diff options
| -rw-r--r-- | pkg/sentry/fsimpl/gofer/filesystem.go | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go index 40c9243f0..c1c9ec008 100644 --- a/pkg/sentry/fsimpl/gofer/filesystem.go +++ b/pkg/sentry/fsimpl/gofer/filesystem.go @@ -364,21 +364,40 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir parent.dirMu.Lock() defer parent.dirMu.Unlock() - child, err := fs.getChildLocked(ctx, parent, name, &ds) - switch { - case err != nil && err != syserror.ENOENT: - return err - case child != nil: + if len(name) > maxFilenameLen { + return syserror.ENAMETOOLONG + } + // Check for existence only if caching information is available. Otherwise, + // don't check for existence just yet. We will check for existence if the + // checks for writability fail below. Existence check is done by the creation + // RPCs themselves. + if child, ok := parent.children[name]; ok && child != nil { return syserror.EEXIST } + checkExistence := func() error { + if child, err := fs.getChildLocked(ctx, parent, name, &ds); err != nil && err != syserror.ENOENT { + return err + } else if child != nil { + return syserror.EEXIST + } + return nil + } mnt := rp.Mount() if err := mnt.CheckBeginWrite(); err != nil { + // Existence check takes precedence. + if existenceErr := checkExistence(); existenceErr != nil { + return existenceErr + } return err } defer mnt.EndWrite() if err := parent.checkPermissions(rp.Credentials(), vfs.MayWrite); err != nil { + // Existence check takes precedence. + if existenceErr := checkExistence(); existenceErr != nil { + return existenceErr + } return err } if !dir && rp.MustBeDir() { |