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authorAyush Ranjan <ayushranjan@google.com>2021-08-20 17:46:45 -0700
committergVisor bot <gvisor-bot@google.com>2021-08-20 17:51:34 -0700
commit2b0615c76c8acf88de1add9bad1758384fecb9e5 (patch)
tree7310c0c5e96510afb428a75c6b1028b4ce384908
parent0e49e0821910ae03f029d372f9244148c214cb16 (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.go16
-rw-r--r--runsc/fsgofer/fsgofer.go16
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
}