Commit b95aa98e authored Jun 23, 2017 by NeilBrown Committed by Greg Kroah-Hartman Jun 29, 2017

autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL

commit 9fa4eb8e490a28de40964b1b0e583d8db4c7e57c upstream.

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 1d3d0f8b

fs/autofs4/dev-ioctl.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -331,7 +331,7 @@ static int autofs_dev_ioctl_fail(struct file *fp,
		int status;

		token = (autofs_wqt_t) param->fail.token;
		status = param->fail.status ? param->fail.status : -ENOENT;
		status = param->fail.status < 0 ? param->fail.status : -ENOENT;
		return autofs4_wait_release(sbi, token, status);
		}