diff options
Diffstat (limited to 'pkg/sentry/fs/copy_up.go')
| -rw-r--r-- | pkg/sentry/fs/copy_up.go | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go index ee2d3d115..41265704c 100644 --- a/pkg/sentry/fs/copy_up.go +++ b/pkg/sentry/fs/copy_up.go @@ -113,13 +113,13 @@ func copyUpLockedForRename(ctx context.Context, d *Dirent) error { // Did we race with another copy up or does there // already exist something in the upper filesystem // for d? - d.Inode.overlay.copyMu.Lock() + d.Inode.overlay.copyMu.RLock() if d.Inode.overlay.upper != nil { - d.Inode.overlay.copyMu.Unlock() + d.Inode.overlay.copyMu.RUnlock() // Done, d is in the upper filesystem. return nil } - d.Inode.overlay.copyMu.Unlock() + d.Inode.overlay.copyMu.RUnlock() // Find the next component to copy up. We will work our way // down to the last component of d and finally copy it. @@ -155,6 +155,14 @@ func findNextCopyUp(ctx context.Context, d *Dirent) *Dirent { } func doCopyUp(ctx context.Context, d *Dirent) error { + // Fail fast on Inode types we won't be able to copy up anyways. These + // Inodes may block in GetFile while holding copyMu for reading. If we + // then try to take copyMu for writing here, we'd deadlock. + t := d.Inode.overlay.lower.StableAttr.Type + if t != RegularFile && t != Directory && t != Symlink { + return syserror.EINVAL + } + // Wait to get exclusive access to the upper Inode. d.Inode.overlay.copyMu.Lock() defer d.Inode.overlay.copyMu.Unlock() @@ -177,6 +185,8 @@ func doCopyUp(ctx context.Context, d *Dirent) error { // - parent.Inode.overlay.upper must be non-nil. // - next.Inode.overlay.copyMu must be locked writable. // - next.Inode.overlay.lower must be non-nil. +// - next.Inode.overlay.lower.StableAttr.Type must be RegularFile, Directory, +// or Symlink. // - upper filesystem must support setting file ownership and timestamps. func copyUpLocked(ctx context.Context, parent *Dirent, next *Dirent) error { // Extract the attributes of the file we wish to copy. @@ -239,7 +249,7 @@ func copyUpLocked(ctx context.Context, parent *Dirent, next *Dirent) error { childUpperInode = childUpper.Inode default: - return syserror.EINVAL + panic(fmt.Sprintf("copy up of invalid type %v on %+v", next.Inode.StableAttr.Type, next)) } // Bring file attributes up to date. This does not include size, which will be |