UPSTREAM: futex: Prevent overflow by strengthen input validation
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.
CVE-2018-6927
Change-Id: I1781665147d862a58ce75199b929e5dc679f0e7e
Signed-off-by: Li Jinyue <lijinyue@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: peterz@infradead.org
Cc: dvhart@infradead.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1513242294-31786-1-git-send-email-lijinyue@huawei.com
diff --git a/kernel/futex.c b/kernel/futex.c
index 19edadf..f985bd0 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1552,6 +1552,9 @@
struct futex_hash_bucket *hb1, *hb2;
struct futex_q *this, *next;
+ if (nr_wake < 0 || nr_requeue < 0)
+ return -EINVAL;
+
if (requeue_pi) {
/*
* Requeue PI only works on two distinct uaddrs. This
