autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL
authorNeilBrown <neilb@suse.com>
Fri, 23 Jun 2017 22:08:43 +0000 (15:08 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 23 Jun 2017 23:15:55 +0000 (16:15 -0700)
commit9fa4eb8e490a28de40964b1b0e583d8db4c7e57c
treec0564c06d93a123e67da1a0e973c2a0f14133c36
parent029c54b09599573015a5c18dbe59cbdf42742237
autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL

If a positive status is passed with the AUTOFS_DEV_IOCTL_FAIL ioctl,
autofs4_d_automount() will return

   ERR_PTR(status)

with that status to follow_automount(), which will then dereference an
invalid pointer.

So treat a positive status the same as zero, and map to ENOENT.

See comment in systemd src/core/automount.c::automount_send_ready().

Link: http://lkml.kernel.org/r/871sqwczx5.fsf@notabene.neil.brown.name
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: Ian Kent <raven@themaw.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/autofs4/dev-ioctl.c