimplementedEvent(t *kernel.Task, name int) { linux.SO_MARK, linux.SO_MAX_PACING_RATE, linux.SO_NOFCS, - linux.SO_NO_CHECK, linux.SO_OOBINLINE, linux.SO_PASSCRED, linux.SO_PASSSEC, diff --git a/pkg/sentry/socket/unix/BUILD b/pkg/sentry/socket/unix/BUILD index de2cc4bdf..061a689a9 100644 --- a/pkg/sentry/socket/unix/BUILD +++ b/pkg/sentry/socket/unix/BUILD @@ -21,6 +21,7 @@ go_library( "//pkg/sentry/device", "//pkg/sentry/fs", "//pkg/sentry/fs/fsutil", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsimpl/sockfs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/time", @@ -34,5 +35,6 @@ go_library( "//pkg/tcpip", "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", ], ) diff --git a/pkg/sentry/socket/unix/transport/connectioned.go b/pkg/sentry/socket/unix/transport/connectioned.go index ce5b94ee7..c67b602f0 100644 --- a/pkg/sentry/socket/unix/transport/connectioned.go +++ b/pkg/sentry/socket/unix/transport/connectioned.go @@ -211,7 +211,7 @@ func (e *connectionedEndpoint) Listening() bool { // The socket will be a fresh state after a call to close and may be reused. // That is, close may be used to "unbind" or "disconnect" the socket in error // paths. -func (e *connectionedEndpoint) Close() { +func (e *connectionedEndpoint) Close(ctx context.Context) { e.Lock() var c ConnectedEndpoint var r Receiver @@ -233,7 +233,7 @@ func (e *connectionedEndpoint) Close() { case e.Listening(): close(e.acceptedChan) for n := range e.acceptedChan { - n.Close() + n.Close(ctx) } e.acceptedChan = nil e.path = "" @@ -241,18 +241,18 @@ func (e *connectionedEndpoint) Close() { e.Unlock() if c != nil { c.CloseNotify() - c.Release() + c.Release(ctx) } if r != nil { r.CloseNotify() - r.Release() + r.Release(ctx) } } // BidirectionalConnect implements BoundEndpoint.BidirectionalConnect. func (e *connectionedEndpoint) BidirectionalConnect(ctx context.Context, ce ConnectingEndpoint, returnConnect func(Receiver, ConnectedEndpoint)) *syserr.Error { if ce.Type() != e.stype { - return syserr.ErrConnectionRefused + return syserr.ErrWrongProtocolForSocket } // Check if ce is e to avoid a deadlock. @@ -340,7 +340,7 @@ func (e *connectionedEndpoint) BidirectionalConnect(ctx context.Context, ce Conn return nil default: // Busy; return ECONNREFUSED per spec. - ne.Close() + ne.Close(ctx) e.Unlock() ce.Unlock() return syserr.ErrConnectionRefused @@ -476,6 +476,9 @@ func (e *connectionedEndpoint) Readiness(mask waiter.EventMask) waiter.EventMask // State implements socket.Socket.State. func (e *connectionedEndpoint) State() uint32 { + e.Lock() + defer e.Unlock() + if e.Connected() { return linux.SS_CONNECTED } diff --git a/pkg/sentry/socket/unix/transport/connectionless.go b/pkg/sentry/socket/unix/transport/connectionless.go index 4b06d63ac..70ee8f9b8 100644 --- a/pkg/sentry/socket/unix/transport/connectionless.go +++ b/pkg/sentry/socket/unix/transport/connectionless.go @@ -54,10 +54,10 @@ func (e *connectionlessEndpoint) isBound() bool { // Close puts the endpoint in a closed state and frees all resources associated // with it. -func (e *connectionlessEndpoint) Close() { +func (e *connectionlessEndpoint) Close(ctx context.Context) { e.Lock() if e.connected != nil { - e.connected.Release() + e.connected.Release(ctx) e.connected = nil } @@ -71,7 +71,7 @@ func (e *connectionlessEndpoint) Close() { e.Unlock() r.CloseNotify() - r.Release() + r.Release(ctx) } // BidirectionalConnect implements BoundEndpoint.BidirectionalConnect. @@ -108,10 +108,10 @@ func (e *connectionlessEndpoint) SendMsg(ctx context.Context, data [][]byte, c C if err != nil { return 0, syserr.ErrInvalidEndpointState } - defer connected.Release() + defer connected.Release(ctx) e.Lock() - n, notify, err := connected.Send(data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)}) + n, notify, err := connected.Send(ctx, data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)}) e.Unlock() if notify { @@ -135,7 +135,7 @@ func (e *connectionlessEndpoint) Connect(ctx context.Context, server BoundEndpoi e.Lock() if e.connected != nil { - e.connected.Release() + e.connected.Release(ctx) } e.connected = connected e.Unlock() diff --git a/pkg/sentry/socket/unix/transport/queue.go b/pkg/sentry/socket/unix/transport/queue.go index d8f3ad63d..ef6043e19 100644 --- a/pkg/sentry/socket/unix/transport/queue.go +++ b/pkg/sentry/socket/unix/transport/queue.go @@ -15,6 +15,7 @@ package transport import ( + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/refs" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserr" @@ -57,10 +58,10 @@ func (q *queue) Close() { // Both the read and write queues must be notified after resetting: // q.ReaderQueue.Notify(waiter.EventIn) // q.WriterQueue.Notify(waiter.EventOut) -func (q *queue) Reset() { +func (q *queue) Reset(ctx context.Context) { q.mu.Lock() for cur := q.dataList.Front(); cur != nil; cur = cur.Next() { - cur.Release() + cur.Release(ctx) } q.dataList.Reset() q.used = 0 @@ -68,8 +69,8 @@ func (q *queue) Reset() { } // DecRef implements RefCounter.DecRef with destructor q.Reset. -func (q *queue) DecRef() { - q.DecRefWithDestructor(q.Reset) +func (q *queue) DecRef(ctx context.Context) { + q.DecRefWithDestructor(ctx, q.Reset) // We don't need to notify after resetting because no one cares about // this queue after all references have been dropped. } @@ -111,7 +112,7 @@ func (q *queue) IsWritable() bool { // // If notify is true, ReaderQueue.Notify must be called: // q.ReaderQueue.Notify(waiter.EventIn) -func (q *queue) Enqueue(data [][]byte, c ControlMessages, from tcpip.FullAddress, discardEmpty bool, truncate bool) (l int64, notify bool, err *syserr.Error) { +func (q *queue) Enqueue(ctx context.Context, data [][]byte, c ControlMessages, from tcpip.FullAddress, discardEmpty bool, truncate bool) (l int64, notify bool, err *syserr.Error) { q.mu.Lock() if q.closed { @@ -124,7 +125,7 @@ func (q *queue) Enqueue(data [][]byte, c ControlMessages, from tcpip.FullAddress } if discardEmpty && l == 0 { q.mu.Unlock() - c.Release() + c.Release(ctx) return 0, false, nil } diff --git a/pkg/sentry/socket/unix/transport/unix.go b/pkg/sentry/socket/unix/transport/unix.go index 2f1b127df..475d7177e 100644 --- a/pkg/sentry/socket/unix/transport/unix.go +++ b/pkg/sentry/socket/unix/transport/unix.go @@ -37,7 +37,7 @@ type RightsControlMessage interface { Clone() RightsControlMessage // Release releases any resources owned by the RightsControlMessage. - Release() + Release(ctx context.Context) } // A CredentialsControlMessage is a control message containing Unix credentials. @@ -74,9 +74,9 @@ func (c *ControlMessages) Clone() ControlMessages { } // Release releases both the credentials and the rights. -func (c *ControlMessages) Release() { +func (c *ControlMessages) Release(ctx context.Context) { if c.Rights != nil { - c.Rights.Release() + c.Rights.Release(ctx) } *c = ControlMessages{} } @@ -90,7 +90,7 @@ type Endpoint interface { // Close puts the endpoint in a closed state and frees all resources // associated with it. - Close() + Close(ctx context.Context) // RecvMsg reads data and a control message from the endpoint. This method // does not block if there is no data pending. @@ -252,7 +252,7 @@ type BoundEndpoint interface { // Release releases any resources held by the BoundEndpoint. It must be // called before dropping all references to a BoundEndpoint returned by a // function. - Release() + Release(ctx context.Context) } // message represents a message passed over a Unix domain socket. @@ -281,8 +281,8 @@ func (m *message) Length() int64 { } // Release releases any resources held by the message. -func (m *message) Release() { - m.Control.Release() +func (m *message) Release(ctx context.Context) { + m.Control.Release(ctx) } // Peek returns a copy of the message. @@ -304,7 +304,7 @@ type Receiver interface { // See Endpoint.RecvMsg for documentation on shared arguments. // // notify indicates if RecvNotify should be called. - Recv(data [][]byte, creds bool, numRights int, peek bool) (recvLen, msgLen int64, cm ControlMessages, CMTruncated bool, source tcpip.FullAddress, notify bool, err *syserr.Error) + Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (recvLen, msgLen int64, cm ControlMessages, CMTruncated bool, source tcpip.FullAddress, notify bool, err *syserr.Error) // RecvNotify notifies the Receiver of a successful Recv. This must not be // called while holding any endpoint locks. @@ -333,7 +333,7 @@ type Receiver interface { // Release releases any resources owned by the Receiver. It should be // called before droping all references to a Receiver. - Release() + Release(ctx context.Context) } // queueReceiver implements Receiver for datagram sockets. @@ -344,7 +344,7 @@ type queueReceiver struct { } // Recv implements Receiver.Recv. -func (q *queueReceiver) Recv(data [][]byte, creds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { +func (q *queueReceiver) Recv(ctx context.Context, data [][]byte, creds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { var m *message var notify bool var err *syserr.Error @@ -398,8 +398,8 @@ func (q *queueReceiver) RecvMaxQueueSize() int64 { } // Release implements Receiver.Release. -func (q *queueReceiver) Release() { - q.readQueue.DecRef() +func (q *queueReceiver) Release(ctx context.Context) { + q.readQueue.DecRef(ctx) } // streamQueueReceiver implements Receiver for stream sockets. @@ -456,7 +456,7 @@ func (q *streamQueueReceiver) RecvMaxQueueSize() int64 { } // Recv implements Receiver.Recv. -func (q *streamQueueReceiver) Recv(data [][]byte, wantCreds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { +func (q *streamQueueReceiver) Recv(ctx context.Context, data [][]byte, wantCreds bool, numRights int, peek bool) (int64, int64, ControlMessages, bool, tcpip.FullAddress, bool, *syserr.Error) { q.mu.Lock() defer q.mu.Unlock() @@ -502,7 +502,7 @@ func (q *streamQueueReceiver) Recv(data [][]byte, wantCreds bool, numRights int, var cmTruncated bool if c.Rights != nil && numRights == 0 { - c.Rights.Release() + c.Rights.Release(ctx) c.Rights = nil cmTruncated = true } @@ -557,7 +557,7 @@ func (q *streamQueueReceiver) Recv(data [][]byte, wantCreds bool, numRights int, // Consume rights. if numRights == 0 { cmTruncated = true - q.control.Rights.Release() + q.control.Rights.Release(ctx) } else { c.Rights = q.control.Rights haveRights = true @@ -582,7 +582,7 @@ type ConnectedEndpoint interface { // // syserr.ErrWouldBlock can be returned along with a partial write if // the caller should block to send the rest of the data. - Send(data [][]byte, c ControlMessages, from tcpip.FullAddress) (n int64, notify bool, err *syserr.Error) + Send(ctx context.Context, data [][]byte, c ControlMessages, from tcpip.FullAddress) (n int64, notify bool, err *syserr.Error) // SendNotify notifies the ConnectedEndpoint of a successful Send. This // must not be called while holding any endpoint locks. @@ -616,7 +616,7 @@ type ConnectedEndpoint interface { // Release releases any resources owned by the ConnectedEndpoint. It should // be called before droping all references to a ConnectedEndpoint. - Release() + Release(ctx context.Context) // CloseUnread sets the fact that this end is closed with unread data to // the peer socket. @@ -654,7 +654,7 @@ func (e *connectedEndpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) } // Send implements ConnectedEndpoint.Send. -func (e *connectedEndpoint) Send(data [][]byte, c ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { +func (e *connectedEndpoint) Send(ctx context.Context, data [][]byte, c ControlMessages, from tcpip.FullAddress) (int64, bool, *syserr.Error) { discardEmpty := false truncate := false if e.endpoint.Type() == linux.SOCK_STREAM { @@ -669,7 +669,7 @@ func (e *connectedEndpoint) Send(data [][]byte, c ControlMessages, from tcpip.Fu truncate = true } - return e.writeQueue.Enqueue(data, c, from, discardEmpty, truncate) + return e.writeQueue.Enqueue(ctx, data, c, from, discardEmpty, truncate) } // SendNotify implements ConnectedEndpoint.SendNotify. @@ -707,8 +707,8 @@ func (e *connectedEndpoint) SendMaxQueueSize() int64 { } // Release implements ConnectedEndpoint.Release. -func (e *connectedEndpoint) Release() { - e.writeQueue.DecRef() +func (e *connectedEndpoint) Release(ctx context.Context) { + e.writeQueue.DecRef(ctx) } // CloseUnread implements ConnectedEndpoint.CloseUnread. @@ -798,7 +798,7 @@ func (e *baseEndpoint) RecvMsg(ctx context.Context, data [][]byte, creds bool, n return 0, 0, ControlMessages{}, false, syserr.ErrNotConnected } - recvLen, msgLen, cms, cmt, a, notify, err := e.receiver.Recv(data, creds, numRights, peek) + recvLen, msgLen, cms, cmt, a, notify, err := e.receiver.Recv(ctx, data, creds, numRights, peek) e.Unlock() if err != nil { return 0, 0, ControlMessages{}, false, err @@ -827,7 +827,7 @@ func (e *baseEndpoint) SendMsg(ctx context.Context, data [][]byte, c ControlMess return 0, syserr.ErrAlreadyConnected } - n, notify, err := e.connected.Send(data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)}) + n, notify, err := e.connected.Send(ctx, data, c, tcpip.FullAddress{Addr: tcpip.Address(e.path)}) e.Unlock() if notify { @@ -1001,6 +1001,6 @@ func (e *baseEndpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) { } // Release implements BoundEndpoint.Release. -func (*baseEndpoint) Release() { +func (*baseEndpoint) Release(context.Context) { // Binding a baseEndpoint doesn't take a reference. } diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go index 5b29e9d7f..2b8454edb 100644 --- a/pkg/sentry/socket/unix/unix.go +++ b/pkg/sentry/socket/unix/unix.go @@ -40,6 +40,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" ) // SocketOperations is a Unix socket. It is similar to a netstack socket, @@ -61,7 +62,7 @@ type SocketOperations struct { // New creates a new unix socket. func New(ctx context.Context, endpoint transport.Endpoint, stype linux.SockType) *fs.File { dirent := socket.NewDirent(ctx, unixSocketDevice) - defer dirent.DecRef() + defer dirent.DecRef(ctx) return NewWithDirent(ctx, dirent, endpoint, stype, fs.FileFlags{Read: true, Write: true, NonSeekable: true}) } @@ -96,17 +97,17 @@ type socketOpsCommon struct { } // DecRef implements RefCounter.DecRef. -func (s *socketOpsCommon) DecRef() { - s.DecRefWithDestructor(func() { - s.ep.Close() +func (s *socketOpsCommon) DecRef(ctx context.Context) { + s.DecRefWithDestructor(ctx, func(context.Context) { + s.ep.Close(ctx) }) } // Release implemements fs.FileOperations.Release. -func (s *socketOpsCommon) Release() { +func (s *socketOpsCommon) Release(ctx context.Context) { // Release only decrements a reference on s because s may be referenced in // the abstract socket namespace. - s.DecRef() + s.DecRef(ctx) } func (s *socketOpsCommon) isPacket() bool { @@ -184,7 +185,7 @@ func (s *SocketOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO, // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by // a transport.Endpoint. -func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *SocketOperations) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { return netstack.GetSockOpt(t, s, s.ep, linux.AF_UNIX, s.ep.Type(), level, name, outLen) } @@ -233,7 +234,7 @@ func (s *SocketOperations) Accept(t *kernel.Task, peerRequested bool, flags int, } ns := New(t, ep, s.stype) - defer ns.DecRef() + defer ns.DecRef(t) if flags&linux.SOCK_NONBLOCK != 0 { flags := ns.Flags() @@ -283,7 +284,7 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { if t.IsNetworkNamespaced() { return syserr.ErrInvalidEndpointState } - if err := t.AbstractSockets().Bind(p[1:], bep, s); err != nil { + if err := t.AbstractSockets().Bind(t, p[1:], bep, s); err != nil { // syserr.ErrPortInUse corresponds to EADDRINUSE. return syserr.ErrPortInUse } @@ -293,7 +294,7 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { var name string cwd := t.FSContext().WorkingDirectory() - defer cwd.DecRef() + defer cwd.DecRef(t) // Is there no slash at all? if !strings.Contains(p, "/") { @@ -301,7 +302,7 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { name = p } else { root := t.FSContext().RootDirectory() - defer root.DecRef() + defer root.DecRef(t) // Find the last path component, we know that something follows // that final slash, otherwise extractPath() would have failed. lastSlash := strings.LastIndex(p, "/") @@ -317,7 +318,7 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { // No path available. return syserr.ErrNoSuchFile } - defer d.DecRef() + defer d.DecRef(t) name = p[lastSlash+1:] } @@ -331,7 +332,7 @@ func (s *SocketOperations) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { if err != nil { return syserr.ErrPortInUse } - childDir.DecRef() + childDir.DecRef(t) } return nil @@ -377,9 +378,9 @@ func extractEndpoint(t *kernel.Task, sockaddr []byte) (transport.BoundEndpoint, FollowFinalSymlink: true, } ep, e := t.Kernel().VFS().BoundEndpointAt(t, t.Credentials(), &pop, &vfs.BoundEndpointOptions{path}) - root.DecRef() + root.DecRef(t) if relPath { - start.DecRef() + start.DecRef(t) } if e != nil { return nil, syserr.FromError(e) @@ -392,15 +393,15 @@ func extractEndpoint(t *kernel.Task, sockaddr []byte) (transport.BoundEndpoint, cwd := t.FSContext().WorkingDirectory() remainingTraversals := uint(fs.DefaultTraversalLimit) d, e := t.MountNamespace().FindInode(t, root, cwd, path, &remainingTraversals) - cwd.DecRef() - root.DecRef() + cwd.DecRef(t) + root.DecRef(t) if e != nil { return nil, syserr.FromError(e) } // Extract the endpoint if one is there. ep := d.Inode.BoundEndpoint(path) - d.DecRef() + d.DecRef(t) if ep == nil { // No socket! return nil, syserr.ErrConnectionRefused @@ -414,10 +415,21 @@ func (s *socketOpsCommon) Connect(t *kernel.Task, sockaddr []byte, blocking bool if err != nil { return err } - defer ep.Release() + defer ep.Release(t) // Connect the server endpoint. - return s.ep.Connect(t, ep) + err = s.ep.Connect(t, ep) + + if err == syserr.ErrWrongProtocolForSocket { + // Linux for abstract sockets returns ErrConnectionRefused + // instead of ErrWrongProtocolForSocket. + path, _ := extractPath(sockaddr) + if len(path) > 0 && path[0] == 0 { + err = syserr.ErrConnectionRefused + } + } + + return err } // Write implements fs.FileOperations.Write. @@ -448,15 +460,25 @@ func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []b To: nil, } if len(to) > 0 { - ep, err := extractEndpoint(t, to) - if err != nil { - return 0, err - } - defer ep.Release() - w.To = ep + switch s.stype { + case linux.SOCK_SEQPACKET: + to = nil + case linux.SOCK_STREAM: + if s.State() == linux.SS_CONNECTED { + return 0, syserr.ErrAlreadyConnected + } + return 0, syserr.ErrNotSupported + default: + ep, err := extractEndpoint(t, to) + if err != nil { + return 0, err + } + defer ep.Release(t) + w.To = ep - if ep.Passcred() && w.Control.Credentials == nil { - w.Control.Credentials = control.MakeCreds(t) + if ep.Passcred() && w.Control.Credentials == nil { + w.Control.Credentials = control.MakeCreds(t) + } } } diff --git a/pkg/sentry/socket/unix/unix_vfs2.go b/pkg/sentry/socket/unix/unix_vfs2.go index 45e109361..dfa25241a 100644 --- a/pkg/sentry/socket/unix/unix_vfs2.go +++ b/pkg/sentry/socket/unix/unix_vfs2.go @@ -19,6 +19,7 @@ import ( "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/fspath" "gvisor.dev/gvisor/pkg/sentry/arch" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/sockfs" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/socket" @@ -31,6 +32,7 @@ import ( "gvisor.dev/gvisor/pkg/tcpip" "gvisor.dev/gvisor/pkg/usermem" "gvisor.dev/gvisor/pkg/waiter" + "gvisor.dev/gvisor/tools/go_marshal/marshal" ) // SocketVFS2 implements socket.SocketVFS2 (and by extension, @@ -39,6 +41,7 @@ type SocketVFS2 struct { vfsfd vfs.FileDescription vfs.FileDescriptionDefaultImpl vfs.DentryMetadataFileDescriptionImpl + vfs.LockFD socketOpsCommon } @@ -51,7 +54,7 @@ func NewSockfsFile(t *kernel.Task, ep transport.Endpoint, stype linux.SockType) mnt := t.Kernel().SocketMount() d := sockfs.NewDentry(t.Credentials(), mnt) - fd, err := NewFileDescription(ep, stype, linux.O_RDWR, mnt, d) + fd, err := NewFileDescription(ep, stype, linux.O_RDWR, mnt, d, &vfs.FileLocks{}) if err != nil { return nil, syserr.FromError(err) } @@ -60,7 +63,7 @@ func NewSockfsFile(t *kernel.Task, ep transport.Endpoint, stype linux.SockType) // NewFileDescription creates and returns a socket file description // corresponding to the given mount and dentry. -func NewFileDescription(ep transport.Endpoint, stype linux.SockType, flags uint32, mnt *vfs.Mount, d *vfs.Dentry) (*vfs.FileDescription, error) { +func NewFileDescription(ep transport.Endpoint, stype linux.SockType, flags uint32, mnt *vfs.Mount, d *vfs.Dentry, locks *vfs.FileLocks) (*vfs.FileDescription, error) { // You can create AF_UNIX, SOCK_RAW sockets. They're the same as // SOCK_DGRAM and don't require CAP_NET_RAW. if stype == linux.SOCK_RAW { @@ -73,6 +76,7 @@ func NewFileDescription(ep transport.Endpoint, stype linux.SockType, flags uint3 stype: stype, }, } + sock.LockFD.Init(locks) vfsfd := &sock.vfsfd if err := vfsfd.Init(sock, flags, mnt, d, &vfs.FileDescriptionOptions{ DenyPRead: true, @@ -86,7 +90,7 @@ func NewFileDescription(ep transport.Endpoint, stype linux.SockType, flags uint3 // GetSockOpt implements the linux syscall getsockopt(2) for sockets backed by // a transport.Endpoint. -func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level int, name int, outPtr usermem.Addr, outLen int) (interface{}, *syserr.Error) { +func (s *SocketVFS2) GetSockOpt(t *kernel.Task, level, name int, outPtr usermem.Addr, outLen int) (marshal.Marshallable, *syserr.Error) { return netstack.GetSockOpt(t, s, s.ep, linux.AF_UNIX, s.ep.Type(), level, name, outLen) } @@ -132,7 +136,7 @@ func (s *SocketVFS2) Accept(t *kernel.Task, peerRequested bool, flags int, block if err != nil { return 0, nil, 0, err } - defer ns.DecRef() + defer ns.DecRef(t) if flags&linux.SOCK_NONBLOCK != 0 { ns.SetStatusFlags(t, t.Credentials(), linux.SOCK_NONBLOCK) @@ -179,19 +183,19 @@ func (s *SocketVFS2) Bind(t *kernel.Task, sockaddr []byte) *syserr.Error { if t.IsNetworkNamespaced() { return syserr.ErrInvalidEndpointState } - if err := t.AbstractSockets().Bind(p[1:], bep, s); err != nil { + if err := t.AbstractSockets().Bind(t, p[1:], bep, s); err != nil { // syserr.ErrPortInUse corresponds to EADDRINUSE. return syserr.ErrPortInUse } } else { path := fspath.Parse(p) root := t.FSContext().RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) start := root relPath := !path.Absolute if relPath { start = t.FSContext().WorkingDirectoryVFS2() - defer start.DecRef() + defer start.DecRef(t) } pop := vfs.PathOperation{ Root: root, @@ -297,6 +301,16 @@ func (s *SocketVFS2) SetSockOpt(t *kernel.Task, level int, name int, optVal []by return netstack.SetSockOpt(t, s, s.ep, level, name, optVal) } +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (s *SocketVFS2) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return s.Locks().LockPOSIX(ctx, &s.vfsfd, uid, t, start, length, whence, block) +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (s *SocketVFS2) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return s.Locks().UnlockPOSIX(ctx, &s.vfsfd, uid, start, length, whence) +} + // providerVFS2 is a unix domain socket provider for VFS2. type providerVFS2 struct{} @@ -319,7 +333,7 @@ func (*providerVFS2) Socket(t *kernel.Task, stype linux.SockType, protocol int) f, err := NewSockfsFile(t, ep, stype) if err != nil { - ep.Close() + ep.Close(t) return nil, err } return f, nil @@ -343,14 +357,14 @@ func (*providerVFS2) Pair(t *kernel.Task, stype linux.SockType, protocol int) (* ep1, ep2 := transport.NewPair(t, stype, t.Kernel()) s1, err := NewSockfsFile(t, ep1, stype) if err != nil { - ep1.Close() - ep2.Close() + ep1.Close(t) + ep2.Close(t) return nil, nil, err } s2, err := NewSockfsFile(t, ep2, stype) if err != nil { - s1.DecRef() - ep2.Close() + s1.DecRef(t) + ep2.Close(t) return nil, nil, err } diff --git a/pkg/sentry/state/state.go b/pkg/sentry/state/state.go index 9eb626b76..a06c9b8ab 100644 --- a/pkg/sentry/state/state.go +++ b/pkg/sentry/state/state.go @@ -60,6 +60,7 @@ type SaveOpts struct { func (opts SaveOpts) Save(k *kernel.Kernel, w *watchdog.Watchdog) error { log.Infof("Sandbox save started, pausing all tasks.") k.Pause() + k.ReceiveTaskStates() defer k.Unpause() defer log.Infof("Tasks resumed after save.") diff --git a/pkg/sentry/strace/epoll.go b/pkg/sentry/strace/epoll.go index a6e48b836..5d51a7792 100644 --- a/pkg/sentry/strace/epoll.go +++ b/pkg/sentry/strace/epoll.go @@ -50,10 +50,10 @@ func epollEvents(t *kernel.Task, eventsAddr usermem.Addr, numEvents, maxBytes ui sb.WriteString("...") break } - if _, ok := addr.AddLength(uint64(linux.SizeOfEpollEvent)); !ok { - fmt.Fprintf(&sb, "{error reading event at %#x: EFAULT}", addr) - continue - } + // Allowing addr to overflow is consistent with Linux, and harmless; if + // this isn't the last iteration of the loop, the next call to CopyIn + // will just fail with EFAULT. + addr, _ = addr.AddLength(uint64(linux.SizeOfEpollEvent)) } sb.WriteString("}") return sb.String() @@ -75,7 +75,7 @@ var epollEventEvents = abi.FlagSet{ {Flag: linux.EPOLLPRI, Name: "EPOLLPRI"}, {Flag: linux.EPOLLOUT, Name: "EPOLLOUT"}, {Flag: linux.EPOLLERR, Name: "EPOLLERR"}, - {Flag: linux.EPOLLHUP, Name: "EPULLHUP"}, + {Flag: linux.EPOLLHUP, Name: "EPOLLHUP"}, {Flag: linux.EPOLLRDNORM, Name: "EPOLLRDNORM"}, {Flag: linux.EPOLLRDBAND, Name: "EPOLLRDBAND"}, {Flag: linux.EPOLLWRNORM, Name: "EPOLLWRNORM"}, diff --git a/pkg/sentry/strace/socket.go b/pkg/sentry/strace/socket.go index c0512de89..b51c4c941 100644 --- a/pkg/sentry/strace/socket.go +++ b/pkg/sentry/strace/socket.go @@ -521,6 +521,7 @@ var sockOptNames = map[uint64]abi.ValueSet{ linux.IP_ROUTER_ALERT: "IP_ROUTER_ALERT", linux.IP_PKTOPTIONS: "IP_PKTOPTIONS", linux.IP_MTU: "IP_MTU", + linux.SO_ORIGINAL_DST: "SO_ORIGINAL_DST", }, linux.SOL_SOCKET: { linux.SO_ERROR: "SO_ERROR", diff --git a/pkg/sentry/strace/strace.go b/pkg/sentry/strace/strace.go index 68ca537c8..87b239730 100644 --- a/pkg/sentry/strace/strace.go +++ b/pkg/sentry/strace/strace.go @@ -147,14 +147,14 @@ func fd(t *kernel.Task, fd int32) string { root := t.FSContext().RootDirectory() if root != nil { - defer root.DecRef() + defer root.DecRef(t) } if fd == linux.AT_FDCWD { wd := t.FSContext().WorkingDirectory() var name string if wd != nil { - defer wd.DecRef() + defer wd.DecRef(t) name, _ = wd.FullName(root) } else { name = "(unknown cwd)" @@ -167,7 +167,7 @@ func fd(t *kernel.Task, fd int32) string { // Cast FD to uint64 to avoid printing negative hex. return fmt.Sprintf("%#x (bad FD)", uint64(fd)) } - defer file.DecRef() + defer file.DecRef(t) name, _ := file.Dirent.FullName(root) return fmt.Sprintf("%#x %s", fd, name) @@ -175,12 +175,12 @@ func fd(t *kernel.Task, fd int32) string { func fdVFS2(t *kernel.Task, fd int32) string { root := t.FSContext().RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) vfsObj := root.Mount().Filesystem().VirtualFilesystem() if fd == linux.AT_FDCWD { wd := t.FSContext().WorkingDirectoryVFS2() - defer wd.DecRef() + defer wd.DecRef(t) name, _ := vfsObj.PathnameWithDeleted(t, root, wd) return fmt.Sprintf("AT_FDCWD %s", name) @@ -191,7 +191,7 @@ func fdVFS2(t *kernel.Task, fd int32) string { // Cast FD to uint64 to avoid printing negative hex. return fmt.Sprintf("%#x (bad FD)", uint64(fd)) } - defer file.DecRef() + defer file.DecRef(t) name, _ := vfsObj.PathnameWithDeleted(t, root, file.VirtualDentry()) return fmt.Sprintf("%#x %s", fd, name) diff --git a/pkg/sentry/syscalls/epoll.go b/pkg/sentry/syscalls/epoll.go index d9fb808c0..d23a0068a 100644 --- a/pkg/sentry/syscalls/epoll.go +++ b/pkg/sentry/syscalls/epoll.go @@ -28,7 +28,7 @@ import ( // CreateEpoll implements the epoll_create(2) linux syscall. func CreateEpoll(t *kernel.Task, closeOnExec bool) (int32, error) { file := epoll.NewEventPoll(t) - defer file.DecRef() + defer file.DecRef(t) fd, err := t.NewFDFrom(0, file, kernel.FDFlags{ CloseOnExec: closeOnExec, @@ -47,14 +47,14 @@ func AddEpoll(t *kernel.Task, epfd int32, fd int32, flags epoll.EntryFlags, mask if epollfile == nil { return syserror.EBADF } - defer epollfile.DecRef() + defer epollfile.DecRef(t) // Get the target file id. file := t.GetFile(fd) if file == nil { return syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the epollPoll operations. e, ok := epollfile.FileOperations.(*epoll.EventPoll) @@ -73,14 +73,14 @@ func UpdateEpoll(t *kernel.Task, epfd int32, fd int32, flags epoll.EntryFlags, m if epollfile == nil { return syserror.EBADF } - defer epollfile.DecRef() + defer epollfile.DecRef(t) // Get the target file id. file := t.GetFile(fd) if file == nil { return syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the epollPoll operations. e, ok := epollfile.FileOperations.(*epoll.EventPoll) @@ -99,14 +99,14 @@ func RemoveEpoll(t *kernel.Task, epfd int32, fd int32) error { if epollfile == nil { return syserror.EBADF } - defer epollfile.DecRef() + defer epollfile.DecRef(t) // Get the target file id. file := t.GetFile(fd) if file == nil { return syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the epollPoll operations. e, ok := epollfile.FileOperations.(*epoll.EventPoll) @@ -115,7 +115,7 @@ func RemoveEpoll(t *kernel.Task, epfd int32, fd int32) error { } // Try to remove the entry. - return e.RemoveEntry(epoll.FileIdentifier{file, fd}) + return e.RemoveEntry(t, epoll.FileIdentifier{file, fd}) } // WaitEpoll implements the epoll_wait(2) linux syscall. @@ -125,7 +125,7 @@ func WaitEpoll(t *kernel.Task, fd int32, max int, timeout int) ([]linux.EpollEve if epollfile == nil { return nil, syserror.EBADF } - defer epollfile.DecRef() + defer epollfile.DecRef(t) // Extract the epollPoll operations. e, ok := epollfile.FileOperations.(*epoll.EventPoll) diff --git a/pkg/sentry/syscalls/linux/BUILD b/pkg/sentry/syscalls/linux/BUILD index 217fcfef2..4a9b04fd0 100644 --- a/pkg/sentry/syscalls/linux/BUILD +++ b/pkg/sentry/syscalls/linux/BUILD @@ -99,5 +99,7 @@ go_library( "//pkg/syserror", "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", ], ) diff --git a/pkg/sentry/syscalls/linux/linux64.go b/pkg/sentry/syscalls/linux/linux64.go index ea4f9b1a7..80c65164a 100644 --- a/pkg/sentry/syscalls/linux/linux64.go +++ b/pkg/sentry/syscalls/linux/linux64.go @@ -325,8 +325,8 @@ var AMD64 = &kernel.SyscallTable{ 270: syscalls.Supported("pselect", Pselect), 271: syscalls.Supported("ppoll", Ppoll), 272: syscalls.PartiallySupported("unshare", Unshare, "Mount, cgroup namespaces not supported. Network namespaces supported but must be empty.", nil), - 273: syscalls.Error("set_robust_list", syserror.ENOSYS, "Obsolete.", nil), - 274: syscalls.Error("get_robust_list", syserror.ENOSYS, "Obsolete.", nil), + 273: syscalls.Supported("set_robust_list", SetRobustList), + 274: syscalls.Supported("get_robust_list", GetRobustList), 275: syscalls.Supported("splice", Splice), 276: syscalls.Supported("tee", Tee), 277: syscalls.PartiallySupported("sync_file_range", SyncFileRange, "Full data flush is not guaranteed at this time.", nil), diff --git a/pkg/sentry/syscalls/linux/sys_aio.go b/pkg/sentry/syscalls/linux/sys_aio.go index d781d6a04..e9d64dec5 100644 --- a/pkg/sentry/syscalls/linux/sys_aio.go +++ b/pkg/sentry/syscalls/linux/sys_aio.go @@ -15,8 +15,8 @@ package linux import ( - "encoding/binary" - + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/kernel" @@ -27,59 +27,6 @@ import ( "gvisor.dev/gvisor/pkg/usermem" ) -// I/O commands. -const ( - _IOCB_CMD_PREAD = 0 - _IOCB_CMD_PWRITE = 1 - _IOCB_CMD_FSYNC = 2 - _IOCB_CMD_FDSYNC = 3 - _IOCB_CMD_NOOP = 6 - _IOCB_CMD_PREADV = 7 - _IOCB_CMD_PWRITEV = 8 -) - -// I/O flags. -const ( - _IOCB_FLAG_RESFD = 1 -) - -// ioCallback describes an I/O request. -// -// The priority field is currently ignored in the implementation below. Also -// note that the IOCB_FLAG_RESFD feature is not supported. -type ioCallback struct { - Data uint64 - Key uint32 - Reserved1 uint32 - - OpCode uint16 - ReqPrio int16 - FD int32 - - Buf uint64 - Bytes uint64 - Offset int64 - - Reserved2 uint64 - Flags uint32 - - // eventfd to signal if IOCB_FLAG_RESFD is set in flags. - ResFD int32 -} - -// ioEvent describes an I/O result. -// -// +stateify savable -type ioEvent struct { - Data uint64 - Obj uint64 - Result int64 - Result2 int64 -} - -// ioEventSize is the size of an ioEvent encoded. -var ioEventSize = binary.Size(ioEvent{}) - // IoSetup implements linux syscall io_setup(2). func IoSetup(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { nrEvents := args[0].Int() @@ -192,7 +139,7 @@ func IoGetevents(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S } } - ev := v.(*ioEvent) + ev := v.(*linux.IOEvent) // Copy out the result. if _, err := t.CopyOut(eventsAddr, ev); err != nil { @@ -204,7 +151,7 @@ func IoGetevents(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S } // Keep rolling. - eventsAddr += usermem.Addr(ioEventSize) + eventsAddr += usermem.Addr(linux.IOEventSize) } // Everything finished. @@ -231,7 +178,7 @@ func waitForRequest(ctx *mm.AIOContext, t *kernel.Task, haveDeadline bool, deadl } // memoryFor returns appropriate memory for the given callback. -func memoryFor(t *kernel.Task, cb *ioCallback) (usermem.IOSequence, error) { +func memoryFor(t *kernel.Task, cb *linux.IOCallback) (usermem.IOSequence, error) { bytes := int(cb.Bytes) if bytes < 0 { // Linux also requires that this field fit in ssize_t. @@ -242,17 +189,17 @@ func memoryFor(t *kernel.Task, cb *ioCallback) (usermem.IOSequence, error) { // we have no guarantee that t's AddressSpace will be active during the // I/O. switch cb.OpCode { - case _IOCB_CMD_PREAD, _IOCB_CMD_PWRITE: + case linux.IOCB_CMD_PREAD, linux.IOCB_CMD_PWRITE: return t.SingleIOSequence(usermem.Addr(cb.Buf), bytes, usermem.IOOpts{ AddressSpaceActive: false, }) - case _IOCB_CMD_PREADV, _IOCB_CMD_PWRITEV: + case linux.IOCB_CMD_PREADV, linux.IOCB_CMD_PWRITEV: return t.IovecsIOSequence(usermem.Addr(cb.Buf), bytes, usermem.IOOpts{ AddressSpaceActive: false, }) - case _IOCB_CMD_FSYNC, _IOCB_CMD_FDSYNC, _IOCB_CMD_NOOP: + case linux.IOCB_CMD_FSYNC, linux.IOCB_CMD_FDSYNC, linux.IOCB_CMD_NOOP: return usermem.IOSequence{}, nil default: @@ -261,70 +208,78 @@ func memoryFor(t *kernel.Task, cb *ioCallback) (usermem.IOSequence, error) { } } -func performCallback(t *kernel.Task, file *fs.File, cbAddr usermem.Addr, cb *ioCallback, ioseq usermem.IOSequence, ctx *mm.AIOContext, eventFile *fs.File) { - if ctx.Dead() { - ctx.CancelPendingRequest() - return - } - ev := &ioEvent{ - Data: cb.Data, - Obj: uint64(cbAddr), - } +// IoCancel implements linux syscall io_cancel(2). +// +// It is not presently supported (ENOSYS indicates no support on this +// architecture). +func IoCancel(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + return 0, nil, syserror.ENOSYS +} - // Construct a context.Context that will not be interrupted if t is - // interrupted. - c := t.AsyncContext() +// LINT.IfChange - var err error - switch cb.OpCode { - case _IOCB_CMD_PREAD, _IOCB_CMD_PREADV: - ev.Result, err = file.Preadv(c, ioseq, cb.Offset) - case _IOCB_CMD_PWRITE, _IOCB_CMD_PWRITEV: - ev.Result, err = file.Pwritev(c, ioseq, cb.Offset) - case _IOCB_CMD_FSYNC: - err = file.Fsync(c, 0, fs.FileMaxOffset, fs.SyncAll) - case _IOCB_CMD_FDSYNC: - err = file.Fsync(c, 0, fs.FileMaxOffset, fs.SyncData) - } +func getAIOCallback(t *kernel.Task, file *fs.File, cbAddr usermem.Addr, cb *linux.IOCallback, ioseq usermem.IOSequence, actx *mm.AIOContext, eventFile *fs.File) kernel.AIOCallback { + return func(ctx context.Context) { + if actx.Dead() { + actx.CancelPendingRequest() + return + } + ev := &linux.IOEvent{ + Data: cb.Data, + Obj: uint64(cbAddr), + } - // Update the result. - if err != nil { - err = handleIOError(t, ev.Result != 0 /* partial */, err, nil /* never interrupted */, "aio", file) - ev.Result = -int64(kernel.ExtractErrno(err, 0)) - } + var err error + switch cb.OpCode { + case linux.IOCB_CMD_PREAD, linux.IOCB_CMD_PREADV: + ev.Result, err = file.Preadv(ctx, ioseq, cb.Offset) + case linux.IOCB_CMD_PWRITE, linux.IOCB_CMD_PWRITEV: + ev.Result, err = file.Pwritev(ctx, ioseq, cb.Offset) + case linux.IOCB_CMD_FSYNC: + err = file.Fsync(ctx, 0, fs.FileMaxOffset, fs.SyncAll) + case linux.IOCB_CMD_FDSYNC: + err = file.Fsync(ctx, 0, fs.FileMaxOffset, fs.SyncData) + } + + // Update the result. + if err != nil { + err = handleIOError(t, ev.Result != 0 /* partial */, err, nil /* never interrupted */, "aio", file) + ev.Result = -int64(kernel.ExtractErrno(err, 0)) + } - file.DecRef() + file.DecRef(ctx) - // Queue the result for delivery. - ctx.FinishRequest(ev) + // Queue the result for delivery. + actx.FinishRequest(ev) - // Notify the event file if one was specified. This needs to happen - // *after* queueing the result to avoid racing with the thread we may - // wake up. - if eventFile != nil { - eventFile.FileOperations.(*eventfd.EventOperations).Signal(1) - eventFile.DecRef() + // Notify the event file if one was specified. This needs to happen + // *after* queueing the result to avoid racing with the thread we may + // wake up. + if eventFile != nil { + eventFile.FileOperations.(*eventfd.EventOperations).Signal(1) + eventFile.DecRef(ctx) + } } } // submitCallback processes a single callback. -func submitCallback(t *kernel.Task, id uint64, cb *ioCallback, cbAddr usermem.Addr) error { +func submitCallback(t *kernel.Task, id uint64, cb *linux.IOCallback, cbAddr usermem.Addr) error { file := t.GetFile(cb.FD) if file == nil { // File not found. return syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Was there an eventFD? Extract it. var eventFile *fs.File - if cb.Flags&_IOCB_FLAG_RESFD != 0 { + if cb.Flags&linux.IOCB_FLAG_RESFD != 0 { eventFile = t.GetFile(cb.ResFD) if eventFile == nil { // Bad FD. return syserror.EBADF } - defer eventFile.DecRef() + defer eventFile.DecRef(t) // Check that it is an eventfd. if _, ok := eventFile.FileOperations.(*eventfd.EventOperations); !ok { @@ -340,7 +295,7 @@ func submitCallback(t *kernel.Task, id uint64, cb *ioCallback, cbAddr usermem.Ad // Check offset for reads/writes. switch cb.OpCode { - case _IOCB_CMD_PREAD, _IOCB_CMD_PREADV, _IOCB_CMD_PWRITE, _IOCB_CMD_PWRITEV: + case linux.IOCB_CMD_PREAD, linux.IOCB_CMD_PREADV, linux.IOCB_CMD_PWRITE, linux.IOCB_CMD_PWRITEV: if cb.Offset < 0 { return syserror.EINVAL } @@ -366,7 +321,7 @@ func submitCallback(t *kernel.Task, id uint64, cb *ioCallback, cbAddr usermem.Ad // Perform the request asynchronously. file.IncRef() - fs.Async(func() { performCallback(t, file, cbAddr, cb, ioseq, ctx, eventFile) }) + t.QueueAIO(getAIOCallback(t, file, cbAddr, cb, ioseq, ctx, eventFile)) // All set. return nil @@ -395,7 +350,7 @@ func IoSubmit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc } // Copy in this callback. - var cb ioCallback + var cb linux.IOCallback cbAddr := usermem.Addr(t.Arch().Value(cbAddrNative)) if _, err := t.CopyIn(cbAddr, &cb); err != nil { @@ -424,10 +379,4 @@ func IoSubmit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc return uintptr(nrEvents), nil, nil } -// IoCancel implements linux syscall io_cancel(2). -// -// It is not presently supported (ENOSYS indicates no support on this -// architecture). -func IoCancel(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { - return 0, nil, syserror.ENOSYS -} +// LINT.ThenChange(vfs2/aio.go) diff --git a/pkg/sentry/syscalls/linux/sys_eventfd.go b/pkg/sentry/syscalls/linux/sys_eventfd.go index ed3413ca6..3b4f879e4 100644 --- a/pkg/sentry/syscalls/linux/sys_eventfd.go +++ b/pkg/sentry/syscalls/linux/sys_eventfd.go @@ -37,7 +37,7 @@ func Eventfd2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc event.SetFlags(fs.SettableFileFlags{ NonBlocking: flags&linux.EFD_NONBLOCK != 0, }) - defer event.DecRef() + defer event.DecRef(t) fd, err := t.NewFDFrom(0, event, kernel.FDFlags{ CloseOnExec: flags&linux.EFD_CLOEXEC != 0, diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go index 35a98212a..1bc9b184e 100644 --- a/pkg/sentry/syscalls/linux/sys_file.go +++ b/pkg/sentry/syscalls/linux/sys_file.go @@ -40,7 +40,7 @@ func fileOpAt(t *kernel.Task, dirFD int32, path string, fn func(root *fs.Dirent, // Common case: we are accessing a file in the root. root := t.FSContext().RootDirectory() err := fn(root, root, name, linux.MaxSymlinkTraversals) - root.DecRef() + root.DecRef(t) return err } else if dir == "." && dirFD == linux.AT_FDCWD { // Common case: we are accessing a file relative to the current @@ -48,8 +48,8 @@ func fileOpAt(t *kernel.Task, dirFD int32, path string, fn func(root *fs.Dirent, wd := t.FSContext().WorkingDirectory() root := t.FSContext().RootDirectory() err := fn(root, wd, name, linux.MaxSymlinkTraversals) - wd.DecRef() - root.DecRef() + wd.DecRef(t) + root.DecRef(t) return err } @@ -97,19 +97,19 @@ func fileOpOn(t *kernel.Task, dirFD int32, path string, resolve bool, fn func(ro } else { d, err = t.MountNamespace().FindLink(t, root, rel, path, &remainingTraversals) } - root.DecRef() + root.DecRef(t) if wd != nil { - wd.DecRef() + wd.DecRef(t) } if f != nil { - f.DecRef() + f.DecRef(t) } if err != nil { return err } err = fn(root, d, remainingTraversals) - d.DecRef() + d.DecRef(t) return err } @@ -186,7 +186,7 @@ func openAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint) (fd uint if err != nil { return syserror.ConvertIntr(err, kernel.ERESTARTSYS) } - defer file.DecRef() + defer file.DecRef(t) // Success. newFD, err := t.NewFDFrom(0, file, kernel.FDFlags{ @@ -242,7 +242,7 @@ func mknodAt(t *kernel.Task, dirFD int32, addr usermem.Addr, mode linux.FileMode if err != nil { return err } - file.DecRef() + file.DecRef(t) return nil case linux.ModeNamedPipe: @@ -332,7 +332,7 @@ func createAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint, mode l if err != nil { break } - defer found.DecRef() + defer found.DecRef(t) // We found something (possibly a symlink). If the // O_EXCL flag was passed, then we can immediately @@ -357,7 +357,7 @@ func createAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint, mode l resolved, err = found.Inode.Getlink(t) if err == nil { // No more resolution necessary. - defer resolved.DecRef() + defer resolved.DecRef(t) break } if err != fs.ErrResolveViaReadlink { @@ -384,7 +384,7 @@ func createAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint, mode l if err != nil { break } - defer newParent.DecRef() + defer newParent.DecRef(t) // Repeat the process with the parent and name of the // symlink target. @@ -416,7 +416,7 @@ func createAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint, mode l if err != nil { return syserror.ConvertIntr(err, kernel.ERESTARTSYS) } - defer newFile.DecRef() + defer newFile.DecRef(t) case syserror.ENOENT: // File does not exist. Proceed with creation. @@ -432,7 +432,7 @@ func createAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint, mode l // No luck, bail. return err } - defer newFile.DecRef() + defer newFile.DecRef(t) found = newFile.Dirent default: return err @@ -596,7 +596,7 @@ func Ioctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Shared flags between file and socket. switch request { @@ -671,9 +671,9 @@ func Getcwd(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal addr := args[0].Pointer() size := args[1].SizeT() cwd := t.FSContext().WorkingDirectory() - defer cwd.DecRef() + defer cwd.DecRef(t) root := t.FSContext().RootDirectory() - defer root.DecRef() + defer root.DecRef(t) // Get our fullname from the root and preprend unreachable if the root was // unreachable from our current dirent this is the same behavior as on linux. @@ -722,7 +722,7 @@ func Chroot(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal return err } - t.FSContext().SetRootDirectory(d) + t.FSContext().SetRootDirectory(t, d) return nil }) } @@ -747,7 +747,7 @@ func Chdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return err } - t.FSContext().SetWorkingDirectory(d) + t.FSContext().SetWorkingDirectory(t, d) return nil }) } @@ -760,7 +760,7 @@ func Fchdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Is it a directory? if !fs.IsDir(file.Dirent.Inode.StableAttr) { @@ -772,7 +772,7 @@ func Fchdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal return 0, nil, err } - t.FSContext().SetWorkingDirectory(file.Dirent) + t.FSContext().SetWorkingDirectory(t, file.Dirent) return 0, nil, nil } @@ -791,7 +791,7 @@ func Close(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) err := file.Flush(t) return 0, nil, handleIOError(t, false /* partial */, err, syserror.EINTR, "close", file) @@ -805,7 +805,7 @@ func Dup(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallCo if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) newFD, err := t.NewFDFrom(0, file, kernel.FDFlags{}) if err != nil { @@ -826,7 +826,7 @@ func Dup2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if oldFile == nil { return 0, nil, syserror.EBADF } - defer oldFile.DecRef() + defer oldFile.DecRef(t) return uintptr(newfd), nil, nil } @@ -850,7 +850,7 @@ func Dup3(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if oldFile == nil { return 0, nil, syserror.EBADF } - defer oldFile.DecRef() + defer oldFile.DecRef(t) err := t.NewFDAt(newfd, oldFile, kernel.FDFlags{CloseOnExec: flags&linux.O_CLOEXEC != 0}) if err != nil { @@ -900,14 +900,20 @@ func fGetOwn(t *kernel.Task, file *fs.File) int32 { // // If who is positive, it represents a PID. If negative, it represents a PGID. // If the PID or PGID is invalid, the owner is silently unset. -func fSetOwn(t *kernel.Task, file *fs.File, who int32) { +func fSetOwn(t *kernel.Task, file *fs.File, who int32) error { a := file.Async(fasync.New).(*fasync.FileAsync) if who < 0 { + // Check for overflow before flipping the sign. + if who-1 > who { + return syserror.EINVAL + } pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(-who)) a.SetOwnerProcessGroup(t, pg) + } else { + tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(who)) + a.SetOwnerThreadGroup(t, tg) } - tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(who)) - a.SetOwnerThreadGroup(t, tg) + return nil } // Fcntl implements linux syscall fcntl(2). @@ -919,7 +925,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) switch cmd { case linux.F_DUPFD, linux.F_DUPFD_CLOEXEC: @@ -935,10 +941,10 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return uintptr(flags.ToLinuxFDFlags()), nil, nil case linux.F_SETFD: flags := args[2].Uint() - t.FDTable().SetFlags(fd, kernel.FDFlags{ + err := t.FDTable().SetFlags(fd, kernel.FDFlags{ CloseOnExec: flags&linux.FD_CLOEXEC != 0, }) - return 0, nil, nil + return 0, nil, err case linux.F_GETFL: return uintptr(file.Flags().ToLinux()), nil, nil case linux.F_SETFL: @@ -998,9 +1004,6 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return 0, nil, err } - // The lock uid is that of the Task's FDTable. - lockUniqueID := lock.UniqueID(t.FDTable().ID()) - // These locks don't block; execute the non-blocking operation using the inode's lock // context directly. switch flock.Type { @@ -1010,12 +1013,12 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } if cmd == linux.F_SETLK { // Non-blocking lock, provide a nil lock.Blocker. - if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.ReadLock, rng, nil) { + if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.ReadLock, rng, nil) { return 0, nil, syserror.EAGAIN } } else { // Blocking lock, pass in the task to satisfy the lock.Blocker interface. - if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.ReadLock, rng, t) { + if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.ReadLock, rng, t) { return 0, nil, syserror.EINTR } } @@ -1026,18 +1029,18 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } if cmd == linux.F_SETLK { // Non-blocking lock, provide a nil lock.Blocker. - if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.WriteLock, rng, nil) { + if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.WriteLock, rng, nil) { return 0, nil, syserror.EAGAIN } } else { // Blocking lock, pass in the task to satisfy the lock.Blocker interface. - if !file.Dirent.Inode.LockCtx.Posix.LockRegion(lockUniqueID, lock.WriteLock, rng, t) { + if !file.Dirent.Inode.LockCtx.Posix.LockRegion(t.FDTable(), lock.WriteLock, rng, t) { return 0, nil, syserror.EINTR } } return 0, nil, nil case linux.F_UNLCK: - file.Dirent.Inode.LockCtx.Posix.UnlockRegion(lockUniqueID, rng) + file.Dirent.Inode.LockCtx.Posix.UnlockRegion(t.FDTable(), rng) return 0, nil, nil default: return 0, nil, syserror.EINVAL @@ -1045,8 +1048,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall case linux.F_GETOWN: return uintptr(fGetOwn(t, file)), nil, nil case linux.F_SETOWN: - fSetOwn(t, file, args[2].Int()) - return 0, nil, nil + return 0, nil, fSetOwn(t, file, args[2].Int()) case linux.F_GETOWN_EX: addr := args[2].Pointer() owner := fGetOwnEx(t, file) @@ -1055,7 +1057,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall case linux.F_SETOWN_EX: addr := args[2].Pointer() var owner linux.FOwnerEx - n, err := t.CopyIn(addr, &owner) + _, err := t.CopyIn(addr, &owner) if err != nil { return 0, nil, err } @@ -1067,21 +1069,21 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return 0, nil, syserror.ESRCH } a.SetOwnerTask(t, task) - return uintptr(n), nil, nil + return 0, nil, nil case linux.F_OWNER_PID: tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(owner.PID)) if tg == nil { return 0, nil, syserror.ESRCH } a.SetOwnerThreadGroup(t, tg) - return uintptr(n), nil, nil + return 0, nil, nil case linux.F_OWNER_PGRP: pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(owner.PID)) if pg == nil { return 0, nil, syserror.ESRCH } a.SetOwnerProcessGroup(t, pg) - return uintptr(n), nil, nil + return 0, nil, nil default: return 0, nil, syserror.EINVAL } @@ -1114,17 +1116,6 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } } -// LINT.ThenChange(vfs2/fd.go) - -const ( - _FADV_NORMAL = 0 - _FADV_RANDOM = 1 - _FADV_SEQUENTIAL = 2 - _FADV_WILLNEED = 3 - _FADV_DONTNEED = 4 - _FADV_NOREUSE = 5 -) - // Fadvise64 implements linux syscall fadvise64(2). // This implementation currently ignores the provided advice. func Fadvise64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { @@ -1141,7 +1132,7 @@ func Fadvise64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // If the FD refers to a pipe or FIFO, return error. if fs.IsPipe(file.Dirent.Inode.StableAttr) { @@ -1149,12 +1140,12 @@ func Fadvise64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys } switch advice { - case _FADV_NORMAL: - case _FADV_RANDOM: - case _FADV_SEQUENTIAL: - case _FADV_WILLNEED: - case _FADV_DONTNEED: - case _FADV_NOREUSE: + case linux.POSIX_FADV_NORMAL: + case linux.POSIX_FADV_RANDOM: + case linux.POSIX_FADV_SEQUENTIAL: + case linux.POSIX_FADV_WILLNEED: + case linux.POSIX_FADV_DONTNEED: + case linux.POSIX_FADV_NOREUSE: default: return 0, nil, syserror.EINVAL } @@ -1163,8 +1154,6 @@ func Fadvise64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys return 0, nil, nil } -// LINT.IfChange - func mkdirAt(t *kernel.Task, dirFD int32, addr usermem.Addr, mode linux.FileMode) error { path, _, err := copyInPath(t, addr, false /* allowEmpty */) if err != nil { @@ -1182,7 +1171,7 @@ func mkdirAt(t *kernel.Task, dirFD int32, addr usermem.Addr, mode linux.FileMode switch err { case nil: // The directory existed. - defer f.DecRef() + defer f.DecRef(t) return syserror.EEXIST case syserror.EACCES: // Permission denied while walking to the directory. @@ -1360,7 +1349,7 @@ func linkAt(t *kernel.Task, oldDirFD int32, oldAddr usermem.Addr, newDirFD int32 if target == nil { return syserror.EBADF } - defer target.DecRef() + defer target.DecRef(t) if err := mayLinkAt(t, target.Dirent.Inode); err != nil { return err } @@ -1613,7 +1602,7 @@ func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Reject truncation if the file flags do not permit this operation. // This is different from truncate(2) above. @@ -1741,7 +1730,7 @@ func chownAt(t *kernel.Task, fd int32, addr usermem.Addr, resolve, allowEmpty bo if file == nil { return syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return chown(t, file.Dirent, uid, gid) } @@ -1779,7 +1768,7 @@ func Fchown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, chown(t, file.Dirent, uid, gid) } @@ -1844,7 +1833,7 @@ func Fchmod(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, chmod(t, file.Dirent, mode) } @@ -1904,10 +1893,10 @@ func utimes(t *kernel.Task, dirFD int32, addr usermem.Addr, ts fs.TimeSpec, reso if f == nil { return syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) root := t.FSContext().RootDirectory() - defer root.DecRef() + defer root.DecRef(t) return setTimestamp(root, f.Dirent, linux.MaxSymlinkTraversals) } @@ -2099,7 +2088,7 @@ func Fallocate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) if offset < 0 || length <= 0 { return 0, nil, syserror.EINVAL @@ -2152,27 +2141,11 @@ func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall // flock(2): EBADF fd is not an open file descriptor. return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) nonblocking := operation&linux.LOCK_NB != 0 operation &^= linux.LOCK_NB - // flock(2): - // Locks created by flock() are associated with an open file table entry. This means that - // duplicate file descriptors (created by, for example, fork(2) or dup(2)) refer to the - // same lock, and this lock may be modified or released using any of these descriptors. Furthermore, - // the lock is released either by an explicit LOCK_UN operation on any of these duplicate - // descriptors, or when all such descriptors have been closed. - // - // If a process uses open(2) (or similar) to obtain more than one descriptor for the same file, - // these descriptors are treated independently by flock(). An attempt to lock the file using - // one of these file descriptors may be denied by a lock that the calling process has already placed via - // another descriptor. - // - // We use the File UniqueID as the lock UniqueID because it needs to reference the same lock across dup(2) - // and fork(2). - lockUniqueID := lock.UniqueID(file.UniqueID) - // A BSD style lock spans the entire file. rng := lock.LockRange{ Start: 0, @@ -2183,29 +2156,29 @@ func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall case linux.LOCK_EX: if nonblocking { // Since we're nonblocking we pass a nil lock.Blocker implementation. - if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.WriteLock, rng, nil) { + if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.WriteLock, rng, nil) { return 0, nil, syserror.EWOULDBLOCK } } else { // Because we're blocking we will pass the task to satisfy the lock.Blocker interface. - if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.WriteLock, rng, t) { + if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.WriteLock, rng, t) { return 0, nil, syserror.EINTR } } case linux.LOCK_SH: if nonblocking { // Since we're nonblocking we pass a nil lock.Blocker implementation. - if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.ReadLock, rng, nil) { + if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.ReadLock, rng, nil) { return 0, nil, syserror.EWOULDBLOCK } } else { // Because we're blocking we will pass the task to satisfy the lock.Blocker interface. - if !file.Dirent.Inode.LockCtx.BSD.LockRegion(lockUniqueID, lock.ReadLock, rng, t) { + if !file.Dirent.Inode.LockCtx.BSD.LockRegion(file, lock.ReadLock, rng, t) { return 0, nil, syserror.EINTR } } case linux.LOCK_UN: - file.Dirent.Inode.LockCtx.BSD.UnlockRegion(lockUniqueID, rng) + file.Dirent.Inode.LockCtx.BSD.UnlockRegion(file, rng) default: // flock(2): EINVAL operation is invalid. return 0, nil, syserror.EINVAL @@ -2251,8 +2224,8 @@ func MemfdCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S return 0, nil, err } - defer dirent.DecRef() - defer file.DecRef() + defer dirent.DecRef(t) + defer file.DecRef(t) newFD, err := t.NewFDFrom(0, file, kernel.FDFlags{ CloseOnExec: cloExec, diff --git a/pkg/sentry/syscalls/linux/sys_futex.go b/pkg/sentry/syscalls/linux/sys_futex.go index b68261f72..9d1b2edb1 100644 --- a/pkg/sentry/syscalls/linux/sys_futex.go +++ b/pkg/sentry/syscalls/linux/sys_futex.go @@ -73,7 +73,7 @@ func futexWaitAbsolute(t *kernel.Task, clockRealtime bool, ts linux.Timespec, fo err = t.BlockWithDeadline(w.C, true, ktime.FromTimespec(ts)) } - t.Futex().WaitComplete(w) + t.Futex().WaitComplete(w, t) return 0, syserror.ConvertIntr(err, kernel.ERESTARTSYS) } @@ -95,7 +95,7 @@ func futexWaitDuration(t *kernel.Task, duration time.Duration, forever bool, add } remaining, err := t.BlockWithTimeout(w.C, !forever, duration) - t.Futex().WaitComplete(w) + t.Futex().WaitComplete(w, t) if err == nil { return 0, nil } @@ -148,7 +148,7 @@ func futexLockPI(t *kernel.Task, ts linux.Timespec, forever bool, addr usermem.A timer.Destroy() } - t.Futex().WaitComplete(w) + t.Futex().WaitComplete(w, t) return syserror.ConvertIntr(err, kernel.ERESTARTSYS) } @@ -198,7 +198,7 @@ func Futex(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall switch cmd { case linux.FUTEX_WAIT: // WAIT uses a relative timeout. - mask = ^uint32(0) + mask = linux.FUTEX_BITSET_MATCH_ANY var timeoutDur time.Duration if !forever { timeoutDur = time.Duration(timespec.ToNsecCapped()) * time.Nanosecond @@ -286,3 +286,49 @@ func Futex(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return 0, nil, syserror.ENOSYS } } + +// SetRobustList implements linux syscall set_robust_list(2). +func SetRobustList(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + // Despite the syscall using the name 'pid' for this variable, it is + // very much a tid. + head := args[0].Pointer() + length := args[1].SizeT() + + if length != uint(linux.SizeOfRobustListHead) { + return 0, nil, syserror.EINVAL + } + t.SetRobustList(head) + return 0, nil, nil +} + +// GetRobustList implements linux syscall get_robust_list(2). +func GetRobustList(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + // Despite the syscall using the name 'pid' for this variable, it is + // very much a tid. + tid := args[0].Int() + head := args[1].Pointer() + size := args[2].Pointer() + + if tid < 0 { + return 0, nil, syserror.EINVAL + } + + ot := t + if tid != 0 { + if ot = t.PIDNamespace().TaskWithID(kernel.ThreadID(tid)); ot == nil { + return 0, nil, syserror.ESRCH + } + } + + // Copy out head pointer. + if _, err := t.CopyOut(head, uint64(ot.GetRobustList())); err != nil { + return 0, nil, err + } + + // Copy out size, which is a constant. + if _, err := t.CopyOut(size, uint64(linux.SizeOfRobustListHead)); err != nil { + return 0, nil, err + } + + return 0, nil, nil +} diff --git a/pkg/sentry/syscalls/linux/sys_getdents.go b/pkg/sentry/syscalls/linux/sys_getdents.go index b126fecc0..f5699e55d 100644 --- a/pkg/sentry/syscalls/linux/sys_getdents.go +++ b/pkg/sentry/syscalls/linux/sys_getdents.go @@ -68,7 +68,7 @@ func getdents(t *kernel.Task, fd int32, addr usermem.Addr, size int, f func(*dir if dir == nil { return 0, syserror.EBADF } - defer dir.DecRef() + defer dir.DecRef(t) w := &usermem.IOReadWriter{ Ctx: t, diff --git a/pkg/sentry/syscalls/linux/sys_inotify.go b/pkg/sentry/syscalls/linux/sys_inotify.go index b2c7b3444..cf47bb9dd 100644 --- a/pkg/sentry/syscalls/linux/sys_inotify.go +++ b/pkg/sentry/syscalls/linux/sys_inotify.go @@ -40,7 +40,7 @@ func InotifyInit1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel. NonBlocking: flags&linux.IN_NONBLOCK != 0, } n := fs.NewFile(t, dirent, fileFlags, fs.NewInotify(t)) - defer n.DecRef() + defer n.DecRef(t) fd, err := t.NewFDFrom(0, n, kernel.FDFlags{ CloseOnExec: flags&linux.IN_CLOEXEC != 0, @@ -71,7 +71,7 @@ func fdToInotify(t *kernel.Task, fd int32) (*fs.Inotify, *fs.File, error) { ino, ok := file.FileOperations.(*fs.Inotify) if !ok { // Not an inotify fd. - file.DecRef() + file.DecRef(t) return nil, nil, syserror.EINVAL } @@ -98,7 +98,7 @@ func InotifyAddWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kern if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) path, _, err := copyInPath(t, addr, false /* allowEmpty */) if err != nil { @@ -128,6 +128,6 @@ func InotifyRmWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne if err != nil { return 0, nil, err } - defer file.DecRef() - return 0, nil, ino.RmWatch(wd) + defer file.DecRef(t) + return 0, nil, ino.RmWatch(t, wd) } diff --git a/pkg/sentry/syscalls/linux/sys_lseek.go b/pkg/sentry/syscalls/linux/sys_lseek.go index 3f7691eae..1c38f8f4f 100644 --- a/pkg/sentry/syscalls/linux/sys_lseek.go +++ b/pkg/sentry/syscalls/linux/sys_lseek.go @@ -33,7 +33,7 @@ func Lseek(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) var sw fs.SeekWhence switch whence { diff --git a/pkg/sentry/syscalls/linux/sys_mmap.go b/pkg/sentry/syscalls/linux/sys_mmap.go index 91694d374..72786b032 100644 --- a/pkg/sentry/syscalls/linux/sys_mmap.go +++ b/pkg/sentry/syscalls/linux/sys_mmap.go @@ -75,7 +75,7 @@ func Mmap(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC } defer func() { if opts.MappingIdentity != nil { - opts.MappingIdentity.DecRef() + opts.MappingIdentity.DecRef(t) } }() @@ -85,7 +85,7 @@ func Mmap(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) flags := file.Flags() // mmap unconditionally requires that the FD is readable. diff --git a/pkg/sentry/syscalls/linux/sys_mount.go b/pkg/sentry/syscalls/linux/sys_mount.go index eb5ff48f5..bd0633564 100644 --- a/pkg/sentry/syscalls/linux/sys_mount.go +++ b/pkg/sentry/syscalls/linux/sys_mount.go @@ -115,7 +115,7 @@ func Mount(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall }); err != nil { // Something went wrong. Drop our ref on rootInode before // returning the error. - rootInode.DecRef() + rootInode.DecRef(t) return 0, nil, err } diff --git a/pkg/sentry/syscalls/linux/sys_pipe.go b/pkg/sentry/syscalls/linux/sys_pipe.go index 43c510930..3149e4aad 100644 --- a/pkg/sentry/syscalls/linux/sys_pipe.go +++ b/pkg/sentry/syscalls/linux/sys_pipe.go @@ -34,10 +34,10 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags uint) (uintptr, error) { r, w := pipe.NewConnectedPipe(t, pipe.DefaultPipeSize, usermem.PageSize) r.SetFlags(linuxToFlags(flags).Settable()) - defer r.DecRef() + defer r.DecRef(t) w.SetFlags(linuxToFlags(flags).Settable()) - defer w.DecRef() + defer w.DecRef(t) fds, err := t.NewFDs(0, []*fs.File{r, w}, kernel.FDFlags{ CloseOnExec: flags&linux.O_CLOEXEC != 0, @@ -49,7 +49,7 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags uint) (uintptr, error) { if _, err := t.CopyOut(addr, fds); err != nil { for _, fd := range fds { if file, _ := t.FDTable().Remove(fd); file != nil { - file.DecRef() + file.DecRef(t) } } return 0, err diff --git a/pkg/sentry/syscalls/linux/sys_poll.go b/pkg/sentry/syscalls/linux/sys_poll.go index f0198141c..3435bdf77 100644 --- a/pkg/sentry/syscalls/linux/sys_poll.go +++ b/pkg/sentry/syscalls/linux/sys_poll.go @@ -70,7 +70,7 @@ func initReadiness(t *kernel.Task, pfd *linux.PollFD, state *pollState, ch chan } if ch == nil { - defer file.DecRef() + defer file.DecRef(t) } else { state.file = file state.waiter, _ = waiter.NewChannelEntry(ch) @@ -82,11 +82,11 @@ func initReadiness(t *kernel.Task, pfd *linux.PollFD, state *pollState, ch chan } // releaseState releases all the pollState in "state". -func releaseState(state []pollState) { +func releaseState(t *kernel.Task, state []pollState) { for i := range state { if state[i].file != nil { state[i].file.EventUnregister(&state[i].waiter) - state[i].file.DecRef() + state[i].file.DecRef(t) } } } @@ -107,7 +107,7 @@ func pollBlock(t *kernel.Task, pfd []linux.PollFD, timeout time.Duration) (time. // result, we stop registering for events but still go through all files // to get their ready masks. state := make([]pollState, len(pfd)) - defer releaseState(state) + defer releaseState(t, state) n := uintptr(0) for i := range pfd { initReadiness(t, &pfd[i], &state[i], ch) @@ -266,7 +266,7 @@ func doSelect(t *kernel.Task, nfds int, readFDs, writeFDs, exceptFDs usermem.Add if file == nil { return 0, syserror.EBADF } - file.DecRef() + file.DecRef(t) var mask int16 if (rV & m) != 0 { diff --git a/pkg/sentry/syscalls/linux/sys_prctl.go b/pkg/sentry/syscalls/linux/sys_prctl.go index f92bf8096..64a725296 100644 --- a/pkg/sentry/syscalls/linux/sys_prctl.go +++ b/pkg/sentry/syscalls/linux/sys_prctl.go @@ -128,7 +128,7 @@ func Prctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // They trying to set exe to a non-file? if !fs.IsFile(file.Dirent.Inode.StableAttr) { @@ -136,7 +136,7 @@ func Prctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } // Set the underlying executable. - t.MemoryManager().SetExecutable(fsbridge.NewFSFile(file)) + t.MemoryManager().SetExecutable(t, fsbridge.NewFSFile(file)) case linux.PR_SET_MM_AUXV, linux.PR_SET_MM_START_CODE, diff --git a/pkg/sentry/syscalls/linux/sys_read.go b/pkg/sentry/syscalls/linux/sys_read.go index 071b4bacc..3bbc3fa4b 100644 --- a/pkg/sentry/syscalls/linux/sys_read.go +++ b/pkg/sentry/syscalls/linux/sys_read.go @@ -48,7 +48,7 @@ func Read(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the file is readable. if !file.Flags().Read { @@ -84,7 +84,7 @@ func Readahead(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the file is readable. if !file.Flags().Read { @@ -118,7 +118,7 @@ func Pread64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate and does not overflow. if offset < 0 || offset+int64(size) < 0 { @@ -164,7 +164,7 @@ func Readv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the file is readable. if !file.Flags().Read { @@ -195,7 +195,7 @@ func Preadv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < 0 { @@ -244,7 +244,7 @@ func Preadv2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < -1 { diff --git a/pkg/sentry/syscalls/linux/sys_shm.go b/pkg/sentry/syscalls/linux/sys_shm.go index 4a8bc24a2..f0ae8fa8e 100644 --- a/pkg/sentry/syscalls/linux/sys_shm.go +++ b/pkg/sentry/syscalls/linux/sys_shm.go @@ -39,7 +39,7 @@ func Shmget(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, err } - defer segment.DecRef() + defer segment.DecRef(t) return uintptr(segment.ID), nil, nil } @@ -66,7 +66,7 @@ func Shmat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if err != nil { return 0, nil, syserror.EINVAL } - defer segment.DecRef() + defer segment.DecRef(t) opts, err := segment.ConfigureAttach(t, addr, shm.AttachOpts{ Execute: flag&linux.SHM_EXEC == linux.SHM_EXEC, @@ -108,7 +108,7 @@ func Shmctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, syserror.EINVAL } - defer segment.DecRef() + defer segment.DecRef(t) stat, err := segment.IPCStat(t) if err == nil { @@ -132,7 +132,7 @@ func Shmctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, syserror.EINVAL } - defer segment.DecRef() + defer segment.DecRef(t) switch cmd { case linux.IPC_SET: @@ -145,7 +145,7 @@ func Shmctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal return 0, nil, err case linux.IPC_RMID: - segment.MarkDestroyed() + segment.MarkDestroyed(t) return 0, nil, nil case linux.SHM_LOCK, linux.SHM_UNLOCK: diff --git a/pkg/sentry/syscalls/linux/sys_signal.go b/pkg/sentry/syscalls/linux/sys_signal.go index d2b0012ae..20cb1a5cb 100644 --- a/pkg/sentry/syscalls/linux/sys_signal.go +++ b/pkg/sentry/syscalls/linux/sys_signal.go @@ -536,7 +536,7 @@ func sharedSignalfd(t *kernel.Task, fd int32, sigset usermem.Addr, sigsetsize ui if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Is this a signalfd? if s, ok := file.FileOperations.(*signalfd.SignalOperations); ok { @@ -553,7 +553,7 @@ func sharedSignalfd(t *kernel.Task, fd int32, sigset usermem.Addr, sigsetsize ui if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) // Set appropriate flags. file.SetFlags(fs.SettableFileFlags{ diff --git a/pkg/sentry/syscalls/linux/sys_socket.go b/pkg/sentry/syscalls/linux/sys_socket.go index 0760af77b..fec1c1974 100644 --- a/pkg/sentry/syscalls/linux/sys_socket.go +++ b/pkg/sentry/syscalls/linux/sys_socket.go @@ -29,6 +29,8 @@ import ( "gvisor.dev/gvisor/pkg/syserr" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) // LINT.IfChange @@ -198,7 +200,7 @@ func Socket(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal s.SetFlags(fs.SettableFileFlags{ NonBlocking: stype&linux.SOCK_NONBLOCK != 0, }) - defer s.DecRef() + defer s.DecRef(t) fd, err := t.NewFDFrom(0, s, kernel.FDFlags{ CloseOnExec: stype&linux.SOCK_CLOEXEC != 0, @@ -233,8 +235,8 @@ func SocketPair(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy } s1.SetFlags(fileFlags) s2.SetFlags(fileFlags) - defer s1.DecRef() - defer s2.DecRef() + defer s1.DecRef(t) + defer s2.DecRef(t) // Create the FDs for the sockets. fds, err := t.NewFDs(0, []*fs.File{s1, s2}, kernel.FDFlags{ @@ -248,7 +250,7 @@ func SocketPair(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if _, err := t.CopyOut(socks, fds); err != nil { for _, fd := range fds { if file, _ := t.FDTable().Remove(fd); file != nil { - file.DecRef() + file.DecRef(t) } } return 0, nil, err @@ -268,7 +270,7 @@ func Connect(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -299,7 +301,7 @@ func accept(t *kernel.Task, fd int32, addr usermem.Addr, addrLen usermem.Addr, f if file == nil { return 0, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -358,7 +360,7 @@ func Bind(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -385,7 +387,7 @@ func Listen(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -414,7 +416,7 @@ func Shutdown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -445,7 +447,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -474,7 +476,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy } if v != nil { - if _, err := t.CopyOut(optValAddr, v); err != nil { + if _, err := v.CopyOut(t, optValAddr); err != nil { return 0, nil, err } } @@ -484,7 +486,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy // getSockOpt tries to handle common socket options, or dispatches to a specific // socket implementation. -func getSockOpt(t *kernel.Task, s socket.Socket, level, name int, optValAddr usermem.Addr, len int) (interface{}, *syserr.Error) { +func getSockOpt(t *kernel.Task, s socket.Socket, level, name int, optValAddr usermem.Addr, len int) (marshal.Marshallable, *syserr.Error) { if level == linux.SOL_SOCKET { switch name { case linux.SO_TYPE, linux.SO_DOMAIN, linux.SO_PROTOCOL: @@ -496,13 +498,16 @@ func getSockOpt(t *kernel.Task, s socket.Socket, level, name int, optValAddr use switch name { case linux.SO_TYPE: _, skType, _ := s.Type() - return int32(skType), nil + v := primitive.Int32(skType) + return &v, nil case linux.SO_DOMAIN: family, _, _ := s.Type() - return int32(family), nil + v := primitive.Int32(family) + return &v, nil case linux.SO_PROTOCOL: _, _, protocol := s.Type() - return int32(protocol), nil + v := primitive.Int32(protocol) + return &v, nil } } @@ -524,7 +529,7 @@ func SetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -539,7 +544,7 @@ func SetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy return 0, nil, syserror.EINVAL } buf := t.CopyScratchBuffer(int(optLen)) - if _, err := t.CopyIn(optValAddr, &buf); err != nil { + if _, err := t.CopyInBytes(optValAddr, buf); err != nil { return 0, nil, err } @@ -562,7 +567,7 @@ func GetSockName(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -590,7 +595,7 @@ func GetPeerName(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -623,7 +628,7 @@ func RecvMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -676,7 +681,7 @@ func RecvMMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -770,7 +775,7 @@ func recvSingleMsg(t *kernel.Task, s socket.Socket, msgPtr usermem.Addr, flags i } if !cms.Unix.Empty() { mflags |= linux.MSG_CTRUNC - cms.Release() + cms.Release(t) } if int(msg.Flags) != mflags { @@ -790,7 +795,7 @@ func recvSingleMsg(t *kernel.Task, s socket.Socket, msgPtr usermem.Addr, flags i if e != nil { return 0, syserror.ConvertIntr(e.ToError(), kernel.ERESTARTSYS) } - defer cms.Release() + defer cms.Release(t) controlData := make([]byte, 0, msg.ControlLen) controlData = control.PackControlMessages(t, cms, controlData) @@ -846,7 +851,7 @@ func recvFrom(t *kernel.Task, fd int32, bufPtr usermem.Addr, bufLen uint64, flag if file == nil { return 0, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -875,7 +880,7 @@ func recvFrom(t *kernel.Task, fd int32, bufPtr usermem.Addr, bufLen uint64, flag } n, _, sender, senderLen, cm, e := s.RecvMsg(t, dst, int(flags), haveDeadline, deadline, nameLenPtr != 0, 0) - cm.Release() + cm.Release(t) if e != nil { return 0, syserror.ConvertIntr(e.ToError(), kernel.ERESTARTSYS) } @@ -919,7 +924,7 @@ func SendMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -957,7 +962,7 @@ func SendMMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) @@ -1061,7 +1066,7 @@ func sendSingleMsg(t *kernel.Task, s socket.Socket, file *fs.File, msgPtr userme n, e := s.SendMsg(t, src, to, int(flags), haveDeadline, deadline, controlMessages) err = handleIOError(t, n != 0, e.ToError(), kernel.ERESTARTSYS, "sendmsg", file) if err != nil { - controlMessages.Release() + controlMessages.Release(t) } return uintptr(n), err } @@ -1079,7 +1084,7 @@ func sendTo(t *kernel.Task, fd int32, bufPtr usermem.Addr, bufLen uint64, flags if file == nil { return 0, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.FileOperations.(socket.Socket) diff --git a/pkg/sentry/syscalls/linux/sys_splice.go b/pkg/sentry/syscalls/linux/sys_splice.go index 39f2b79ec..b8846a10a 100644 --- a/pkg/sentry/syscalls/linux/sys_splice.go +++ b/pkg/sentry/syscalls/linux/sys_splice.go @@ -80,6 +80,12 @@ func doSplice(t *kernel.Task, outFile, inFile *fs.File, opts fs.SpliceOpts, nonB } } + if total > 0 { + // On Linux, inotify behavior is not very consistent with splice(2). We try + // our best to emulate Linux for very basic calls to splice, where for some + // reason, events are generated for output files, but not input files. + outFile.Dirent.InotifyEvent(linux.IN_MODIFY, 0) + } return total, err } @@ -95,7 +101,7 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if inFile == nil { return 0, nil, syserror.EBADF } - defer inFile.DecRef() + defer inFile.DecRef(t) if !inFile.Flags().Read { return 0, nil, syserror.EBADF @@ -105,7 +111,7 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if outFile == nil { return 0, nil, syserror.EBADF } - defer outFile.DecRef() + defer outFile.DecRef(t) if !outFile.Flags().Write { return 0, nil, syserror.EBADF @@ -186,13 +192,13 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if outFile == nil { return 0, nil, syserror.EBADF } - defer outFile.DecRef() + defer outFile.DecRef(t) inFile := t.GetFile(inFD) if inFile == nil { return 0, nil, syserror.EBADF } - defer inFile.DecRef() + defer inFile.DecRef(t) // The operation is non-blocking if anything is non-blocking. // @@ -294,13 +300,13 @@ func Tee(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallCo if outFile == nil { return 0, nil, syserror.EBADF } - defer outFile.DecRef() + defer outFile.DecRef(t) inFile := t.GetFile(inFD) if inFile == nil { return 0, nil, syserror.EBADF } - defer inFile.DecRef() + defer inFile.DecRef(t) // All files must be pipes. if !fs.IsPipe(inFile.Dirent.Inode.StableAttr) || !fs.IsPipe(outFile.Dirent.Inode.StableAttr) { diff --git a/pkg/sentry/syscalls/linux/sys_stat.go b/pkg/sentry/syscalls/linux/sys_stat.go index 46ebf27a2..a5826f2dd 100644 --- a/pkg/sentry/syscalls/linux/sys_stat.go +++ b/pkg/sentry/syscalls/linux/sys_stat.go @@ -58,7 +58,7 @@ func Fstatat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, fstat(t, file, statAddr) } @@ -100,7 +100,7 @@ func Fstat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, fstat(t, file, statAddr) } @@ -158,7 +158,7 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) uattr, err := file.UnstableAttr(t) if err != nil { return 0, nil, err @@ -249,7 +249,7 @@ func Fstatfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, statfsImpl(t, file.Dirent, statfsAddr) } diff --git a/pkg/sentry/syscalls/linux/sys_sync.go b/pkg/sentry/syscalls/linux/sys_sync.go index 5ad465ae3..f2c0e5069 100644 --- a/pkg/sentry/syscalls/linux/sys_sync.go +++ b/pkg/sentry/syscalls/linux/sys_sync.go @@ -39,7 +39,7 @@ func Syncfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Use "sync-the-world" for now, it's guaranteed that fd is at least // on the root filesystem. @@ -54,7 +54,7 @@ func Fsync(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) err := file.Fsync(t, 0, fs.FileMaxOffset, fs.SyncAll) return 0, nil, syserror.ConvertIntr(err, kernel.ERESTARTSYS) @@ -70,7 +70,7 @@ func Fdatasync(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) err := file.Fsync(t, 0, fs.FileMaxOffset, fs.SyncData) return 0, nil, syserror.ConvertIntr(err, kernel.ERESTARTSYS) @@ -103,7 +103,7 @@ func SyncFileRange(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // SYNC_FILE_RANGE_WAIT_BEFORE waits upon write-out of all pages in the // specified range that have already been submitted to the device diff --git a/pkg/sentry/syscalls/linux/sys_thread.go b/pkg/sentry/syscalls/linux/sys_thread.go index 00915fdde..2d16e4933 100644 --- a/pkg/sentry/syscalls/linux/sys_thread.go +++ b/pkg/sentry/syscalls/linux/sys_thread.go @@ -117,7 +117,7 @@ func execveat(t *kernel.Task, dirFD int32, pathnameAddr, argvAddr, envvAddr user resolveFinal := flags&linux.AT_SYMLINK_NOFOLLOW == 0 root := t.FSContext().RootDirectory() - defer root.DecRef() + defer root.DecRef(t) var wd *fs.Dirent var executable fsbridge.File @@ -133,7 +133,7 @@ func execveat(t *kernel.Task, dirFD int32, pathnameAddr, argvAddr, envvAddr user if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) closeOnExec = fdFlags.CloseOnExec if atEmptyPath && len(pathname) == 0 { @@ -155,7 +155,7 @@ func execveat(t *kernel.Task, dirFD int32, pathnameAddr, argvAddr, envvAddr user } } if wd != nil { - defer wd.DecRef() + defer wd.DecRef(t) } // Load the new TaskContext. diff --git a/pkg/sentry/syscalls/linux/sys_timerfd.go b/pkg/sentry/syscalls/linux/sys_timerfd.go index cf49b43db..34b03e4ee 100644 --- a/pkg/sentry/syscalls/linux/sys_timerfd.go +++ b/pkg/sentry/syscalls/linux/sys_timerfd.go @@ -43,7 +43,7 @@ func TimerfdCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel return 0, nil, syserror.EINVAL } f := timerfd.NewFile(t, c) - defer f.DecRef() + defer f.DecRef(t) f.SetFlags(fs.SettableFileFlags{ NonBlocking: flags&linux.TFD_NONBLOCK != 0, }) @@ -73,7 +73,7 @@ func TimerfdSettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) tf, ok := f.FileOperations.(*timerfd.TimerOperations) if !ok { @@ -107,7 +107,7 @@ func TimerfdGettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) tf, ok := f.FileOperations.(*timerfd.TimerOperations) if !ok { diff --git a/pkg/sentry/syscalls/linux/sys_write.go b/pkg/sentry/syscalls/linux/sys_write.go index 6ec0de96e..485526e28 100644 --- a/pkg/sentry/syscalls/linux/sys_write.go +++ b/pkg/sentry/syscalls/linux/sys_write.go @@ -48,7 +48,7 @@ func Write(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the file is writable. if !file.Flags().Write { @@ -85,7 +85,7 @@ func Pwrite64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate and does not overflow. if offset < 0 || offset+int64(size) < 0 { @@ -131,7 +131,7 @@ func Writev(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the file is writable. if !file.Flags().Write { @@ -162,7 +162,7 @@ func Pwritev(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < 0 { @@ -215,7 +215,7 @@ func Pwritev2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < -1 { diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go index 2de5e3422..97474fd3c 100644 --- a/pkg/sentry/syscalls/linux/sys_xattr.go +++ b/pkg/sentry/syscalls/linux/sys_xattr.go @@ -49,7 +49,7 @@ func FGetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) n, err := getXattr(t, f.Dirent, nameAddr, valueAddr, size) if err != nil { @@ -153,7 +153,7 @@ func FSetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) return 0, nil, setXattr(t, f.Dirent, nameAddr, valueAddr, uint64(size), flags) } @@ -207,7 +207,11 @@ func setXattr(t *kernel.Task, d *fs.Dirent, nameAddr, valueAddr usermem.Addr, si return syserror.EOPNOTSUPP } - return d.Inode.SetXattr(t, d, name, value, flags) + if err := d.Inode.SetXattr(t, d, name, value, flags); err != nil { + return err + } + d.InotifyEvent(linux.IN_ATTRIB, 0) + return nil } func copyInXattrName(t *kernel.Task, nameAddr usermem.Addr) (string, error) { @@ -266,7 +270,7 @@ func FListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) n, err := listXattr(t, f.Dirent, listAddr, size) if err != nil { @@ -380,7 +384,7 @@ func FRemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel. if f == nil { return 0, nil, syserror.EBADF } - defer f.DecRef() + defer f.DecRef(t) return 0, nil, removeXattr(t, f.Dirent, nameAddr) } @@ -418,7 +422,11 @@ func removeXattr(t *kernel.Task, d *fs.Dirent, nameAddr usermem.Addr) error { return syserror.EOPNOTSUPP } - return d.Inode.RemoveXattr(t, d, name) + if err := d.Inode.RemoveXattr(t, d, name); err != nil { + return err + } + d.InotifyEvent(linux.IN_ATTRIB, 0) + return nil } // LINT.ThenChange(vfs2/xattr.go) diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD index f882ef840..64696b438 100644 --- a/pkg/sentry/syscalls/linux/vfs2/BUILD +++ b/pkg/sentry/syscalls/linux/vfs2/BUILD @@ -5,6 +5,7 @@ package(licenses = ["notice"]) go_library( name = "vfs2", srcs = [ + "aio.go", "epoll.go", "eventfd.go", "execve.go", @@ -12,9 +13,12 @@ go_library( "filesystem.go", "fscontext.go", "getdents.go", + "inotify.go", "ioctl.go", + "lock.go", "memfd.go", "mmap.go", + "mount.go", "path.go", "pipe.go", "poll.go", @@ -22,6 +26,7 @@ go_library( "setstat.go", "signal.go", "socket.go", + "splice.go", "stat.go", "stat_amd64.go", "stat_arm64.go", @@ -36,9 +41,11 @@ go_library( "//pkg/abi/linux", "//pkg/binary", "//pkg/bits", + "//pkg/context", "//pkg/fspath", "//pkg/gohacks", "//pkg/sentry/arch", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsbridge", "//pkg/sentry/fsimpl/eventfd", "//pkg/sentry/fsimpl/pipefs", @@ -47,11 +54,13 @@ go_library( "//pkg/sentry/fsimpl/tmpfs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/fasync", "//pkg/sentry/kernel/pipe", "//pkg/sentry/kernel/time", "//pkg/sentry/limits", "//pkg/sentry/loader", "//pkg/sentry/memmap", + "//pkg/sentry/mm", "//pkg/sentry/socket", "//pkg/sentry/socket/control", "//pkg/sentry/socket/unix/transport", @@ -63,5 +72,7 @@ go_library( "//pkg/syserror", "//pkg/usermem", "//pkg/waiter", + "//tools/go_marshal/marshal", + "//tools/go_marshal/primitive", ], ) diff --git a/pkg/sentry/syscalls/linux/vfs2/aio.go b/pkg/sentry/syscalls/linux/vfs2/aio.go new file mode 100644 index 000000000..42559bf69 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/aio.go @@ -0,0 +1,219 @@ +// Copyright 2018 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs2 + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fsimpl/eventfd" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/mm" + slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" +) + +// IoSubmit implements linux syscall io_submit(2). +func IoSubmit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + id := args[0].Uint64() + nrEvents := args[1].Int() + addr := args[2].Pointer() + + if nrEvents < 0 { + return 0, nil, syserror.EINVAL + } + + for i := int32(0); i < nrEvents; i++ { + // Copy in the address. + cbAddrNative := t.Arch().Native(0) + if _, err := t.CopyIn(addr, cbAddrNative); err != nil { + if i > 0 { + // Some successful. + return uintptr(i), nil, nil + } + // Nothing done. + return 0, nil, err + } + + // Copy in this callback. + var cb linux.IOCallback + cbAddr := usermem.Addr(t.Arch().Value(cbAddrNative)) + if _, err := t.CopyIn(cbAddr, &cb); err != nil { + if i > 0 { + // Some have been successful. + return uintptr(i), nil, nil + } + // Nothing done. + return 0, nil, err + } + + // Process this callback. + if err := submitCallback(t, id, &cb, cbAddr); err != nil { + if i > 0 { + // Partial success. + return uintptr(i), nil, nil + } + // Nothing done. + return 0, nil, err + } + + // Advance to the next one. + addr += usermem.Addr(t.Arch().Width()) + } + + return uintptr(nrEvents), nil, nil +} + +// submitCallback processes a single callback. +func submitCallback(t *kernel.Task, id uint64, cb *linux.IOCallback, cbAddr usermem.Addr) error { + if cb.Reserved2 != 0 { + return syserror.EINVAL + } + + fd := t.GetFileVFS2(cb.FD) + if fd == nil { + return syserror.EBADF + } + defer fd.DecRef(t) + + // Was there an eventFD? Extract it. + var eventFD *vfs.FileDescription + if cb.Flags&linux.IOCB_FLAG_RESFD != 0 { + eventFD = t.GetFileVFS2(cb.ResFD) + if eventFD == nil { + return syserror.EBADF + } + defer eventFD.DecRef(t) + + // Check that it is an eventfd. + if _, ok := eventFD.Impl().(*eventfd.EventFileDescription); !ok { + return syserror.EINVAL + } + } + + ioseq, err := memoryFor(t, cb) + if err != nil { + return err + } + + // Check offset for reads/writes. + switch cb.OpCode { + case linux.IOCB_CMD_PREAD, linux.IOCB_CMD_PREADV, linux.IOCB_CMD_PWRITE, linux.IOCB_CMD_PWRITEV: + if cb.Offset < 0 { + return syserror.EINVAL + } + } + + // Prepare the request. + aioCtx, ok := t.MemoryManager().LookupAIOContext(t, id) + if !ok { + return syserror.EINVAL + } + if ready := aioCtx.Prepare(); !ready { + // Context is busy. + return syserror.EAGAIN + } + + if eventFD != nil { + // The request is set. Make sure there's a ref on the file. + // + // This is necessary when the callback executes on completion, + // which is also what will release this reference. + eventFD.IncRef() + } + + // Perform the request asynchronously. + fd.IncRef() + t.QueueAIO(getAIOCallback(t, fd, eventFD, cbAddr, cb, ioseq, aioCtx)) + return nil +} + +func getAIOCallback(t *kernel.Task, fd, eventFD *vfs.FileDescription, cbAddr usermem.Addr, cb *linux.IOCallback, ioseq usermem.IOSequence, aioCtx *mm.AIOContext) kernel.AIOCallback { + return func(ctx context.Context) { + // Release references after completing the callback. + defer fd.DecRef(ctx) + if eventFD != nil { + defer eventFD.DecRef(ctx) + } + + if aioCtx.Dead() { + aioCtx.CancelPendingRequest() + return + } + ev := &linux.IOEvent{ + Data: cb.Data, + Obj: uint64(cbAddr), + } + + var err error + switch cb.OpCode { + case linux.IOCB_CMD_PREAD, linux.IOCB_CMD_PREADV: + ev.Result, err = fd.PRead(ctx, ioseq, cb.Offset, vfs.ReadOptions{}) + case linux.IOCB_CMD_PWRITE, linux.IOCB_CMD_PWRITEV: + ev.Result, err = fd.PWrite(ctx, ioseq, cb.Offset, vfs.WriteOptions{}) + case linux.IOCB_CMD_FSYNC, linux.IOCB_CMD_FDSYNC: + err = fd.Sync(ctx) + } + + // Update the result. + if err != nil { + err = slinux.HandleIOErrorVFS2(t, ev.Result != 0 /* partial */, err, nil /* never interrupted */, "aio", fd) + ev.Result = -int64(kernel.ExtractErrno(err, 0)) + } + + // Queue the result for delivery. + aioCtx.FinishRequest(ev) + + // Notify the event file if one was specified. This needs to happen + // *after* queueing the result to avoid racing with the thread we may + // wake up. + if eventFD != nil { + eventFD.Impl().(*eventfd.EventFileDescription).Signal(1) + } + } +} + +// memoryFor returns appropriate memory for the given callback. +func memoryFor(t *kernel.Task, cb *linux.IOCallback) (usermem.IOSequence, error) { + bytes := int(cb.Bytes) + if bytes < 0 { + // Linux also requires that this field fit in ssize_t. + return usermem.IOSequence{}, syserror.EINVAL + } + + // Since this I/O will be asynchronous with respect to t's task goroutine, + // we have no guarantee that t's AddressSpace will be active during the + // I/O. + switch cb.OpCode { + case linux.IOCB_CMD_PREAD, linux.IOCB_CMD_PWRITE: + return t.SingleIOSequence(usermem.Addr(cb.Buf), bytes, usermem.IOOpts{ + AddressSpaceActive: false, + }) + + case linux.IOCB_CMD_PREADV, linux.IOCB_CMD_PWRITEV: + return t.IovecsIOSequence(usermem.Addr(cb.Buf), bytes, usermem.IOOpts{ + AddressSpaceActive: false, + }) + + case linux.IOCB_CMD_FSYNC, linux.IOCB_CMD_FDSYNC, linux.IOCB_CMD_NOOP: + return usermem.IOSequence{}, nil + + default: + // Not a supported command. + return usermem.IOSequence{}, syserror.EINVAL + } +} diff --git a/pkg/sentry/syscalls/linux/vfs2/epoll.go b/pkg/sentry/syscalls/linux/vfs2/epoll.go index 34c90ae3e..c62f03509 100644 --- a/pkg/sentry/syscalls/linux/vfs2/epoll.go +++ b/pkg/sentry/syscalls/linux/vfs2/epoll.go @@ -37,11 +37,11 @@ func EpollCreate1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel. return 0, nil, syserror.EINVAL } - file, err := t.Kernel().VFS().NewEpollInstanceFD() + file, err := t.Kernel().VFS().NewEpollInstanceFD(t) if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) fd, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{ CloseOnExec: flags&linux.EPOLL_CLOEXEC != 0, @@ -62,11 +62,11 @@ func EpollCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S return 0, nil, syserror.EINVAL } - file, err := t.Kernel().VFS().NewEpollInstanceFD() + file, err := t.Kernel().VFS().NewEpollInstanceFD(t) if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) fd, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{}) if err != nil { @@ -86,7 +86,7 @@ func EpollCtl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if epfile == nil { return 0, nil, syserror.EBADF } - defer epfile.DecRef() + defer epfile.DecRef(t) ep, ok := epfile.Impl().(*vfs.EpollInstance) if !ok { return 0, nil, syserror.EINVAL @@ -95,7 +95,7 @@ func EpollCtl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) if epfile == file { return 0, nil, syserror.EINVAL } @@ -135,7 +135,7 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if epfile == nil { return 0, nil, syserror.EBADF } - defer epfile.DecRef() + defer epfile.DecRef(t) ep, ok := epfile.Impl().(*vfs.EpollInstance) if !ok { return 0, nil, syserror.EINVAL diff --git a/pkg/sentry/syscalls/linux/vfs2/eventfd.go b/pkg/sentry/syscalls/linux/vfs2/eventfd.go index aff1a2070..807f909da 100644 --- a/pkg/sentry/syscalls/linux/vfs2/eventfd.go +++ b/pkg/sentry/syscalls/linux/vfs2/eventfd.go @@ -38,11 +38,11 @@ func Eventfd2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc fileFlags |= linux.O_NONBLOCK } semMode := flags&linux.EFD_SEMAPHORE != 0 - eventfd, err := eventfd.New(vfsObj, initVal, semMode, fileFlags) + eventfd, err := eventfd.New(t, vfsObj, initVal, semMode, fileFlags) if err != nil { return 0, nil, err } - defer eventfd.DecRef() + defer eventfd.DecRef(t) fd, err := t.NewFDFromVFS2(0, eventfd, kernel.FDFlags{ CloseOnExec: flags&linux.EFD_CLOEXEC != 0, diff --git a/pkg/sentry/syscalls/linux/vfs2/execve.go b/pkg/sentry/syscalls/linux/vfs2/execve.go index aef0078a8..066ee0863 100644 --- a/pkg/sentry/syscalls/linux/vfs2/execve.go +++ b/pkg/sentry/syscalls/linux/vfs2/execve.go @@ -71,7 +71,7 @@ func execveat(t *kernel.Task, dirfd int32, pathnameAddr, argvAddr, envvAddr user } root := t.FSContext().RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) var executable fsbridge.File closeOnExec := false if path := fspath.Parse(pathname); dirfd != linux.AT_FDCWD && !path.Absolute { @@ -90,7 +90,7 @@ func execveat(t *kernel.Task, dirfd int32, pathnameAddr, argvAddr, envvAddr user } start := dirfile.VirtualDentry() start.IncRef() - dirfile.DecRef() + dirfile.DecRef(t) closeOnExec = dirfileFlags.CloseOnExec file, err := t.Kernel().VFS().OpenAt(t, t.Credentials(), &vfs.PathOperation{ Root: root, @@ -101,19 +101,19 @@ func execveat(t *kernel.Task, dirfd int32, pathnameAddr, argvAddr, envvAddr user Flags: linux.O_RDONLY, FileExec: true, }) - start.DecRef() + start.DecRef(t) if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) executable = fsbridge.NewVFSFile(file) } // Load the new TaskContext. mntns := t.MountNamespaceVFS2() // FIXME(jamieliu): useless refcount change - defer mntns.DecRef() + defer mntns.DecRef(t) wd := t.FSContext().WorkingDirectoryVFS2() - defer wd.DecRef() + defer wd.DecRef(t) remainingTraversals := uint(linux.MaxSymlinkTraversals) loadArgs := loader.LoadArgs{ Opener: fsbridge.NewVFSLookup(mntns, root, wd), diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go index ca0f7fd1e..4856554fe 100644 --- a/pkg/sentry/syscalls/linux/vfs2/fd.go +++ b/pkg/sentry/syscalls/linux/vfs2/fd.go @@ -17,10 +17,13 @@ package vfs2 import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs" "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/fasync" "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux" + "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/syserror" ) @@ -35,7 +38,7 @@ func Close(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) err := file.OnClose(t) return 0, nil, slinux.HandleIOErrorVFS2(t, false /* partial */, err, syserror.EINTR, "close", file) @@ -49,7 +52,7 @@ func Dup(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallCo if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) newFD, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{}) if err != nil { @@ -69,7 +72,7 @@ func Dup2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - file.DecRef() + file.DecRef(t) return uintptr(newfd), nil, nil } @@ -98,7 +101,7 @@ func dup3(t *kernel.Task, oldfd, newfd int32, flags uint32) (uintptr, *kernel.Sy if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) err := t.NewFDAtVFS2(newfd, file, kernel.FDFlags{ CloseOnExec: flags&linux.O_CLOEXEC != 0, @@ -118,7 +121,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) switch cmd { case linux.F_DUPFD, linux.F_DUPFD_CLOEXEC: @@ -134,10 +137,10 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return uintptr(flags.ToLinuxFDFlags()), nil, nil case linux.F_SETFD: flags := args[2].Uint() - t.FDTable().SetFlags(fd, kernel.FDFlags{ + err := t.FDTable().SetFlagsVFS2(fd, kernel.FDFlags{ CloseOnExec: flags&linux.FD_CLOEXEC != 0, }) - return 0, nil, nil + return 0, nil, err case linux.F_GETFL: return uintptr(file.StatusFlags()), nil, nil case linux.F_SETFL: @@ -152,6 +155,41 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return 0, nil, err } return uintptr(n), nil, nil + case linux.F_GETOWN: + owner, hasOwner := getAsyncOwner(t, file) + if !hasOwner { + return 0, nil, nil + } + if owner.Type == linux.F_OWNER_PGRP { + return uintptr(-owner.PID), nil, nil + } + return uintptr(owner.PID), nil, nil + case linux.F_SETOWN: + who := args[2].Int() + ownerType := int32(linux.F_OWNER_PID) + if who < 0 { + // Check for overflow before flipping the sign. + if who-1 > who { + return 0, nil, syserror.EINVAL + } + ownerType = linux.F_OWNER_PGRP + who = -who + } + return 0, nil, setAsyncOwner(t, file, ownerType, who) + case linux.F_GETOWN_EX: + owner, hasOwner := getAsyncOwner(t, file) + if !hasOwner { + return 0, nil, nil + } + _, err := t.CopyOut(args[2].Pointer(), &owner) + return 0, nil, err + case linux.F_SETOWN_EX: + var owner linux.FOwnerEx + _, err := t.CopyIn(args[2].Pointer(), &owner) + if err != nil { + return 0, nil, err + } + return 0, nil, setAsyncOwner(t, file, owner.Type, owner.PID) case linux.F_GETPIPE_SZ: pipefile, ok := file.Impl().(*pipe.VFSPipeFD) if !ok { @@ -167,8 +205,151 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } err := tmpfs.AddSeals(file, args[2].Uint()) return 0, nil, err + case linux.F_SETLK, linux.F_SETLKW: + return 0, nil, posixLock(t, args, file, cmd) default: - // TODO(gvisor.dev/issue/1623): Everything else is not yet supported. + // Everything else is not yet supported. return 0, nil, syserror.EINVAL } } + +func getAsyncOwner(t *kernel.Task, fd *vfs.FileDescription) (ownerEx linux.FOwnerEx, hasOwner bool) { + a := fd.AsyncHandler() + if a == nil { + return linux.FOwnerEx{}, false + } + + ot, otg, opg := a.(*fasync.FileAsync).Owner() + switch { + case ot != nil: + return linux.FOwnerEx{ + Type: linux.F_OWNER_TID, + PID: int32(t.PIDNamespace().IDOfTask(ot)), + }, true + case otg != nil: + return linux.FOwnerEx{ + Type: linux.F_OWNER_PID, + PID: int32(t.PIDNamespace().IDOfThreadGroup(otg)), + }, true + case opg != nil: + return linux.FOwnerEx{ + Type: linux.F_OWNER_PGRP, + PID: int32(t.PIDNamespace().IDOfProcessGroup(opg)), + }, true + default: + return linux.FOwnerEx{}, true + } +} + +func setAsyncOwner(t *kernel.Task, fd *vfs.FileDescription, ownerType, pid int32) error { + switch ownerType { + case linux.F_OWNER_TID, linux.F_OWNER_PID, linux.F_OWNER_PGRP: + // Acceptable type. + default: + return syserror.EINVAL + } + + a := fd.SetAsyncHandler(fasync.NewVFS2).(*fasync.FileAsync) + if pid == 0 { + a.ClearOwner() + return nil + } + + switch ownerType { + case linux.F_OWNER_TID: + task := t.PIDNamespace().TaskWithID(kernel.ThreadID(pid)) + if task == nil { + return syserror.ESRCH + } + a.SetOwnerTask(t, task) + return nil + case linux.F_OWNER_PID: + tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(pid)) + if tg == nil { + return syserror.ESRCH + } + a.SetOwnerThreadGroup(t, tg) + return nil + case linux.F_OWNER_PGRP: + pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(pid)) + if pg == nil { + return syserror.ESRCH + } + a.SetOwnerProcessGroup(t, pg) + return nil + default: + return syserror.EINVAL + } +} + +func posixLock(t *kernel.Task, args arch.SyscallArguments, file *vfs.FileDescription, cmd int32) error { + // Copy in the lock request. + flockAddr := args[2].Pointer() + var flock linux.Flock + if _, err := t.CopyIn(flockAddr, &flock); err != nil { + return err + } + + var blocker lock.Blocker + if cmd == linux.F_SETLKW { + blocker = t + } + + switch flock.Type { + case linux.F_RDLCK: + if !file.IsReadable() { + return syserror.EBADF + } + return file.LockPOSIX(t, t.FDTable(), lock.ReadLock, uint64(flock.Start), uint64(flock.Len), flock.Whence, blocker) + + case linux.F_WRLCK: + if !file.IsWritable() { + return syserror.EBADF + } + return file.LockPOSIX(t, t.FDTable(), lock.WriteLock, uint64(flock.Start), uint64(flock.Len), flock.Whence, blocker) + + case linux.F_UNLCK: + return file.UnlockPOSIX(t, t.FDTable(), uint64(flock.Start), uint64(flock.Len), flock.Whence) + + default: + return syserror.EINVAL + } +} + +// Fadvise64 implements fadvise64(2). +// This implementation currently ignores the provided advice. +func Fadvise64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + length := args[2].Int64() + advice := args[3].Int() + + // Note: offset is allowed to be negative. + if length < 0 { + return 0, nil, syserror.EINVAL + } + + file := t.GetFileVFS2(fd) + if file == nil { + return 0, nil, syserror.EBADF + } + defer file.DecRef(t) + + // If the FD refers to a pipe or FIFO, return error. + if _, isPipe := file.Impl().(*pipe.VFSPipeFD); isPipe { + return 0, nil, syserror.ESPIPE + } + + switch advice { + case linux.POSIX_FADV_NORMAL: + case linux.POSIX_FADV_RANDOM: + case linux.POSIX_FADV_SEQUENTIAL: + case linux.POSIX_FADV_WILLNEED: + case linux.POSIX_FADV_DONTNEED: + case linux.POSIX_FADV_NOREUSE: + default: + return 0, nil, syserror.EINVAL + } + + // Sure, whatever. + return 0, nil, nil +} diff --git a/pkg/sentry/syscalls/linux/vfs2/filesystem.go b/pkg/sentry/syscalls/linux/vfs2/filesystem.go index 46d3e189c..01e0f9010 100644 --- a/pkg/sentry/syscalls/linux/vfs2/filesystem.go +++ b/pkg/sentry/syscalls/linux/vfs2/filesystem.go @@ -56,7 +56,7 @@ func linkat(t *kernel.Task, olddirfd int32, oldpathAddr usermem.Addr, newdirfd i if err != nil { return err } - defer oldtpop.Release() + defer oldtpop.Release(t) newpath, err := copyInPath(t, newpathAddr) if err != nil { @@ -66,7 +66,7 @@ func linkat(t *kernel.Task, olddirfd int32, oldpathAddr usermem.Addr, newdirfd i if err != nil { return err } - defer newtpop.Release() + defer newtpop.Release(t) return t.Kernel().VFS().LinkAt(t, t.Credentials(), &oldtpop.pop, &newtpop.pop) } @@ -95,7 +95,7 @@ func mkdirat(t *kernel.Task, dirfd int32, addr usermem.Addr, mode uint) error { if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) return t.Kernel().VFS().MkdirAt(t, t.Credentials(), &tpop.pop, &vfs.MkdirOptions{ Mode: linux.FileMode(mode & (0777 | linux.S_ISVTX) &^ t.FSContext().Umask()), }) @@ -106,7 +106,7 @@ func Mknod(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall addr := args[0].Pointer() mode := args[1].ModeT() dev := args[2].Uint() - return 0, nil, mknodat(t, linux.AT_FDCWD, addr, mode, dev) + return 0, nil, mknodat(t, linux.AT_FDCWD, addr, linux.FileMode(mode), dev) } // Mknodat implements Linux syscall mknodat(2). @@ -115,10 +115,10 @@ func Mknodat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca addr := args[1].Pointer() mode := args[2].ModeT() dev := args[3].Uint() - return 0, nil, mknodat(t, dirfd, addr, mode, dev) + return 0, nil, mknodat(t, dirfd, addr, linux.FileMode(mode), dev) } -func mknodat(t *kernel.Task, dirfd int32, addr usermem.Addr, mode uint, dev uint32) error { +func mknodat(t *kernel.Task, dirfd int32, addr usermem.Addr, mode linux.FileMode, dev uint32) error { path, err := copyInPath(t, addr) if err != nil { return err @@ -127,10 +127,15 @@ func mknodat(t *kernel.Task, dirfd int32, addr usermem.Addr, mode uint, dev uint if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) + + // "Zero file type is equivalent to type S_IFREG." - mknod(2) + if mode.FileType() == 0 { + mode |= linux.ModeRegular + } major, minor := linux.DecodeDeviceID(dev) return t.Kernel().VFS().MknodAt(t, t.Credentials(), &tpop.pop, &vfs.MknodOptions{ - Mode: linux.FileMode(mode &^ t.FSContext().Umask()), + Mode: mode &^ linux.FileMode(t.FSContext().Umask()), DevMajor: uint32(major), DevMinor: minor, }) @@ -169,7 +174,7 @@ func openat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr, flags uint32, mo if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) file, err := t.Kernel().VFS().OpenAt(t, t.Credentials(), &tpop.pop, &vfs.OpenOptions{ Flags: flags | linux.O_LARGEFILE, @@ -178,7 +183,7 @@ func openat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr, flags uint32, mo if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) fd, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{ CloseOnExec: flags&linux.O_CLOEXEC != 0, @@ -222,7 +227,7 @@ func renameat(t *kernel.Task, olddirfd int32, oldpathAddr usermem.Addr, newdirfd if err != nil { return err } - defer oldtpop.Release() + defer oldtpop.Release(t) newpath, err := copyInPath(t, newpathAddr) if err != nil { @@ -232,7 +237,7 @@ func renameat(t *kernel.Task, olddirfd int32, oldpathAddr usermem.Addr, newdirfd if err != nil { return err } - defer newtpop.Release() + defer newtpop.Release(t) return t.Kernel().VFS().RenameAt(t, t.Credentials(), &oldtpop.pop, &newtpop.pop, &vfs.RenameOptions{ Flags: flags, @@ -254,7 +259,7 @@ func rmdirat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr) error { if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) return t.Kernel().VFS().RmdirAt(t, t.Credentials(), &tpop.pop) } @@ -273,7 +278,7 @@ func unlinkat(t *kernel.Task, dirfd int32, pathAddr usermem.Addr) error { if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) return t.Kernel().VFS().UnlinkAt(t, t.Credentials(), &tpop.pop) } @@ -313,6 +318,9 @@ func symlinkat(t *kernel.Task, targetAddr usermem.Addr, newdirfd int32, linkpath if err != nil { return err } + if len(target) == 0 { + return syserror.ENOENT + } linkpath, err := copyInPath(t, linkpathAddr) if err != nil { return err @@ -321,6 +329,6 @@ func symlinkat(t *kernel.Task, targetAddr usermem.Addr, newdirfd int32, linkpath if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) return t.Kernel().VFS().SymlinkAt(t, t.Credentials(), &tpop.pop, target) } diff --git a/pkg/sentry/syscalls/linux/vfs2/fscontext.go b/pkg/sentry/syscalls/linux/vfs2/fscontext.go index 317409a18..a7d4d2a36 100644 --- a/pkg/sentry/syscalls/linux/vfs2/fscontext.go +++ b/pkg/sentry/syscalls/linux/vfs2/fscontext.go @@ -31,8 +31,8 @@ func Getcwd(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal root := t.FSContext().RootDirectoryVFS2() wd := t.FSContext().WorkingDirectoryVFS2() s, err := t.Kernel().VFS().PathnameForGetcwd(t, root, wd) - root.DecRef() - wd.DecRef() + root.DecRef(t) + wd.DecRef(t) if err != nil { return 0, nil, err } @@ -67,7 +67,7 @@ func Chdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) vd, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{ CheckSearchable: true, @@ -75,8 +75,8 @@ func Chdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if err != nil { return 0, nil, err } - t.FSContext().SetWorkingDirectoryVFS2(vd) - vd.DecRef() + t.FSContext().SetWorkingDirectoryVFS2(t, vd) + vd.DecRef(t) return 0, nil, nil } @@ -88,7 +88,7 @@ func Fchdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) vd, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{ CheckSearchable: true, @@ -96,8 +96,8 @@ func Fchdir(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, err } - t.FSContext().SetWorkingDirectoryVFS2(vd) - vd.DecRef() + t.FSContext().SetWorkingDirectoryVFS2(t, vd) + vd.DecRef(t) return 0, nil, nil } @@ -117,7 +117,7 @@ func Chroot(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) vd, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{ CheckSearchable: true, @@ -125,7 +125,7 @@ func Chroot(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, err } - t.FSContext().SetRootDirectoryVFS2(vd) - vd.DecRef() + t.FSContext().SetRootDirectoryVFS2(t, vd) + vd.DecRef(t) return 0, nil, nil } diff --git a/pkg/sentry/syscalls/linux/vfs2/getdents.go b/pkg/sentry/syscalls/linux/vfs2/getdents.go index c7c7bf7ce..5517595b5 100644 --- a/pkg/sentry/syscalls/linux/vfs2/getdents.go +++ b/pkg/sentry/syscalls/linux/vfs2/getdents.go @@ -44,7 +44,7 @@ func getdents(t *kernel.Task, args arch.SyscallArguments, isGetdents64 bool) (ui if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) cb := getGetdentsCallback(t, addr, size, isGetdents64) err := file.IterDirents(t, cb) diff --git a/pkg/sentry/syscalls/linux/vfs2/inotify.go b/pkg/sentry/syscalls/linux/vfs2/inotify.go new file mode 100644 index 000000000..11753d8e5 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/inotify.go @@ -0,0 +1,137 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs2 + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" +) + +const allFlags = linux.IN_NONBLOCK | linux.IN_CLOEXEC + +// InotifyInit1 implements the inotify_init1() syscalls. +func InotifyInit1(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + flags := args[0].Int() + if flags&^allFlags != 0 { + return 0, nil, syserror.EINVAL + } + + ino, err := vfs.NewInotifyFD(t, t.Kernel().VFS(), uint32(flags)) + if err != nil { + return 0, nil, err + } + defer ino.DecRef(t) + + fd, err := t.NewFDFromVFS2(0, ino, kernel.FDFlags{ + CloseOnExec: flags&linux.IN_CLOEXEC != 0, + }) + + if err != nil { + return 0, nil, err + } + + return uintptr(fd), nil, nil +} + +// InotifyInit implements the inotify_init() syscalls. +func InotifyInit(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + args[0].Value = 0 + return InotifyInit1(t, args) +} + +// fdToInotify resolves an fd to an inotify object. If successful, the file will +// have an extra ref and the caller is responsible for releasing the ref. +func fdToInotify(t *kernel.Task, fd int32) (*vfs.Inotify, *vfs.FileDescription, error) { + f := t.GetFileVFS2(fd) + if f == nil { + // Invalid fd. + return nil, nil, syserror.EBADF + } + + ino, ok := f.Impl().(*vfs.Inotify) + if !ok { + // Not an inotify fd. + f.DecRef(t) + return nil, nil, syserror.EINVAL + } + + return ino, f, nil +} + +// InotifyAddWatch implements the inotify_add_watch() syscall. +func InotifyAddWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + addr := args[1].Pointer() + mask := args[2].Uint() + + // "EINVAL: The given event mask contains no valid events." + // -- inotify_add_watch(2) + if mask&linux.ALL_INOTIFY_BITS == 0 { + return 0, nil, syserror.EINVAL + } + + // "IN_DONT_FOLLOW: Don't dereference pathname if it is a symbolic link." + // -- inotify(7) + follow := followFinalSymlink + if mask&linux.IN_DONT_FOLLOW == 0 { + follow = nofollowFinalSymlink + } + + ino, f, err := fdToInotify(t, fd) + if err != nil { + return 0, nil, err + } + defer f.DecRef(t) + + path, err := copyInPath(t, addr) + if err != nil { + return 0, nil, err + } + if mask&linux.IN_ONLYDIR != 0 { + path.Dir = true + } + tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, follow) + if err != nil { + return 0, nil, err + } + defer tpop.Release(t) + d, err := t.Kernel().VFS().GetDentryAt(t, t.Credentials(), &tpop.pop, &vfs.GetDentryOptions{}) + if err != nil { + return 0, nil, err + } + defer d.DecRef(t) + + fd, err = ino.AddWatch(d.Dentry(), mask) + if err != nil { + return 0, nil, err + } + return uintptr(fd), nil, nil +} + +// InotifyRmWatch implements the inotify_rm_watch() syscall. +func InotifyRmWatch(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + wd := args[1].Int() + + ino, f, err := fdToInotify(t, fd) + if err != nil { + return 0, nil, err + } + defer f.DecRef(t) + return 0, nil, ino.RmWatch(t, wd) +} diff --git a/pkg/sentry/syscalls/linux/vfs2/ioctl.go b/pkg/sentry/syscalls/linux/vfs2/ioctl.go index 5a2418da9..38778a388 100644 --- a/pkg/sentry/syscalls/linux/vfs2/ioctl.go +++ b/pkg/sentry/syscalls/linux/vfs2/ioctl.go @@ -15,6 +15,7 @@ package vfs2 import ( + "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/syserror" @@ -28,7 +29,78 @@ func Ioctl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) + + // Handle ioctls that apply to all FDs. + switch args[1].Int() { + case linux.FIONCLEX: + t.FDTable().SetFlagsVFS2(fd, kernel.FDFlags{ + CloseOnExec: false, + }) + return 0, nil, nil + + case linux.FIOCLEX: + t.FDTable().SetFlagsVFS2(fd, kernel.FDFlags{ + CloseOnExec: true, + }) + return 0, nil, nil + + case linux.FIONBIO: + var set int32 + if _, err := t.CopyIn(args[2].Pointer(), &set); err != nil { + return 0, nil, err + } + flags := file.StatusFlags() + if set != 0 { + flags |= linux.O_NONBLOCK + } else { + flags &^= linux.O_NONBLOCK + } + return 0, nil, file.SetStatusFlags(t, t.Credentials(), flags) + + case linux.FIOASYNC: + var set int32 + if _, err := t.CopyIn(args[2].Pointer(), &set); err != nil { + return 0, nil, err + } + flags := file.StatusFlags() + if set != 0 { + flags |= linux.O_ASYNC + } else { + flags &^= linux.O_ASYNC + } + file.SetStatusFlags(t, t.Credentials(), flags) + return 0, nil, nil + + case linux.FIOGETOWN, linux.SIOCGPGRP: + var who int32 + owner, hasOwner := getAsyncOwner(t, file) + if hasOwner { + if owner.Type == linux.F_OWNER_PGRP { + who = -owner.PID + } else { + who = owner.PID + } + } + _, err := t.CopyOut(args[2].Pointer(), &who) + return 0, nil, err + + case linux.FIOSETOWN, linux.SIOCSPGRP: + var who int32 + if _, err := t.CopyIn(args[2].Pointer(), &who); err != nil { + return 0, nil, err + } + ownerType := int32(linux.F_OWNER_PID) + if who < 0 { + // Check for overflow before flipping the sign. + if who-1 > who { + return 0, nil, syserror.EINVAL + } + ownerType = linux.F_OWNER_PGRP + who = -who + } + return 0, nil, setAsyncOwner(t, file, ownerType, who) + } ret, err := file.Ioctl(t, t.MemoryManager(), args) return ret, nil, err diff --git a/pkg/sentry/syscalls/linux/vfs2/lock.go b/pkg/sentry/syscalls/linux/vfs2/lock.go new file mode 100644 index 000000000..b910b5a74 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/lock.go @@ -0,0 +1,64 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs2 + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fs/lock" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/syserror" +) + +// Flock implements linux syscall flock(2). +func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + operation := args[1].Int() + + file := t.GetFileVFS2(fd) + if file == nil { + // flock(2): EBADF fd is not an open file descriptor. + return 0, nil, syserror.EBADF + } + defer file.DecRef(t) + + nonblocking := operation&linux.LOCK_NB != 0 + operation &^= linux.LOCK_NB + + var blocker lock.Blocker + if !nonblocking { + blocker = t + } + + switch operation { + case linux.LOCK_EX: + if err := file.LockBSD(t, lock.WriteLock, blocker); err != nil { + return 0, nil, err + } + case linux.LOCK_SH: + if err := file.LockBSD(t, lock.ReadLock, blocker); err != nil { + return 0, nil, err + } + case linux.LOCK_UN: + if err := file.UnlockBSD(t); err != nil { + return 0, nil, err + } + default: + // flock(2): EINVAL operation is invalid. + return 0, nil, syserror.EINVAL + } + + return 0, nil, nil +} diff --git a/pkg/sentry/syscalls/linux/vfs2/memfd.go b/pkg/sentry/syscalls/linux/vfs2/memfd.go index bbe248d17..c4c0f9e0a 100644 --- a/pkg/sentry/syscalls/linux/vfs2/memfd.go +++ b/pkg/sentry/syscalls/linux/vfs2/memfd.go @@ -47,10 +47,11 @@ func MemfdCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S } shmMount := t.Kernel().ShmMount() - file, err := tmpfs.NewMemfd(shmMount, t.Credentials(), allowSeals, memfdPrefix+name) + file, err := tmpfs.NewMemfd(t, t.Credentials(), shmMount, allowSeals, memfdPrefix+name) if err != nil { return 0, nil, err } + defer file.DecRef(t) fd, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{ CloseOnExec: cloExec, diff --git a/pkg/sentry/syscalls/linux/vfs2/mmap.go b/pkg/sentry/syscalls/linux/vfs2/mmap.go index 60a43f0a0..dc05c2994 100644 --- a/pkg/sentry/syscalls/linux/vfs2/mmap.go +++ b/pkg/sentry/syscalls/linux/vfs2/mmap.go @@ -61,7 +61,7 @@ func Mmap(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC } defer func() { if opts.MappingIdentity != nil { - opts.MappingIdentity.DecRef() + opts.MappingIdentity.DecRef(t) } }() @@ -71,7 +71,7 @@ func Mmap(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // mmap unconditionally requires that the FD is readable. if !file.IsReadable() { diff --git a/pkg/sentry/syscalls/linux/vfs2/mount.go b/pkg/sentry/syscalls/linux/vfs2/mount.go new file mode 100644 index 000000000..4bd5c7ca2 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/mount.go @@ -0,0 +1,150 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs2 + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" +) + +// Mount implements Linux syscall mount(2). +func Mount(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + sourceAddr := args[0].Pointer() + targetAddr := args[1].Pointer() + typeAddr := args[2].Pointer() + flags := args[3].Uint64() + dataAddr := args[4].Pointer() + + // For null-terminated strings related to mount(2), Linux copies in at most + // a page worth of data. See fs/namespace.c:copy_mount_string(). + fsType, err := t.CopyInString(typeAddr, usermem.PageSize) + if err != nil { + return 0, nil, err + } + source, err := t.CopyInString(sourceAddr, usermem.PageSize) + if err != nil { + return 0, nil, err + } + + targetPath, err := copyInPath(t, targetAddr) + if err != nil { + return 0, nil, err + } + + data := "" + if dataAddr != 0 { + // In Linux, a full page is always copied in regardless of null + // character placement, and the address is passed to each file system. + // Most file systems always treat this data as a string, though, and so + // do all of the ones we implement. + data, err = t.CopyInString(dataAddr, usermem.PageSize) + if err != nil { + return 0, nil, err + } + } + + // Ignore magic value that was required before Linux 2.4. + if flags&linux.MS_MGC_MSK == linux.MS_MGC_VAL { + flags = flags &^ linux.MS_MGC_MSK + } + + // Must have CAP_SYS_ADMIN in the current mount namespace's associated user + // namespace. + creds := t.Credentials() + if !creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, t.MountNamespaceVFS2().Owner) { + return 0, nil, syserror.EPERM + } + + const unsupportedOps = linux.MS_REMOUNT | linux.MS_BIND | + linux.MS_SHARED | linux.MS_PRIVATE | linux.MS_SLAVE | + linux.MS_UNBINDABLE | linux.MS_MOVE + + // Silently allow MS_NOSUID, since we don't implement set-id bits + // anyway. + const unsupportedFlags = linux.MS_NODIRATIME | linux.MS_STRICTATIME + + // Linux just allows passing any flags to mount(2) - it won't fail when + // unknown or unsupported flags are passed. Since we don't implement + // everything, we fail explicitly on flags that are unimplemented. + if flags&(unsupportedOps|unsupportedFlags) != 0 { + return 0, nil, syserror.EINVAL + } + + var opts vfs.MountOptions + if flags&linux.MS_NOATIME == linux.MS_NOATIME { + opts.Flags.NoATime = true + } + if flags&linux.MS_NOEXEC == linux.MS_NOEXEC { + opts.Flags.NoExec = true + } + if flags&linux.MS_NODEV == linux.MS_NODEV { + opts.Flags.NoDev = true + } + if flags&linux.MS_NOSUID == linux.MS_NOSUID { + opts.Flags.NoSUID = true + } + if flags&linux.MS_RDONLY == linux.MS_RDONLY { + opts.ReadOnly = true + } + opts.GetFilesystemOptions.Data = data + + target, err := getTaskPathOperation(t, linux.AT_FDCWD, targetPath, disallowEmptyPath, nofollowFinalSymlink) + if err != nil { + return 0, nil, err + } + defer target.Release(t) + + return 0, nil, t.Kernel().VFS().MountAt(t, creds, source, &target.pop, fsType, &opts) +} + +// Umount2 implements Linux syscall umount2(2). +func Umount2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + addr := args[0].Pointer() + flags := args[1].Int() + + // Must have CAP_SYS_ADMIN in the mount namespace's associated user + // namespace. + // + // Currently, this is always the init task's user namespace. + creds := t.Credentials() + if !creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, t.MountNamespaceVFS2().Owner) { + return 0, nil, syserror.EPERM + } + + const unsupported = linux.MNT_FORCE | linux.MNT_EXPIRE + if flags&unsupported != 0 { + return 0, nil, syserror.EINVAL + } + + path, err := copyInPath(t, addr) + if err != nil { + return 0, nil, err + } + tpop, err := getTaskPathOperation(t, linux.AT_FDCWD, path, disallowEmptyPath, nofollowFinalSymlink) + if err != nil { + return 0, nil, err + } + defer tpop.Release(t) + + opts := vfs.UmountOptions{ + Flags: uint32(flags), + } + + return 0, nil, t.Kernel().VFS().UmountAt(t, creds, &tpop.pop, &opts) +} diff --git a/pkg/sentry/syscalls/linux/vfs2/path.go b/pkg/sentry/syscalls/linux/vfs2/path.go index 97da6c647..90a511d9a 100644 --- a/pkg/sentry/syscalls/linux/vfs2/path.go +++ b/pkg/sentry/syscalls/linux/vfs2/path.go @@ -42,7 +42,7 @@ func getTaskPathOperation(t *kernel.Task, dirfd int32, path fspath.Path, shouldA haveStartRef := false if !path.Absolute { if !path.HasComponents() && !bool(shouldAllowEmptyPath) { - root.DecRef() + root.DecRef(t) return taskPathOperation{}, syserror.ENOENT } if dirfd == linux.AT_FDCWD { @@ -51,13 +51,13 @@ func getTaskPathOperation(t *kernel.Task, dirfd int32, path fspath.Path, shouldA } else { dirfile := t.GetFileVFS2(dirfd) if dirfile == nil { - root.DecRef() + root.DecRef(t) return taskPathOperation{}, syserror.EBADF } start = dirfile.VirtualDentry() start.IncRef() haveStartRef = true - dirfile.DecRef() + dirfile.DecRef(t) } } return taskPathOperation{ @@ -71,10 +71,10 @@ func getTaskPathOperation(t *kernel.Task, dirfd int32, path fspath.Path, shouldA }, nil } -func (tpop *taskPathOperation) Release() { - tpop.pop.Root.DecRef() +func (tpop *taskPathOperation) Release(t *kernel.Task) { + tpop.pop.Root.DecRef(t) if tpop.haveStartRef { - tpop.pop.Start.DecRef() + tpop.pop.Start.DecRef(t) tpop.haveStartRef = false } } diff --git a/pkg/sentry/syscalls/linux/vfs2/pipe.go b/pkg/sentry/syscalls/linux/vfs2/pipe.go index 4a01e4209..9b4848d9e 100644 --- a/pkg/sentry/syscalls/linux/vfs2/pipe.go +++ b/pkg/sentry/syscalls/linux/vfs2/pipe.go @@ -42,8 +42,8 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags int32) error { return syserror.EINVAL } r, w := pipefs.NewConnectedPipeFDs(t, t.Kernel().PipeMount(), uint32(flags&linux.O_NONBLOCK)) - defer r.DecRef() - defer w.DecRef() + defer r.DecRef(t) + defer w.DecRef(t) fds, err := t.NewFDsVFS2(0, []*vfs.FileDescription{r, w}, kernel.FDFlags{ CloseOnExec: flags&linux.O_CLOEXEC != 0, @@ -54,7 +54,7 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags int32) error { if _, err := t.CopyOut(addr, fds); err != nil { for _, fd := range fds { if _, file := t.FDTable().Remove(fd); file != nil { - file.DecRef() + file.DecRef(t) } } return err diff --git a/pkg/sentry/syscalls/linux/vfs2/poll.go b/pkg/sentry/syscalls/linux/vfs2/poll.go index ff1b25d7b..7b9d5e18a 100644 --- a/pkg/sentry/syscalls/linux/vfs2/poll.go +++ b/pkg/sentry/syscalls/linux/vfs2/poll.go @@ -73,7 +73,7 @@ func initReadiness(t *kernel.Task, pfd *linux.PollFD, state *pollState, ch chan } if ch == nil { - defer file.DecRef() + defer file.DecRef(t) } else { state.file = file state.waiter, _ = waiter.NewChannelEntry(ch) @@ -85,11 +85,11 @@ func initReadiness(t *kernel.Task, pfd *linux.PollFD, state *pollState, ch chan } // releaseState releases all the pollState in "state". -func releaseState(state []pollState) { +func releaseState(t *kernel.Task, state []pollState) { for i := range state { if state[i].file != nil { state[i].file.EventUnregister(&state[i].waiter) - state[i].file.DecRef() + state[i].file.DecRef(t) } } } @@ -110,7 +110,7 @@ func pollBlock(t *kernel.Task, pfd []linux.PollFD, timeout time.Duration) (time. // result, we stop registering for events but still go through all files // to get their ready masks. state := make([]pollState, len(pfd)) - defer releaseState(state) + defer releaseState(t, state) n := uintptr(0) for i := range pfd { initReadiness(t, &pfd[i], &state[i], ch) @@ -269,7 +269,7 @@ func doSelect(t *kernel.Task, nfds int, readFDs, writeFDs, exceptFDs usermem.Add if file == nil { return 0, syserror.EBADF } - file.DecRef() + file.DecRef(t) var mask int16 if (rV & m) != 0 { diff --git a/pkg/sentry/syscalls/linux/vfs2/read_write.go b/pkg/sentry/syscalls/linux/vfs2/read_write.go index 3a7ef24f5..a905dae0a 100644 --- a/pkg/sentry/syscalls/linux/vfs2/read_write.go +++ b/pkg/sentry/syscalls/linux/vfs2/read_write.go @@ -44,7 +44,7 @@ func Read(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the size is legitimate. si := int(size) @@ -75,7 +75,7 @@ func Readv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Get the destination of the read. dst, err := t.IovecsIOSequence(addr, iovcnt, usermem.IOOpts{ @@ -93,11 +93,17 @@ func Readv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { n, err := file.Read(t, dst, opts) if err != syserror.ErrWouldBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return n, err } allowBlock, deadline, hasDeadline := blockPolicy(t, file) if !allowBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return n, err } @@ -128,6 +134,9 @@ func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opt } file.EventUnregister(&w) + if total > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return total, err } @@ -142,7 +151,7 @@ func Pread64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate and does not overflow. if offset < 0 || offset+int64(size) < 0 { @@ -179,7 +188,7 @@ func Preadv(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < 0 { @@ -217,7 +226,7 @@ func Preadv2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < -1 { @@ -248,11 +257,17 @@ func Preadv2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca func pread(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) { n, err := file.PRead(t, dst, offset, opts) if err != syserror.ErrWouldBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return n, err } allowBlock, deadline, hasDeadline := blockPolicy(t, file) if !allowBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return n, err } @@ -283,6 +298,9 @@ func pread(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, of } file.EventUnregister(&w) + if total > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return total, err } @@ -296,7 +314,7 @@ func Write(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the size is legitimate. si := int(size) @@ -327,7 +345,7 @@ func Writev(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Get the source of the write. src, err := t.IovecsIOSequence(addr, iovcnt, usermem.IOOpts{ @@ -345,11 +363,17 @@ func Writev(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal func write(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) { n, err := file.Write(t, src, opts) if err != syserror.ErrWouldBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + } return n, err } allowBlock, deadline, hasDeadline := blockPolicy(t, file) if !allowBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + } return n, err } @@ -380,6 +404,9 @@ func write(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, op } file.EventUnregister(&w) + if total > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + } return total, err } @@ -394,7 +421,7 @@ func Pwrite64(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate and does not overflow. if offset < 0 || offset+int64(size) < 0 { @@ -431,7 +458,7 @@ func Pwritev(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < 0 { @@ -469,7 +496,7 @@ func Pwritev2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Check that the offset is legitimate. if offset < -1 { @@ -500,11 +527,17 @@ func Pwritev2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc func pwrite(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) { n, err := file.PWrite(t, src, offset, opts) if err != syserror.ErrWouldBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + } return n, err } allowBlock, deadline, hasDeadline := blockPolicy(t, file) if !allowBlock { + if n > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return n, err } @@ -535,6 +568,9 @@ func pwrite(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, o } file.EventUnregister(&w) + if total > 0 { + file.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + } return total, err } @@ -565,8 +601,41 @@ func Lseek(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) newoff, err := file.Seek(t, offset, whence) return uintptr(newoff), nil, err } + +// Readahead implements readahead(2). +func Readahead(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + offset := args[1].Int64() + size := args[2].SizeT() + + file := t.GetFileVFS2(fd) + if file == nil { + return 0, nil, syserror.EBADF + } + defer file.DecRef(t) + + // Check that the file is readable. + if !file.IsReadable() { + return 0, nil, syserror.EBADF + } + + // Check that the size is valid. + if int(size) < 0 { + return 0, nil, syserror.EINVAL + } + + // Check that the offset is legitimate and does not overflow. + if offset < 0 || offset+int64(size) < 0 { + return 0, nil, syserror.EINVAL + } + + // Return EINVAL; if the underlying file type does not support readahead, + // then Linux will return EINVAL to indicate as much. In the future, we + // may extend this function to actually support readahead hints. + return 0, nil, syserror.EINVAL +} diff --git a/pkg/sentry/syscalls/linux/vfs2/setstat.go b/pkg/sentry/syscalls/linux/vfs2/setstat.go index 09ecfed26..5e6eb13ba 100644 --- a/pkg/sentry/syscalls/linux/vfs2/setstat.go +++ b/pkg/sentry/syscalls/linux/vfs2/setstat.go @@ -20,6 +20,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/limits" "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" @@ -65,7 +66,7 @@ func Fchmod(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, file.SetStat(t, vfs.SetStatOptions{ Stat: linux.Statx{ @@ -150,7 +151,7 @@ func Fchown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) var opts vfs.SetStatOptions if err := populateSetStatOptionsForChown(t, owner, group, &opts); err != nil { @@ -178,6 +179,7 @@ func Truncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc Mask: linux.STATX_SIZE, Size: uint64(length), }, + NeedWritePerm: true, }) return 0, nil, handleSetSizeError(t, err) } @@ -195,7 +197,11 @@ func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) + + if !file.IsWritable() { + return 0, nil, syserror.EINVAL + } err := file.SetStat(t, vfs.SetStatOptions{ Stat: linux.Statx{ @@ -206,6 +212,56 @@ func Ftruncate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys return 0, nil, handleSetSizeError(t, err) } +// Fallocate implements linux system call fallocate(2). +func Fallocate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + mode := args[1].Uint64() + offset := args[2].Int64() + length := args[3].Int64() + + file := t.GetFileVFS2(fd) + + if file == nil { + return 0, nil, syserror.EBADF + } + defer file.DecRef(t) + + if !file.IsWritable() { + return 0, nil, syserror.EBADF + } + + if mode != 0 { + return 0, nil, syserror.ENOTSUP + } + + if offset < 0 || length <= 0 { + return 0, nil, syserror.EINVAL + } + + size := offset + length + + if size < 0 { + return 0, nil, syserror.EFBIG + } + + limit := limits.FromContext(t).Get(limits.FileSize).Cur + + if uint64(size) >= limit { + t.SendSignal(&arch.SignalInfo{ + Signo: int32(linux.SIGXFSZ), + Code: arch.SignalInfoUser, + }) + return 0, nil, syserror.EFBIG + } + + if err := file.Allocate(t, mode, uint64(offset), uint64(length)); err != nil { + return 0, nil, err + } + + file.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + return 0, nil, nil +} + // Utime implements Linux syscall utime(2). func Utime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { pathAddr := args[0].Pointer() @@ -382,7 +438,7 @@ func populateSetStatOptionsForUtimens(t *kernel.Task, timesAddr usermem.Addr, op func setstatat(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPath shouldAllowEmptyPath, shouldFollowFinalSymlink shouldFollowFinalSymlink, opts *vfs.SetStatOptions) error { root := t.FSContext().RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) start := root if !path.Absolute { if !path.HasComponents() && !bool(shouldAllowEmptyPath) { @@ -390,7 +446,7 @@ func setstatat(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPa } if dirfd == linux.AT_FDCWD { start = t.FSContext().WorkingDirectoryVFS2() - defer start.DecRef() + defer start.DecRef(t) } else { dirfile := t.GetFileVFS2(dirfd) if dirfile == nil { @@ -401,13 +457,13 @@ func setstatat(t *kernel.Task, dirfd int32, path fspath.Path, shouldAllowEmptyPa // VirtualFilesystem.SetStatAt(), since the former may be able // to use opened file state to expedite the SetStat. err := dirfile.SetStat(t, *opts) - dirfile.DecRef() + dirfile.DecRef(t) return err } start = dirfile.VirtualDentry() start.IncRef() - defer start.DecRef() - dirfile.DecRef() + defer start.DecRef(t) + dirfile.DecRef(t) } } return t.Kernel().VFS().SetStatAt(t, t.Credentials(), &vfs.PathOperation{ diff --git a/pkg/sentry/syscalls/linux/vfs2/signal.go b/pkg/sentry/syscalls/linux/vfs2/signal.go index 623992f6f..b89f34cdb 100644 --- a/pkg/sentry/syscalls/linux/vfs2/signal.go +++ b/pkg/sentry/syscalls/linux/vfs2/signal.go @@ -45,7 +45,7 @@ func sharedSignalfd(t *kernel.Task, fd int32, sigset usermem.Addr, sigsetsize ui if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Is this a signalfd? if sfd, ok := file.Impl().(*signalfd.SignalFileDescription); ok { @@ -68,7 +68,7 @@ func sharedSignalfd(t *kernel.Task, fd int32, sigset usermem.Addr, sigsetsize ui if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) // Create a new descriptor. fd, err = t.NewFDFromVFS2(0, file, kernel.FDFlags{ diff --git a/pkg/sentry/syscalls/linux/vfs2/socket.go b/pkg/sentry/syscalls/linux/vfs2/socket.go index 10b668477..4a68c64f3 100644 --- a/pkg/sentry/syscalls/linux/vfs2/socket.go +++ b/pkg/sentry/syscalls/linux/vfs2/socket.go @@ -30,6 +30,8 @@ import ( "gvisor.dev/gvisor/pkg/syserr" "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/tools/go_marshal/marshal" + "gvisor.dev/gvisor/tools/go_marshal/primitive" ) // minListenBacklog is the minimum reasonable backlog for listening sockets. @@ -194,7 +196,7 @@ func Socket(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if e != nil { return 0, nil, e.ToError() } - defer s.DecRef() + defer s.DecRef(t) if err := s.SetStatusFlags(t, t.Credentials(), uint32(stype&linux.SOCK_NONBLOCK)); err != nil { return 0, nil, err @@ -228,8 +230,8 @@ func SocketPair(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy return 0, nil, e.ToError() } // Adding to the FD table will cause an extra reference to be acquired. - defer s1.DecRef() - defer s2.DecRef() + defer s1.DecRef(t) + defer s2.DecRef(t) nonblocking := uint32(stype & linux.SOCK_NONBLOCK) if err := s1.SetStatusFlags(t, t.Credentials(), nonblocking); err != nil { @@ -251,7 +253,7 @@ func SocketPair(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if _, err := t.CopyOut(addr, fds); err != nil { for _, fd := range fds { if _, file := t.FDTable().Remove(fd); file != nil { - file.DecRef() + file.DecRef(t) } } return 0, nil, err @@ -271,7 +273,7 @@ func Connect(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -302,7 +304,7 @@ func accept(t *kernel.Task, fd int32, addr usermem.Addr, addrLen usermem.Addr, f if file == nil { return 0, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -361,7 +363,7 @@ func Bind(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -388,7 +390,7 @@ func Listen(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -417,7 +419,7 @@ func Shutdown(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -448,7 +450,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -477,7 +479,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy } if v != nil { - if _, err := t.CopyOut(optValAddr, v); err != nil { + if _, err := v.CopyOut(t, optValAddr); err != nil { return 0, nil, err } } @@ -487,7 +489,7 @@ func GetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy // getSockOpt tries to handle common socket options, or dispatches to a specific // socket implementation. -func getSockOpt(t *kernel.Task, s socket.SocketVFS2, level, name int, optValAddr usermem.Addr, len int) (interface{}, *syserr.Error) { +func getSockOpt(t *kernel.Task, s socket.SocketVFS2, level, name int, optValAddr usermem.Addr, len int) (marshal.Marshallable, *syserr.Error) { if level == linux.SOL_SOCKET { switch name { case linux.SO_TYPE, linux.SO_DOMAIN, linux.SO_PROTOCOL: @@ -499,13 +501,16 @@ func getSockOpt(t *kernel.Task, s socket.SocketVFS2, level, name int, optValAddr switch name { case linux.SO_TYPE: _, skType, _ := s.Type() - return int32(skType), nil + v := primitive.Int32(skType) + return &v, nil case linux.SO_DOMAIN: family, _, _ := s.Type() - return int32(family), nil + v := primitive.Int32(family) + return &v, nil case linux.SO_PROTOCOL: _, _, protocol := s.Type() - return int32(protocol), nil + v := primitive.Int32(protocol) + return &v, nil } } @@ -527,7 +532,7 @@ func SetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -542,7 +547,7 @@ func SetSockOpt(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy return 0, nil, syserror.EINVAL } buf := t.CopyScratchBuffer(int(optLen)) - if _, err := t.CopyIn(optValAddr, &buf); err != nil { + if _, err := t.CopyInBytes(optValAddr, buf); err != nil { return 0, nil, err } @@ -565,7 +570,7 @@ func GetSockName(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -593,7 +598,7 @@ func GetPeerName(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -626,7 +631,7 @@ func RecvMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -679,7 +684,7 @@ func RecvMMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -773,7 +778,7 @@ func recvSingleMsg(t *kernel.Task, s socket.SocketVFS2, msgPtr usermem.Addr, fla } if !cms.Unix.Empty() { mflags |= linux.MSG_CTRUNC - cms.Release() + cms.Release(t) } if int(msg.Flags) != mflags { @@ -793,7 +798,7 @@ func recvSingleMsg(t *kernel.Task, s socket.SocketVFS2, msgPtr usermem.Addr, fla if e != nil { return 0, syserror.ConvertIntr(e.ToError(), kernel.ERESTARTSYS) } - defer cms.Release() + defer cms.Release(t) controlData := make([]byte, 0, msg.ControlLen) controlData = control.PackControlMessages(t, cms, controlData) @@ -849,7 +854,7 @@ func recvFrom(t *kernel.Task, fd int32, bufPtr usermem.Addr, bufLen uint64, flag if file == nil { return 0, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -878,7 +883,7 @@ func recvFrom(t *kernel.Task, fd int32, bufPtr usermem.Addr, bufLen uint64, flag } n, _, sender, senderLen, cm, e := s.RecvMsg(t, dst, int(flags), haveDeadline, deadline, nameLenPtr != 0, 0) - cm.Release() + cm.Release(t) if e != nil { return 0, syserror.ConvertIntr(e.ToError(), kernel.ERESTARTSYS) } @@ -922,7 +927,7 @@ func SendMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -960,7 +965,7 @@ func SendMMsg(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) @@ -1064,7 +1069,7 @@ func sendSingleMsg(t *kernel.Task, s socket.SocketVFS2, file *vfs.FileDescriptio n, e := s.SendMsg(t, src, to, int(flags), haveDeadline, deadline, controlMessages) err = slinux.HandleIOErrorVFS2(t, n != 0, e.ToError(), kernel.ERESTARTSYS, "sendmsg", file) if err != nil { - controlMessages.Release() + controlMessages.Release(t) } return uintptr(n), err } @@ -1082,7 +1087,7 @@ func sendTo(t *kernel.Task, fd int32, bufPtr usermem.Addr, bufLen uint64, flags if file == nil { return 0, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) // Extract the socket. s, ok := file.Impl().(socket.SocketVFS2) diff --git a/pkg/sentry/syscalls/linux/vfs2/splice.go b/pkg/sentry/syscalls/linux/vfs2/splice.go new file mode 100644 index 000000000..75bfa2c79 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/splice.go @@ -0,0 +1,490 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs2 + +import ( + "io" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +// Splice implements Linux syscall splice(2). +func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + inFD := args[0].Int() + inOffsetPtr := args[1].Pointer() + outFD := args[2].Int() + outOffsetPtr := args[3].Pointer() + count := int64(args[4].SizeT()) + flags := args[5].Int() + + if count == 0 { + return 0, nil, nil + } + if count > int64(kernel.MAX_RW_COUNT) { + count = int64(kernel.MAX_RW_COUNT) + } + + // Check for invalid flags. + if flags&^(linux.SPLICE_F_MOVE|linux.SPLICE_F_NONBLOCK|linux.SPLICE_F_MORE|linux.SPLICE_F_GIFT) != 0 { + return 0, nil, syserror.EINVAL + } + + // Get file descriptions. + inFile := t.GetFileVFS2(inFD) + if inFile == nil { + return 0, nil, syserror.EBADF + } + defer inFile.DecRef(t) + outFile := t.GetFileVFS2(outFD) + if outFile == nil { + return 0, nil, syserror.EBADF + } + defer outFile.DecRef(t) + + // Check that both files support the required directionality. + if !inFile.IsReadable() || !outFile.IsWritable() { + return 0, nil, syserror.EBADF + } + + // The operation is non-blocking if anything is non-blocking. + // + // N.B. This is a rather simplistic heuristic that avoids some + // poor edge case behavior since the exact semantics here are + // underspecified and vary between versions of Linux itself. + nonBlock := ((inFile.StatusFlags()|outFile.StatusFlags())&linux.O_NONBLOCK != 0) || (flags&linux.SPLICE_F_NONBLOCK != 0) + + // At least one file description must represent a pipe. + inPipeFD, inIsPipe := inFile.Impl().(*pipe.VFSPipeFD) + outPipeFD, outIsPipe := outFile.Impl().(*pipe.VFSPipeFD) + if !inIsPipe && !outIsPipe { + return 0, nil, syserror.EINVAL + } + + // Copy in offsets. + inOffset := int64(-1) + if inOffsetPtr != 0 { + if inIsPipe { + return 0, nil, syserror.ESPIPE + } + if inFile.Options().DenyPRead { + return 0, nil, syserror.EINVAL + } + if _, err := t.CopyIn(inOffsetPtr, &inOffset); err != nil { + return 0, nil, err + } + if inOffset < 0 { + return 0, nil, syserror.EINVAL + } + } + outOffset := int64(-1) + if outOffsetPtr != 0 { + if outIsPipe { + return 0, nil, syserror.ESPIPE + } + if outFile.Options().DenyPWrite { + return 0, nil, syserror.EINVAL + } + if _, err := t.CopyIn(outOffsetPtr, &outOffset); err != nil { + return 0, nil, err + } + if outOffset < 0 { + return 0, nil, syserror.EINVAL + } + } + + // Move data. + var ( + n int64 + err error + ) + dw := dualWaiter{ + inFile: inFile, + outFile: outFile, + } + defer dw.destroy() + for { + // If both input and output are pipes, delegate to the pipe + // implementation. Otherwise, exactly one end is a pipe, which + // we ensure is consistently ordered after the non-pipe FD's + // locks by passing the pipe FD as usermem.IO to the non-pipe + // end. + switch { + case inIsPipe && outIsPipe: + n, err = pipe.Splice(t, outPipeFD, inPipeFD, count) + case inIsPipe: + if outOffset != -1 { + n, err = outFile.PWrite(t, inPipeFD.IOSequence(count), outOffset, vfs.WriteOptions{}) + outOffset += n + } else { + n, err = outFile.Write(t, inPipeFD.IOSequence(count), vfs.WriteOptions{}) + } + case outIsPipe: + if inOffset != -1 { + n, err = inFile.PRead(t, outPipeFD.IOSequence(count), inOffset, vfs.ReadOptions{}) + inOffset += n + } else { + n, err = inFile.Read(t, outPipeFD.IOSequence(count), vfs.ReadOptions{}) + } + default: + panic("not possible") + } + + if n != 0 || err != syserror.ErrWouldBlock || nonBlock { + break + } + if err = dw.waitForBoth(t); err != nil { + break + } + } + + // Copy updated offsets out. + if inOffsetPtr != 0 { + if _, err := t.CopyOut(inOffsetPtr, &inOffset); err != nil { + return 0, nil, err + } + } + if outOffsetPtr != 0 { + if _, err := t.CopyOut(outOffsetPtr, &outOffset); err != nil { + return 0, nil, err + } + } + + if n == 0 { + return 0, nil, err + } + + // On Linux, inotify behavior is not very consistent with splice(2). We try + // our best to emulate Linux for very basic calls to splice, where for some + // reason, events are generated for output files, but not input files. + outFile.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + return uintptr(n), nil, nil +} + +// Tee implements Linux syscall tee(2). +func Tee(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + inFD := args[0].Int() + outFD := args[1].Int() + count := int64(args[2].SizeT()) + flags := args[3].Int() + + if count == 0 { + return 0, nil, nil + } + if count > int64(kernel.MAX_RW_COUNT) { + count = int64(kernel.MAX_RW_COUNT) + } + + // Check for invalid flags. + if flags&^(linux.SPLICE_F_MOVE|linux.SPLICE_F_NONBLOCK|linux.SPLICE_F_MORE|linux.SPLICE_F_GIFT) != 0 { + return 0, nil, syserror.EINVAL + } + + // Get file descriptions. + inFile := t.GetFileVFS2(inFD) + if inFile == nil { + return 0, nil, syserror.EBADF + } + defer inFile.DecRef(t) + outFile := t.GetFileVFS2(outFD) + if outFile == nil { + return 0, nil, syserror.EBADF + } + defer outFile.DecRef(t) + + // Check that both files support the required directionality. + if !inFile.IsReadable() || !outFile.IsWritable() { + return 0, nil, syserror.EBADF + } + + // The operation is non-blocking if anything is non-blocking. + // + // N.B. This is a rather simplistic heuristic that avoids some + // poor edge case behavior since the exact semantics here are + // underspecified and vary between versions of Linux itself. + nonBlock := ((inFile.StatusFlags()|outFile.StatusFlags())&linux.O_NONBLOCK != 0) || (flags&linux.SPLICE_F_NONBLOCK != 0) + + // Both file descriptions must represent pipes. + inPipeFD, inIsPipe := inFile.Impl().(*pipe.VFSPipeFD) + outPipeFD, outIsPipe := outFile.Impl().(*pipe.VFSPipeFD) + if !inIsPipe || !outIsPipe { + return 0, nil, syserror.EINVAL + } + + // Copy data. + var ( + n int64 + err error + ) + dw := dualWaiter{ + inFile: inFile, + outFile: outFile, + } + defer dw.destroy() + for { + n, err = pipe.Tee(t, outPipeFD, inPipeFD, count) + if n != 0 || err != syserror.ErrWouldBlock || nonBlock { + break + } + if err = dw.waitForBoth(t); err != nil { + break + } + } + if n == 0 { + return 0, nil, err + } + outFile.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + return uintptr(n), nil, nil +} + +// Sendfile implements linux system call sendfile(2). +func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + outFD := args[0].Int() + inFD := args[1].Int() + offsetAddr := args[2].Pointer() + count := int64(args[3].SizeT()) + + inFile := t.GetFileVFS2(inFD) + if inFile == nil { + return 0, nil, syserror.EBADF + } + defer inFile.DecRef(t) + if !inFile.IsReadable() { + return 0, nil, syserror.EBADF + } + + outFile := t.GetFileVFS2(outFD) + if outFile == nil { + return 0, nil, syserror.EBADF + } + defer outFile.DecRef(t) + if !outFile.IsWritable() { + return 0, nil, syserror.EBADF + } + + // Verify that the outFile Append flag is not set. + if outFile.StatusFlags()&linux.O_APPEND != 0 { + return 0, nil, syserror.EINVAL + } + + // Verify that inFile is a regular file or block device. This is a + // requirement; the same check appears in Linux + // (fs/splice.c:splice_direct_to_actor). + if stat, err := inFile.Stat(t, vfs.StatOptions{Mask: linux.STATX_TYPE}); err != nil { + return 0, nil, err + } else if stat.Mask&linux.STATX_TYPE == 0 || + (stat.Mode&linux.S_IFMT != linux.S_IFREG && stat.Mode&linux.S_IFMT != linux.S_IFBLK) { + return 0, nil, syserror.EINVAL + } + + // Copy offset if it exists. + offset := int64(-1) + if offsetAddr != 0 { + if inFile.Options().DenyPRead { + return 0, nil, syserror.ESPIPE + } + if _, err := t.CopyIn(offsetAddr, &offset); err != nil { + return 0, nil, err + } + if offset < 0 { + return 0, nil, syserror.EINVAL + } + if offset+count < 0 { + return 0, nil, syserror.EINVAL + } + } + + // Validate count. This must come after offset checks. + if count < 0 { + return 0, nil, syserror.EINVAL + } + if count == 0 { + return 0, nil, nil + } + if count > int64(kernel.MAX_RW_COUNT) { + count = int64(kernel.MAX_RW_COUNT) + } + + // Copy data. + var ( + n int64 + err error + ) + dw := dualWaiter{ + inFile: inFile, + outFile: outFile, + } + defer dw.destroy() + outPipeFD, outIsPipe := outFile.Impl().(*pipe.VFSPipeFD) + // Reading from input file should never block, since it is regular or + // block device. We only need to check if writing to the output file + // can block. + nonBlock := outFile.StatusFlags()&linux.O_NONBLOCK != 0 + if outIsPipe { + for n < count { + var spliceN int64 + if offset != -1 { + spliceN, err = inFile.PRead(t, outPipeFD.IOSequence(count), offset, vfs.ReadOptions{}) + offset += spliceN + } else { + spliceN, err = inFile.Read(t, outPipeFD.IOSequence(count), vfs.ReadOptions{}) + } + if spliceN == 0 && err == io.EOF { + // We reached the end of the file. Eat the error and exit the loop. + err = nil + break + } + n += spliceN + if err == syserror.ErrWouldBlock && !nonBlock { + err = dw.waitForBoth(t) + } + if err != nil { + break + } + } + } else { + // Read inFile to buffer, then write the contents to outFile. + buf := make([]byte, count) + for n < count { + var readN int64 + if offset != -1 { + readN, err = inFile.PRead(t, usermem.BytesIOSequence(buf), offset, vfs.ReadOptions{}) + offset += readN + } else { + readN, err = inFile.Read(t, usermem.BytesIOSequence(buf), vfs.ReadOptions{}) + } + if readN == 0 && err == io.EOF { + // We reached the end of the file. Eat the error and exit the loop. + err = nil + break + } + n += readN + if err != nil { + break + } + + // Write all of the bytes that we read. This may need + // multiple write calls to complete. + wbuf := buf[:n] + for len(wbuf) > 0 { + var writeN int64 + writeN, err = outFile.Write(t, usermem.BytesIOSequence(wbuf), vfs.WriteOptions{}) + wbuf = wbuf[writeN:] + if err == syserror.ErrWouldBlock && !nonBlock { + err = dw.waitForOut(t) + } + if err != nil { + // We didn't complete the write. Only + // report the bytes that were actually + // written, and rewind the offset. + notWritten := int64(len(wbuf)) + n -= notWritten + if offset != -1 { + offset -= notWritten + } + break + } + } + if err == syserror.ErrWouldBlock && !nonBlock { + err = dw.waitForBoth(t) + } + if err != nil { + break + } + } + } + + if offsetAddr != 0 { + // Copy out the new offset. + if _, err := t.CopyOut(offsetAddr, offset); err != nil { + return 0, nil, err + } + } + + if n == 0 { + return 0, nil, err + } + + inFile.Dentry().InotifyWithParent(t, linux.IN_ACCESS, 0, vfs.PathEvent) + outFile.Dentry().InotifyWithParent(t, linux.IN_MODIFY, 0, vfs.PathEvent) + return uintptr(n), nil, nil +} + +// dualWaiter is used to wait on one or both vfs.FileDescriptions. It is not +// thread-safe, and does not take a reference on the vfs.FileDescriptions. +// +// Users must call destroy() when finished. +type dualWaiter struct { + inFile *vfs.FileDescription + outFile *vfs.FileDescription + + inW waiter.Entry + inCh chan struct{} + outW waiter.Entry + outCh chan struct{} +} + +// waitForBoth waits for both dw.inFile and dw.outFile to be ready. +func (dw *dualWaiter) waitForBoth(t *kernel.Task) error { + if dw.inFile.Readiness(eventMaskRead)&eventMaskRead == 0 { + if dw.inCh == nil { + dw.inW, dw.inCh = waiter.NewChannelEntry(nil) + dw.inFile.EventRegister(&dw.inW, eventMaskRead) + // We might be ready now. Try again before blocking. + return nil + } + if err := t.Block(dw.inCh); err != nil { + return err + } + } + return dw.waitForOut(t) +} + +// waitForOut waits for dw.outfile to be read. +func (dw *dualWaiter) waitForOut(t *kernel.Task) error { + if dw.outFile.Readiness(eventMaskWrite)&eventMaskWrite == 0 { + if dw.outCh == nil { + dw.outW, dw.outCh = waiter.NewChannelEntry(nil) + dw.outFile.EventRegister(&dw.outW, eventMaskWrite) + // We might be ready now. Try again before blocking. + return nil + } + if err := t.Block(dw.outCh); err != nil { + return err + } + } + return nil +} + +// destroy cleans up resources help by dw. No more calls to wait* can occur +// after destroy is called. +func (dw *dualWaiter) destroy() { + if dw.inCh != nil { + dw.inFile.EventUnregister(&dw.inW) + dw.inCh = nil + } + if dw.outCh != nil { + dw.outFile.EventUnregister(&dw.outW) + dw.outCh = nil + } + dw.inFile = nil + dw.outFile = nil +} diff --git a/pkg/sentry/syscalls/linux/vfs2/stat.go b/pkg/sentry/syscalls/linux/vfs2/stat.go index bb1d5cac4..0f5d5189c 100644 --- a/pkg/sentry/syscalls/linux/vfs2/stat.go +++ b/pkg/sentry/syscalls/linux/vfs2/stat.go @@ -65,7 +65,7 @@ func fstatat(t *kernel.Task, dirfd int32, pathAddr, statAddr usermem.Addr, flags } root := t.FSContext().RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) start := root if !path.Absolute { if !path.HasComponents() && flags&linux.AT_EMPTY_PATH == 0 { @@ -73,7 +73,7 @@ func fstatat(t *kernel.Task, dirfd int32, pathAddr, statAddr usermem.Addr, flags } if dirfd == linux.AT_FDCWD { start = t.FSContext().WorkingDirectoryVFS2() - defer start.DecRef() + defer start.DecRef(t) } else { dirfile := t.GetFileVFS2(dirfd) if dirfile == nil { @@ -85,7 +85,7 @@ func fstatat(t *kernel.Task, dirfd int32, pathAddr, statAddr usermem.Addr, flags // former may be able to use opened file state to expedite the // Stat. statx, err := dirfile.Stat(t, opts) - dirfile.DecRef() + dirfile.DecRef(t) if err != nil { return err } @@ -96,8 +96,8 @@ func fstatat(t *kernel.Task, dirfd int32, pathAddr, statAddr usermem.Addr, flags } start = dirfile.VirtualDentry() start.IncRef() - defer start.DecRef() - dirfile.DecRef() + defer start.DecRef(t) + dirfile.DecRef(t) } } @@ -132,7 +132,7 @@ func Fstat(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) statx, err := file.Stat(t, vfs.StatOptions{ Mask: linux.STATX_BASIC_STATS, @@ -177,7 +177,7 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } root := t.FSContext().RootDirectoryVFS2() - defer root.DecRef() + defer root.DecRef(t) start := root if !path.Absolute { if !path.HasComponents() && flags&linux.AT_EMPTY_PATH == 0 { @@ -185,7 +185,7 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } if dirfd == linux.AT_FDCWD { start = t.FSContext().WorkingDirectoryVFS2() - defer start.DecRef() + defer start.DecRef(t) } else { dirfile := t.GetFileVFS2(dirfd) if dirfile == nil { @@ -197,7 +197,7 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall // former may be able to use opened file state to expedite the // Stat. statx, err := dirfile.Stat(t, opts) - dirfile.DecRef() + dirfile.DecRef(t) if err != nil { return 0, nil, err } @@ -207,8 +207,8 @@ func Statx(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } start = dirfile.VirtualDentry() start.IncRef() - defer start.DecRef() - dirfile.DecRef() + defer start.DecRef(t) + dirfile.DecRef(t) } } @@ -282,7 +282,7 @@ func accessAt(t *kernel.Task, dirfd int32, pathAddr usermem.Addr, mode uint) err if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) // access(2) and faccessat(2) check permissions using real // UID/GID, not effective UID/GID. @@ -328,7 +328,7 @@ func readlinkat(t *kernel.Task, dirfd int32, pathAddr, bufAddr usermem.Addr, siz if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) target, err := t.Kernel().VFS().ReadlinkAt(t, t.Credentials(), &tpop.pop) if err != nil { @@ -358,7 +358,7 @@ func Statfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) statfs, err := t.Kernel().VFS().StatFSAt(t, t.Credentials(), &tpop.pop) if err != nil { @@ -377,7 +377,7 @@ func Fstatfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) statfs, err := t.Kernel().VFS().StatFSAt(t, t.Credentials(), &tpop.pop) if err != nil { diff --git a/pkg/sentry/syscalls/linux/vfs2/sync.go b/pkg/sentry/syscalls/linux/vfs2/sync.go index 365250b0b..a6491ac37 100644 --- a/pkg/sentry/syscalls/linux/vfs2/sync.go +++ b/pkg/sentry/syscalls/linux/vfs2/sync.go @@ -34,7 +34,7 @@ func Syncfs(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, file.SyncFS(t) } @@ -47,7 +47,7 @@ func Fsync(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) return 0, nil, file.Sync(t) } @@ -65,10 +65,8 @@ func SyncFileRange(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel nbytes := args[2].Int64() flags := args[3].Uint() - if offset < 0 { - return 0, nil, syserror.EINVAL - } - if nbytes < 0 { + // Check for negative values and overflow. + if offset < 0 || offset+nbytes < 0 { return 0, nil, syserror.EINVAL } if flags&^(linux.SYNC_FILE_RANGE_WAIT_BEFORE|linux.SYNC_FILE_RANGE_WRITE|linux.SYNC_FILE_RANGE_WAIT_AFTER) != 0 { @@ -79,9 +77,39 @@ func SyncFileRange(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) - // TODO(gvisor.dev/issue/1897): Avoid writeback of data ranges outside of - // [offset, offset+nbytes). - return 0, nil, file.Sync(t) + // TODO(gvisor.dev/issue/1897): Currently, the only file syncing we support + // is a full-file sync, i.e. fsync(2). As a result, there are severe + // limitations on how much we support sync_file_range: + // - In Linux, sync_file_range(2) doesn't write out the file's metadata, even + // if the file size is changed. We do. + // - We always sync the entire file instead of [offset, offset+nbytes). + // - We do not support the use of WAIT_BEFORE without WAIT_AFTER. For + // correctness, we would have to perform a write-out every time WAIT_BEFORE + // was used, but this would be much more expensive than expected if there + // were no write-out operations in progress. + // - Whenever WAIT_AFTER is used, we sync the file. + // - Ignore WRITE. If this flag is used with WAIT_AFTER, then the file will + // be synced anyway. If this flag is used without WAIT_AFTER, then it is + // safe (and less expensive) to do nothing, because the syscall will not + // wait for the write-out to complete--we only need to make sure that the + // next time WAIT_BEFORE or WAIT_AFTER are used, the write-out completes. + // - According to fs/sync.c, WAIT_BEFORE|WAIT_AFTER "will detect any I/O + // errors or ENOSPC conditions and will return those to the caller, after + // clearing the EIO and ENOSPC flags in the address_space." We don't do + // this. + + if flags&linux.SYNC_FILE_RANGE_WAIT_BEFORE != 0 && + flags&linux.SYNC_FILE_RANGE_WAIT_AFTER == 0 { + t.Kernel().EmitUnimplementedEvent(t) + return 0, nil, syserror.ENOSYS + } + + if flags&linux.SYNC_FILE_RANGE_WAIT_AFTER != 0 { + if err := file.Sync(t); err != nil { + return 0, nil, syserror.ConvertIntr(err, kernel.ERESTARTSYS) + } + } + return 0, nil, nil } diff --git a/pkg/sentry/syscalls/linux/vfs2/timerfd.go b/pkg/sentry/syscalls/linux/vfs2/timerfd.go index 5ac79bc09..7a26890ef 100644 --- a/pkg/sentry/syscalls/linux/vfs2/timerfd.go +++ b/pkg/sentry/syscalls/linux/vfs2/timerfd.go @@ -50,11 +50,11 @@ func TimerfdCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel return 0, nil, syserror.EINVAL } vfsObj := t.Kernel().VFS() - file, err := timerfd.New(vfsObj, clock, fileFlags) + file, err := timerfd.New(t, vfsObj, clock, fileFlags) if err != nil { return 0, nil, err } - defer file.DecRef() + defer file.DecRef(t) fd, err := t.NewFDFromVFS2(0, file, kernel.FDFlags{ CloseOnExec: flags&linux.TFD_CLOEXEC != 0, }) @@ -79,7 +79,7 @@ func TimerfdSettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) tfd, ok := file.Impl().(*timerfd.TimerFileDescription) if !ok { @@ -113,7 +113,7 @@ func TimerfdGettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kerne if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) tfd, ok := file.Impl().(*timerfd.TimerFileDescription) if !ok { diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go index a332d01bd..c576d9475 100644 --- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go +++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go @@ -44,7 +44,7 @@ func Override() { s.Table[23] = syscalls.Supported("select", Select) s.Table[32] = syscalls.Supported("dup", Dup) s.Table[33] = syscalls.Supported("dup2", Dup2) - delete(s.Table, 40) // sendfile + s.Table[40] = syscalls.Supported("sendfile", Sendfile) s.Table[41] = syscalls.Supported("socket", Socket) s.Table[42] = syscalls.Supported("connect", Connect) s.Table[43] = syscalls.Supported("accept", Accept) @@ -62,7 +62,7 @@ func Override() { s.Table[55] = syscalls.Supported("getsockopt", GetSockOpt) s.Table[59] = syscalls.Supported("execve", Execve) s.Table[72] = syscalls.Supported("fcntl", Fcntl) - delete(s.Table, 73) // flock + s.Table[73] = syscalls.Supported("flock", Flock) s.Table[74] = syscalls.Supported("fsync", Fsync) s.Table[75] = syscalls.Supported("fdatasync", Fdatasync) s.Table[76] = syscalls.Supported("truncate", Truncate) @@ -90,9 +90,9 @@ func Override() { s.Table[138] = syscalls.Supported("fstatfs", Fstatfs) s.Table[161] = syscalls.Supported("chroot", Chroot) s.Table[162] = syscalls.Supported("sync", Sync) - delete(s.Table, 165) // mount - delete(s.Table, 166) // umount2 - delete(s.Table, 187) // readahead + s.Table[165] = syscalls.Supported("mount", Mount) + s.Table[166] = syscalls.Supported("umount2", Umount2) + s.Table[187] = syscalls.Supported("readahead", Readahead) s.Table[188] = syscalls.Supported("setxattr", Setxattr) s.Table[189] = syscalls.Supported("lsetxattr", Lsetxattr) s.Table[190] = syscalls.Supported("fsetxattr", Fsetxattr) @@ -105,20 +105,16 @@ func Override() { s.Table[197] = syscalls.Supported("removexattr", Removexattr) s.Table[198] = syscalls.Supported("lremovexattr", Lremovexattr) s.Table[199] = syscalls.Supported("fremovexattr", Fremovexattr) - delete(s.Table, 206) // io_setup - delete(s.Table, 207) // io_destroy - delete(s.Table, 208) // io_getevents - delete(s.Table, 209) // io_submit - delete(s.Table, 210) // io_cancel + s.Table[209] = syscalls.PartiallySupported("io_submit", IoSubmit, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}) s.Table[213] = syscalls.Supported("epoll_create", EpollCreate) s.Table[217] = syscalls.Supported("getdents64", Getdents64) - delete(s.Table, 221) // fdavise64 + s.Table[221] = syscalls.PartiallySupported("fadvise64", Fadvise64, "The syscall is 'supported', but ignores all provided advice.", nil) s.Table[232] = syscalls.Supported("epoll_wait", EpollWait) s.Table[233] = syscalls.Supported("epoll_ctl", EpollCtl) s.Table[235] = syscalls.Supported("utimes", Utimes) - delete(s.Table, 253) // inotify_init - delete(s.Table, 254) // inotify_add_watch - delete(s.Table, 255) // inotify_rm_watch + s.Table[253] = syscalls.PartiallySupported("inotify_init", InotifyInit, "inotify events are only available inside the sandbox.", nil) + s.Table[254] = syscalls.PartiallySupported("inotify_add_watch", InotifyAddWatch, "inotify events are only available inside the sandbox.", nil) + s.Table[255] = syscalls.PartiallySupported("inotify_rm_watch", InotifyRmWatch, "inotify events are only available inside the sandbox.", nil) s.Table[257] = syscalls.Supported("openat", Openat) s.Table[258] = syscalls.Supported("mkdirat", Mkdirat) s.Table[259] = syscalls.Supported("mknodat", Mknodat) @@ -134,15 +130,15 @@ func Override() { s.Table[269] = syscalls.Supported("faccessat", Faccessat) s.Table[270] = syscalls.Supported("pselect", Pselect) s.Table[271] = syscalls.Supported("ppoll", Ppoll) - delete(s.Table, 275) // splice - delete(s.Table, 276) // tee + s.Table[275] = syscalls.Supported("splice", Splice) + s.Table[276] = syscalls.Supported("tee", Tee) s.Table[277] = syscalls.Supported("sync_file_range", SyncFileRange) s.Table[280] = syscalls.Supported("utimensat", Utimensat) s.Table[281] = syscalls.Supported("epoll_pwait", EpollPwait) s.Table[282] = syscalls.Supported("signalfd", Signalfd) s.Table[283] = syscalls.Supported("timerfd_create", TimerfdCreate) s.Table[284] = syscalls.Supported("eventfd", Eventfd) - delete(s.Table, 285) // fallocate + s.Table[285] = syscalls.PartiallySupported("fallocate", Fallocate, "Not all options are supported.", nil) s.Table[286] = syscalls.Supported("timerfd_settime", TimerfdSettime) s.Table[287] = syscalls.Supported("timerfd_gettime", TimerfdGettime) s.Table[288] = syscalls.Supported("accept4", Accept4) @@ -151,7 +147,7 @@ func Override() { s.Table[291] = syscalls.Supported("epoll_create1", EpollCreate1) s.Table[292] = syscalls.Supported("dup3", Dup3) s.Table[293] = syscalls.Supported("pipe2", Pipe2) - delete(s.Table, 294) // inotify_init1 + s.Table[294] = syscalls.PartiallySupported("inotify_init1", InotifyInit1, "inotify events are only available inside the sandbox.", nil) s.Table[295] = syscalls.Supported("preadv", Preadv) s.Table[296] = syscalls.Supported("pwritev", Pwritev) s.Table[299] = syscalls.Supported("recvmmsg", RecvMMsg) @@ -167,6 +163,106 @@ func Override() { // Override ARM64. s = linux.ARM64 + s.Table[5] = syscalls.Supported("setxattr", Setxattr) + s.Table[6] = syscalls.Supported("lsetxattr", Lsetxattr) + s.Table[7] = syscalls.Supported("fsetxattr", Fsetxattr) + s.Table[8] = syscalls.Supported("getxattr", Getxattr) + s.Table[9] = syscalls.Supported("lgetxattr", Lgetxattr) + s.Table[10] = syscalls.Supported("fgetxattr", Fgetxattr) + s.Table[11] = syscalls.Supported("listxattr", Listxattr) + s.Table[12] = syscalls.Supported("llistxattr", Llistxattr) + s.Table[13] = syscalls.Supported("flistxattr", Flistxattr) + s.Table[14] = syscalls.Supported("removexattr", Removexattr) + s.Table[15] = syscalls.Supported("lremovexattr", Lremovexattr) + s.Table[16] = syscalls.Supported("fremovexattr", Fremovexattr) + s.Table[17] = syscalls.Supported("getcwd", Getcwd) + s.Table[19] = syscalls.Supported("eventfd2", Eventfd2) + s.Table[20] = syscalls.Supported("epoll_create1", EpollCreate1) + s.Table[21] = syscalls.Supported("epoll_ctl", EpollCtl) + s.Table[22] = syscalls.Supported("epoll_pwait", EpollPwait) + s.Table[23] = syscalls.Supported("dup", Dup) + s.Table[24] = syscalls.Supported("dup3", Dup3) + s.Table[25] = syscalls.Supported("fcntl", Fcntl) + s.Table[26] = syscalls.PartiallySupported("inotify_init1", InotifyInit1, "inotify events are only available inside the sandbox.", nil) + s.Table[27] = syscalls.PartiallySupported("inotify_add_watch", InotifyAddWatch, "inotify events are only available inside the sandbox.", nil) + s.Table[28] = syscalls.PartiallySupported("inotify_rm_watch", InotifyRmWatch, "inotify events are only available inside the sandbox.", nil) + s.Table[29] = syscalls.Supported("ioctl", Ioctl) + s.Table[32] = syscalls.Supported("flock", Flock) + s.Table[33] = syscalls.Supported("mknodat", Mknodat) + s.Table[34] = syscalls.Supported("mkdirat", Mkdirat) + s.Table[35] = syscalls.Supported("unlinkat", Unlinkat) + s.Table[36] = syscalls.Supported("symlinkat", Symlinkat) + s.Table[37] = syscalls.Supported("linkat", Linkat) + s.Table[38] = syscalls.Supported("renameat", Renameat) + s.Table[39] = syscalls.Supported("umount2", Umount2) + s.Table[40] = syscalls.Supported("mount", Mount) + s.Table[43] = syscalls.Supported("statfs", Statfs) + s.Table[44] = syscalls.Supported("fstatfs", Fstatfs) + s.Table[45] = syscalls.Supported("truncate", Truncate) + s.Table[46] = syscalls.Supported("ftruncate", Ftruncate) + s.Table[48] = syscalls.Supported("faccessat", Faccessat) + s.Table[49] = syscalls.Supported("chdir", Chdir) + s.Table[50] = syscalls.Supported("fchdir", Fchdir) + s.Table[51] = syscalls.Supported("chroot", Chroot) + s.Table[52] = syscalls.Supported("fchmod", Fchmod) + s.Table[53] = syscalls.Supported("fchmodat", Fchmodat) + s.Table[54] = syscalls.Supported("fchownat", Fchownat) + s.Table[55] = syscalls.Supported("fchown", Fchown) + s.Table[56] = syscalls.Supported("openat", Openat) + s.Table[57] = syscalls.Supported("close", Close) + s.Table[59] = syscalls.Supported("pipe2", Pipe2) + s.Table[61] = syscalls.Supported("getdents64", Getdents64) + s.Table[62] = syscalls.Supported("lseek", Lseek) s.Table[63] = syscalls.Supported("read", Read) + s.Table[64] = syscalls.Supported("write", Write) + s.Table[65] = syscalls.Supported("readv", Readv) + s.Table[66] = syscalls.Supported("writev", Writev) + s.Table[67] = syscalls.Supported("pread64", Pread64) + s.Table[68] = syscalls.Supported("pwrite64", Pwrite64) + s.Table[69] = syscalls.Supported("preadv", Preadv) + s.Table[70] = syscalls.Supported("pwritev", Pwritev) + s.Table[72] = syscalls.Supported("pselect", Pselect) + s.Table[73] = syscalls.Supported("ppoll", Ppoll) + s.Table[74] = syscalls.Supported("signalfd4", Signalfd4) + s.Table[76] = syscalls.Supported("splice", Splice) + s.Table[77] = syscalls.Supported("tee", Tee) + s.Table[78] = syscalls.Supported("readlinkat", Readlinkat) + s.Table[80] = syscalls.Supported("fstat", Fstat) + s.Table[81] = syscalls.Supported("sync", Sync) + s.Table[82] = syscalls.Supported("fsync", Fsync) + s.Table[83] = syscalls.Supported("fdatasync", Fdatasync) + s.Table[84] = syscalls.Supported("sync_file_range", SyncFileRange) + s.Table[85] = syscalls.Supported("timerfd_create", TimerfdCreate) + s.Table[86] = syscalls.Supported("timerfd_settime", TimerfdSettime) + s.Table[87] = syscalls.Supported("timerfd_gettime", TimerfdGettime) + s.Table[88] = syscalls.Supported("utimensat", Utimensat) + s.Table[198] = syscalls.Supported("socket", Socket) + s.Table[199] = syscalls.Supported("socketpair", SocketPair) + s.Table[200] = syscalls.Supported("bind", Bind) + s.Table[201] = syscalls.Supported("listen", Listen) + s.Table[202] = syscalls.Supported("accept", Accept) + s.Table[203] = syscalls.Supported("connect", Connect) + s.Table[204] = syscalls.Supported("getsockname", GetSockName) + s.Table[205] = syscalls.Supported("getpeername", GetPeerName) + s.Table[206] = syscalls.Supported("sendto", SendTo) + s.Table[207] = syscalls.Supported("recvfrom", RecvFrom) + s.Table[208] = syscalls.Supported("setsockopt", SetSockOpt) + s.Table[209] = syscalls.Supported("getsockopt", GetSockOpt) + s.Table[210] = syscalls.Supported("shutdown", Shutdown) + s.Table[211] = syscalls.Supported("sendmsg", SendMsg) + s.Table[212] = syscalls.Supported("recvmsg", RecvMsg) + s.Table[221] = syscalls.Supported("execve", Execve) + s.Table[222] = syscalls.Supported("mmap", Mmap) + s.Table[242] = syscalls.Supported("accept4", Accept4) + s.Table[243] = syscalls.Supported("recvmmsg", RecvMMsg) + s.Table[267] = syscalls.Supported("syncfs", Syncfs) + s.Table[269] = syscalls.Supported("sendmmsg", SendMMsg) + s.Table[276] = syscalls.Supported("renameat2", Renameat2) + s.Table[279] = syscalls.Supported("memfd_create", MemfdCreate) + s.Table[281] = syscalls.Supported("execveat", Execveat) + s.Table[286] = syscalls.Supported("preadv2", Preadv2) + s.Table[287] = syscalls.Supported("pwritev2", Pwritev2) + s.Table[291] = syscalls.Supported("statx", Statx) + s.Init() } diff --git a/pkg/sentry/syscalls/linux/vfs2/xattr.go b/pkg/sentry/syscalls/linux/vfs2/xattr.go index af455d5c1..ef99246ed 100644 --- a/pkg/sentry/syscalls/linux/vfs2/xattr.go +++ b/pkg/sentry/syscalls/linux/vfs2/xattr.go @@ -49,7 +49,7 @@ func listxattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSyml if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) names, err := t.Kernel().VFS().ListxattrAt(t, t.Credentials(), &tpop.pop, uint64(size)) if err != nil { @@ -72,7 +72,7 @@ func Flistxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) names, err := file.Listxattr(t, uint64(size)) if err != nil { @@ -109,7 +109,7 @@ func getxattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSymli if err != nil { return 0, nil, err } - defer tpop.Release() + defer tpop.Release(t) name, err := copyInXattrName(t, nameAddr) if err != nil { @@ -141,7 +141,7 @@ func Fgetxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) name, err := copyInXattrName(t, nameAddr) if err != nil { @@ -188,7 +188,7 @@ func setxattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSymli if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) name, err := copyInXattrName(t, nameAddr) if err != nil { @@ -222,7 +222,7 @@ func Fsetxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) name, err := copyInXattrName(t, nameAddr) if err != nil { @@ -262,7 +262,7 @@ func removexattr(t *kernel.Task, args arch.SyscallArguments, shouldFollowFinalSy if err != nil { return err } - defer tpop.Release() + defer tpop.Release(t) name, err := copyInXattrName(t, nameAddr) if err != nil { @@ -281,7 +281,7 @@ func Fremovexattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel. if file == nil { return 0, nil, syserror.EBADF } - defer file.DecRef() + defer file.DecRef(t) name, err := copyInXattrName(t, nameAddr) if err != nil { diff --git a/pkg/sentry/time/muldiv_arm64.s b/pkg/sentry/time/muldiv_arm64.s index 5ad57a8a3..8afc62d53 100644 --- a/pkg/sentry/time/muldiv_arm64.s +++ b/pkg/sentry/time/muldiv_arm64.s @@ -12,12 +12,15 @@ // See the License for the specific language governing permissions and // limitations under the License. +#include "funcdata.h" #include "textflag.h" // Documentation is available in parameters.go. // // func muldiv64(value, multiplier, divisor uint64) (uint64, bool) TEXT ·muldiv64(SB),NOSPLIT,$40-33 + GO_ARGS + NO_LOCAL_POINTERS MOVD value+0(FP), R0 MOVD multiplier+8(FP), R1 MOVD divisor+16(FP), R2 diff --git a/pkg/sentry/time/parameters.go b/pkg/sentry/time/parameters.go index 65868cb26..cd1b95117 100644 --- a/pkg/sentry/time/parameters.go +++ b/pkg/sentry/time/parameters.go @@ -228,11 +228,15 @@ func errorAdjust(prevParams Parameters, newParams Parameters, now TSCValue) (Par // // The log level is determined by the error severity. func logErrorAdjustment(clock ClockID, errorNS ReferenceNS, orig, adjusted Parameters) { - fn := log.Debugf - if int64(errorNS.Magnitude()) > time.Millisecond.Nanoseconds() { + magNS := int64(errorNS.Magnitude()) + if magNS <= 10*time.Microsecond.Nanoseconds() { + // Don't log small errors. + return + } + fn := log.Infof + if magNS > time.Millisecond.Nanoseconds() { + // Upgrade large errors to warning. fn = log.Warningf - } else if int64(errorNS.Magnitude()) > 10*time.Microsecond.Nanoseconds() { - fn = log.Infof } fn("Clock(%v): error: %v ns, adjusted frequency from %v Hz to %v Hz", clock, errorNS, orig.Frequency, adjusted.Frequency) diff --git a/pkg/sentry/time/parameters_test.go b/pkg/sentry/time/parameters_test.go index e1b9084ac..0ce1257f6 100644 --- a/pkg/sentry/time/parameters_test.go +++ b/pkg/sentry/time/parameters_test.go @@ -484,3 +484,18 @@ func TestMulDivOverflow(t *testing.T) { }) } } + +func BenchmarkMuldiv64(b *testing.B) { + var v uint64 = math.MaxUint64 + for i := uint64(1); i <= 1000000; i++ { + mult := uint64(1000000000) + div := i * mult + res, ok := muldiv64(v, mult, div) + if !ok { + b.Errorf("Result of %v * %v / %v ok got false want true", v, mult, div) + } + if want := v / i; res != want { + b.Errorf("Bad result of %v * %v / %v: got %v, want %v", v, mult, div, res, want) + } + } +} diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD index 94d69c1cc..642769e7c 100644 --- a/pkg/sentry/vfs/BUILD +++ b/pkg/sentry/vfs/BUILD @@ -15,6 +15,18 @@ go_template_instance( }, ) +go_template_instance( + name = "event_list", + out = "event_list.go", + package = "vfs", + prefix = "event", + template = "//pkg/ilist:generic_list", + types = { + "Element": "*Event", + "Linker": "*Event", + }, +) + go_library( name = "vfs", srcs = [ @@ -25,11 +37,14 @@ go_library( "device.go", "epoll.go", "epoll_interest_list.go", + "event_list.go", "file_description.go", "file_description_impl_util.go", "filesystem.go", "filesystem_impl_util.go", "filesystem_type.go", + "inotify.go", + "lock.go", "mount.go", "mount_unsafe.go", "options.go", @@ -57,6 +72,7 @@ go_library( "//pkg/sentry/limits", "//pkg/sentry/memmap", "//pkg/sentry/socket/unix/transport", + "//pkg/sentry/uniqueid", "//pkg/sync", "//pkg/syserror", "//pkg/usermem", diff --git a/pkg/sentry/vfs/README.md b/pkg/sentry/vfs/README.md index 9aa133bcb..4b9faf2ea 100644 --- a/pkg/sentry/vfs/README.md +++ b/pkg/sentry/vfs/README.md @@ -39,8 +39,8 @@ Mount references are held by: - Mount: Each referenced Mount holds a reference on its parent, which is the mount containing its mount point. -- VirtualFilesystem: A reference is held on each Mount that has not been - umounted. +- VirtualFilesystem: A reference is held on each Mount that has been connected + to a mount point, but not yet umounted. MountNamespace and FileDescription references are held by users of VFS. The expectation is that each `kernel.Task` holds a reference on its corresponding @@ -169,8 +169,6 @@ This construction, which is essentially a type-safe analogue to Linux's - binder, which is similarly far too incomplete to use. - - whitelistfs, which we are already actively attempting to remove. - - Save/restore. For instance, it is unclear if the current implementation of the `state` package supports the inheritance pattern described above. diff --git a/pkg/sentry/vfs/anonfs.go b/pkg/sentry/vfs/anonfs.go index caf770fd5..5a0e3e6b5 100644 --- a/pkg/sentry/vfs/anonfs.go +++ b/pkg/sentry/vfs/anonfs.go @@ -82,7 +82,7 @@ type anonDentry struct { } // Release implements FilesystemImpl.Release. -func (fs *anonFilesystem) Release() { +func (fs *anonFilesystem) Release(ctx context.Context) { } // Sync implements FilesystemImpl.Sync. @@ -294,6 +294,21 @@ func (d *anonDentry) TryIncRef() bool { } // DecRef implements DentryImpl.DecRef. -func (d *anonDentry) DecRef() { +func (d *anonDentry) DecRef(ctx context.Context) { // no-op } + +// InotifyWithParent implements DentryImpl.InotifyWithParent. +// +// Although Linux technically supports inotify on pseudo filesystems (inotify +// is implemented at the vfs layer), it is not particularly useful. It is left +// unimplemented until someone actually needs it. +func (d *anonDentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et EventType) {} + +// Watches implements DentryImpl.Watches. +func (d *anonDentry) Watches() *Watches { + return nil +} + +// OnZeroWatches implements Dentry.OnZeroWatches. +func (d *anonDentry) OnZeroWatches(context.Context) {} diff --git a/pkg/sentry/vfs/dentry.go b/pkg/sentry/vfs/dentry.go index 8624dbd5d..bc7ea93ea 100644 --- a/pkg/sentry/vfs/dentry.go +++ b/pkg/sentry/vfs/dentry.go @@ -17,6 +17,7 @@ package vfs import ( "sync/atomic" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" ) @@ -102,7 +103,40 @@ type DentryImpl interface { TryIncRef() bool // DecRef decrements the Dentry's reference count. - DecRef() + DecRef(ctx context.Context) + + // InotifyWithParent notifies all watches on the targets represented by this + // dentry and its parent. The parent's watches are notified first, followed + // by this dentry's. + // + // InotifyWithParent automatically adds the IN_ISDIR flag for dentries + // representing directories. + // + // Note that the events may not actually propagate up to the user, depending + // on the event masks. + InotifyWithParent(ctx context.Context, events, cookie uint32, et EventType) + + // Watches returns the set of inotify watches for the file corresponding to + // the Dentry. Dentries that are hard links to the same underlying file + // share the same watches. + // + // Watches may return nil if the dentry belongs to a FilesystemImpl that + // does not support inotify. If an implementation returns a non-nil watch + // set, it must always return a non-nil watch set. Likewise, if an + // implementation returns a nil watch set, it must always return a nil watch + // set. + // + // The caller does not need to hold a reference on the dentry. + Watches() *Watches + + // OnZeroWatches is called whenever the number of watches on a dentry drops + // to zero. This is needed by some FilesystemImpls (e.g. gofer) to manage + // dentry lifetime. + // + // The caller does not need to hold a reference on the dentry. OnZeroWatches + // may acquire inotify locks, so to prevent deadlock, no inotify locks should + // be held by the caller. + OnZeroWatches(ctx context.Context) } // IncRef increments d's reference count. @@ -117,8 +151,8 @@ func (d *Dentry) TryIncRef() bool { } // DecRef decrements d's reference count. -func (d *Dentry) DecRef() { - d.impl.DecRef() +func (d *Dentry) DecRef(ctx context.Context) { + d.impl.DecRef(ctx) } // IsDead returns true if d has been deleted or invalidated by its owning @@ -133,6 +167,26 @@ func (d *Dentry) isMounted() bool { return atomic.LoadUint32(&d.mounts) != 0 } +// InotifyWithParent notifies all watches on the targets represented by d and +// its parent of events. +func (d *Dentry) InotifyWithParent(ctx context.Context, events, cookie uint32, et EventType) { + d.impl.InotifyWithParent(ctx, events, cookie, et) +} + +// Watches returns the set of inotify watches associated with d. +// +// Watches will return nil if d belongs to a FilesystemImpl that does not +// support inotify. +func (d *Dentry) Watches() *Watches { + return d.impl.Watches() +} + +// OnZeroWatches performs cleanup tasks whenever the number of watches on a +// dentry drops to zero. +func (d *Dentry) OnZeroWatches(ctx context.Context) { + d.impl.OnZeroWatches(ctx) +} + // The following functions are exported so that filesystem implementations can // use them. The vfs package, and users of VFS, should not call these // functions. @@ -161,11 +215,11 @@ func (vfs *VirtualFilesystem) AbortDeleteDentry(d *Dentry) { // CommitDeleteDentry must be called after PrepareDeleteDentry if the deletion // succeeds. -func (vfs *VirtualFilesystem) CommitDeleteDentry(d *Dentry) { +func (vfs *VirtualFilesystem) CommitDeleteDentry(ctx context.Context, d *Dentry) { d.dead = true d.mu.Unlock() if d.isMounted() { - vfs.forgetDeadMountpoint(d) + vfs.forgetDeadMountpoint(ctx, d) } } @@ -173,12 +227,12 @@ func (vfs *VirtualFilesystem) CommitDeleteDentry(d *Dentry) { // did for reasons outside of VFS' control (e.g. d represents the local state // of a file on a remote filesystem on which the file has already been // deleted). -func (vfs *VirtualFilesystem) InvalidateDentry(d *Dentry) { +func (vfs *VirtualFilesystem) InvalidateDentry(ctx context.Context, d *Dentry) { d.mu.Lock() d.dead = true d.mu.Unlock() if d.isMounted() { - vfs.forgetDeadMountpoint(d) + vfs.forgetDeadMountpoint(ctx, d) } } @@ -225,13 +279,13 @@ func (vfs *VirtualFilesystem) AbortRenameDentry(from, to *Dentry) { // that was replaced by from. // // Preconditions: PrepareRenameDentry was previously called on from and to. -func (vfs *VirtualFilesystem) CommitRenameReplaceDentry(from, to *Dentry) { +func (vfs *VirtualFilesystem) CommitRenameReplaceDentry(ctx context.Context, from, to *Dentry) { from.mu.Unlock() if to != nil { to.dead = true to.mu.Unlock() if to.isMounted() { - vfs.forgetDeadMountpoint(to) + vfs.forgetDeadMountpoint(ctx, to) } } } @@ -250,7 +304,7 @@ func (vfs *VirtualFilesystem) CommitRenameExchangeDentry(from, to *Dentry) { // // forgetDeadMountpoint is analogous to Linux's // fs/namespace.c:__detach_mounts(). -func (vfs *VirtualFilesystem) forgetDeadMountpoint(d *Dentry) { +func (vfs *VirtualFilesystem) forgetDeadMountpoint(ctx context.Context, d *Dentry) { var ( vdsToDecRef []VirtualDentry mountsToDecRef []*Mount @@ -263,9 +317,9 @@ func (vfs *VirtualFilesystem) forgetDeadMountpoint(d *Dentry) { vfs.mounts.seq.EndWrite() vfs.mountMu.Unlock() for _, vd := range vdsToDecRef { - vd.DecRef() + vd.DecRef(ctx) } for _, mnt := range mountsToDecRef { - mnt.DecRef() + mnt.DecRef(ctx) } } diff --git a/pkg/sentry/vfs/epoll.go b/pkg/sentry/vfs/epoll.go index 8297f964b..1b5af9f73 100644 --- a/pkg/sentry/vfs/epoll.go +++ b/pkg/sentry/vfs/epoll.go @@ -31,6 +31,7 @@ type EpollInstance struct { vfsfd FileDescription FileDescriptionDefaultImpl DentryMetadataFileDescriptionImpl + NoLockFD // q holds waiters on this EpollInstance. q waiter.Queue @@ -92,9 +93,9 @@ type epollInterest struct { // NewEpollInstanceFD returns a FileDescription representing a new epoll // instance. A reference is taken on the returned FileDescription. -func (vfs *VirtualFilesystem) NewEpollInstanceFD() (*FileDescription, error) { +func (vfs *VirtualFilesystem) NewEpollInstanceFD(ctx context.Context) (*FileDescription, error) { vd := vfs.NewAnonVirtualDentry("[eventpoll]") - defer vd.DecRef() + defer vd.DecRef(ctx) ep := &EpollInstance{ interest: make(map[epollInterestKey]*epollInterest), } @@ -109,7 +110,7 @@ func (vfs *VirtualFilesystem) NewEpollInstanceFD() (*FileDescription, error) { } // Release implements FileDescriptionImpl.Release. -func (ep *EpollInstance) Release() { +func (ep *EpollInstance) Release(ctx context.Context) { // Unregister all polled fds. ep.interestMu.Lock() defer ep.interestMu.Unlock() @@ -185,7 +186,7 @@ func (ep *EpollInstance) AddInterest(file *FileDescription, num int32, event lin } // Register interest in file. - mask := event.Events | linux.EPOLLERR | linux.EPOLLRDHUP + mask := event.Events | linux.EPOLLERR | linux.EPOLLHUP epi := &epollInterest{ epoll: ep, key: key, @@ -256,7 +257,7 @@ func (ep *EpollInstance) ModifyInterest(file *FileDescription, num int32, event } // Update epi for the next call to ep.ReadEvents(). - mask := event.Events | linux.EPOLLERR | linux.EPOLLRDHUP + mask := event.Events | linux.EPOLLERR | linux.EPOLLHUP ep.mu.Lock() epi.mask = mask epi.userData = event.Data diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go index cfabd936c..dcafffe57 100644 --- a/pkg/sentry/vfs/file_description.go +++ b/pkg/sentry/vfs/file_description.go @@ -42,11 +42,20 @@ type FileDescription struct { // operations. refs int64 + // flagsMu protects statusFlags and asyncHandler below. + flagsMu sync.Mutex + // statusFlags contains status flags, "initialized by open(2) and possibly - // modified by fcntl()" - fcntl(2). statusFlags is accessed using atomic - // memory operations. + // modified by fcntl()" - fcntl(2). statusFlags can be read using atomic + // memory operations when it does not need to be synchronized with an + // access to asyncHandler. statusFlags uint32 + // asyncHandler handles O_ASYNC signal generation. It is set with the + // F_SETOWN or F_SETOWN_EX fcntls. For asyncHandler to be used, O_ASYNC must + // also be set by fcntl(2). + asyncHandler FileAsync + // epolls is the set of epollInterests registered for this FileDescription. // epolls is protected by epollMu. epollMu sync.Mutex @@ -73,6 +82,8 @@ type FileDescription struct { // writable is analogous to Linux's FMODE_WRITE. writable bool + usedLockBSD uint32 + // impl is the FileDescriptionImpl associated with this Filesystem. impl is // immutable. This should be the last field in FileDescription. impl FileDescriptionImpl @@ -80,8 +91,7 @@ type FileDescription struct { // FileDescriptionOptions contains options to FileDescription.Init(). type FileDescriptionOptions struct { - // If AllowDirectIO is true, allow O_DIRECT to be set on the file. This is - // usually only the case if O_DIRECT would actually have an effect. + // If AllowDirectIO is true, allow O_DIRECT to be set on the file. AllowDirectIO bool // If DenyPRead is true, calls to FileDescription.PRead() return ESPIPE. @@ -106,6 +116,10 @@ type FileDescriptionOptions struct { UseDentryMetadata bool } +// FileCreationFlags are the set of flags passed to FileDescription.Init() but +// omitted from FileDescription.StatusFlags(). +const FileCreationFlags = linux.O_CREAT | linux.O_EXCL | linux.O_NOCTTY | linux.O_TRUNC + // Init must be called before first use of fd. If it succeeds, it takes // references on mnt and d. flags is the initial file description flags, which // is usually the full set of flags passed to open(2). @@ -120,8 +134,8 @@ func (fd *FileDescription) Init(impl FileDescriptionImpl, flags uint32, mnt *Mou fd.refs = 1 // Remove "file creation flags" to mirror the behavior from file.f_flags in - // fs/open.c:do_dentry_open - fd.statusFlags = flags &^ (linux.O_CREAT | linux.O_EXCL | linux.O_NOCTTY | linux.O_TRUNC) + // fs/open.c:do_dentry_open. + fd.statusFlags = flags &^ FileCreationFlags fd.vd = VirtualDentry{ mount: mnt, dentry: d, @@ -157,7 +171,7 @@ func (fd *FileDescription) TryIncRef() bool { } // DecRef decrements fd's reference count. -func (fd *FileDescription) DecRef() { +func (fd *FileDescription) DecRef(ctx context.Context) { if refs := atomic.AddInt64(&fd.refs, -1); refs == 0 { // Unregister fd from all epoll instances. fd.epollMu.Lock() @@ -175,12 +189,25 @@ func (fd *FileDescription) DecRef() { } ep.interestMu.Unlock() } + + // If BSD locks were used, release any lock that it may have acquired. + if atomic.LoadUint32(&fd.usedLockBSD) != 0 { + fd.impl.UnlockBSD(context.Background(), fd) + } + // Release implementation resources. - fd.impl.Release() + fd.impl.Release(ctx) if fd.writable { fd.vd.mount.EndWrite() } - fd.vd.DecRef() + fd.vd.DecRef(ctx) + fd.flagsMu.Lock() + // TODO(gvisor.dev/issue/1663): We may need to unregister during save, as we do in VFS1. + if fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil { + fd.asyncHandler.Unregister(fd) + } + fd.asyncHandler = nil + fd.flagsMu.Unlock() } else if refs < 0 { panic("FileDescription.DecRef() called without holding a reference") } @@ -210,6 +237,11 @@ func (fd *FileDescription) VirtualDentry() VirtualDentry { return fd.vd } +// Options returns the options passed to fd.Init(). +func (fd *FileDescription) Options() FileDescriptionOptions { + return fd.opts +} + // StatusFlags returns file description status flags, as for fcntl(F_GETFL). func (fd *FileDescription) StatusFlags() uint32 { return atomic.LoadUint32(&fd.statusFlags) @@ -257,9 +289,20 @@ func (fd *FileDescription) SetStatusFlags(ctx context.Context, creds *auth.Crede if flags&linux.O_DIRECT != 0 && !fd.opts.AllowDirectIO { return syserror.EINVAL } - // TODO(jamieliu): FileDescriptionImpl.SetOAsync()? + // TODO(gvisor.dev/issue/1035): FileDescriptionImpl.SetOAsync()? const settableFlags = linux.O_APPEND | linux.O_ASYNC | linux.O_DIRECT | linux.O_NOATIME | linux.O_NONBLOCK + fd.flagsMu.Lock() + if fd.asyncHandler != nil { + // Use fd.statusFlags instead of oldFlags, which may have become outdated, + // to avoid double registering/unregistering. + if fd.statusFlags&linux.O_ASYNC == 0 && flags&linux.O_ASYNC != 0 { + fd.asyncHandler.Register(fd) + } else if fd.statusFlags&linux.O_ASYNC != 0 && flags&linux.O_ASYNC == 0 { + fd.asyncHandler.Unregister(fd) + } + } atomic.StoreUint32(&fd.statusFlags, (oldFlags&^settableFlags)|(flags&settableFlags)) + fd.flagsMu.Unlock() return nil } @@ -292,7 +335,7 @@ func (fd *FileDescription) Impl() FileDescriptionImpl { type FileDescriptionImpl interface { // Release is called when the associated FileDescription reaches zero // references. - Release() + Release(ctx context.Context) // OnClose is called when a file descriptor representing the // FileDescription is closed. Note that returning a non-nil error does not @@ -311,6 +354,12 @@ type FileDescriptionImpl interface { // represented by the FileDescription. StatFS(ctx context.Context) (linux.Statfs, error) + // Allocate grows the file to offset + length bytes. + // Only mode == 0 is supported currently. + // + // Preconditions: The FileDescription was opened for writing. + Allocate(ctx context.Context, mode, offset, length uint64) error + // waiter.Waitable methods may be used to poll for I/O events. waiter.Waitable @@ -415,24 +464,16 @@ type FileDescriptionImpl interface { Removexattr(ctx context.Context, name string) error // LockBSD tries to acquire a BSD-style advisory file lock. - // - // TODO(gvisor.dev/issue/1480): BSD-style file locking LockBSD(ctx context.Context, uid lock.UniqueID, t lock.LockType, block lock.Blocker) error - // LockBSD releases a BSD-style advisory file lock. - // - // TODO(gvisor.dev/issue/1480): BSD-style file locking + // UnlockBSD releases a BSD-style advisory file lock. UnlockBSD(ctx context.Context, uid lock.UniqueID) error // LockPOSIX tries to acquire a POSIX-style advisory file lock. - // - // TODO(gvisor.dev/issue/1480): POSIX-style file locking - LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, rng lock.LockRange, block lock.Blocker) error + LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, start, length uint64, whence int16, block lock.Blocker) error // UnlockPOSIX releases a POSIX-style advisory file lock. - // - // TODO(gvisor.dev/issue/1480): POSIX-style file locking - UnlockPOSIX(ctx context.Context, uid lock.UniqueID, rng lock.LockRange) error + UnlockPOSIX(ctx context.Context, uid lock.UniqueID, start, length uint64, whence int16) error } // Dirent holds the information contained in struct linux_dirent64. @@ -462,6 +503,15 @@ type IterDirentsCallback interface { Handle(dirent Dirent) error } +// IterDirentsCallbackFunc implements IterDirentsCallback for a function with +// the semantics of IterDirentsCallback.Handle. +type IterDirentsCallbackFunc func(dirent Dirent) error + +// Handle implements IterDirentsCallback.Handle. +func (f IterDirentsCallbackFunc) Handle(dirent Dirent) error { + return f(dirent) +} + // OnClose is called when a file descriptor representing the FileDescription is // closed. Returning a non-nil error should not prevent the file descriptor // from being closed. @@ -478,7 +528,7 @@ func (fd *FileDescription) Stat(ctx context.Context, opts StatOptions) (linux.St Start: fd.vd, }) stat, err := fd.vd.mount.fs.impl.StatAt(ctx, rp, opts) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return stat, err } return fd.impl.Stat(ctx, opts) @@ -493,7 +543,7 @@ func (fd *FileDescription) SetStat(ctx context.Context, opts SetStatOptions) err Start: fd.vd, }) err := fd.vd.mount.fs.impl.SetStatAt(ctx, rp, opts) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return err } return fd.impl.SetStat(ctx, opts) @@ -509,23 +559,37 @@ func (fd *FileDescription) StatFS(ctx context.Context) (linux.Statfs, error) { Start: fd.vd, }) statfs, err := fd.vd.mount.fs.impl.StatFSAt(ctx, rp) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return statfs, err } return fd.impl.StatFS(ctx) } -// Readiness returns fd's I/O readiness. +// Allocate grows file represented by FileDescription to offset + length bytes. +func (fd *FileDescription) Allocate(ctx context.Context, mode, offset, length uint64) error { + if !fd.IsWritable() { + return syserror.EBADF + } + return fd.impl.Allocate(ctx, mode, offset, length) +} + +// Readiness implements waiter.Waitable.Readiness. +// +// It returns fd's I/O readiness. func (fd *FileDescription) Readiness(mask waiter.EventMask) waiter.EventMask { return fd.impl.Readiness(mask) } -// EventRegister registers e for I/O readiness events in mask. +// EventRegister implements waiter.Waitable.EventRegister. +// +// It registers e for I/O readiness events in mask. func (fd *FileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask) { fd.impl.EventRegister(e, mask) } -// EventUnregister unregisters e for I/O readiness events. +// EventUnregister implements waiter.Waitable.EventUnregister. +// +// It unregisters e for I/O readiness events. func (fd *FileDescription) EventUnregister(e *waiter.Entry) { fd.impl.EventUnregister(e) } @@ -615,7 +679,7 @@ func (fd *FileDescription) Listxattr(ctx context.Context, size uint64) ([]string Start: fd.vd, }) names, err := fd.vd.mount.fs.impl.ListxattrAt(ctx, rp, size) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return names, err } names, err := fd.impl.Listxattr(ctx, size) @@ -644,7 +708,7 @@ func (fd *FileDescription) Getxattr(ctx context.Context, opts *GetxattrOptions) Start: fd.vd, }) val, err := fd.vd.mount.fs.impl.GetxattrAt(ctx, rp, *opts) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return val, err } return fd.impl.Getxattr(ctx, *opts) @@ -660,7 +724,7 @@ func (fd *FileDescription) Setxattr(ctx context.Context, opts *SetxattrOptions) Start: fd.vd, }) err := fd.vd.mount.fs.impl.SetxattrAt(ctx, rp, *opts) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return err } return fd.impl.Setxattr(ctx, *opts) @@ -676,7 +740,7 @@ func (fd *FileDescription) Removexattr(ctx context.Context, name string) error { Start: fd.vd, }) err := fd.vd.mount.fs.impl.RemovexattrAt(ctx, rp, name) - vfsObj.putResolvingPath(rp) + vfsObj.putResolvingPath(ctx, rp) return err } return fd.impl.Removexattr(ctx, name) @@ -693,7 +757,7 @@ func (fd *FileDescription) MappedName(ctx context.Context) string { vfsroot := RootFromContext(ctx) s, _ := fd.vd.mount.vfs.PathnameWithDeleted(ctx, vfsroot, fd.vd) if vfsroot.Ok() { - vfsroot.DecRef() + vfsroot.DecRef(ctx) } return s } @@ -731,3 +795,53 @@ func (fd *FileDescription) InodeID() uint64 { func (fd *FileDescription) Msync(ctx context.Context, mr memmap.MappableRange) error { return fd.Sync(ctx) } + +// LockBSD tries to acquire a BSD-style advisory file lock. +func (fd *FileDescription) LockBSD(ctx context.Context, lockType lock.LockType, blocker lock.Blocker) error { + atomic.StoreUint32(&fd.usedLockBSD, 1) + return fd.impl.LockBSD(ctx, fd, lockType, blocker) +} + +// UnlockBSD releases a BSD-style advisory file lock. +func (fd *FileDescription) UnlockBSD(ctx context.Context) error { + return fd.impl.UnlockBSD(ctx, fd) +} + +// LockPOSIX locks a POSIX-style file range lock. +func (fd *FileDescription) LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, start, end uint64, whence int16, block lock.Blocker) error { + return fd.impl.LockPOSIX(ctx, uid, t, start, end, whence, block) +} + +// UnlockPOSIX unlocks a POSIX-style file range lock. +func (fd *FileDescription) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, start, end uint64, whence int16) error { + return fd.impl.UnlockPOSIX(ctx, uid, start, end, whence) +} + +// A FileAsync sends signals to its owner when w is ready for IO. This is only +// implemented by pkg/sentry/fasync:FileAsync, but we unfortunately need this +// interface to avoid circular dependencies. +type FileAsync interface { + Register(w waiter.Waitable) + Unregister(w waiter.Waitable) +} + +// AsyncHandler returns the FileAsync for fd. +func (fd *FileDescription) AsyncHandler() FileAsync { + fd.flagsMu.Lock() + defer fd.flagsMu.Unlock() + return fd.asyncHandler +} + +// SetAsyncHandler sets fd.asyncHandler if it has not been set before and +// returns it. +func (fd *FileDescription) SetAsyncHandler(newHandler func() FileAsync) FileAsync { + fd.flagsMu.Lock() + defer fd.flagsMu.Unlock() + if fd.asyncHandler == nil { + fd.asyncHandler = newHandler() + if fd.statusFlags&linux.O_ASYNC != 0 { + fd.asyncHandler.Register(fd) + } + } + return fd.asyncHandler +} diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go index f4c111926..6b8b4ad49 100644 --- a/pkg/sentry/vfs/file_description_impl_util.go +++ b/pkg/sentry/vfs/file_description_impl_util.go @@ -21,7 +21,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/sentry/arch" - "gvisor.dev/gvisor/pkg/sentry/fs/lock" + fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/syserror" @@ -56,6 +56,12 @@ func (FileDescriptionDefaultImpl) StatFS(ctx context.Context) (linux.Statfs, err return linux.Statfs{}, syserror.ENOSYS } +// Allocate implements FileDescriptionImpl.Allocate analogously to +// fallocate called on regular file, directory or FIFO in Linux. +func (FileDescriptionDefaultImpl) Allocate(ctx context.Context, mode, offset, length uint64) error { + return syserror.ENODEV +} + // Readiness implements waiter.Waitable.Readiness analogously to // file_operations::poll == NULL in Linux. func (FileDescriptionDefaultImpl) Readiness(mask waiter.EventMask) waiter.EventMask { @@ -153,31 +159,16 @@ func (FileDescriptionDefaultImpl) Removexattr(ctx context.Context, name string) return syserror.ENOTSUP } -// LockBSD implements FileDescriptionImpl.LockBSD. -func (FileDescriptionDefaultImpl) LockBSD(ctx context.Context, uid lock.UniqueID, t lock.LockType, block lock.Blocker) error { - return syserror.EBADF -} - -// UnlockBSD implements FileDescriptionImpl.UnlockBSD. -func (FileDescriptionDefaultImpl) UnlockBSD(ctx context.Context, uid lock.UniqueID) error { - return syserror.EBADF -} - -// LockPOSIX implements FileDescriptionImpl.LockPOSIX. -func (FileDescriptionDefaultImpl) LockPOSIX(ctx context.Context, uid lock.UniqueID, t lock.LockType, rng lock.LockRange, block lock.Blocker) error { - return syserror.EBADF -} - -// UnlockPOSIX implements FileDescriptionImpl.UnlockPOSIX. -func (FileDescriptionDefaultImpl) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, rng lock.LockRange) error { - return syserror.EBADF -} - // DirectoryFileDescriptionDefaultImpl may be embedded by implementations of // FileDescriptionImpl that always represent directories to obtain // implementations of non-directory I/O methods that return EISDIR. type DirectoryFileDescriptionDefaultImpl struct{} +// Allocate implements DirectoryFileDescriptionDefaultImpl.Allocate. +func (DirectoryFileDescriptionDefaultImpl) Allocate(ctx context.Context, mode, offset, length uint64) error { + return syserror.EISDIR +} + // PRead implements FileDescriptionImpl.PRead. func (DirectoryFileDescriptionDefaultImpl) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts ReadOptions) (int64, error) { return 0, syserror.EISDIR @@ -347,7 +338,7 @@ func (fd *DynamicBytesFileDescriptionImpl) pwriteLocked(ctx context.Context, src writable, ok := fd.data.(WritableDynamicBytesSource) if !ok { - return 0, syserror.EINVAL + return 0, syserror.EIO } n, err := writable.Write(ctx, src, offset) if err != nil { @@ -384,3 +375,54 @@ func GenericConfigureMMap(fd *FileDescription, m memmap.Mappable, opts *memmap.M fd.IncRef() return nil } + +// LockFD may be used by most implementations of FileDescriptionImpl.Lock* +// functions. Caller must call Init(). +type LockFD struct { + locks *FileLocks +} + +// Init initializes fd with FileLocks to use. +func (fd *LockFD) Init(locks *FileLocks) { + fd.locks = locks +} + +// Locks returns the locks associated with this file. +func (fd *LockFD) Locks() *FileLocks { + return fd.locks +} + +// LockBSD implements vfs.FileDescriptionImpl.LockBSD. +func (fd *LockFD) LockBSD(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, block fslock.Blocker) error { + return fd.locks.LockBSD(uid, t, block) +} + +// UnlockBSD implements vfs.FileDescriptionImpl.UnlockBSD. +func (fd *LockFD) UnlockBSD(ctx context.Context, uid fslock.UniqueID) error { + fd.locks.UnlockBSD(uid) + return nil +} + +// NoLockFD implements Lock*/Unlock* portion of FileDescriptionImpl interface +// returning ENOLCK. +type NoLockFD struct{} + +// LockBSD implements vfs.FileDescriptionImpl.LockBSD. +func (NoLockFD) LockBSD(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, block fslock.Blocker) error { + return syserror.ENOLCK +} + +// UnlockBSD implements vfs.FileDescriptionImpl.UnlockBSD. +func (NoLockFD) UnlockBSD(ctx context.Context, uid fslock.UniqueID) error { + return syserror.ENOLCK +} + +// LockPOSIX implements vfs.FileDescriptionImpl.LockPOSIX. +func (NoLockFD) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + return syserror.ENOLCK +} + +// UnlockPOSIX implements vfs.FileDescriptionImpl.UnlockPOSIX. +func (NoLockFD) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error { + return syserror.ENOLCK +} diff --git a/pkg/sentry/vfs/file_description_impl_util_test.go b/pkg/sentry/vfs/file_description_impl_util_test.go index 3a75d4d62..1cd607c0a 100644 --- a/pkg/sentry/vfs/file_description_impl_util_test.go +++ b/pkg/sentry/vfs/file_description_impl_util_test.go @@ -33,6 +33,7 @@ import ( type fileDescription struct { vfsfd FileDescription FileDescriptionDefaultImpl + NoLockFD } // genCount contains the number of times its DynamicBytesSource.Generate() @@ -79,9 +80,9 @@ type testFD struct { data DynamicBytesSource } -func newTestFD(vfsObj *VirtualFilesystem, statusFlags uint32, data DynamicBytesSource) *FileDescription { +func newTestFD(ctx context.Context, vfsObj *VirtualFilesystem, statusFlags uint32, data DynamicBytesSource) *FileDescription { vd := vfsObj.NewAnonVirtualDentry("genCountFD") - defer vd.DecRef() + defer vd.DecRef(ctx) var fd testFD fd.vfsfd.Init(&fd, statusFlags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{}) fd.DynamicBytesFileDescriptionImpl.SetDataSource(data) @@ -89,7 +90,7 @@ func newTestFD(vfsObj *VirtualFilesystem, statusFlags uint32, data DynamicBytesS } // Release implements FileDescriptionImpl.Release. -func (fd *testFD) Release() { +func (fd *testFD) Release(context.Context) { } // SetStatusFlags implements FileDescriptionImpl.SetStatusFlags. @@ -108,11 +109,11 @@ func TestGenCountFD(t *testing.T) { ctx := contexttest.Context(t) vfsObj := &VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } - fd := newTestFD(vfsObj, linux.O_RDWR, &genCount{}) - defer fd.DecRef() + fd := newTestFD(ctx, vfsObj, linux.O_RDWR, &genCount{}) + defer fd.DecRef(ctx) // The first read causes Generate to be called to fill the FD's buffer. buf := make([]byte, 2) @@ -154,11 +155,11 @@ func TestGenCountFD(t *testing.T) { } // Write and PWrite fails. - if _, err := fd.Write(ctx, ioseq, WriteOptions{}); err != syserror.EINVAL { - t.Errorf("Write: got err %v, wanted %v", err, syserror.EINVAL) + if _, err := fd.Write(ctx, ioseq, WriteOptions{}); err != syserror.EIO { + t.Errorf("Write: got err %v, wanted %v", err, syserror.EIO) } - if _, err := fd.PWrite(ctx, ioseq, 0, WriteOptions{}); err != syserror.EINVAL { - t.Errorf("Write: got err %v, wanted %v", err, syserror.EINVAL) + if _, err := fd.PWrite(ctx, ioseq, 0, WriteOptions{}); err != syserror.EIO { + t.Errorf("Write: got err %v, wanted %v", err, syserror.EIO) } } @@ -166,11 +167,11 @@ func TestWritable(t *testing.T) { ctx := contexttest.Context(t) vfsObj := &VirtualFilesystem{} - if err := vfsObj.Init(); err != nil { + if err := vfsObj.Init(ctx); err != nil { t.Fatalf("VFS init: %v", err) } - fd := newTestFD(vfsObj, linux.O_RDWR, &storeData{data: "init"}) - defer fd.DecRef() + fd := newTestFD(ctx, vfsObj, linux.O_RDWR, &storeData{data: "init"}) + defer fd.DecRef(ctx) buf := make([]byte, 10) ioseq := usermem.BytesIOSequence(buf) diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go index 1edd584c9..df3758fd1 100644 --- a/pkg/sentry/vfs/filesystem.go +++ b/pkg/sentry/vfs/filesystem.go @@ -100,12 +100,12 @@ func (fs *Filesystem) TryIncRef() bool { } // DecRef decrements fs' reference count. -func (fs *Filesystem) DecRef() { +func (fs *Filesystem) DecRef(ctx context.Context) { if refs := atomic.AddInt64(&fs.refs, -1); refs == 0 { fs.vfs.filesystemsMu.Lock() delete(fs.vfs.filesystems, fs) fs.vfs.filesystemsMu.Unlock() - fs.impl.Release() + fs.impl.Release(ctx) } else if refs < 0 { panic("Filesystem.decRef() called without holding a reference") } @@ -149,7 +149,7 @@ func (fs *Filesystem) DecRef() { type FilesystemImpl interface { // Release is called when the associated Filesystem reaches zero // references. - Release() + Release(ctx context.Context) // Sync "causes all pending modifications to filesystem metadata and cached // file data to be written to the underlying [filesystem]", as by syncfs(2). @@ -524,8 +524,6 @@ type FilesystemImpl interface { // // Preconditions: vd.Mount().Filesystem().Impl() == this FilesystemImpl. PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error - - // TODO(gvisor.dev/issue/1479): inotify_add_watch() } // PrependPathAtVFSRootError is returned by implementations of diff --git a/pkg/sentry/vfs/g3doc/inotify.md b/pkg/sentry/vfs/g3doc/inotify.md new file mode 100644 index 000000000..e7da49faa --- /dev/null +++ b/pkg/sentry/vfs/g3doc/inotify.md @@ -0,0 +1,210 @@ +# Inotify + +Inotify is a mechanism for monitoring filesystem events in Linux--see +inotify(7). An inotify instance can be used to monitor files and directories for +modifications, creation/deletion, etc. The inotify API consists of system calls +that create inotify instances (inotify_init/inotify_init1) and add/remove +watches on files to an instance (inotify_add_watch/inotify_rm_watch). Events are +generated from various places in the sentry, including the syscall layer, the +vfs layer, the process fd table, and within each filesystem implementation. This +document outlines the implementation details of inotify in VFS2. + +## Inotify Objects + +Inotify data structures are implemented in the vfs package. + +### vfs.Inotify + +Inotify instances are represented by vfs.Inotify objects, which implement +vfs.FileDescriptionImpl. As in Linux, inotify fds are backed by a +pseudo-filesystem (anonfs). Each inotify instance receives events from a set of +vfs.Watch objects, which can be modified with inotify_add_watch(2) and +inotify_rm_watch(2). An application can retrieve events by reading the inotify +fd. + +### vfs.Watches + +The set of all watches held on a single file (i.e., the watch target) is stored +in vfs.Watches. Each watch will belong to a different inotify instance (an +instance can only have one watch on any watch target). The watches are stored in +a map indexed by their vfs.Inotify owner’s id. Hard links and file descriptions +to a single file will all share the same vfs.Watches. Activity on the target +causes its vfs.Watches to generate notifications on its watches’ inotify +instances. + +### vfs.Watch + +A single watch, owned by one inotify instance and applied to one watch target. +Both the vfs.Inotify owner and vfs.Watches on the target will hold a vfs.Watch, +which leads to some complicated locking behavior (see Lock Ordering). Whenever a +watch is notified of an event on its target, it will queue events to its inotify +instance for delivery to the user. + +### vfs.Event + +vfs.Event is a simple struct encapsulating all the fields for an inotify event. +It is generated by vfs.Watches and forwarded to the watches' owners. It is +serialized to the user during read(2) syscalls on the associated fs.Inotify's +fd. + +## Lock Ordering + +There are three locks related to the inotify implementation: + +Inotify.mu: the inotify instance lock. Inotify.evMu: the inotify event queue +lock. Watches.mu: the watch set lock, used to protect the collection of watches +on a target. + +The correct lock ordering for inotify code is: + +Inotify.mu -> Watches.mu -> Inotify.evMu. + +Note that we use a distinct lock to protect the inotify event queue. If we +simply used Inotify.mu, we could simultaneously have locks being acquired in the +order of Inotify.mu -> Watches.mu and Watches.mu -> Inotify.mu, which would +cause deadlocks. For instance, adding a watch to an inotify instance would +require locking Inotify.mu, and then adding the same watch to the target would +cause Watches.mu to be held. At the same time, generating an event on the target +would require Watches.mu to be held before iterating through each watch, and +then notifying the owner of each watch would cause Inotify.mu to be held. + +See the vfs package comment to understand how inotify locks fit into the overall +ordering of filesystem locks. + +## Watch Targets in Different Filesystem Implementations + +In Linux, watches reside on inodes at the virtual filesystem layer. As a result, +all hard links and file descriptions on a single file will all share the same +watch set. In VFS2, there is no common inode structure across filesystem types +(some may not even have inodes), so we have to plumb inotify support through +each specific filesystem implementation. Some of the technical considerations +are outlined below. + +### Tmpfs + +For filesystems with inodes, like tmpfs, the design is quite similar to that of +Linux, where watches reside on the inode. + +### Pseudo-filesystems + +Technically, because inotify is implemented at the vfs layer in Linux, +pseudo-filesystems on top of kernfs support inotify passively. However, watches +can only track explicit filesystem operations like read/write, open/close, +mknod, etc., so watches on a target like /proc/self/fd will not generate events +every time a new fd is added or removed. As of this writing, we leave inotify +unimplemented in kernfs and anonfs; it does not seem particularly useful. + +### Gofer Filesystem (fsimpl/gofer) + +The gofer filesystem has several traits that make it difficult to support +inotify: + +* **There are no inodes.** A file is represented as a dentry that holds an + unopened p9 file (and possibly an open FID), through which the Sentry + interacts with the gofer. + * *Solution:* Because there is no inode structure stored in the sandbox, + inotify watches must be held on the dentry. This would be an issue in + the presence of hard links, where multiple dentries would need to share + the same set of watches, but in VFS2, we do not support the internal + creation of hard links on gofer fs. As a result, we make the assumption + that every dentry corresponds to a unique inode. However, the next point + raises an issue with this assumption: +* **The Sentry cannot always be aware of hard links on the remote + filesystem.** There is no way for us to confirm whether two files on the + remote filesystem are actually links to the same inode. QIDs and inodes are + not always 1:1. The assumption that dentries and inodes are 1:1 is + inevitably broken if there are remote hard links that we cannot detect. + * *Solution:* this is an issue with gofer fs in general, not only inotify, + and we will have to live with it. +* **Dentries can be cached, and then evicted.** Dentry lifetime does not + correspond to file lifetime. Because gofer fs is not entirely in-memory, the + absence of a dentry does not mean that the corresponding file does not + exist, nor does a dentry reaching zero references mean that the + corresponding file no longer exists. When a dentry reaches zero references, + it will be cached, in case the file at that path is needed again in the + future. However, the dentry may be evicted from the cache, which will cause + a new dentry to be created next time the same file path is used. The + existing watches will be lost. + * *Solution:* When a dentry reaches zero references, do not cache it if it + has any watches, so we can avoid eviction/destruction. Note that if the + dentry was deleted or invalidated (d.vfsd.IsDead()), we should still + destroy it along with its watches. Additionally, when a dentry’s last + watch is removed, we cache it if it also has zero references. This way, + the dentry can eventually be evicted from memory if it is no longer + needed. +* **Dentries can be invalidated.** Another issue with dentry lifetime is that + the remote file at the file path represented may change from underneath the + dentry. In this case, the next time that the dentry is used, it will be + invalidated and a new dentry will replace it. In this case, it is not clear + what should be done with the watches on the old dentry. + * *Solution:* Silently destroy the watches when invalidation occurs. We + have no way of knowing exactly what happened, when it happens. Inotify + instances on NFS files in Linux probably behave in a similar fashion, + since inotify is implemented at the vfs layer and is not aware of the + complexities of remote file systems. + * An alternative would be to issue some kind of event upon invalidation, + e.g. a delete event, but this has several issues: + * We cannot discern whether the remote file was invalidated because it was + moved, deleted, etc. This information is crucial, because these cases + should result in different events. Furthermore, the watches should only + be destroyed if the file has been deleted. + * Moreover, the mechanism for detecting whether the underlying file has + changed is to check whether a new QID is given by the gofer. This may + result in false positives, e.g. suppose that the server closed and + re-opened the same file, which may result in a new QID. + * Finally, the time of the event may be completely different from the time + of the file modification, since a dentry is not immediately notified + when the underlying file has changed. It would be quite unexpected to + receive the notification when invalidation was triggered, i.e. the next + time the file was accessed within the sandbox, because then the + read/write/etc. operation on the file would not result in the expected + event. + * Another point in favor of the first solution: inotify in Linux can + already be lossy on local filesystems (one of the sacrifices made so + that filesystem performance isn’t killed), and it is lossy on NFS for + similar reasons to gofer fs. Therefore, it is better for inotify to be + silent than to emit incorrect notifications. +* **There may be external users of the remote filesystem.** We can only track + operations performed on the file within the sandbox. This is sufficient + under InteropModeExclusive, but whenever there are external users, the set + of actions we are aware of is incomplete. + * *Solution:* We could either return an error or just issue a warning when + inotify is used without InteropModeExclusive. Although faulty, VFS1 + allows it when the filesystem is shared, and Linux does the same for + remote filesystems (as mentioned above, inotify sits at the vfs level). + +## Dentry Interface + +For events that must be generated above the vfs layer, we provide the following +DentryImpl methods to allow interactions with targets on any FilesystemImpl: + +* **InotifyWithParent()** generates events on the dentry’s watches as well as + its parent’s. +* **Watches()** retrieves the watch set of the target represented by the + dentry. This is used to access and modify watches on a target. +* **OnZeroWatches()** performs cleanup tasks after the last watch is removed + from a dentry. This is needed by gofer fs, which must allow a watched dentry + to be cached once it has no more watches. Most implementations can just do + nothing. Note that OnZeroWatches() must be called after all inotify locks + are released to preserve lock ordering, since it may acquire + FilesystemImpl-specific locks. + +## IN_EXCL_UNLINK + +There are several options that can be set for a watch, specified as part of the +mask in inotify_add_watch(2). In particular, IN_EXCL_UNLINK requires some +additional support in each filesystem. + +A watch with IN_EXCL_UNLINK will not generate events for its target if it +corresponds to a path that was unlinked. For instance, if an fd is opened on +“foo/bar” and “foo/bar” is subsequently unlinked, any reads/writes/etc. on the +fd will be ignored by watches on “foo” or “foo/bar” with IN_EXCL_UNLINK. This +requires each DentryImpl to keep track of whether it has been unlinked, in order +to determine whether events should be sent to watches with IN_EXCL_UNLINK. + +## IN_ONESHOT + +One-shot watches expire after generating a single event. When an event occurs, +all one-shot watches on the target that successfully generated an event are +removed. Lock ordering can cause the management of one-shot watches to be quite +expensive; see Watches.Notify() for more information. diff --git a/pkg/sentry/vfs/genericfstree/genericfstree.go b/pkg/sentry/vfs/genericfstree/genericfstree.go index 286510195..8882fa84a 100644 --- a/pkg/sentry/vfs/genericfstree/genericfstree.go +++ b/pkg/sentry/vfs/genericfstree/genericfstree.go @@ -43,7 +43,7 @@ type Dentry struct { // IsAncestorDentry returns true if d is an ancestor of d2; that is, d is // either d2's parent or an ancestor of d2's parent. func IsAncestorDentry(d, d2 *Dentry) bool { - for { + for d2 != nil { // Stop at root, where d2.parent == nil. if d2.parent == d { return true } @@ -52,6 +52,7 @@ func IsAncestorDentry(d, d2 *Dentry) bool { } d2 = d2.parent } + return false } // ParentOrSelf returns d.parent. If d.parent is nil, ParentOrSelf returns d. diff --git a/pkg/sentry/vfs/inotify.go b/pkg/sentry/vfs/inotify.go new file mode 100644 index 000000000..aff220a61 --- /dev/null +++ b/pkg/sentry/vfs/inotify.go @@ -0,0 +1,774 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs + +import ( + "bytes" + "fmt" + "sync/atomic" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/uniqueid" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +// inotifyEventBaseSize is the base size of linux's struct inotify_event. This +// must be a power 2 for rounding below. +const inotifyEventBaseSize = 16 + +// EventType defines different kinds of inotfiy events. +// +// The way events are labelled appears somewhat arbitrary, but they must match +// Linux so that IN_EXCL_UNLINK behaves as it does in Linux. +type EventType uint8 + +// PathEvent and InodeEvent correspond to FSNOTIFY_EVENT_PATH and +// FSNOTIFY_EVENT_INODE in Linux. +const ( + PathEvent EventType = iota + InodeEvent EventType = iota +) + +// Inotify represents an inotify instance created by inotify_init(2) or +// inotify_init1(2). Inotify implements FileDescriptionImpl. +// +// +stateify savable +type Inotify struct { + vfsfd FileDescription + FileDescriptionDefaultImpl + DentryMetadataFileDescriptionImpl + NoLockFD + + // Unique identifier for this inotify instance. We don't just reuse the + // inotify fd because fds can be duped. These should not be exposed to the + // user, since we may aggressively reuse an id on S/R. + id uint64 + + // queue is used to notify interested parties when the inotify instance + // becomes readable or writable. + queue waiter.Queue `state:"nosave"` + + // evMu *only* protects the events list. We need a separate lock while + // queuing events: using mu may violate lock ordering, since at that point + // the calling goroutine may already hold Watches.mu. + evMu sync.Mutex `state:"nosave"` + + // A list of pending events for this inotify instance. Protected by evMu. + events eventList + + // A scratch buffer, used to serialize inotify events. Allocate this + // ahead of time for the sake of performance. Protected by evMu. + scratch []byte + + // mu protects the fields below. + mu sync.Mutex `state:"nosave"` + + // nextWatchMinusOne is used to allocate watch descriptors on this Inotify + // instance. Note that Linux starts numbering watch descriptors from 1. + nextWatchMinusOne int32 + + // Map from watch descriptors to watch objects. + watches map[int32]*Watch +} + +var _ FileDescriptionImpl = (*Inotify)(nil) + +// NewInotifyFD constructs a new Inotify instance. +func NewInotifyFD(ctx context.Context, vfsObj *VirtualFilesystem, flags uint32) (*FileDescription, error) { + // O_CLOEXEC affects file descriptors, so it must be handled outside of vfs. + flags &^= linux.O_CLOEXEC + if flags&^linux.O_NONBLOCK != 0 { + return nil, syserror.EINVAL + } + + id := uniqueid.GlobalFromContext(ctx) + vd := vfsObj.NewAnonVirtualDentry(fmt.Sprintf("[inotifyfd:%d]", id)) + defer vd.DecRef(ctx) + fd := &Inotify{ + id: id, + scratch: make([]byte, inotifyEventBaseSize), + watches: make(map[int32]*Watch), + } + if err := fd.vfsfd.Init(fd, flags, vd.Mount(), vd.Dentry(), &FileDescriptionOptions{ + UseDentryMetadata: true, + DenyPRead: true, + DenyPWrite: true, + }); err != nil { + return nil, err + } + return &fd.vfsfd, nil +} + +// Release implements FileDescriptionImpl.Release. Release removes all +// watches and frees all resources for an inotify instance. +func (i *Inotify) Release(ctx context.Context) { + var ds []*Dentry + + // We need to hold i.mu to avoid a race with concurrent calls to + // Inotify.handleDeletion from Watches. There's no risk of Watches + // accessing this Inotify after the destructor ends, because we remove all + // references to it below. + i.mu.Lock() + for _, w := range i.watches { + // Remove references to the watch from the watches set on the target. We + // don't need to worry about the references from i.watches, since this + // file description is about to be destroyed. + d := w.target + ws := d.Watches() + // Watchable dentries should never return a nil watch set. + if ws == nil { + panic("Cannot remove watch from an unwatchable dentry") + } + ws.Remove(i.id) + if ws.Size() == 0 { + ds = append(ds, d) + } + } + i.mu.Unlock() + + for _, d := range ds { + d.OnZeroWatches(ctx) + } +} + +// Allocate implements FileDescription.Allocate. +func (i *Inotify) Allocate(ctx context.Context, mode, offset, length uint64) error { + panic("Allocate should not be called on read-only inotify fds") +} + +// EventRegister implements waiter.Waitable. +func (i *Inotify) EventRegister(e *waiter.Entry, mask waiter.EventMask) { + i.queue.EventRegister(e, mask) +} + +// EventUnregister implements waiter.Waitable. +func (i *Inotify) EventUnregister(e *waiter.Entry) { + i.queue.EventUnregister(e) +} + +// Readiness implements waiter.Waitable.Readiness. +// +// Readiness indicates whether there are pending events for an inotify instance. +func (i *Inotify) Readiness(mask waiter.EventMask) waiter.EventMask { + ready := waiter.EventMask(0) + + i.evMu.Lock() + defer i.evMu.Unlock() + + if !i.events.Empty() { + ready |= waiter.EventIn + } + + return mask & ready +} + +// PRead implements FileDescriptionImpl.PRead. +func (*Inotify) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts ReadOptions) (int64, error) { + return 0, syserror.ESPIPE +} + +// PWrite implements FileDescriptionImpl.PWrite. +func (*Inotify) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts WriteOptions) (int64, error) { + return 0, syserror.ESPIPE +} + +// Write implements FileDescriptionImpl.Write. +func (*Inotify) Write(ctx context.Context, src usermem.IOSequence, opts WriteOptions) (int64, error) { + return 0, syserror.EBADF +} + +// Read implements FileDescriptionImpl.Read. +func (i *Inotify) Read(ctx context.Context, dst usermem.IOSequence, opts ReadOptions) (int64, error) { + if dst.NumBytes() < inotifyEventBaseSize { + return 0, syserror.EINVAL + } + + i.evMu.Lock() + defer i.evMu.Unlock() + + if i.events.Empty() { + // Nothing to read yet, tell caller to block. + return 0, syserror.ErrWouldBlock + } + + var writeLen int64 + for it := i.events.Front(); it != nil; { + // Advance `it` before the element is removed from the list, or else + // it.Next() will always be nil. + event := it + it = it.Next() + + // Does the buffer have enough remaining space to hold the event we're + // about to write out? + if dst.NumBytes() < int64(event.sizeOf()) { + if writeLen > 0 { + // Buffer wasn't big enough for all pending events, but we did + // write some events out. + return writeLen, nil + } + return 0, syserror.EINVAL + } + + // Linux always dequeues an available event as long as there's enough + // buffer space to copy it out, even if the copy below fails. Emulate + // this behaviour. + i.events.Remove(event) + + // Buffer has enough space, copy event to the read buffer. + n, err := event.CopyTo(ctx, i.scratch, dst) + if err != nil { + return 0, err + } + + writeLen += n + dst = dst.DropFirst64(n) + } + return writeLen, nil +} + +// Ioctl implements FileDescriptionImpl.Ioctl. +func (i *Inotify) Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) { + switch args[1].Int() { + case linux.FIONREAD: + i.evMu.Lock() + defer i.evMu.Unlock() + var n uint32 + for e := i.events.Front(); e != nil; e = e.Next() { + n += uint32(e.sizeOf()) + } + var buf [4]byte + usermem.ByteOrder.PutUint32(buf[:], n) + _, err := uio.CopyOut(ctx, args[2].Pointer(), buf[:], usermem.IOOpts{}) + return 0, err + + default: + return 0, syserror.ENOTTY + } +} + +func (i *Inotify) queueEvent(ev *Event) { + i.evMu.Lock() + + // Check if we should coalesce the event we're about to queue with the last + // one currently in the queue. Events are coalesced if they are identical. + if last := i.events.Back(); last != nil { + if ev.equals(last) { + // "Coalesce" the two events by simply not queuing the new one. We + // don't need to raise a waiter.EventIn notification because no new + // data is available for reading. + i.evMu.Unlock() + return + } + } + + i.events.PushBack(ev) + + // Release mutex before notifying waiters because we don't control what they + // can do. + i.evMu.Unlock() + + i.queue.Notify(waiter.EventIn) +} + +// newWatchLocked creates and adds a new watch to target. +// +// Precondition: i.mu must be locked. ws must be the watch set for target d. +func (i *Inotify) newWatchLocked(d *Dentry, ws *Watches, mask uint32) *Watch { + w := &Watch{ + owner: i, + wd: i.nextWatchIDLocked(), + target: d, + mask: mask, + } + + // Hold the watch in this inotify instance as well as the watch set on the + // target. + i.watches[w.wd] = w + ws.Add(w) + return w +} + +// newWatchIDLocked allocates and returns a new watch descriptor. +// +// Precondition: i.mu must be locked. +func (i *Inotify) nextWatchIDLocked() int32 { + i.nextWatchMinusOne++ + return i.nextWatchMinusOne +} + +// AddWatch constructs a new inotify watch and adds it to the target. It +// returns the watch descriptor returned by inotify_add_watch(2). +// +// The caller must hold a reference on target. +func (i *Inotify) AddWatch(target *Dentry, mask uint32) (int32, error) { + // Note: Locking this inotify instance protects the result returned by + // Lookup() below. With the lock held, we know for sure the lookup result + // won't become stale because it's impossible for *this* instance to + // add/remove watches on target. + i.mu.Lock() + defer i.mu.Unlock() + + ws := target.Watches() + if ws == nil { + // While Linux supports inotify watches on all filesystem types, watches on + // filesystems like kernfs are not generally useful, so we do not. + return 0, syserror.EPERM + } + // Does the target already have a watch from this inotify instance? + if existing := ws.Lookup(i.id); existing != nil { + newmask := mask + if mask&linux.IN_MASK_ADD != 0 { + // "Add (OR) events to watch mask for this pathname if it already + // exists (instead of replacing mask)." -- inotify(7) + newmask |= atomic.LoadUint32(&existing.mask) + } + atomic.StoreUint32(&existing.mask, newmask) + return existing.wd, nil + } + + // No existing watch, create a new watch. + w := i.newWatchLocked(target, ws, mask) + return w.wd, nil +} + +// RmWatch looks up an inotify watch for the given 'wd' and configures the +// target to stop sending events to this inotify instance. +func (i *Inotify) RmWatch(ctx context.Context, wd int32) error { + i.mu.Lock() + + // Find the watch we were asked to removed. + w, ok := i.watches[wd] + if !ok { + i.mu.Unlock() + return syserror.EINVAL + } + + // Remove the watch from this instance. + delete(i.watches, wd) + + // Remove the watch from the watch target. + ws := w.target.Watches() + // AddWatch ensures that w.target has a non-nil watch set. + if ws == nil { + panic("Watched dentry cannot have nil watch set") + } + ws.Remove(w.OwnerID()) + remaining := ws.Size() + i.mu.Unlock() + + if remaining == 0 { + w.target.OnZeroWatches(ctx) + } + + // Generate the event for the removal. + i.queueEvent(newEvent(wd, "", linux.IN_IGNORED, 0)) + + return nil +} + +// Watches is the collection of all inotify watches on a single file. +// +// +stateify savable +type Watches struct { + // mu protects the fields below. + mu sync.RWMutex `state:"nosave"` + + // ws is the map of active watches in this collection, keyed by the inotify + // instance id of the owner. + ws map[uint64]*Watch +} + +// Size returns the number of watches held by w. +func (w *Watches) Size() int { + w.mu.Lock() + defer w.mu.Unlock() + return len(w.ws) +} + +// Lookup returns the watch owned by an inotify instance with the given id. +// Returns nil if no such watch exists. +// +// Precondition: the inotify instance with the given id must be locked to +// prevent the returned watch from being concurrently modified or replaced in +// Inotify.watches. +func (w *Watches) Lookup(id uint64) *Watch { + w.mu.Lock() + defer w.mu.Unlock() + return w.ws[id] +} + +// Add adds watch into this set of watches. +// +// Precondition: the inotify instance with the given id must be locked. +func (w *Watches) Add(watch *Watch) { + w.mu.Lock() + defer w.mu.Unlock() + + owner := watch.OwnerID() + // Sanity check, we should never have two watches for one owner on the + // same target. + if _, exists := w.ws[owner]; exists { + panic(fmt.Sprintf("Watch collision with ID %+v", owner)) + } + if w.ws == nil { + w.ws = make(map[uint64]*Watch) + } + w.ws[owner] = watch +} + +// Remove removes a watch with the given id from this set of watches and +// releases it. The caller is responsible for generating any watch removal +// event, as appropriate. The provided id must match an existing watch in this +// collection. +// +// Precondition: the inotify instance with the given id must be locked. +func (w *Watches) Remove(id uint64) { + w.mu.Lock() + defer w.mu.Unlock() + + if w.ws == nil { + // This watch set is being destroyed. The thread executing the + // destructor is already in the process of deleting all our watches. We + // got here with no references on the target because we raced with the + // destructor notifying all the watch owners of destruction. See the + // comment in Watches.HandleDeletion for why this race exists. + return + } + + // It is possible for w.Remove() to be called for the same watch multiple + // times. See the treatment of one-shot watches in Watches.Notify(). + if _, ok := w.ws[id]; ok { + delete(w.ws, id) + } +} + +// Notify queues a new event with watches in this set. Watches with +// IN_EXCL_UNLINK are skipped if the event is coming from a child that has been +// unlinked. +func (w *Watches) Notify(ctx context.Context, name string, events, cookie uint32, et EventType, unlinked bool) { + var hasExpired bool + w.mu.RLock() + for _, watch := range w.ws { + if unlinked && watch.ExcludeUnlinked() && et == PathEvent { + continue + } + if watch.Notify(name, events, cookie) { + hasExpired = true + } + } + w.mu.RUnlock() + + if hasExpired { + w.cleanupExpiredWatches(ctx) + } +} + +// This function is relatively expensive and should only be called where there +// are expired watches. +func (w *Watches) cleanupExpiredWatches(ctx context.Context) { + // Because of lock ordering, we cannot acquire Inotify.mu for each watch + // owner while holding w.mu. As a result, store expired watches locally + // before removing. + var toRemove []*Watch + w.mu.RLock() + for _, watch := range w.ws { + if atomic.LoadInt32(&watch.expired) == 1 { + toRemove = append(toRemove, watch) + } + } + w.mu.RUnlock() + for _, watch := range toRemove { + watch.owner.RmWatch(ctx, watch.wd) + } +} + +// HandleDeletion is called when the watch target is destroyed. Clear the +// watch set, detach watches from the inotify instances they belong to, and +// generate the appropriate events. +func (w *Watches) HandleDeletion(ctx context.Context) { + w.Notify(ctx, "", linux.IN_DELETE_SELF, 0, InodeEvent, true /* unlinked */) + + // As in Watches.Notify, we can't hold w.mu while acquiring Inotify.mu for + // the owner of each watch being deleted. Instead, atomically store the + // watches map in a local variable and set it to nil so we can iterate over + // it with the assurance that there will be no concurrent accesses. + var ws map[uint64]*Watch + w.mu.Lock() + ws = w.ws + w.ws = nil + w.mu.Unlock() + + // Remove each watch from its owner's watch set, and generate a corresponding + // watch removal event. + for _, watch := range ws { + i := watch.owner + i.mu.Lock() + _, found := i.watches[watch.wd] + delete(i.watches, watch.wd) + + // Release mutex before notifying waiters because we don't control what + // they can do. + i.mu.Unlock() + + // If watch was not found, it was removed from the inotify instance before + // we could get to it, in which case we should not generate an event. + if found { + i.queueEvent(newEvent(watch.wd, "", linux.IN_IGNORED, 0)) + } + } +} + +// Watch represent a particular inotify watch created by inotify_add_watch. +// +// +stateify savable +type Watch struct { + // Inotify instance which owns this watch. + // + // This field is immutable after creation. + owner *Inotify + + // Descriptor for this watch. This is unique across an inotify instance. + // + // This field is immutable after creation. + wd int32 + + // target is a dentry representing the watch target. Its watch set contains this watch. + // + // This field is immutable after creation. + target *Dentry + + // Events being monitored via this watch. Must be accessed with atomic + // memory operations. + mask uint32 + + // expired is set to 1 to indicate that this watch is a one-shot that has + // already sent a notification and therefore can be removed. Must be accessed + // with atomic memory operations. + expired int32 +} + +// OwnerID returns the id of the inotify instance that owns this watch. +func (w *Watch) OwnerID() uint64 { + return w.owner.id +} + +// ExcludeUnlinked indicates whether the watched object should continue to be +// notified of events originating from a path that has been unlinked. +// +// For example, if "foo/bar" is opened and then unlinked, operations on the +// open fd may be ignored by watches on "foo" and "foo/bar" with IN_EXCL_UNLINK. +func (w *Watch) ExcludeUnlinked() bool { + return atomic.LoadUint32(&w.mask)&linux.IN_EXCL_UNLINK != 0 +} + +// Notify queues a new event on this watch. Returns true if this is a one-shot +// watch that should be deleted, after this event was successfully queued. +func (w *Watch) Notify(name string, events uint32, cookie uint32) bool { + if atomic.LoadInt32(&w.expired) == 1 { + // This is a one-shot watch that is already in the process of being + // removed. This may happen if a second event reaches the watch target + // before this watch has been removed. + return false + } + + mask := atomic.LoadUint32(&w.mask) + if mask&events == 0 { + // We weren't watching for this event. + return false + } + + // Event mask should include bits matched from the watch plus all control + // event bits. + unmaskableBits := ^uint32(0) &^ linux.IN_ALL_EVENTS + effectiveMask := unmaskableBits | mask + matchedEvents := effectiveMask & events + w.owner.queueEvent(newEvent(w.wd, name, matchedEvents, cookie)) + if mask&linux.IN_ONESHOT != 0 { + atomic.StoreInt32(&w.expired, 1) + return true + } + return false +} + +// Event represents a struct inotify_event from linux. +// +// +stateify savable +type Event struct { + eventEntry + + wd int32 + mask uint32 + cookie uint32 + + // len is computed based on the name field is set automatically by + // Event.setName. It should be 0 when no name is set; otherwise it is the + // length of the name slice. + len uint32 + + // The name field has special padding requirements and should only be set by + // calling Event.setName. + name []byte +} + +func newEvent(wd int32, name string, events, cookie uint32) *Event { + e := &Event{ + wd: wd, + mask: events, + cookie: cookie, + } + if name != "" { + e.setName(name) + } + return e +} + +// paddedBytes converts a go string to a null-terminated c-string, padded with +// null bytes to a total size of 'l'. 'l' must be large enough for all the bytes +// in the 's' plus at least one null byte. +func paddedBytes(s string, l uint32) []byte { + if l < uint32(len(s)+1) { + panic("Converting string to byte array results in truncation, this can lead to buffer-overflow due to the missing null-byte!") + } + b := make([]byte, l) + copy(b, s) + + // b was zero-value initialized during make(), so the rest of the slice is + // already filled with null bytes. + + return b +} + +// setName sets the optional name for this event. +func (e *Event) setName(name string) { + // We need to pad the name such that the entire event length ends up a + // multiple of inotifyEventBaseSize. + unpaddedLen := len(name) + 1 + // Round up to nearest multiple of inotifyEventBaseSize. + e.len = uint32((unpaddedLen + inotifyEventBaseSize - 1) & ^(inotifyEventBaseSize - 1)) + // Make sure we haven't overflowed and wrapped around when rounding. + if unpaddedLen > int(e.len) { + panic("Overflow when rounding inotify event size, the 'name' field was too big.") + } + e.name = paddedBytes(name, e.len) +} + +func (e *Event) sizeOf() int { + s := inotifyEventBaseSize + int(e.len) + if s < inotifyEventBaseSize { + panic("Overflowed event size") + } + return s +} + +// CopyTo serializes this event to dst. buf is used as a scratch buffer to +// construct the output. We use a buffer allocated ahead of time for +// performance. buf must be at least inotifyEventBaseSize bytes. +func (e *Event) CopyTo(ctx context.Context, buf []byte, dst usermem.IOSequence) (int64, error) { + usermem.ByteOrder.PutUint32(buf[0:], uint32(e.wd)) + usermem.ByteOrder.PutUint32(buf[4:], e.mask) + usermem.ByteOrder.PutUint32(buf[8:], e.cookie) + usermem.ByteOrder.PutUint32(buf[12:], e.len) + + writeLen := 0 + + n, err := dst.CopyOut(ctx, buf) + if err != nil { + return 0, err + } + writeLen += n + dst = dst.DropFirst(n) + + if e.len > 0 { + n, err = dst.CopyOut(ctx, e.name) + if err != nil { + return 0, err + } + writeLen += n + } + + // Santiy check. + if writeLen != e.sizeOf() { + panic(fmt.Sprintf("Serialized unexpected amount of data for an event, expected %d, wrote %d.", e.sizeOf(), writeLen)) + } + + return int64(writeLen), nil +} + +func (e *Event) equals(other *Event) bool { + return e.wd == other.wd && + e.mask == other.mask && + e.cookie == other.cookie && + e.len == other.len && + bytes.Equal(e.name, other.name) +} + +// InotifyEventFromStatMask generates the appropriate events for an operation +// that set the stats specified in mask. +func InotifyEventFromStatMask(mask uint32) uint32 { + var ev uint32 + if mask&(linux.STATX_UID|linux.STATX_GID|linux.STATX_MODE) != 0 { + ev |= linux.IN_ATTRIB + } + if mask&linux.STATX_SIZE != 0 { + ev |= linux.IN_MODIFY + } + + if (mask & (linux.STATX_ATIME | linux.STATX_MTIME)) == (linux.STATX_ATIME | linux.STATX_MTIME) { + // Both times indicates a utime(s) call. + ev |= linux.IN_ATTRIB + } else if mask&linux.STATX_ATIME != 0 { + ev |= linux.IN_ACCESS + } else if mask&linux.STATX_MTIME != 0 { + mask |= linux.IN_MODIFY + } + return ev +} + +// InotifyRemoveChild sends the appriopriate notifications to the watch sets of +// the child being removed and its parent. Note that unlike most pairs of +// parent/child notifications, the child is notified first in this case. +func InotifyRemoveChild(ctx context.Context, self, parent *Watches, name string) { + if self != nil { + self.Notify(ctx, "", linux.IN_ATTRIB, 0, InodeEvent, true /* unlinked */) + } + if parent != nil { + parent.Notify(ctx, name, linux.IN_DELETE, 0, InodeEvent, true /* unlinked */) + } +} + +// InotifyRename sends the appriopriate notifications to the watch sets of the +// file being renamed and its old/new parents. +func InotifyRename(ctx context.Context, renamed, oldParent, newParent *Watches, oldName, newName string, isDir bool) { + var dirEv uint32 + if isDir { + dirEv = linux.IN_ISDIR + } + cookie := uniqueid.InotifyCookie(ctx) + if oldParent != nil { + oldParent.Notify(ctx, oldName, dirEv|linux.IN_MOVED_FROM, cookie, InodeEvent, false /* unlinked */) + } + if newParent != nil { + newParent.Notify(ctx, newName, dirEv|linux.IN_MOVED_TO, cookie, InodeEvent, false /* unlinked */) + } + // Somewhat surprisingly, self move events do not have a cookie. + if renamed != nil { + renamed.Notify(ctx, "", linux.IN_MOVE_SELF, 0, InodeEvent, false /* unlinked */) + } +} diff --git a/pkg/sentry/vfs/lock/lock.go b/pkg/sentry/vfs/lock.go index 724dfe743..6c7583a81 100644 --- a/pkg/sentry/vfs/lock/lock.go +++ b/pkg/sentry/vfs/lock.go @@ -17,9 +17,11 @@ // // The actual implementations can be found in the lock package under // sentry/fs/lock. -package lock +package vfs import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/syserror" ) @@ -56,7 +58,11 @@ func (fl *FileLocks) UnlockBSD(uid fslock.UniqueID) { } // LockPOSIX tries to acquire a POSIX-style lock on a file region. -func (fl *FileLocks) LockPOSIX(uid fslock.UniqueID, t fslock.LockType, rng fslock.LockRange, block fslock.Blocker) error { +func (fl *FileLocks) LockPOSIX(ctx context.Context, fd *FileDescription, uid fslock.UniqueID, t fslock.LockType, start, length uint64, whence int16, block fslock.Blocker) error { + rng, err := computeRange(ctx, fd, start, length, whence) + if err != nil { + return err + } if fl.posix.LockRegion(uid, t, rng, block) { return nil } @@ -67,6 +73,37 @@ func (fl *FileLocks) LockPOSIX(uid fslock.UniqueID, t fslock.LockType, rng fsloc // // This operation is always successful, even if there did not exist a lock on // the requested region held by uid in the first place. -func (fl *FileLocks) UnlockPOSIX(uid fslock.UniqueID, rng fslock.LockRange) { +func (fl *FileLocks) UnlockPOSIX(ctx context.Context, fd *FileDescription, uid fslock.UniqueID, start, length uint64, whence int16) error { + rng, err := computeRange(ctx, fd, start, length, whence) + if err != nil { + return err + } fl.posix.UnlockRegion(uid, rng) + return nil +} + +func computeRange(ctx context.Context, fd *FileDescription, start uint64, length uint64, whence int16) (fslock.LockRange, error) { + var off int64 + switch whence { + case linux.SEEK_SET: + off = 0 + case linux.SEEK_CUR: + // Note that Linux does not hold any mutexes while retrieving the file + // offset, see fs/locks.c:flock_to_posix_lock and fs/locks.c:fcntl_setlk. + curOff, err := fd.Seek(ctx, 0, linux.SEEK_CUR) + if err != nil { + return fslock.LockRange{}, err + } + off = curOff + case linux.SEEK_END: + stat, err := fd.Stat(ctx, StatOptions{Mask: linux.STATX_SIZE}) + if err != nil { + return fslock.LockRange{}, err + } + off = int64(stat.Size) + default: + return fslock.LockRange{}, syserror.EINVAL + } + + return fslock.ComputeRange(int64(start), int64(length), off) } diff --git a/pkg/sentry/vfs/lock/BUILD b/pkg/sentry/vfs/lock/BUILD deleted file mode 100644 index d9ab063b7..000000000 --- a/pkg/sentry/vfs/lock/BUILD +++ /dev/null @@ -1,13 +0,0 @@ -load("//tools:defs.bzl", "go_library") - -package(licenses = ["notice"]) - -go_library( - name = "lock", - srcs = ["lock.go"], - visibility = ["//pkg/sentry:internal"], - deps = [ - "//pkg/sentry/fs/lock", - "//pkg/syserror", - ], -) diff --git a/pkg/sentry/vfs/mount.go b/pkg/sentry/vfs/mount.go index 02850b65c..d1d29d0cd 100644 --- a/pkg/sentry/vfs/mount.go +++ b/pkg/sentry/vfs/mount.go @@ -28,9 +28,6 @@ import ( "gvisor.dev/gvisor/pkg/syserror" ) -// lastMountID is used to allocate mount ids. Must be accessed atomically. -var lastMountID uint64 - // A Mount is a replacement of a Dentry (Mount.key.point) from one Filesystem // (Mount.key.parent.fs) with a Dentry (Mount.root) from another Filesystem // (Mount.fs), which applies to path resolution in the context of a particular @@ -58,6 +55,10 @@ type Mount struct { // ID is the immutable mount ID. ID uint64 + // Flags contains settings as specified for mount(2), e.g. MS_NOEXEC, except + // for MS_RDONLY which is tracked in "writers". Immutable. + Flags MountFlags + // key is protected by VirtualFilesystem.mountMu and // VirtualFilesystem.mounts.seq, and may be nil. References are held on // key.parent and key.point if they are not nil. @@ -84,10 +85,6 @@ type Mount struct { // umounted is true. umounted is protected by VirtualFilesystem.mountMu. umounted bool - // flags contains settings as specified for mount(2), e.g. MS_NOEXEC, except - // for MS_RDONLY which is tracked in "writers". - flags MountFlags - // The lower 63 bits of writers is the number of calls to // Mount.CheckBeginWrite() that have not yet been paired with a call to // Mount.EndWrite(). The MSB of writers is set if MS_RDONLY is in effect. @@ -97,11 +94,11 @@ type Mount struct { func newMount(vfs *VirtualFilesystem, fs *Filesystem, root *Dentry, mntns *MountNamespace, opts *MountOptions) *Mount { mnt := &Mount{ - ID: atomic.AddUint64(&lastMountID, 1), + ID: atomic.AddUint64(&vfs.lastMountID, 1), + Flags: opts.Flags, vfs: vfs, fs: fs, root: root, - flags: opts.Flags, ns: mntns, refs: 1, } @@ -111,8 +108,17 @@ func newMount(vfs *VirtualFilesystem, fs *Filesystem, root *Dentry, mntns *Mount return mnt } -// A MountNamespace is a collection of Mounts. -// +// Options returns a copy of the MountOptions currently applicable to mnt. +func (mnt *Mount) Options() MountOptions { + mnt.vfs.mountMu.Lock() + defer mnt.vfs.mountMu.Unlock() + return MountOptions{ + Flags: mnt.Flags, + ReadOnly: mnt.readOnly(), + } +} + +// A MountNamespace is a collection of Mounts.// // MountNamespaces are reference-counted. Unless otherwise specified, all // MountNamespace methods require that a reference is held. // @@ -120,6 +126,9 @@ func newMount(vfs *VirtualFilesystem, fs *Filesystem, root *Dentry, mntns *Mount // // +stateify savable type MountNamespace struct { + // Owner is the usernamespace that owns this mount namespace. + Owner *auth.UserNamespace + // root is the MountNamespace's root mount. root is immutable. root *Mount @@ -148,7 +157,7 @@ type MountNamespace struct { func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth.Credentials, source, fsTypeName string, opts *GetFilesystemOptions) (*MountNamespace, error) { rft := vfs.getFilesystemType(fsTypeName) if rft == nil { - ctx.Warningf("Unknown filesystem: %s", fsTypeName) + ctx.Warningf("Unknown filesystem type: %s", fsTypeName) return nil, syserror.ENODEV } fs, root, err := rft.fsType.GetFilesystem(ctx, vfs, creds, source, *opts) @@ -156,6 +165,7 @@ func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth return nil, err } mntns := &MountNamespace{ + Owner: creds.UserNamespace, refs: 1, mountpoints: make(map[*Dentry]uint32), } @@ -175,26 +185,34 @@ func (vfs *VirtualFilesystem) NewDisconnectedMount(fs *Filesystem, root *Dentry, return newMount(vfs, fs, root, nil /* mntns */, opts), nil } -// MountAt creates and mounts a Filesystem configured by the given arguments. -func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentials, source string, target *PathOperation, fsTypeName string, opts *MountOptions) error { +// MountDisconnected creates a Filesystem configured by the given arguments, +// then returns a Mount representing it. The new Mount is not associated with +// any MountNamespace and is not connected to any other Mounts. +func (vfs *VirtualFilesystem) MountDisconnected(ctx context.Context, creds *auth.Credentials, source string, fsTypeName string, opts *MountOptions) (*Mount, error) { rft := vfs.getFilesystemType(fsTypeName) if rft == nil { - return syserror.ENODEV + return nil, syserror.ENODEV } if !opts.InternalMount && !rft.opts.AllowUserMount { - return syserror.ENODEV + return nil, syserror.ENODEV } fs, root, err := rft.fsType.GetFilesystem(ctx, vfs, creds, source, opts.GetFilesystemOptions) if err != nil { - return err + return nil, err } + defer root.DecRef(ctx) + defer fs.DecRef(ctx) + return vfs.NewDisconnectedMount(fs, root, opts) +} +// ConnectMountAt connects mnt at the path represented by target. +// +// Preconditions: mnt must be disconnected. +func (vfs *VirtualFilesystem) ConnectMountAt(ctx context.Context, creds *auth.Credentials, mnt *Mount, target *PathOperation) error { // We can't hold vfs.mountMu while calling FilesystemImpl methods due to // lock ordering. vd, err := vfs.GetDentryAt(ctx, creds, target, &GetDentryOptions{}) if err != nil { - root.DecRef() - fs.DecRef() return err } vfs.mountMu.Lock() @@ -203,9 +221,7 @@ func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentia if vd.dentry.dead { vd.dentry.mu.Unlock() vfs.mountMu.Unlock() - vd.DecRef() - root.DecRef() - fs.DecRef() + vd.DecRef(ctx) return syserror.ENOENT } // vd might have been mounted over between vfs.GetDentryAt() and @@ -227,7 +243,7 @@ func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentia // This can't fail since we're holding vfs.mountMu. nextmnt.root.IncRef() vd.dentry.mu.Unlock() - vd.DecRef() + vd.DecRef(ctx) vd = VirtualDentry{ mount: nextmnt, dentry: nextmnt.root, @@ -238,7 +254,6 @@ func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentia // point and the mount root are directories, or neither are, and returns // ENOTDIR if this is not the case. mntns := vd.mount.ns - mnt := newMount(vfs, fs, root, mntns, opts) vfs.mounts.seq.BeginWrite() vfs.connectLocked(mnt, vd, mntns) vfs.mounts.seq.EndWrite() @@ -247,6 +262,19 @@ func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentia return nil } +// MountAt creates and mounts a Filesystem configured by the given arguments. +func (vfs *VirtualFilesystem) MountAt(ctx context.Context, creds *auth.Credentials, source string, target *PathOperation, fsTypeName string, opts *MountOptions) error { + mnt, err := vfs.MountDisconnected(ctx, creds, source, fsTypeName, opts) + if err != nil { + return err + } + defer mnt.DecRef(ctx) + if err := vfs.ConnectMountAt(ctx, creds, mnt, target); err != nil { + return err + } + return nil +} + // UmountAt removes the Mount at the given path. func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *UmountOptions) error { if opts.Flags&^(linux.MNT_FORCE|linux.MNT_DETACH) != 0 { @@ -254,6 +282,9 @@ func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credenti } // MNT_FORCE is currently unimplemented except for the permission check. + // Force unmounting specifically requires CAP_SYS_ADMIN in the root user + // namespace, and not in the owner user namespace for the target mount. See + // fs/namespace.c:SYSCALL_DEFINE2(umount, ...) if opts.Flags&linux.MNT_FORCE != 0 && creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, creds.UserNamespace.Root()) { return syserror.EPERM } @@ -262,13 +293,13 @@ func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credenti if err != nil { return err } - defer vd.DecRef() + defer vd.DecRef(ctx) if vd.dentry != vd.mount.root { return syserror.EINVAL } vfs.mountMu.Lock() if mntns := MountNamespaceFromContext(ctx); mntns != nil { - defer mntns.DecRef() + defer mntns.DecRef(ctx) if mntns != vd.mount.ns { vfs.mountMu.Unlock() return syserror.EINVAL @@ -304,10 +335,10 @@ func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credenti vfs.mounts.seq.EndWrite() vfs.mountMu.Unlock() for _, vd := range vdsToDecRef { - vd.DecRef() + vd.DecRef(ctx) } for _, mnt := range mountsToDecRef { - mnt.DecRef() + mnt.DecRef(ctx) } return nil } @@ -369,14 +400,22 @@ func (vfs *VirtualFilesystem) umountRecursiveLocked(mnt *Mount, opts *umountRecu // references held by vd. // // Preconditions: vfs.mountMu must be locked. vfs.mounts.seq must be in a -// writer critical section. d.mu must be locked. mnt.parent() == nil. +// writer critical section. d.mu must be locked. mnt.parent() == nil, i.e. mnt +// must not already be connected. func (vfs *VirtualFilesystem) connectLocked(mnt *Mount, vd VirtualDentry, mntns *MountNamespace) { + if checkInvariants { + if mnt.parent() != nil { + panic("VFS.connectLocked called on connected mount") + } + } + mnt.IncRef() // dropped by callers of umountRecursiveLocked mnt.storeKey(vd) if vd.mount.children == nil { vd.mount.children = make(map[*Mount]struct{}) } vd.mount.children[mnt] = struct{}{} atomic.AddUint32(&vd.dentry.mounts, 1) + mnt.ns = mntns mntns.mountpoints[vd.dentry]++ vfs.mounts.insertSeqed(mnt) vfsmpmounts, ok := vfs.mountpoints[vd.dentry] @@ -394,6 +433,11 @@ func (vfs *VirtualFilesystem) connectLocked(mnt *Mount, vd VirtualDentry, mntns // writer critical section. mnt.parent() != nil. func (vfs *VirtualFilesystem) disconnectLocked(mnt *Mount) VirtualDentry { vd := mnt.loadKey() + if checkInvariants { + if vd.mount != nil { + panic("VFS.disconnectLocked called on disconnected mount") + } + } mnt.storeKey(VirtualDentry{}) delete(vd.mount.children, mnt) atomic.AddUint32(&vd.dentry.mounts, math.MaxUint32) // -1 @@ -435,7 +479,7 @@ func (mnt *Mount) IncRef() { } // DecRef decrements mnt's reference count. -func (mnt *Mount) DecRef() { +func (mnt *Mount) DecRef(ctx context.Context) { refs := atomic.AddInt64(&mnt.refs, -1) if refs&^math.MinInt64 == 0 { // mask out MSB var vd VirtualDentry @@ -446,10 +490,10 @@ func (mnt *Mount) DecRef() { mnt.vfs.mounts.seq.EndWrite() mnt.vfs.mountMu.Unlock() } - mnt.root.DecRef() - mnt.fs.DecRef() + mnt.root.DecRef(ctx) + mnt.fs.DecRef(ctx) if vd.Ok() { - vd.DecRef() + vd.DecRef(ctx) } } } @@ -462,7 +506,7 @@ func (mntns *MountNamespace) IncRef() { } // DecRef decrements mntns' reference count. -func (mntns *MountNamespace) DecRef() { +func (mntns *MountNamespace) DecRef(ctx context.Context) { vfs := mntns.root.fs.VirtualFilesystem() if refs := atomic.AddInt64(&mntns.refs, -1); refs == 0 { vfs.mountMu.Lock() @@ -473,10 +517,10 @@ func (mntns *MountNamespace) DecRef() { vfs.mounts.seq.EndWrite() vfs.mountMu.Unlock() for _, vd := range vdsToDecRef { - vd.DecRef() + vd.DecRef(ctx) } for _, mnt := range mountsToDecRef { - mnt.DecRef() + mnt.DecRef(ctx) } } else if refs < 0 { panic("MountNamespace.DecRef() called without holding a reference") @@ -490,7 +534,7 @@ func (mntns *MountNamespace) DecRef() { // getMountAt is analogous to Linux's fs/namei.c:follow_mount(). // // Preconditions: References are held on mnt and d. -func (vfs *VirtualFilesystem) getMountAt(mnt *Mount, d *Dentry) *Mount { +func (vfs *VirtualFilesystem) getMountAt(ctx context.Context, mnt *Mount, d *Dentry) *Mount { // The first mount is special-cased: // // - The caller is assumed to have checked d.isMounted() already. (This @@ -521,7 +565,7 @@ retryFirst: // Raced with umount. continue } - mnt.DecRef() + mnt.DecRef(ctx) mnt = next d = next.root } @@ -534,7 +578,7 @@ retryFirst: // // Preconditions: References are held on mnt and root. vfsroot is not (mnt, // mnt.root). -func (vfs *VirtualFilesystem) getMountpointAt(mnt *Mount, vfsroot VirtualDentry) VirtualDentry { +func (vfs *VirtualFilesystem) getMountpointAt(ctx context.Context, mnt *Mount, vfsroot VirtualDentry) VirtualDentry { // The first mount is special-cased: // // - The caller must have already checked mnt against vfsroot. @@ -558,12 +602,12 @@ retryFirst: if !point.TryIncRef() { // Since Mount holds a reference on Mount.key.point, this can only // happen due to a racing change to Mount.key. - parent.DecRef() + parent.DecRef(ctx) goto retryFirst } if !vfs.mounts.seq.ReadOk(epoch) { - point.DecRef() - parent.DecRef() + point.DecRef(ctx) + parent.DecRef(ctx) goto retryFirst } mnt = parent @@ -591,16 +635,16 @@ retryFirst: if !point.TryIncRef() { // Since Mount holds a reference on Mount.key.point, this can // only happen due to a racing change to Mount.key. - parent.DecRef() + parent.DecRef(ctx) goto retryNotFirst } if !vfs.mounts.seq.ReadOk(epoch) { - point.DecRef() - parent.DecRef() + point.DecRef(ctx) + parent.DecRef(ctx) goto retryNotFirst } - d.DecRef() - mnt.DecRef() + d.DecRef(ctx) + mnt.DecRef(ctx) mnt = parent d = point } @@ -715,7 +759,10 @@ func (vfs *VirtualFilesystem) GenerateProcMounts(ctx context.Context, taskRootDi if mnt.readOnly() { opts = "ro" } - if mnt.flags.NoExec { + if mnt.Flags.NoATime { + opts = ",noatime" + } + if mnt.Flags.NoExec { opts += ",noexec" } @@ -800,11 +847,12 @@ func (vfs *VirtualFilesystem) GenerateProcMountInfo(ctx context.Context, taskRoo if mnt.readOnly() { opts = "ro" } - if mnt.flags.NoExec { + if mnt.Flags.NoATime { + opts = ",noatime" + } + if mnt.Flags.NoExec { opts += ",noexec" } - // TODO(gvisor.dev/issue/1193): Add "noatime" if MS_NOATIME is - // set. fmt.Fprintf(buf, "%s ", opts) // (7) Optional fields: zero or more fields of the form "tag[:value]". diff --git a/pkg/sentry/vfs/mount_unsafe.go b/pkg/sentry/vfs/mount_unsafe.go index bc7581698..70f850ca4 100644 --- a/pkg/sentry/vfs/mount_unsafe.go +++ b/pkg/sentry/vfs/mount_unsafe.go @@ -13,7 +13,7 @@ // limitations under the License. // +build go1.12 -// +build !go1.15 +// +build !go1.16 // Check go:linkname function signatures when updating Go version. diff --git a/pkg/sentry/vfs/options.go b/pkg/sentry/vfs/options.go index 53d364c5c..dfc8573fd 100644 --- a/pkg/sentry/vfs/options.go +++ b/pkg/sentry/vfs/options.go @@ -75,6 +75,21 @@ type MknodOptions struct { type MountFlags struct { // NoExec is equivalent to MS_NOEXEC. NoExec bool + + // NoATime is equivalent to MS_NOATIME and indicates that the + // filesystem should not update access time in-place. + NoATime bool + + // NoDev is equivalent to MS_NODEV and indicates that the + // filesystem should not allow access to devices (special files). + // TODO(gVisor.dev/issue/3186): respect this flag in non FUSE + // filesystems. + NoDev bool + + // NoSUID is equivalent to MS_NOSUID and indicates that the + // filesystem should not honor set-user-ID and set-group-ID bits or + // file capabilities when executing programs. + NoSUID bool } // MountOptions contains options to VirtualFilesystem.MountAt(). @@ -149,6 +164,12 @@ type SetStatOptions struct { // == UTIME_OMIT (VFS users must unset the corresponding bit in Stat.Mask // instead). Stat linux.Statx + + // NeedWritePerm indicates that write permission on the file is needed for + // this operation. This is needed for truncate(2) (note that ftruncate(2) + // does not require the same check--instead, it checks that the fd is + // writable). + NeedWritePerm bool } // BoundEndpointOptions contains options to VirtualFilesystem.BoundEndpointAt() diff --git a/pkg/sentry/vfs/pathname.go b/pkg/sentry/vfs/pathname.go index cd78d66bc..e4da15009 100644 --- a/pkg/sentry/vfs/pathname.go +++ b/pkg/sentry/vfs/pathname.go @@ -47,7 +47,7 @@ func (vfs *VirtualFilesystem) PathnameWithDeleted(ctx context.Context, vfsroot, haveRef := false defer func() { if haveRef { - vd.DecRef() + vd.DecRef(ctx) } }() @@ -64,12 +64,12 @@ loop: // of FilesystemImpl.PrependPath() may return nil instead. break loop } - nextVD := vfs.getMountpointAt(vd.mount, vfsroot) + nextVD := vfs.getMountpointAt(ctx, vd.mount, vfsroot) if !nextVD.Ok() { break loop } if haveRef { - vd.DecRef() + vd.DecRef(ctx) } vd = nextVD haveRef = true @@ -101,7 +101,7 @@ func (vfs *VirtualFilesystem) PathnameReachable(ctx context.Context, vfsroot, vd haveRef := false defer func() { if haveRef { - vd.DecRef() + vd.DecRef(ctx) } }() loop: @@ -112,12 +112,12 @@ loop: if vd.mount == vfsroot.mount && vd.mount.root == vfsroot.dentry { break loop } - nextVD := vfs.getMountpointAt(vd.mount, vfsroot) + nextVD := vfs.getMountpointAt(ctx, vd.mount, vfsroot) if !nextVD.Ok() { return "", nil } if haveRef { - vd.DecRef() + vd.DecRef(ctx) } vd = nextVD haveRef = true @@ -145,7 +145,7 @@ func (vfs *VirtualFilesystem) PathnameForGetcwd(ctx context.Context, vfsroot, vd haveRef := false defer func() { if haveRef { - vd.DecRef() + vd.DecRef(ctx) } }() unreachable := false @@ -157,13 +157,13 @@ loop: if vd.mount == vfsroot.mount && vd.mount.root == vfsroot.dentry { break loop } - nextVD := vfs.getMountpointAt(vd.mount, vfsroot) + nextVD := vfs.getMountpointAt(ctx, vd.mount, vfsroot) if !nextVD.Ok() { unreachable = true break loop } if haveRef { - vd.DecRef() + vd.DecRef(ctx) } vd = nextVD haveRef = true diff --git a/pkg/sentry/vfs/permissions.go b/pkg/sentry/vfs/permissions.go index f9647f90e..33389c1df 100644 --- a/pkg/sentry/vfs/permissions.go +++ b/pkg/sentry/vfs/permissions.go @@ -94,6 +94,37 @@ func GenericCheckPermissions(creds *auth.Credentials, ats AccessTypes, mode linu return syserror.EACCES } +// MayLink determines whether creating a hard link to a file with the given +// mode, kuid, and kgid is permitted. +// +// This corresponds to Linux's fs/namei.c:may_linkat. +func MayLink(creds *auth.Credentials, mode linux.FileMode, kuid auth.KUID, kgid auth.KGID) error { + // Source inode owner can hardlink all they like; otherwise, it must be a + // safe source. + if CanActAsOwner(creds, kuid) { + return nil + } + + // Only regular files can be hard linked. + if mode.FileType() != linux.S_IFREG { + return syserror.EPERM + } + + // Setuid files should not get pinned to the filesystem. + if mode&linux.S_ISUID != 0 { + return syserror.EPERM + } + + // Executable setgid files should not get pinned to the filesystem, but we + // don't support S_IXGRP anyway. + + // Hardlinking to unreadable or unwritable sources is dangerous. + if err := GenericCheckPermissions(creds, MayRead|MayWrite, mode, kuid, kgid); err != nil { + return syserror.EPERM + } + return nil +} + // AccessTypesForOpenFlags returns the access types required to open a file // with the given OpenOptions.Flags. Note that this is NOT the same thing as // the set of accesses permitted for the opened file: @@ -152,7 +183,8 @@ func MayWriteFileWithOpenFlags(flags uint32) bool { // CheckSetStat checks that creds has permission to change the metadata of a // file with the given permissions, UID, and GID as specified by stat, subject // to the rules of Linux's fs/attr.c:setattr_prepare(). -func CheckSetStat(ctx context.Context, creds *auth.Credentials, stat *linux.Statx, mode linux.FileMode, kuid auth.KUID, kgid auth.KGID) error { +func CheckSetStat(ctx context.Context, creds *auth.Credentials, opts *SetStatOptions, mode linux.FileMode, kuid auth.KUID, kgid auth.KGID) error { + stat := &opts.Stat if stat.Mask&linux.STATX_SIZE != 0 { limit, err := CheckLimit(ctx, 0, int64(stat.Size)) if err != nil { @@ -184,6 +216,11 @@ func CheckSetStat(ctx context.Context, creds *auth.Credentials, stat *linux.Stat return syserror.EPERM } } + if opts.NeedWritePerm && !creds.HasCapability(linux.CAP_DAC_OVERRIDE) { + if err := GenericCheckPermissions(creds, MayWrite, mode, kuid, kgid); err != nil { + return err + } + } if stat.Mask&(linux.STATX_ATIME|linux.STATX_MTIME|linux.STATX_CTIME) != 0 { if !CanActAsOwner(creds, kuid) { if (stat.Mask&linux.STATX_ATIME != 0 && stat.Atime.Nsec != linux.UTIME_NOW) || @@ -199,6 +236,20 @@ func CheckSetStat(ctx context.Context, creds *auth.Credentials, stat *linux.Stat return nil } +// CheckDeleteSticky checks whether the sticky bit is set on a directory with +// the given file mode, and if so, checks whether creds has permission to +// remove a file owned by childKUID from a directory with the given mode. +// CheckDeleteSticky is consistent with fs/linux.h:check_sticky(). +func CheckDeleteSticky(creds *auth.Credentials, parentMode linux.FileMode, childKUID auth.KUID) error { + if parentMode&linux.ModeSticky == 0 { + return nil + } + if CanActAsOwner(creds, childKUID) { + return nil + } + return syserror.EPERM +} + // CanActAsOwner returns true if creds can act as the owner of a file with the // given owning UID, consistent with Linux's // fs/inode.c:inode_owner_or_capable(). diff --git a/pkg/sentry/vfs/resolving_path.go b/pkg/sentry/vfs/resolving_path.go index 9d047ff88..3304372d9 100644 --- a/pkg/sentry/vfs/resolving_path.go +++ b/pkg/sentry/vfs/resolving_path.go @@ -18,6 +18,7 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" "gvisor.dev/gvisor/pkg/fspath" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" "gvisor.dev/gvisor/pkg/sync" @@ -136,31 +137,31 @@ func (vfs *VirtualFilesystem) getResolvingPath(creds *auth.Credentials, pop *Pat return rp } -func (vfs *VirtualFilesystem) putResolvingPath(rp *ResolvingPath) { +func (vfs *VirtualFilesystem) putResolvingPath(ctx context.Context, rp *ResolvingPath) { rp.root = VirtualDentry{} - rp.decRefStartAndMount() + rp.decRefStartAndMount(ctx) rp.mount = nil rp.start = nil - rp.releaseErrorState() + rp.releaseErrorState(ctx) resolvingPathPool.Put(rp) } -func (rp *ResolvingPath) decRefStartAndMount() { +func (rp *ResolvingPath) decRefStartAndMount(ctx context.Context) { if rp.flags&rpflagsHaveStartRef != 0 { - rp.start.DecRef() + rp.start.DecRef(ctx) } if rp.flags&rpflagsHaveMountRef != 0 { - rp.mount.DecRef() + rp.mount.DecRef(ctx) } } -func (rp *ResolvingPath) releaseErrorState() { +func (rp *ResolvingPath) releaseErrorState(ctx context.Context) { if rp.nextStart != nil { - rp.nextStart.DecRef() + rp.nextStart.DecRef(ctx) rp.nextStart = nil } if rp.nextMount != nil { - rp.nextMount.DecRef() + rp.nextMount.DecRef(ctx) rp.nextMount = nil } } @@ -236,13 +237,13 @@ func (rp *ResolvingPath) Advance() { // Restart resets the stream of path components represented by rp to its state // on entry to the current FilesystemImpl method. -func (rp *ResolvingPath) Restart() { +func (rp *ResolvingPath) Restart(ctx context.Context) { rp.pit = rp.origParts[rp.numOrigParts-1] rp.mustBeDir = rp.mustBeDirOrig rp.symlinks = rp.symlinksOrig rp.curPart = rp.numOrigParts - 1 copy(rp.parts[:], rp.origParts[:rp.numOrigParts]) - rp.releaseErrorState() + rp.releaseErrorState(ctx) } func (rp *ResolvingPath) relpathCommit() { @@ -260,13 +261,13 @@ func (rp *ResolvingPath) relpathCommit() { // Mount, CheckRoot returns (unspecified, non-nil error). Otherwise, path // resolution should resolve d's parent normally, and CheckRoot returns (false, // nil). -func (rp *ResolvingPath) CheckRoot(d *Dentry) (bool, error) { +func (rp *ResolvingPath) CheckRoot(ctx context.Context, d *Dentry) (bool, error) { if d == rp.root.dentry && rp.mount == rp.root.mount { // At contextual VFS root (due to e.g. chroot(2)). return true, nil } else if d == rp.mount.root { // At mount root ... - vd := rp.vfs.getMountpointAt(rp.mount, rp.root) + vd := rp.vfs.getMountpointAt(ctx, rp.mount, rp.root) if vd.Ok() { // ... of non-root mount. rp.nextMount = vd.mount @@ -283,11 +284,11 @@ func (rp *ResolvingPath) CheckRoot(d *Dentry) (bool, error) { // to d. If d is a mount point, such that path resolution should switch to // another Mount, CheckMount returns a non-nil error. Otherwise, CheckMount // returns nil. -func (rp *ResolvingPath) CheckMount(d *Dentry) error { +func (rp *ResolvingPath) CheckMount(ctx context.Context, d *Dentry) error { if !d.isMounted() { return nil } - if mnt := rp.vfs.getMountAt(rp.mount, d); mnt != nil { + if mnt := rp.vfs.getMountAt(ctx, rp.mount, d); mnt != nil { rp.nextMount = mnt return resolveMountPointError{} } @@ -389,11 +390,11 @@ func (rp *ResolvingPath) HandleJump(target VirtualDentry) error { return resolveMountRootOrJumpError{} } -func (rp *ResolvingPath) handleError(err error) bool { +func (rp *ResolvingPath) handleError(ctx context.Context, err error) bool { switch err.(type) { case resolveMountRootOrJumpError: // Switch to the new Mount. We hold references on the Mount and Dentry. - rp.decRefStartAndMount() + rp.decRefStartAndMount(ctx) rp.mount = rp.nextMount rp.start = rp.nextStart rp.flags |= rpflagsHaveMountRef | rpflagsHaveStartRef @@ -412,7 +413,7 @@ func (rp *ResolvingPath) handleError(err error) bool { case resolveMountPointError: // Switch to the new Mount. We hold a reference on the Mount, but // borrow the reference on the mount root from the Mount. - rp.decRefStartAndMount() + rp.decRefStartAndMount(ctx) rp.mount = rp.nextMount rp.start = rp.nextMount.root rp.flags = rp.flags&^rpflagsHaveStartRef | rpflagsHaveMountRef @@ -423,12 +424,12 @@ func (rp *ResolvingPath) handleError(err error) bool { // path. rp.relpathCommit() // Restart path resolution on the new Mount. - rp.releaseErrorState() + rp.releaseErrorState(ctx) return true case resolveAbsSymlinkError: // Switch to the new Mount. References are borrowed from rp.root. - rp.decRefStartAndMount() + rp.decRefStartAndMount(ctx) rp.mount = rp.root.mount rp.start = rp.root.dentry rp.flags &^= rpflagsHaveMountRef | rpflagsHaveStartRef @@ -440,7 +441,7 @@ func (rp *ResolvingPath) handleError(err error) bool { // path, including the symlink target we just prepended. rp.relpathCommit() // Restart path resolution on the new Mount. - rp.releaseErrorState() + rp.releaseErrorState(ctx) return true default: diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go index 8d7f8f8af..9c2420683 100644 --- a/pkg/sentry/vfs/vfs.go +++ b/pkg/sentry/vfs/vfs.go @@ -24,6 +24,9 @@ // Locks acquired by FilesystemImpls between Prepare{Delete,Rename}Dentry and Commit{Delete,Rename*}Dentry // VirtualFilesystem.filesystemsMu // EpollInstance.mu +// Inotify.mu +// Watches.mu +// Inotify.evMu // VirtualFilesystem.fsTypesMu // // Locking Dentry.mu in multiple Dentries requires holding @@ -82,6 +85,10 @@ type VirtualFilesystem struct { // mountpoints is analogous to Linux's mountpoint_hashtable. mountpoints map[*Dentry]map[*Mount]struct{} + // lastMountID is the last allocated mount ID. lastMountID is accessed + // using atomic memory operations. + lastMountID uint64 + // anonMount is a Mount, not included in mounts or mountpoints, // representing an anonFilesystem. anonMount is used to back // VirtualDentries returned by VirtualFilesystem.NewAnonVirtualDentry(). @@ -115,7 +122,10 @@ type VirtualFilesystem struct { } // Init initializes a new VirtualFilesystem with no mounts or FilesystemTypes. -func (vfs *VirtualFilesystem) Init() error { +func (vfs *VirtualFilesystem) Init(ctx context.Context) error { + if vfs.mountpoints != nil { + panic("VFS already initialized") + } vfs.mountpoints = make(map[*Dentry]map[*Mount]struct{}) vfs.devices = make(map[devTuple]*registeredDevice) vfs.anonBlockDevMinorNext = 1 @@ -135,7 +145,7 @@ func (vfs *VirtualFilesystem) Init() error { devMinor: anonfsDevMinor, } anonfs.vfsfs.Init(vfs, &anonFilesystemType{}, &anonfs) - defer anonfs.vfsfs.DecRef() + defer anonfs.vfsfs.DecRef(ctx) anonMount, err := vfs.NewDisconnectedMount(&anonfs.vfsfs, nil, &MountOptions{}) if err != nil { // We should not be passing any MountOptions that would cause @@ -182,11 +192,11 @@ func (vfs *VirtualFilesystem) AccessAt(ctx context.Context, creds *auth.Credenti for { err := rp.mount.fs.impl.AccessAt(ctx, rp, creds, ats) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -204,11 +214,11 @@ func (vfs *VirtualFilesystem) GetDentryAt(ctx context.Context, creds *auth.Crede dentry: d, } rp.mount.IncRef() - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return vd, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return VirtualDentry{}, err } } @@ -226,7 +236,7 @@ func (vfs *VirtualFilesystem) getParentDirAndName(ctx context.Context, creds *au } rp.mount.IncRef() name := rp.Component() - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return parentVD, name, nil } if checkInvariants { @@ -234,8 +244,8 @@ func (vfs *VirtualFilesystem) getParentDirAndName(ctx context.Context, creds *au panic(fmt.Sprintf("%T.GetParentDentryAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return VirtualDentry{}, "", err } } @@ -250,14 +260,14 @@ func (vfs *VirtualFilesystem) LinkAt(ctx context.Context, creds *auth.Credential } if !newpop.Path.Begin.Ok() { - oldVD.DecRef() + oldVD.DecRef(ctx) if newpop.Path.Absolute { return syserror.EEXIST } return syserror.ENOENT } if newpop.FollowFinalSymlink { - oldVD.DecRef() + oldVD.DecRef(ctx) ctx.Warningf("VirtualFilesystem.LinkAt: file creation paths can't follow final symlink") return syserror.EINVAL } @@ -266,8 +276,8 @@ func (vfs *VirtualFilesystem) LinkAt(ctx context.Context, creds *auth.Credential for { err := rp.mount.fs.impl.LinkAt(ctx, rp, oldVD) if err == nil { - vfs.putResolvingPath(rp) - oldVD.DecRef() + vfs.putResolvingPath(ctx, rp) + oldVD.DecRef(ctx) return nil } if checkInvariants { @@ -275,9 +285,9 @@ func (vfs *VirtualFilesystem) LinkAt(ctx context.Context, creds *auth.Credential panic(fmt.Sprintf("%T.LinkAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) - oldVD.DecRef() + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) + oldVD.DecRef(ctx) return err } } @@ -303,7 +313,7 @@ func (vfs *VirtualFilesystem) MkdirAt(ctx context.Context, creds *auth.Credentia for { err := rp.mount.fs.impl.MkdirAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } if checkInvariants { @@ -311,8 +321,8 @@ func (vfs *VirtualFilesystem) MkdirAt(ctx context.Context, creds *auth.Credentia panic(fmt.Sprintf("%T.MkdirAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -336,7 +346,7 @@ func (vfs *VirtualFilesystem) MknodAt(ctx context.Context, creds *auth.Credentia for { err := rp.mount.fs.impl.MknodAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } if checkInvariants { @@ -344,8 +354,8 @@ func (vfs *VirtualFilesystem) MknodAt(ctx context.Context, creds *auth.Credentia panic(fmt.Sprintf("%T.MknodAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -398,30 +408,31 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential for { fd, err := rp.mount.fs.impl.OpenAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) if opts.FileExec { - if fd.Mount().flags.NoExec { - fd.DecRef() + if fd.Mount().Flags.NoExec { + fd.DecRef(ctx) return nil, syserror.EACCES } // Only a regular file can be executed. stat, err := fd.Stat(ctx, StatOptions{Mask: linux.STATX_TYPE}) if err != nil { - fd.DecRef() + fd.DecRef(ctx) return nil, err } if stat.Mask&linux.STATX_TYPE == 0 || stat.Mode&linux.S_IFMT != linux.S_IFREG { - fd.DecRef() + fd.DecRef(ctx) return nil, syserror.EACCES } } + fd.Dentry().InotifyWithParent(ctx, linux.IN_OPEN, 0, PathEvent) return fd, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return nil, err } } @@ -433,11 +444,11 @@ func (vfs *VirtualFilesystem) ReadlinkAt(ctx context.Context, creds *auth.Creden for { target, err := rp.mount.fs.impl.ReadlinkAt(ctx, rp) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return target, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return "", err } } @@ -461,19 +472,19 @@ func (vfs *VirtualFilesystem) RenameAt(ctx context.Context, creds *auth.Credenti return err } if oldName == "." || oldName == ".." { - oldParentVD.DecRef() + oldParentVD.DecRef(ctx) return syserror.EBUSY } if !newpop.Path.Begin.Ok() { - oldParentVD.DecRef() + oldParentVD.DecRef(ctx) if newpop.Path.Absolute { return syserror.EBUSY } return syserror.ENOENT } if newpop.FollowFinalSymlink { - oldParentVD.DecRef() + oldParentVD.DecRef(ctx) ctx.Warningf("VirtualFilesystem.RenameAt: destination path can't follow final symlink") return syserror.EINVAL } @@ -486,8 +497,8 @@ func (vfs *VirtualFilesystem) RenameAt(ctx context.Context, creds *auth.Credenti for { err := rp.mount.fs.impl.RenameAt(ctx, rp, oldParentVD, oldName, renameOpts) if err == nil { - vfs.putResolvingPath(rp) - oldParentVD.DecRef() + vfs.putResolvingPath(ctx, rp) + oldParentVD.DecRef(ctx) return nil } if checkInvariants { @@ -495,9 +506,9 @@ func (vfs *VirtualFilesystem) RenameAt(ctx context.Context, creds *auth.Credenti panic(fmt.Sprintf("%T.RenameAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) - oldParentVD.DecRef() + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) + oldParentVD.DecRef(ctx) return err } } @@ -520,7 +531,7 @@ func (vfs *VirtualFilesystem) RmdirAt(ctx context.Context, creds *auth.Credentia for { err := rp.mount.fs.impl.RmdirAt(ctx, rp) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } if checkInvariants { @@ -528,8 +539,8 @@ func (vfs *VirtualFilesystem) RmdirAt(ctx context.Context, creds *auth.Credentia panic(fmt.Sprintf("%T.RmdirAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -541,11 +552,11 @@ func (vfs *VirtualFilesystem) SetStatAt(ctx context.Context, creds *auth.Credent for { err := rp.mount.fs.impl.SetStatAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -557,11 +568,11 @@ func (vfs *VirtualFilesystem) StatAt(ctx context.Context, creds *auth.Credential for { stat, err := rp.mount.fs.impl.StatAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return stat, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return linux.Statx{}, err } } @@ -574,11 +585,11 @@ func (vfs *VirtualFilesystem) StatFSAt(ctx context.Context, creds *auth.Credenti for { statfs, err := rp.mount.fs.impl.StatFSAt(ctx, rp) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return statfs, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return linux.Statfs{}, err } } @@ -601,7 +612,7 @@ func (vfs *VirtualFilesystem) SymlinkAt(ctx context.Context, creds *auth.Credent for { err := rp.mount.fs.impl.SymlinkAt(ctx, rp, target) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } if checkInvariants { @@ -609,8 +620,8 @@ func (vfs *VirtualFilesystem) SymlinkAt(ctx context.Context, creds *auth.Credent panic(fmt.Sprintf("%T.SymlinkAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -633,7 +644,7 @@ func (vfs *VirtualFilesystem) UnlinkAt(ctx context.Context, creds *auth.Credenti for { err := rp.mount.fs.impl.UnlinkAt(ctx, rp) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } if checkInvariants { @@ -641,8 +652,8 @@ func (vfs *VirtualFilesystem) UnlinkAt(ctx context.Context, creds *auth.Credenti panic(fmt.Sprintf("%T.UnlinkAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -660,7 +671,7 @@ func (vfs *VirtualFilesystem) BoundEndpointAt(ctx context.Context, creds *auth.C for { bep, err := rp.mount.fs.impl.BoundEndpointAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return bep, nil } if checkInvariants { @@ -668,8 +679,8 @@ func (vfs *VirtualFilesystem) BoundEndpointAt(ctx context.Context, creds *auth.C panic(fmt.Sprintf("%T.BoundEndpointAt() consumed all path components and returned %v", rp.mount.fs.impl, err)) } } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return nil, err } } @@ -682,7 +693,7 @@ func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Crede for { names, err := rp.mount.fs.impl.ListxattrAt(ctx, rp, size) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return names, nil } if err == syserror.ENOTSUP { @@ -690,11 +701,11 @@ func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Crede // fs/xattr.c:vfs_listxattr() falls back to allowing the security // subsystem to return security extended attributes, which by // default don't exist. - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return nil, err } } @@ -707,11 +718,11 @@ func (vfs *VirtualFilesystem) GetxattrAt(ctx context.Context, creds *auth.Creden for { val, err := rp.mount.fs.impl.GetxattrAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return val, nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return "", err } } @@ -724,11 +735,11 @@ func (vfs *VirtualFilesystem) SetxattrAt(ctx context.Context, creds *auth.Creden for { err := rp.mount.fs.impl.SetxattrAt(ctx, rp, *opts) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -740,11 +751,11 @@ func (vfs *VirtualFilesystem) RemovexattrAt(ctx context.Context, creds *auth.Cre for { err := rp.mount.fs.impl.RemovexattrAt(ctx, rp, name) if err == nil { - vfs.putResolvingPath(rp) + vfs.putResolvingPath(ctx, rp) return nil } - if !rp.handleError(err) { - vfs.putResolvingPath(rp) + if !rp.handleError(ctx, err) { + vfs.putResolvingPath(ctx, rp) return err } } @@ -766,7 +777,7 @@ func (vfs *VirtualFilesystem) SyncAllFilesystems(ctx context.Context) error { if err := fs.impl.Sync(ctx); err != nil && retErr == nil { retErr = err } - fs.DecRef() + fs.DecRef(ctx) } return retErr } @@ -820,9 +831,9 @@ func (vd VirtualDentry) IncRef() { // DecRef decrements the reference counts on the Mount and Dentry represented // by vd. -func (vd VirtualDentry) DecRef() { - vd.dentry.DecRef() - vd.mount.DecRef() +func (vd VirtualDentry) DecRef(ctx context.Context) { + vd.dentry.DecRef(ctx) + vd.mount.DecRef(ctx) } // Mount returns the Mount associated with vd. It does not take a reference on diff --git a/pkg/sentry/watchdog/watchdog.go b/pkg/sentry/watchdog/watchdog.go index 101497ed6..748273366 100644 --- a/pkg/sentry/watchdog/watchdog.go +++ b/pkg/sentry/watchdog/watchdog.go @@ -77,7 +77,10 @@ var DefaultOpts = Opts{ // trigger it. const descheduleThreshold = 1 * time.Second -var stuckTasks = metric.MustCreateNewUint64Metric("/watchdog/stuck_tasks_detected", true /* sync */, "Cumulative count of stuck tasks detected") +var ( + stuckStartup = metric.MustCreateNewUint64Metric("/watchdog/stuck_startup_detected", true /* sync */, "Incremented once on startup watchdog timeout") + stuckTasks = metric.MustCreateNewUint64Metric("/watchdog/stuck_tasks_detected", true /* sync */, "Cumulative count of stuck tasks detected") +) // Amount of time to wait before dumping the stack to the log again when the same task(s) remains stuck. var stackDumpSameTaskPeriod = time.Minute @@ -220,6 +223,9 @@ func (w *Watchdog) waitForStart() { // We are fine. return } + + stuckStartup.Increment() + var buf bytes.Buffer buf.WriteString(fmt.Sprintf("Watchdog.Start() not called within %s", w.StartupTimeout)) w.doAction(w.StartupTimeoutAction, false, &buf) @@ -323,13 +329,13 @@ func (w *Watchdog) report(offenders map[*kernel.Task]*offender, newTaskFound boo func (w *Watchdog) reportStuckWatchdog() { var buf bytes.Buffer - buf.WriteString("Watchdog goroutine is stuck:") + buf.WriteString("Watchdog goroutine is stuck") w.doAction(w.TaskTimeoutAction, false, &buf) } // doAction will take the given action. If the action is LogWarning, the stack -// is not always dumpped to the log to prevent log flooding. "forceStack" -// guarantees that the stack will be dumped regarless. +// is not always dumped to the log to prevent log flooding. "forceStack" +// guarantees that the stack will be dumped regardless. func (w *Watchdog) doAction(action Action, forceStack bool, msg *bytes.Buffer) { switch action { case LogWarning: |