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-rw-r--r--pkg/sentry/fs/dev/BUILD1
-rw-r--r--pkg/sentry/fs/dev/dev.go7
-rw-r--r--pkg/sentry/fs/dev/net_tun.go7
-rw-r--r--pkg/sentry/fs/dirent.go25
-rw-r--r--pkg/sentry/fs/fsutil/inode.go4
-rw-r--r--pkg/sentry/fs/mount_test.go11
-rw-r--r--pkg/sentry/fs/mounts.go10
-rw-r--r--pkg/sentry/fs/proc/mounts.go16
8 files changed, 54 insertions, 27 deletions
diff --git a/pkg/sentry/fs/dev/BUILD b/pkg/sentry/fs/dev/BUILD
index 9b6bb26d0..9379a4d7b 100644
--- a/pkg/sentry/fs/dev/BUILD
+++ b/pkg/sentry/fs/dev/BUILD
@@ -26,6 +26,7 @@ go_library(
"//pkg/sentry/fs/fsutil",
"//pkg/sentry/fs/ramfs",
"//pkg/sentry/fs/tmpfs",
+ "//pkg/sentry/inet",
"//pkg/sentry/kernel",
"//pkg/sentry/memmap",
"//pkg/sentry/mm",
diff --git a/pkg/sentry/fs/dev/dev.go b/pkg/sentry/fs/dev/dev.go
index 7e66c29b0..acbd401a0 100644
--- a/pkg/sentry/fs/dev/dev.go
+++ b/pkg/sentry/fs/dev/dev.go
@@ -22,6 +22,7 @@ import (
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
"gvisor.dev/gvisor/pkg/sentry/fs/tmpfs"
+ "gvisor.dev/gvisor/pkg/sentry/inet"
"gvisor.dev/gvisor/pkg/usermem"
)
@@ -124,10 +125,12 @@ func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
"ptmx": newSymlink(ctx, "pts/ptmx", msrc),
"tty": newCharacterDevice(ctx, newTTYDevice(ctx, fs.RootOwner, 0666), msrc, ttyDevMajor, ttyDevMinor),
+ }
- "net": newDirectory(ctx, map[string]*fs.Inode{
+ if isNetTunSupported(inet.StackFromContext(ctx)) {
+ contents["net"] = newDirectory(ctx, map[string]*fs.Inode{
"tun": newCharacterDevice(ctx, newNetTunDevice(ctx, fs.RootOwner, 0666), msrc, netTunDevMajor, netTunDevMinor),
- }, msrc),
+ }, msrc)
}
iops := ramfs.NewDir(ctx, contents, fs.RootOwner, fs.FilePermsFromMode(0555))
diff --git a/pkg/sentry/fs/dev/net_tun.go b/pkg/sentry/fs/dev/net_tun.go
index 755644488..dc7ad075a 100644
--- a/pkg/sentry/fs/dev/net_tun.go
+++ b/pkg/sentry/fs/dev/net_tun.go
@@ -20,6 +20,7 @@ import (
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
+ "gvisor.dev/gvisor/pkg/sentry/inet"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/sentry/socket/netstack"
"gvisor.dev/gvisor/pkg/syserror"
@@ -168,3 +169,9 @@ func (fops *netTunFileOperations) EventRegister(e *waiter.Entry, mask waiter.Eve
func (fops *netTunFileOperations) EventUnregister(e *waiter.Entry) {
fops.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
+}
diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go
index acab0411a..e0b32e1c1 100644
--- a/pkg/sentry/fs/dirent.go
+++ b/pkg/sentry/fs/dirent.go
@@ -1438,8 +1438,8 @@ func lockForRename(oldParent *Dirent, oldName string, newParent *Dirent, newName
}, nil
}
-func checkSticky(ctx context.Context, dir *Dirent, victim *Dirent) error {
- uattr, err := dir.Inode.UnstableAttr(ctx)
+func (d *Dirent) checkSticky(ctx context.Context, victim *Dirent) error {
+ uattr, err := d.Inode.UnstableAttr(ctx)
if err != nil {
return syserror.EPERM
}
@@ -1465,30 +1465,33 @@ func checkSticky(ctx context.Context, dir *Dirent, victim *Dirent) error {
return syserror.EPERM
}
-// MayDelete determines whether `name`, a child of `dir`, can be deleted or
+// MayDelete determines whether `name`, a child of `d`, can be deleted or
// renamed by `ctx`.
//
// Compare Linux kernel fs/namei.c:may_delete.
-func MayDelete(ctx context.Context, root, dir *Dirent, name string) error {
- if err := dir.Inode.CheckPermission(ctx, PermMask{Write: true, Execute: true}); err != nil {
+func (d *Dirent) MayDelete(ctx context.Context, root *Dirent, name string) error {
+ if err := d.Inode.CheckPermission(ctx, PermMask{Write: true, Execute: true}); err != nil {
return err
}
- victim, err := dir.Walk(ctx, root, name)
+ unlock := d.lockDirectory()
+ defer unlock()
+
+ victim, err := d.walk(ctx, root, name, true /* may unlock */)
if err != nil {
return err
}
defer victim.DecRef()
- return mayDelete(ctx, dir, victim)
+ return d.mayDelete(ctx, victim)
}
// mayDelete determines whether `victim`, a child of `dir`, can be deleted or
// renamed by `ctx`.
//
// Preconditions: `dir` is writable and executable by `ctx`.
-func mayDelete(ctx context.Context, dir, victim *Dirent) error {
- if err := checkSticky(ctx, dir, victim); err != nil {
+func (d *Dirent) mayDelete(ctx context.Context, victim *Dirent) error {
+ if err := d.checkSticky(ctx, victim); err != nil {
return err
}
@@ -1542,7 +1545,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string
defer renamed.DecRef()
// Check that the renamed dirent is deletable.
- if err := mayDelete(ctx, oldParent, renamed); err != nil {
+ if err := oldParent.mayDelete(ctx, renamed); err != nil {
return err
}
@@ -1580,7 +1583,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string
// across the Rename, so must call DecRef manually (no defer).
// Check that we can delete replaced.
- if err := mayDelete(ctx, newParent, replaced); err != nil {
+ if err := newParent.mayDelete(ctx, replaced); err != nil {
replaced.DecRef()
return err
}
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index daecc4ffe..1922ff08c 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -259,8 +259,8 @@ func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode, ui
// RemoveXattr implements fs.InodeOperations.RemoveXattr.
func (i *InodeSimpleExtendedAttributes) RemoveXattr(_ context.Context, _ *fs.Inode, name string) error {
- i.mu.RLock()
- defer i.mu.RUnlock()
+ i.mu.Lock()
+ defer i.mu.Unlock()
if _, ok := i.xattrs[name]; ok {
delete(i.xattrs, name)
return nil
diff --git a/pkg/sentry/fs/mount_test.go b/pkg/sentry/fs/mount_test.go
index e672a438c..a3d10770b 100644
--- a/pkg/sentry/fs/mount_test.go
+++ b/pkg/sentry/fs/mount_test.go
@@ -36,11 +36,12 @@ func mountPathsAre(root *Dirent, got []*Mount, want ...string) error {
gotPaths := make(map[string]struct{}, len(got))
gotStr := make([]string, len(got))
for i, g := range got {
- groot := g.Root()
- name, _ := groot.FullName(root)
- groot.DecRef()
- gotStr[i] = name
- gotPaths[name] = struct{}{}
+ if groot := g.Root(); groot != nil {
+ name, _ := groot.FullName(root)
+ groot.DecRef()
+ gotStr[i] = name
+ gotPaths[name] = struct{}{}
+ }
}
if len(got) != len(want) {
return fmt.Errorf("mount paths are different, got: %q, want: %q", gotStr, want)
diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go
index 574a2cc91..c7981f66e 100644
--- a/pkg/sentry/fs/mounts.go
+++ b/pkg/sentry/fs/mounts.go
@@ -100,10 +100,14 @@ func newUndoMount(d *Dirent) *Mount {
}
}
-// Root returns the root dirent of this mount. Callers must call DecRef on the
-// returned dirent.
+// Root returns the root dirent of this mount.
+//
+// This may return nil if the mount has already been free. Callers must handle this
+// case appropriately. If non-nil, callers must call DecRef on the returned *Dirent.
func (m *Mount) Root() *Dirent {
- m.root.IncRef()
+ if !m.root.TryIncRef() {
+ return nil
+ }
return m.root
}
diff --git a/pkg/sentry/fs/proc/mounts.go b/pkg/sentry/fs/proc/mounts.go
index c10888100..94deb553b 100644
--- a/pkg/sentry/fs/proc/mounts.go
+++ b/pkg/sentry/fs/proc/mounts.go
@@ -60,13 +60,15 @@ func forEachMount(t *kernel.Task, fn func(string, *fs.Mount)) {
})
for _, m := range ms {
mroot := m.Root()
+ if mroot == nil {
+ continue // No longer valid.
+ }
mountPath, desc := mroot.FullName(rootDir)
mroot.DecRef()
if !desc {
// MountSources that are not descendants of the chroot jail are ignored.
continue
}
-
fn(mountPath, m)
}
}
@@ -91,6 +93,12 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
var buf bytes.Buffer
forEachMount(mif.t, func(mountPath string, m *fs.Mount) {
+ mroot := m.Root()
+ if mroot == nil {
+ return // No longer valid.
+ }
+ defer mroot.DecRef()
+
// Format:
// 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
// (1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
@@ -107,9 +115,6 @@ func (mif *mountInfoFile) ReadSeqFileData(ctx context.Context, handle seqfile.Se
// (3) Major:Minor device ID. We don't have a superblock, so we
// just use the root inode device number.
- mroot := m.Root()
- defer mroot.DecRef()
-
sa := mroot.Inode.StableAttr
fmt.Fprintf(&buf, "%d:%d ", sa.DeviceFileMajor, sa.DeviceFileMinor)
@@ -207,6 +212,9 @@ func (mf *mountsFile) ReadSeqFileData(ctx context.Context, handle seqfile.SeqHan
//
// The "needs dump"and fsck flags are always 0, which is allowed.
root := m.Root()
+ if root == nil {
+ return // No longer valid.
+ }
defer root.DecRef()
flags := root.Inode.MountSource.Flags
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-02 16:59:13 +0000