Patch "futex: Prevent overflow by strengthen input validation" 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

futex: Prevent overflow by strengthen input validation

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:
futex-prevent-overflow-by-strengthen-input-validation.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: Li Jinyue <[email protected]>
Date: Thu, 14 Dec 2017 17:04:54 +0800
Subject: futex: Prevent overflow by strengthen input validation

From: Li Jinyue <[email protected]>

commit fbe0e839d1e22d88810f3ee3e2f1479be4c0aa4a upstream.

UBSAN reports signed integer overflow in kernel/futex.c:

 UBSAN: Undefined behaviour in kernel/futex.c:2041:18
 signed integer overflow:
 0 - -2147483648 cannot be represented in type 'int'

Add a sanity check to catch negative values of nr_wake and nr_requeue.

---
 kernel/futex.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -1621,6 +1621,9 @@ static int futex_requeue(u32 __user *uad
 	struct futex_q *this, *next;
 	WAKE_Q(wake_q);
 
+	if (nr_wake < 0 || nr_requeue < 0)
+		return -EINVAL;
+
 	if (requeue_pi) {
 		/*
 		 * Requeue PI only works on two distinct uaddrs. This

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

queue-4.4/futex-prevent-overflow-by-strengthen-input-validation.patch