Assumption never checked, should fail if the mounter creds are not sufficient. Signed-off-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx> Cc: Miklos Szeredi <miklos@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> Cc: Amir Goldstein <amir73il@xxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Stephen Smalley <sds@xxxxxxxxxxxxx> Cc: linux-unionfs@xxxxxxxxxxxxxxx Cc: linux-doc@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: kernel-team@xxxxxxxxxxx --- v7: - This time for realz v6: - rebase v5: - dependency of "overlayfs: override_creds=off option bypass creator_cred" fs/overlayfs/namei.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index efd372312ef1..3ac9dc8f6cc0 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -163,6 +163,9 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, if (!uuid_equal(&fh->uuid, &mnt->mnt_sb->s_uuid)) return NULL; + if (!capable(CAP_DAC_READ_SEARCH)) + return ERR_PTR(-EPERM); + bytes = (fh->len - offsetof(struct ovl_fh, fid)); real = exportfs_decode_fh(mnt, (struct fid *)fh->fid, bytes >> 2, (int)fh->type, -- 2.19.1.930.g4563a0d9d0-goog
