From fa3fd2474b3ea18e28a91cd50eb74fef6440f7e7 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 27 Feb 2016 19:17:33 -0500 Subject: [PATCH] do_last(): don't let a bogus return value from ->open() et.al. to confuse us [ Upstream commit c80567c82ae4814a41287618e315a60ecf513be6 ] ... into returning a positive to path_openat(), which would interpret that as "symlink had been encountered" and proceed to corrupt memory, etc. It can only happen due to a bug in some ->open() instance or in some LSM hook, etc., so we report any such event *and* make sure it doesn't trick us into further unpleasantness. Cc: stable@vger.kernel.org # v3.6+, at least Signed-off-by: Al Viro Signed-off-by: Sasha Levin --- fs/namei.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index be3d538d56b3..2a8ba683a888 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3111,6 +3111,10 @@ static int do_last(struct nameidata *nd, struct path *path, goto exit_fput; } out: + if (unlikely(error > 0)) { + WARN_ON(1); + error = -EINVAL; + } if (got_write) mnt_drop_write(nd->path.mnt); path_put(&save_parent);