diff options
| -rw-r--r-- | pkg/sentry/fs/host/control.go | 6 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/host/BUILD | 3 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/host/control.go | 96 | ||||
| -rw-r--r-- | pkg/sentry/socket/control/BUILD | 6 | ||||
| -rw-r--r-- | pkg/sentry/socket/control/control.go | 24 | ||||
| -rw-r--r-- | pkg/sentry/socket/control/control_vfs2.go | 131 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/socket.go | 2 |
7 files changed, 260 insertions, 8 deletions
diff --git a/pkg/sentry/fs/host/control.go b/pkg/sentry/fs/host/control.go index 52c0504b6..39299b7e4 100644 --- a/pkg/sentry/fs/host/control.go +++ b/pkg/sentry/fs/host/control.go @@ -23,6 +23,8 @@ import ( "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" ) +// LINT.IfChange + type scmRights struct { fds []int } @@ -32,8 +34,6 @@ func newSCMRights(fds []int) control.SCMRights { } // Files implements control.SCMRights.Files. -// -// TODO(gvisor.dev/issue/2017): Port to VFS2. func (c *scmRights) Files(ctx context.Context, max int) (control.RightsFiles, bool) { n := max var trunc bool @@ -93,3 +93,5 @@ func fdsToFiles(ctx context.Context, fds []int) []*fs.File { } return files } + +// LINT.ThenChange(../../fsimpl/host/control.go) diff --git a/pkg/sentry/fsimpl/host/BUILD b/pkg/sentry/fsimpl/host/BUILD index 44dd9f672..2dcb03a73 100644 --- a/pkg/sentry/fsimpl/host/BUILD +++ b/pkg/sentry/fsimpl/host/BUILD @@ -5,6 +5,7 @@ licenses(["notice"]) go_library( name = "host", srcs = [ + "control.go", "host.go", "ioctl_unsafe.go", "tty.go", @@ -23,6 +24,8 @@ go_library( "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", "//pkg/sentry/memmap", + "//pkg/sentry/socket/control", + "//pkg/sentry/socket/unix/transport", "//pkg/sentry/unimpl", "//pkg/sentry/vfs", "//pkg/sync", diff --git a/pkg/sentry/fsimpl/host/control.go b/pkg/sentry/fsimpl/host/control.go new file mode 100644 index 000000000..b9082a20f --- /dev/null +++ b/pkg/sentry/fsimpl/host/control.go @@ -0,0 +1,96 @@ +// 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 host + +import ( + "syscall" + + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/socket/control" + "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" + "gvisor.dev/gvisor/pkg/sentry/vfs" +) + +type scmRights struct { + fds []int +} + +func newSCMRights(fds []int) control.SCMRightsVFS2 { + return &scmRights{fds} +} + +// Files implements control.SCMRights.Files. +func (c *scmRights) Files(ctx context.Context, max int) (control.RightsFilesVFS2, bool) { + n := max + var trunc bool + if l := len(c.fds); n > l { + n = l + } else if n < l { + trunc = true + } + + rf := control.RightsFilesVFS2(fdsToFiles(ctx, c.fds[:n])) + + // Only consume converted FDs (fdsToFiles may convert fewer than n FDs). + c.fds = c.fds[len(rf):] + return rf, trunc +} + +// Clone implements transport.RightsControlMessage.Clone. +func (c *scmRights) Clone() transport.RightsControlMessage { + // Host rights never need to be cloned. + return nil +} + +// Release implements transport.RightsControlMessage.Release. +func (c *scmRights) Release() { + for _, fd := range c.fds { + syscall.Close(fd) + } + c.fds = nil +} + +// If an error is encountered, only files created before the error will be +// returned. This is what Linux does. +func fdsToFiles(ctx context.Context, fds []int) []*vfs.FileDescription { + files := make([]*vfs.FileDescription, 0, len(fds)) + for _, fd := range fds { + // Get flags. We do it here because they may be modified + // by subsequent functions. + fileFlags, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_GETFL, 0) + if errno != 0 { + ctx.Warningf("Error retrieving host FD flags: %v", error(errno)) + break + } + + // Create the file backed by hostFD. + file, err := ImportFD(ctx, kernel.KernelFromContext(ctx).HostMount(), fd, false /* isTTY */) + if err != nil { + ctx.Warningf("Error creating file from host FD: %v", err) + break + } + + if err := file.SetStatusFlags(ctx, auth.CredentialsFromContext(ctx), uint32(fileFlags&linux.O_NONBLOCK)); err != nil { + ctx.Warningf("Error setting flags on host FD file: %v", err) + break + } + + files = append(files, file) + } + return files +} diff --git a/pkg/sentry/socket/control/BUILD b/pkg/sentry/socket/control/BUILD index 4d42d29cb..ca16d0381 100644 --- a/pkg/sentry/socket/control/BUILD +++ b/pkg/sentry/socket/control/BUILD @@ -4,7 +4,10 @@ package(licenses = ["notice"]) go_library( name = "control", - srcs = ["control.go"], + srcs = [ + "control.go", + "control_vfs2.go", + ], imports = [ "gvisor.dev/gvisor/pkg/sentry/fs", ], @@ -18,6 +21,7 @@ go_library( "//pkg/sentry/kernel/auth", "//pkg/sentry/socket", "//pkg/sentry/socket/unix/transport", + "//pkg/sentry/vfs", "//pkg/syserror", "//pkg/tcpip", "//pkg/usermem", diff --git a/pkg/sentry/socket/control/control.go b/pkg/sentry/socket/control/control.go index 8834a1e1a..8b439a078 100644 --- a/pkg/sentry/socket/control/control.go +++ b/pkg/sentry/socket/control/control.go @@ -41,6 +41,8 @@ type SCMCredentials interface { Credentials(t *kernel.Task) (kernel.ThreadID, auth.UID, auth.GID) } +// LINT.IfChange + // SCMRights represents a SCM_RIGHTS socket control message. type SCMRights interface { transport.RightsControlMessage @@ -142,6 +144,8 @@ func PackRights(t *kernel.Task, rights SCMRights, cloexec bool, buf []byte, flag return putCmsg(buf, flags, linux.SCM_RIGHTS, align, fds) } +// LINT.ThenChange(./control_vfs2.go) + // scmCredentials represents an SCM_CREDENTIALS socket control message. // // +stateify savable @@ -537,11 +541,19 @@ func Parse(t *kernel.Task, socketOrEndpoint interface{}, buf []byte) (socket.Con } if len(fds) > 0 { - rights, err := NewSCMRights(t, fds) - if err != nil { - return socket.ControlMessages{}, err + if kernel.VFS2Enabled { + rights, err := NewSCMRightsVFS2(t, fds) + if err != nil { + return socket.ControlMessages{}, err + } + cmsgs.Unix.Rights = rights + } else { + rights, err := NewSCMRights(t, fds) + if err != nil { + return socket.ControlMessages{}, err + } + cmsgs.Unix.Rights = rights } - cmsgs.Unix.Rights = rights } return cmsgs, nil @@ -566,6 +578,8 @@ func MakeCreds(t *kernel.Task) SCMCredentials { return &scmCredentials{t, tcred.EffectiveKUID, tcred.EffectiveKGID} } +// LINT.IfChange + // New creates default control messages if needed. func New(t *kernel.Task, socketOrEndpoint interface{}, rights SCMRights) transport.ControlMessages { return transport.ControlMessages{ @@ -573,3 +587,5 @@ func New(t *kernel.Task, socketOrEndpoint interface{}, rights SCMRights) transpo Rights: rights, } } + +// LINT.ThenChange(./control_vfs2.go) diff --git a/pkg/sentry/socket/control/control_vfs2.go b/pkg/sentry/socket/control/control_vfs2.go new file mode 100644 index 000000000..fd08179be --- /dev/null +++ b/pkg/sentry/socket/control/control_vfs2.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 control + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/context" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/socket/unix/transport" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" +) + +// SCMRightsVFS2 represents a SCM_RIGHTS socket control message. +type SCMRightsVFS2 interface { + transport.RightsControlMessage + + // Files returns up to max RightsFiles. + // + // Returned files are consumed and ownership is transferred to the caller. + // Subsequent calls to Files will return the next files. + Files(ctx context.Context, max int) (rf RightsFilesVFS2, truncated bool) +} + +// RightsFiles represents a SCM_RIGHTS socket control message. A reference is +// maintained for each vfs.FileDescription and is release either when an FD is created or +// when the Release method is called. +type RightsFilesVFS2 []*vfs.FileDescription + +// NewSCMRightsVFS2 creates a new SCM_RIGHTS socket control message +// representation using local sentry FDs. +func NewSCMRightsVFS2(t *kernel.Task, fds []int32) (SCMRightsVFS2, error) { + files := make(RightsFilesVFS2, 0, len(fds)) + for _, fd := range fds { + file := t.GetFileVFS2(fd) + if file == nil { + files.Release() + return nil, syserror.EBADF + } + files = append(files, file) + } + return &files, nil +} + +// Files implements SCMRights.Files. +func (fs *RightsFilesVFS2) Files(ctx context.Context, max int) (RightsFilesVFS2, bool) { + n := max + var trunc bool + if l := len(*fs); n > l { + n = l + } else if n < l { + trunc = true + } + rf := (*fs)[:n] + *fs = (*fs)[n:] + return rf, trunc +} + +// Clone implements transport.RightsControlMessage.Clone. +func (fs *RightsFilesVFS2) Clone() transport.RightsControlMessage { + nfs := append(RightsFilesVFS2(nil), *fs...) + for _, nf := range nfs { + nf.IncRef() + } + return &nfs +} + +// Release implements transport.RightsControlMessage.Release. +func (fs *RightsFilesVFS2) Release() { + for _, f := range *fs { + f.DecRef() + } + *fs = nil +} + +// rightsFDsVFS2 gets up to the specified maximum number of FDs. +func rightsFDsVFS2(t *kernel.Task, rights SCMRightsVFS2, cloexec bool, max int) ([]int32, bool) { + files, trunc := rights.Files(t, max) + fds := make([]int32, 0, len(files)) + for i := 0; i < max && len(files) > 0; i++ { + fd, err := t.NewFDFromVFS2(0, files[0], kernel.FDFlags{ + CloseOnExec: cloexec, + }) + files[0].DecRef() + files = files[1:] + if err != nil { + t.Warningf("Error inserting FD: %v", err) + // This is what Linux does. + break + } + + fds = append(fds, int32(fd)) + } + return fds, trunc +} + +// PackRightsVFS2 packs as many FDs as will fit into the unused capacity of buf. +func PackRightsVFS2(t *kernel.Task, rights SCMRightsVFS2, cloexec bool, buf []byte, flags int) ([]byte, int) { + maxFDs := (cap(buf) - len(buf) - linux.SizeOfControlMessageHeader) / 4 + // Linux does not return any FDs if none fit. + if maxFDs <= 0 { + flags |= linux.MSG_CTRUNC + return buf, flags + } + fds, trunc := rightsFDsVFS2(t, rights, cloexec, maxFDs) + if trunc { + flags |= linux.MSG_CTRUNC + } + align := t.Arch().Width() + return putCmsg(buf, flags, linux.SCM_RIGHTS, align, fds) +} + +// NewVFS2 creates default control messages if needed. +func NewVFS2(t *kernel.Task, socketOrEndpoint interface{}, rights SCMRightsVFS2) transport.ControlMessages { + return transport.ControlMessages{ + Credentials: makeCreds(t, socketOrEndpoint), + Rights: rights, + } +} diff --git a/pkg/sentry/syscalls/linux/vfs2/socket.go b/pkg/sentry/syscalls/linux/vfs2/socket.go index b1ede32f0..10b668477 100644 --- a/pkg/sentry/syscalls/linux/vfs2/socket.go +++ b/pkg/sentry/syscalls/linux/vfs2/socket.go @@ -804,7 +804,7 @@ func recvSingleMsg(t *kernel.Task, s socket.SocketVFS2, msgPtr usermem.Addr, fla } if cms.Unix.Rights != nil { - controlData, mflags = control.PackRights(t, cms.Unix.Rights.(control.SCMRights), flags&linux.MSG_CMSG_CLOEXEC != 0, controlData, mflags) + controlData, mflags = control.PackRightsVFS2(t, cms.Unix.Rights.(control.SCMRightsVFS2), flags&linux.MSG_CMSG_CLOEXEC != 0, controlData, mflags) } // Copy the address to the caller. |