fs: Add a missing permission check to do_umount

[linux-2.6-block.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index ef42d9bee2121f8e6a68937a5ecaa7670721ded9..7f67b463a5b4dafb57373109c416bd67d671d6c1 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1356,6 +1356,8 @@ static int do_umount(struct mount *mnt, int flags)
                 * Special case for "unmounting" root ...
                 * we just try to remount it readonly.
                 */
+               if (!capable(CAP_SYS_ADMIN))
+                       return -EPERM;
                down_write(&sb->s_umount);
                if (!(sb->s_flags & MS_RDONLY))
                        retval = do_remount_sb(sb, MS_RDONLY, NULL, 0);