Patch "autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
autofs-sanity-check-status-reported-with-autofs_dev_ioctl_fail.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: NeilBrown <[email protected]>
Date: Fri, 23 Jun 2017 15:08:43 -0700
Subject: autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL

From: NeilBrown <[email protected]>

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().

---
 fs/autofs4/dev-ioctl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -331,7 +331,7 @@ static int autofs_dev_ioctl_fail(struct
 	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);
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/autofs-sanity-check-status-reported-with-autofs_dev_ioctl_fail.patch