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 <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Al Viro 2016-02-27 19:17:33 -05:00 committed by Greg Kroah-Hartman
parent b19e7a870c
commit 1b153db5ac

View file

@ -2917,6 +2917,10 @@ opened:
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);