Patch "vt: fix unchecked __put_user() in tioclinux ioctls" has been added to the 4.9-stable tree

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

vt: fix unchecked __put_user() in tioclinux ioctls

to the 4.9-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:
vt-fix-unchecked-__put_user-in-tioclinux-ioctls.patch
and it can be found in the queue-4.9 subdirectory.

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

From: Adam Borowski <[email protected]>
Date: Sat, 3 Jun 2017 09:35:06 +0200
Subject: vt: fix unchecked __put_user() in tioclinux ioctls

From: Adam Borowski <[email protected]>

commit 6987dc8a70976561d22450b5858fc9767788cc1c upstream.

Only read access is checked before this call.

Actually, at the moment this is not an issue, as every in-tree arch does the same manual checks for VERIFY_READ vs VERIFY_WRITE, relying on the MMU to tell them apart, but this wasn't the case in the past and may happen again on some odd arch in the future.

If anyone cares about 3.7 and earlier, this is a security hole (untested) on real 80386 CPUs.

---
 drivers/tty/vt/vt.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -2711,13 +2711,13 @@ int tioclinux(struct tty_struct *tty, un
 	 * related to the kernel should not use this.
 	 */
 			data = vt_get_shift_state();
-			ret = __put_user(data, p);
+			ret = put_user(data, p);
 			break;
 		case TIOCL_GETMOUSEREPORTING:
 			console_lock();	/* May be overkill */
 			data = mouse_reporting();
 			console_unlock();
-			ret = __put_user(data, p);
+			ret = put_user(data, p);
 			break;
 		case TIOCL_SETVESABLANK:
 			console_lock();

@@ -2726,7 +2726,7 @@ int tioclinux(struct tty_struct *tty, un
 			break;
 		case TIOCL_GETKMSGREDIRECT:
 			data = vt_get_kmsg_redirect();
-			ret = __put_user(data, p);
+			ret = put_user(data, p);
 			break;
 		case TIOCL_SETKMSGREDIRECT:
 			if (!capable(CAP_SYS_ADMIN)) {

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

queue-4.9/vt-fix-unchecked-__put_user-in-tioclinux-ioctls.patch