diff options
author | Ayush Ranjan <ayushranjan@google.com> | 2021-08-20 17:46:45 -0700 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2021-08-20 17:51:34 -0700 |
commit | 2b0615c76c8acf88de1add9bad1758384fecb9e5 (patch) | |
tree | 7310c0c5e96510afb428a75c6b1028b4ce384908 | |
parent | 0e49e0821910ae03f029d372f9244148c214cb16 (diff) |
[op] Prevent file leak in MultiGetAttr's error path.
The old implementation was mostly correct but error prone - making way for the
issue in question here. In its error path, it would leak the intermediate file
being walked. Each return/break needed explicit cleanup.
This change implements a more clean way to cleaning up intermediate directories.
If the code were to evolve to be more complex, it would still work.
PiperOrigin-RevId: 392102826
-rw-r--r-- | pkg/p9/file.go | 16 | ||||
-rw-r--r-- | runsc/fsgofer/fsgofer.go | 16 |
2 files changed, 15 insertions, 17 deletions
diff --git a/pkg/p9/file.go b/pkg/p9/file.go index 97e0231d6..8d6af2d6b 100644 --- a/pkg/p9/file.go +++ b/pkg/p9/file.go @@ -325,6 +325,12 @@ func (*DisallowServerCalls) Renamed(File, string) { func DefaultMultiGetAttr(start File, names []string) ([]FullStat, error) { stats := make([]FullStat, 0, len(names)) parent := start + closeParent := func() { + if parent != start { + _ = parent.Close() + } + } + defer closeParent() mask := AttrMaskAll() for i, name := range names { if len(name) == 0 && i == 0 { @@ -340,15 +346,14 @@ func DefaultMultiGetAttr(start File, names []string) ([]FullStat, error) { continue } qids, child, valid, attr, err := parent.WalkGetAttr([]string{name}) - if parent != start { - _ = parent.Close() - } if err != nil { if errors.Is(err, unix.ENOENT) { return stats, nil } return nil, err } + closeParent() + parent = child stats = append(stats, FullStat{ QID: qids[0], Valid: valid, @@ -357,13 +362,8 @@ func DefaultMultiGetAttr(start File, names []string) ([]FullStat, error) { if attr.Mode.FileType() != ModeDirectory { // Doesn't need to continue if entry is not a dir. Including symlinks // that cannot be followed. - _ = child.Close() break } - parent = child - } - if parent != start { - _ = parent.Close() } return stats, nil } diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go index 07497e47b..600b21189 100644 --- a/runsc/fsgofer/fsgofer.go +++ b/runsc/fsgofer/fsgofer.go @@ -1242,13 +1242,14 @@ func (l *localFile) MultiGetAttr(names []string) ([]p9.FullStat, error) { } parent := l.file.FD() - for _, name := range names { - child, err := unix.Openat(parent, name, openFlags|unix.O_PATH, 0) + closeParent := func() { if parent != l.file.FD() { - // Parent is no longer needed. _ = unix.Close(parent) - parent = -1 } + } + defer closeParent() + for _, name := range names { + child, err := unix.Openat(parent, name, openFlags|unix.O_PATH, 0) if err != nil { if errors.Is(err, unix.ENOENT) { // No pont in continuing any further. @@ -1256,10 +1257,11 @@ func (l *localFile) MultiGetAttr(names []string) ([]p9.FullStat, error) { } return nil, err } + closeParent() + parent = child var stat unix.Stat_t if err := unix.Fstat(child, &stat); err != nil { - _ = unix.Close(child) return nil, err } valid, attr := l.fillAttr(&stat) @@ -1271,13 +1273,9 @@ func (l *localFile) MultiGetAttr(names []string) ([]p9.FullStat, error) { if (stat.Mode & unix.S_IFMT) != unix.S_IFDIR { // Doesn't need to continue if entry is not a dir. Including symlinks // that cannot be followed. - _ = unix.Close(child) break } parent = child } - if parent != -1 && parent != l.file.FD() { - _ = unix.Close(parent) - } return stats, nil } |