From 66efd9e7538d2f5823e7d2ccae2b16e8e57b7d15 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 commit c80567c82ae4814a41287618e315a60ecf513be6 upstream. ... 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. Signed-off-by: Al Viro Signed-off-by: Jiri Slaby --- fs/namei.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index d1c0b91b4534b..b1b1781faca15 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3116,6 +3116,10 @@ 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);