summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/vfs
diff options
context:
space:
mode:
Diffstat (limited to 'pkg/sentry/vfs')
-rw-r--r--pkg/sentry/vfs/BUILD7
-rw-r--r--pkg/sentry/vfs/context.go7
-rw-r--r--pkg/sentry/vfs/dentry.go4
-rw-r--r--pkg/sentry/vfs/device.go3
-rw-r--r--pkg/sentry/vfs/epoll.go22
-rw-r--r--pkg/sentry/vfs/file_description.go31
-rw-r--r--pkg/sentry/vfs/file_description_impl_util.go25
-rw-r--r--pkg/sentry/vfs/file_description_impl_util_test.go10
-rw-r--r--pkg/sentry/vfs/filesystem.go2
-rw-r--r--pkg/sentry/vfs/filesystem_type.go1
-rw-r--r--pkg/sentry/vfs/lock/BUILD13
-rw-r--r--pkg/sentry/vfs/lock/lock.go72
-rw-r--r--pkg/sentry/vfs/mount.go34
-rw-r--r--pkg/sentry/vfs/mount_unsafe.go20
-rw-r--r--pkg/sentry/vfs/options.go7
-rw-r--r--pkg/sentry/vfs/permissions.go19
-rw-r--r--pkg/sentry/vfs/resolving_path.go2
-rw-r--r--pkg/sentry/vfs/vfs.go65
18 files changed, 273 insertions, 71 deletions
diff --git a/pkg/sentry/vfs/BUILD b/pkg/sentry/vfs/BUILD
index ced9d07b1..cb4deb068 100644
--- a/pkg/sentry/vfs/BUILD
+++ b/pkg/sentry/vfs/BUILD
@@ -42,14 +42,21 @@ go_library(
deps = [
"//pkg/abi/linux",
"//pkg/context",
+ "//pkg/fd",
"//pkg/fspath",
+ "//pkg/gohacks",
+ "//pkg/log",
+ "//pkg/safemem",
"//pkg/sentry/arch",
+ "//pkg/sentry/fs",
+ "//pkg/sentry/fs/lock",
"//pkg/sentry/kernel/auth",
"//pkg/sentry/memmap",
"//pkg/sync",
"//pkg/syserror",
"//pkg/usermem",
"//pkg/waiter",
+ "@org_golang_x_sys//unix:go_default_library",
],
)
diff --git a/pkg/sentry/vfs/context.go b/pkg/sentry/vfs/context.go
index d97362b9a..82781e6d3 100644
--- a/pkg/sentry/vfs/context.go
+++ b/pkg/sentry/vfs/context.go
@@ -29,9 +29,10 @@ const (
CtxRoot
)
-// MountNamespaceFromContext returns the MountNamespace used by ctx. It does
-// not take a reference on the returned MountNamespace. If ctx is not
-// associated with a MountNamespace, MountNamespaceFromContext returns nil.
+// MountNamespaceFromContext returns the MountNamespace used by ctx. If ctx is
+// not associated with a MountNamespace, MountNamespaceFromContext returns nil.
+//
+// A reference is taken on the returned MountNamespace.
func MountNamespaceFromContext(ctx context.Context) *MountNamespace {
if v := ctx.Value(CtxMountNamespace); v != nil {
return v.(*MountNamespace)
diff --git a/pkg/sentry/vfs/dentry.go b/pkg/sentry/vfs/dentry.go
index 486a76475..35b208721 100644
--- a/pkg/sentry/vfs/dentry.go
+++ b/pkg/sentry/vfs/dentry.go
@@ -71,6 +71,8 @@ import (
// lifetime. Dentry reference counts only indicate the extent to which VFS
// requires Dentries to exist; Filesystems may elect to cache or discard
// Dentries with zero references.
+//
+// +stateify savable
type Dentry struct {
// parent is this Dentry's parent in this Filesystem. If this Dentry is
// independent, parent is nil.
@@ -89,7 +91,7 @@ type Dentry struct {
children map[string]*Dentry
// mu synchronizes disowning and mounting over this Dentry.
- mu sync.Mutex
+ mu sync.Mutex `state:"nosave"`
// impl is the DentryImpl associated with this Dentry. impl is immutable.
// This should be the last field in Dentry.
diff --git a/pkg/sentry/vfs/device.go b/pkg/sentry/vfs/device.go
index 3af2aa58d..bda5576fa 100644
--- a/pkg/sentry/vfs/device.go
+++ b/pkg/sentry/vfs/device.go
@@ -56,6 +56,7 @@ type Device interface {
Open(ctx context.Context, mnt *Mount, d *Dentry, opts OpenOptions) (*FileDescription, error)
}
+// +stateify savable
type registeredDevice struct {
dev Device
opts RegisterDeviceOptions
@@ -63,6 +64,8 @@ type registeredDevice struct {
// RegisterDeviceOptions contains options to
// VirtualFilesystem.RegisterDevice().
+//
+// +stateify savable
type RegisterDeviceOptions struct {
// GroupName is the name shown for this device registration in
// /proc/devices. If GroupName is empty, this registration will not be
diff --git a/pkg/sentry/vfs/epoll.go b/pkg/sentry/vfs/epoll.go
index 7c83f9a5a..3da45d744 100644
--- a/pkg/sentry/vfs/epoll.go
+++ b/pkg/sentry/vfs/epoll.go
@@ -85,8 +85,8 @@ type epollInterest struct {
ready bool
epollInterestEntry
- // userData is the epoll_data_t associated with this epollInterest.
- // userData is protected by epoll.mu.
+ // userData is the struct epoll_event::data associated with this
+ // epollInterest. userData is protected by epoll.mu.
userData [2]int32
}
@@ -157,7 +157,7 @@ func (ep *EpollInstance) Seek(ctx context.Context, offset int64, whence int32) (
// AddInterest implements the semantics of EPOLL_CTL_ADD.
//
// Preconditions: A reference must be held on file.
-func (ep *EpollInstance) AddInterest(file *FileDescription, num int32, mask uint32, userData [2]int32) error {
+func (ep *EpollInstance) AddInterest(file *FileDescription, num int32, event linux.EpollEvent) error {
// Check for cyclic polling if necessary.
subep, _ := file.impl.(*EpollInstance)
if subep != nil {
@@ -183,12 +183,12 @@ func (ep *EpollInstance) AddInterest(file *FileDescription, num int32, mask uint
}
// Register interest in file.
- mask |= linux.EPOLLERR | linux.EPOLLRDHUP
+ mask := event.Events | linux.EPOLLERR | linux.EPOLLRDHUP
epi := &epollInterest{
epoll: ep,
key: key,
mask: mask,
- userData: userData,
+ userData: event.Data,
}
ep.interest[key] = epi
wmask := waiter.EventMaskFromLinux(mask)
@@ -202,6 +202,9 @@ func (ep *EpollInstance) AddInterest(file *FileDescription, num int32, mask uint
// Add epi to file.epolls so that it is removed when the last
// FileDescription reference is dropped.
file.epollMu.Lock()
+ if file.epolls == nil {
+ file.epolls = make(map[*epollInterest]struct{})
+ }
file.epolls[epi] = struct{}{}
file.epollMu.Unlock()
@@ -236,7 +239,7 @@ func (ep *EpollInstance) mightPollRecursive(ep2 *EpollInstance, remainingRecursi
// ModifyInterest implements the semantics of EPOLL_CTL_MOD.
//
// Preconditions: A reference must be held on file.
-func (ep *EpollInstance) ModifyInterest(file *FileDescription, num int32, mask uint32, userData [2]int32) error {
+func (ep *EpollInstance) ModifyInterest(file *FileDescription, num int32, event linux.EpollEvent) error {
ep.interestMu.Lock()
defer ep.interestMu.Unlock()
@@ -250,13 +253,13 @@ func (ep *EpollInstance) ModifyInterest(file *FileDescription, num int32, mask u
}
// Update epi for the next call to ep.ReadEvents().
+ mask := event.Events | linux.EPOLLERR | linux.EPOLLRDHUP
ep.mu.Lock()
epi.mask = mask
- epi.userData = userData
+ epi.userData = event.Data
ep.mu.Unlock()
// Re-register with the new mask.
- mask |= linux.EPOLLERR | linux.EPOLLRDHUP
file.EventUnregister(&epi.waiter)
wmask := waiter.EventMaskFromLinux(mask)
file.EventRegister(&epi.waiter, wmask)
@@ -363,8 +366,7 @@ func (ep *EpollInstance) ReadEvents(events []linux.EpollEvent) int {
// Report ievents.
events[i] = linux.EpollEvent{
Events: ievents.ToLinux(),
- Fd: epi.userData[0],
- Data: epi.userData[1],
+ Data: epi.userData,
}
i++
if i == len(events) {
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index badacb55e..9a1ad630c 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -20,6 +20,7 @@ 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"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sync"
@@ -393,7 +394,25 @@ type FileDescriptionImpl interface {
// Removexattr removes the given extended attribute from the file.
Removexattr(ctx context.Context, name string) error
- // TODO: file locking
+ // 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(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
+
+ // 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
}
// Dirent holds the information contained in struct linux_dirent64.
@@ -416,11 +435,11 @@ type Dirent struct {
// IterDirentsCallback receives Dirents from FileDescriptionImpl.IterDirents.
type IterDirentsCallback interface {
- // Handle handles the given iterated Dirent. It returns true if iteration
- // should continue, and false if FileDescriptionImpl.IterDirents should
- // terminate now and restart with the same Dirent the next time it is
- // called.
- Handle(dirent Dirent) bool
+ // Handle handles the given iterated Dirent. If Handle returns a non-nil
+ // error, FileDescriptionImpl.IterDirents must stop iteration and return
+ // the error; the next call to FileDescriptionImpl.IterDirents should
+ // restart with the same Dirent.
+ Handle(dirent Dirent) error
}
// OnClose is called when a file descriptor representing the FileDescription is
diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go
index a4900c170..45191d1c3 100644
--- a/pkg/sentry/vfs/file_description_impl_util.go
+++ b/pkg/sentry/vfs/file_description_impl_util.go
@@ -21,6 +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"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sync"
"gvisor.dev/gvisor/pkg/syserror"
@@ -32,8 +33,8 @@ import (
// implementations to adapt:
// - Have a local fileDescription struct (containing FileDescription) which
// embeds FileDescriptionDefaultImpl and overrides the default methods
-// which are common to all fd implementations for that for that filesystem
-// like StatusFlags, SetStatusFlags, Stat, SetStat, StatFS, etc.
+// which are common to all fd implementations for that filesystem like
+// StatusFlags, SetStatusFlags, Stat, SetStat, StatFS, etc.
// - This should be embedded in all file description implementations as the
// first field by value.
// - Directory FDs would also embed DirectoryFileDescriptionDefaultImpl.
@@ -152,6 +153,26 @@ 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.
diff --git a/pkg/sentry/vfs/file_description_impl_util_test.go b/pkg/sentry/vfs/file_description_impl_util_test.go
index 8fa26418e..3a75d4d62 100644
--- a/pkg/sentry/vfs/file_description_impl_util_test.go
+++ b/pkg/sentry/vfs/file_description_impl_util_test.go
@@ -107,7 +107,10 @@ func (fd *testFD) SetStat(ctx context.Context, opts SetStatOptions) error {
func TestGenCountFD(t *testing.T) {
ctx := contexttest.Context(t)
- vfsObj := New() // vfs.New()
+ vfsObj := &VirtualFilesystem{}
+ if err := vfsObj.Init(); err != nil {
+ t.Fatalf("VFS init: %v", err)
+ }
fd := newTestFD(vfsObj, linux.O_RDWR, &genCount{})
defer fd.DecRef()
@@ -162,7 +165,10 @@ func TestGenCountFD(t *testing.T) {
func TestWritable(t *testing.T) {
ctx := contexttest.Context(t)
- vfsObj := New() // vfs.New()
+ vfsObj := &VirtualFilesystem{}
+ if err := vfsObj.Init(); err != nil {
+ t.Fatalf("VFS init: %v", err)
+ }
fd := newTestFD(vfsObj, linux.O_RDWR, &storeData{data: "init"})
defer fd.DecRef()
diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go
index a06a6caf3..556976d0b 100644
--- a/pkg/sentry/vfs/filesystem.go
+++ b/pkg/sentry/vfs/filesystem.go
@@ -29,6 +29,8 @@ import (
// Filesystem methods require that a reference is held.
//
// Filesystem is analogous to Linux's struct super_block.
+//
+// +stateify savable
type Filesystem struct {
// refs is the reference count. refs is accessed using atomic memory
// operations.
diff --git a/pkg/sentry/vfs/filesystem_type.go b/pkg/sentry/vfs/filesystem_type.go
index c58b70728..bb9cada81 100644
--- a/pkg/sentry/vfs/filesystem_type.go
+++ b/pkg/sentry/vfs/filesystem_type.go
@@ -44,6 +44,7 @@ type GetFilesystemOptions struct {
InternalData interface{}
}
+// +stateify savable
type registeredFilesystemType struct {
fsType FilesystemType
opts RegisterFilesystemTypeOptions
diff --git a/pkg/sentry/vfs/lock/BUILD b/pkg/sentry/vfs/lock/BUILD
new file mode 100644
index 000000000..d9ab063b7
--- /dev/null
+++ b/pkg/sentry/vfs/lock/BUILD
@@ -0,0 +1,13 @@
+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/lock/lock.go b/pkg/sentry/vfs/lock/lock.go
new file mode 100644
index 000000000..724dfe743
--- /dev/null
+++ b/pkg/sentry/vfs/lock/lock.go
@@ -0,0 +1,72 @@
+// 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 lock provides POSIX and BSD style file locking for VFS2 file
+// implementations.
+//
+// The actual implementations can be found in the lock package under
+// sentry/fs/lock.
+package lock
+
+import (
+ fslock "gvisor.dev/gvisor/pkg/sentry/fs/lock"
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// FileLocks supports POSIX and BSD style locks, which correspond to fcntl(2)
+// and flock(2) respectively in Linux. It can be embedded into various file
+// implementations for VFS2 that support locking.
+//
+// Note that in Linux these two types of locks are _not_ cooperative, because
+// race and deadlock conditions make merging them prohibitive. We do the same
+// and keep them oblivious to each other.
+type FileLocks struct {
+ // bsd is a set of BSD-style advisory file wide locks, see flock(2).
+ bsd fslock.Locks
+
+ // posix is a set of POSIX-style regional advisory locks, see fcntl(2).
+ posix fslock.Locks
+}
+
+// LockBSD tries to acquire a BSD-style lock on the entire file.
+func (fl *FileLocks) LockBSD(uid fslock.UniqueID, t fslock.LockType, block fslock.Blocker) error {
+ if fl.bsd.LockRegion(uid, t, fslock.LockRange{0, fslock.LockEOF}, block) {
+ return nil
+ }
+ return syserror.ErrWouldBlock
+}
+
+// UnlockBSD releases a BSD-style lock on the entire file.
+//
+// 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) UnlockBSD(uid fslock.UniqueID) {
+ fl.bsd.UnlockRegion(uid, fslock.LockRange{0, fslock.LockEOF})
+}
+
+// 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 {
+ if fl.posix.LockRegion(uid, t, rng, block) {
+ return nil
+ }
+ return syserror.ErrWouldBlock
+}
+
+// UnlockPOSIX releases a POSIX-style lock on a file region.
+//
+// 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) {
+ fl.posix.UnlockRegion(uid, rng)
+}
diff --git a/pkg/sentry/vfs/mount.go b/pkg/sentry/vfs/mount.go
index d39528051..31a4e5480 100644
--- a/pkg/sentry/vfs/mount.go
+++ b/pkg/sentry/vfs/mount.go
@@ -38,6 +38,8 @@ import (
//
// Mount is analogous to Linux's struct mount. (gVisor does not distinguish
// between struct mount and struct vfsmount.)
+//
+// +stateify savable
type Mount struct {
// vfs, fs, and root are immutable. References are held on fs and root.
//
@@ -85,6 +87,8 @@ type Mount struct {
// MountNamespace methods require that a reference is held.
//
// MountNamespace is analogous to Linux's struct mnt_namespace.
+//
+// +stateify savable
type MountNamespace struct {
// root is the MountNamespace's root mount. root is immutable.
root *Mount
@@ -114,6 +118,7 @@ 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)
return nil, syserror.ENODEV
}
fs, root, err := rft.fsType.GetFilesystem(ctx, vfs, creds, source, *opts)
@@ -134,6 +139,23 @@ func (vfs *VirtualFilesystem) NewMountNamespace(ctx context.Context, creds *auth
return mntns, nil
}
+// NewDisconnectedMount returns a Mount representing fs with the given root
+// (which may be nil). The new Mount is not associated with any MountNamespace
+// and is not connected to any other Mounts. References are taken on fs and
+// root.
+func (vfs *VirtualFilesystem) NewDisconnectedMount(fs *Filesystem, root *Dentry, opts *MountOptions) (*Mount, error) {
+ fs.IncRef()
+ if root != nil {
+ root.IncRef()
+ }
+ return &Mount{
+ vfs: vfs,
+ fs: fs,
+ root: root,
+ refs: 1,
+ }, 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 {
rft := vfs.getFilesystemType(fsTypeName)
@@ -231,9 +253,12 @@ func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credenti
return syserror.EINVAL
}
vfs.mountMu.Lock()
- if mntns := MountNamespaceFromContext(ctx); mntns != nil && mntns != vd.mount.ns {
- vfs.mountMu.Unlock()
- return syserror.EINVAL
+ if mntns := MountNamespaceFromContext(ctx); mntns != nil {
+ defer mntns.DecRef()
+ if mntns != vd.mount.ns {
+ vfs.mountMu.Unlock()
+ return syserror.EINVAL
+ }
}
// TODO(jamieliu): Linux special-cases umount of the caller's root, which
@@ -423,7 +448,8 @@ func (mntns *MountNamespace) IncRef() {
}
// DecRef decrements mntns' reference count.
-func (mntns *MountNamespace) DecRef(vfs *VirtualFilesystem) {
+func (mntns *MountNamespace) DecRef() {
+ vfs := mntns.root.fs.VirtualFilesystem()
if refs := atomic.AddInt64(&mntns.refs, -1); refs == 0 {
vfs.mountMu.Lock()
vfs.mounts.seq.BeginWrite()
diff --git a/pkg/sentry/vfs/mount_unsafe.go b/pkg/sentry/vfs/mount_unsafe.go
index bd90d36c4..bc7581698 100644
--- a/pkg/sentry/vfs/mount_unsafe.go
+++ b/pkg/sentry/vfs/mount_unsafe.go
@@ -26,6 +26,7 @@ import (
"sync/atomic"
"unsafe"
+ "gvisor.dev/gvisor/pkg/gohacks"
"gvisor.dev/gvisor/pkg/sync"
)
@@ -64,6 +65,8 @@ func (mnt *Mount) storeKey(vd VirtualDentry) {
// (provided mutation is sufficiently uncommon).
//
// mountTable.Init() must be called on new mountTables before use.
+//
+// +stateify savable
type mountTable struct {
// mountTable is implemented as a seqcount-protected hash table that
// resolves collisions with linear probing, featuring Robin Hood insertion
@@ -75,8 +78,8 @@ type mountTable struct {
// intrinsics and inline assembly, limiting the performance of this
// approach.)
- seq sync.SeqCount
- seed uint32 // for hashing keys
+ seq sync.SeqCount `state:"nosave"`
+ seed uint32 // for hashing keys
// size holds both length (number of elements) and capacity (number of
// slots): capacity is stored as its base-2 log (referred to as order) in
@@ -89,7 +92,7 @@ type mountTable struct {
// length and cap in separate uint32s) for ~free.
size uint64
- slots unsafe.Pointer // []mountSlot; never nil after Init
+ slots unsafe.Pointer `state:"nosave"` // []mountSlot; never nil after Init
}
type mountSlot struct {
@@ -158,7 +161,7 @@ func newMountTableSlots(cap uintptr) unsafe.Pointer {
// Lookup may be called even if there are concurrent mutators of mt.
func (mt *mountTable) Lookup(parent *Mount, point *Dentry) *Mount {
key := mountKey{parent: unsafe.Pointer(parent), point: unsafe.Pointer(point)}
- hash := memhash(noescape(unsafe.Pointer(&key)), uintptr(mt.seed), mountKeyBytes)
+ hash := memhash(gohacks.Noescape(unsafe.Pointer(&key)), uintptr(mt.seed), mountKeyBytes)
loop:
for {
@@ -359,12 +362,3 @@ func memhash(p unsafe.Pointer, seed, s uintptr) uintptr
//go:linkname rand32 runtime.fastrand
func rand32() uint32
-
-// This is copy/pasted from runtime.noescape(), and is needed because arguments
-// apparently escape from all functions defined by linkname.
-//
-//go:nosplit
-func noescape(p unsafe.Pointer) unsafe.Pointer {
- x := uintptr(p)
- return unsafe.Pointer(x ^ 0)
-}
diff --git a/pkg/sentry/vfs/options.go b/pkg/sentry/vfs/options.go
index b7774bf28..6af7fdac1 100644
--- a/pkg/sentry/vfs/options.go
+++ b/pkg/sentry/vfs/options.go
@@ -61,7 +61,7 @@ type MountOptions struct {
type OpenOptions struct {
// Flags contains access mode and flags as specified for open(2).
//
- // FilesystemImpls is reponsible for implementing the following flags:
+ // FilesystemImpls are responsible for implementing the following flags:
// O_RDONLY, O_WRONLY, O_RDWR, O_APPEND, O_CREAT, O_DIRECT, O_DSYNC,
// O_EXCL, O_NOATIME, O_NOCTTY, O_NONBLOCK, O_PATH, O_SYNC, O_TMPFILE, and
// O_TRUNC. VFS is responsible for handling O_DIRECTORY, O_LARGEFILE, and
@@ -72,6 +72,11 @@ type OpenOptions struct {
// If FilesystemImpl.OpenAt() creates a file, Mode is the file mode for the
// created file.
Mode linux.FileMode
+
+ // FileExec is set when the file is being opened to be executed.
+ // VirtualFilesystem.OpenAt() checks that the caller has execute permissions
+ // on the file, and that the file is a regular file.
+ FileExec bool
}
// ReadOptions contains options to FileDescription.PRead(),
diff --git a/pkg/sentry/vfs/permissions.go b/pkg/sentry/vfs/permissions.go
index f664581f4..8e250998a 100644
--- a/pkg/sentry/vfs/permissions.go
+++ b/pkg/sentry/vfs/permissions.go
@@ -103,17 +103,22 @@ func GenericCheckPermissions(creds *auth.Credentials, ats AccessTypes, isDir boo
// AccessTypesForOpenFlags returns MayRead|MayWrite in this case.
//
// Use May{Read,Write}FileWithOpenFlags() for these checks instead.
-func AccessTypesForOpenFlags(flags uint32) AccessTypes {
- switch flags & linux.O_ACCMODE {
+func AccessTypesForOpenFlags(opts *OpenOptions) AccessTypes {
+ ats := AccessTypes(0)
+ if opts.FileExec {
+ ats |= MayExec
+ }
+
+ switch opts.Flags & linux.O_ACCMODE {
case linux.O_RDONLY:
- if flags&linux.O_TRUNC != 0 {
- return MayRead | MayWrite
+ if opts.Flags&linux.O_TRUNC != 0 {
+ return ats | MayRead | MayWrite
}
- return MayRead
+ return ats | MayRead
case linux.O_WRONLY:
- return MayWrite
+ return ats | MayWrite
default:
- return MayRead | MayWrite
+ return ats | MayRead | MayWrite
}
}
diff --git a/pkg/sentry/vfs/resolving_path.go b/pkg/sentry/vfs/resolving_path.go
index 8a0b382f6..eb4ebb511 100644
--- a/pkg/sentry/vfs/resolving_path.go
+++ b/pkg/sentry/vfs/resolving_path.go
@@ -228,7 +228,7 @@ func (rp *ResolvingPath) Advance() {
rp.pit = next
} else { // at end of path segment, continue with next one
rp.curPart--
- rp.pit = rp.parts[rp.curPart-1]
+ rp.pit = rp.parts[rp.curPart]
}
}
diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index 908c69f91..bde81e1ef 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -46,11 +46,13 @@ import (
//
// There is no analogue to the VirtualFilesystem type in Linux, as the
// equivalent state in Linux is global.
+//
+// +stateify savable
type VirtualFilesystem struct {
// mountMu serializes mount mutations.
//
// mountMu is analogous to Linux's namespace_sem.
- mountMu sync.Mutex
+ mountMu sync.Mutex `state:"nosave"`
// mounts maps (mount parent, mount point) pairs to mounts. (Since mounts
// are uniquely namespaced, including mount parent in the key correctly
@@ -89,56 +91,59 @@ type VirtualFilesystem struct {
// devices contains all registered Devices. devices is protected by
// devicesMu.
- devicesMu sync.RWMutex
+ devicesMu sync.RWMutex `state:"nosave"`
devices map[devTuple]*registeredDevice
// anonBlockDevMinor contains all allocated anonymous block device minor
// numbers. anonBlockDevMinorNext is a lower bound for the smallest
// unallocated anonymous block device number. anonBlockDevMinorNext and
// anonBlockDevMinor are protected by anonBlockDevMinorMu.
- anonBlockDevMinorMu sync.Mutex
+ anonBlockDevMinorMu sync.Mutex `state:"nosave"`
anonBlockDevMinorNext uint32
anonBlockDevMinor map[uint32]struct{}
// fsTypes contains all registered FilesystemTypes. fsTypes is protected by
// fsTypesMu.
- fsTypesMu sync.RWMutex
+ fsTypesMu sync.RWMutex `state:"nosave"`
fsTypes map[string]*registeredFilesystemType
// filesystems contains all Filesystems. filesystems is protected by
// filesystemsMu.
- filesystemsMu sync.Mutex
+ filesystemsMu sync.Mutex `state:"nosave"`
filesystems map[*Filesystem]struct{}
}
-// New returns a new VirtualFilesystem with no mounts or FilesystemTypes.
-func New() *VirtualFilesystem {
- vfs := &VirtualFilesystem{
- mountpoints: make(map[*Dentry]map[*Mount]struct{}),
- devices: make(map[devTuple]*registeredDevice),
- anonBlockDevMinorNext: 1,
- anonBlockDevMinor: make(map[uint32]struct{}),
- fsTypes: make(map[string]*registeredFilesystemType),
- filesystems: make(map[*Filesystem]struct{}),
- }
+// Init initializes a new VirtualFilesystem with no mounts or FilesystemTypes.
+func (vfs *VirtualFilesystem) Init() error {
+ vfs.mountpoints = make(map[*Dentry]map[*Mount]struct{})
+ vfs.devices = make(map[devTuple]*registeredDevice)
+ vfs.anonBlockDevMinorNext = 1
+ vfs.anonBlockDevMinor = make(map[uint32]struct{})
+ vfs.fsTypes = make(map[string]*registeredFilesystemType)
+ vfs.filesystems = make(map[*Filesystem]struct{})
vfs.mounts.Init()
// Construct vfs.anonMount.
anonfsDevMinor, err := vfs.GetAnonBlockDevMinor()
if err != nil {
- panic(fmt.Sprintf("VirtualFilesystem.GetAnonBlockDevMinor() failed during VirtualFilesystem construction: %v", err))
+ // This shouldn't be possible since anonBlockDevMinorNext was
+ // initialized to 1 above (no device numbers have been allocated yet).
+ panic(fmt.Sprintf("VirtualFilesystem.Init: device number allocation for anonfs failed: %v", err))
}
anonfs := anonFilesystem{
devMinor: anonfsDevMinor,
}
anonfs.vfsfs.Init(vfs, &anonfs)
- vfs.anonMount = &Mount{
- vfs: vfs,
- fs: &anonfs.vfsfs,
- refs: 1,
+ defer anonfs.vfsfs.DecRef()
+ anonMount, err := vfs.NewDisconnectedMount(&anonfs.vfsfs, nil, &MountOptions{})
+ if err != nil {
+ // We should not be passing any MountOptions that would cause
+ // construction of this mount to fail.
+ panic(fmt.Sprintf("VirtualFilesystem.Init: anonfs mount failed: %v", err))
}
+ vfs.anonMount = anonMount
- return vfs
+ return nil
}
// PathOperation specifies the path operated on by a VFS method.
@@ -379,6 +384,22 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential
fd, err := rp.mount.fs.impl.OpenAt(ctx, rp, *opts)
if err == nil {
vfs.putResolvingPath(rp)
+
+ // TODO(gvisor.dev/issue/1193): Move inside fsimpl to avoid another call
+ // to FileDescription.Stat().
+ if opts.FileExec {
+ // Only a regular file can be executed.
+ stat, err := fd.Stat(ctx, StatOptions{Mask: linux.STATX_TYPE})
+ if err != nil {
+ fd.DecRef()
+ return nil, err
+ }
+ if stat.Mask&linux.STATX_TYPE == 0 || stat.Mode&linux.S_IFMT != linux.S_IFREG {
+ fd.DecRef()
+ return nil, syserror.EACCES
+ }
+ }
+
return fd, nil
}
if !rp.handleError(err) {
@@ -724,6 +745,8 @@ func (vfs *VirtualFilesystem) SyncAllFilesystems(ctx context.Context) error {
// VirtualDentry methods require that a reference is held on the VirtualDentry.
//
// VirtualDentry is analogous to Linux's struct path.
+//
+// +stateify savable
type VirtualDentry struct {
mount *Mount
dentry *Dentry
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-06 17:05:40 +0000