diff options
| author | Nicolas Lacasse <nlacasse@google.com> | 2018-07-26 15:54:55 -0700 |
|---|---|---|
| committer | Shentubot <shentubot@google.com> | 2018-07-26 15:55:50 -0700 |
| commit | 127c977ab04d56de78c5caf16a8e6446eda340d4 (patch) | |
| tree | 1a745aadb0511ed4da27cad33f55b5c5e5447bbc /pkg/sentry/fs | |
| parent | 6d7199bcffcb45b2bdb662128034a9b728a74efb (diff) | |
Don't copy-up extended attributes that specifically configure a lower overlay.
When copying-up files from a lower fs to an upper, we also copy the extended
attributes on the file. If there is a (nested) overlay inside the lower, some
of these extended attributes configure the lower overlay, and should not be
copied-up to the upper.
In particular, whiteout attributes in the lower fs overlay should not be
copied-up, since the upper fs may actually contain the file.
PiperOrigin-RevId: 206236010
Change-Id: Ia0454ac7b99d0e11383f732a529cb195ed364062
Diffstat (limited to 'pkg/sentry/fs')
| -rw-r--r-- | pkg/sentry/fs/copy_up.go | 5 | ||||
| -rw-r--r-- | pkg/sentry/fs/overlay.go | 7 |
2 files changed, 12 insertions, 0 deletions
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go index ea74d0efd..8c949b176 100644 --- a/pkg/sentry/fs/copy_up.go +++ b/pkg/sentry/fs/copy_up.go @@ -402,6 +402,11 @@ func copyAttributesLocked(ctx context.Context, upper *Inode, lower *Inode) error return err } for name := range lowerXattr { + // Don't copy-up attributes that configure an overlay in the + // lower. + if isXattrOverlay(name) { + continue + } value, err := lower.Getxattr(name) if err != nil { return err diff --git a/pkg/sentry/fs/overlay.go b/pkg/sentry/fs/overlay.go index a63f00e0e..7357d6401 100644 --- a/pkg/sentry/fs/overlay.go +++ b/pkg/sentry/fs/overlay.go @@ -16,6 +16,7 @@ package fs import ( "fmt" + "strings" "sync" "gvisor.googlesource.com/gvisor/pkg/log" @@ -76,6 +77,12 @@ func XattrOverlayWhiteout(name string) string { return XattrOverlayWhiteoutPrefix + name } +// isXattrOverlay returns whether the given extended attribute configures the +// overlay. +func isXattrOverlay(name string) bool { + return strings.HasPrefix(name, XattrOverlayPrefix) +} + // NewOverlayRoot produces the root of an overlay. // // Preconditions: |