futex: Prevent overflow by strengthen input validation
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.
Signed-off-by: Li Jinyue <lijinyue@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: peterz@infradead.org
Cc: dvhart@infradead.org
Link: https://lkml.kernel.org/r/1513242294-31786-1-git-send-email-lijinyue@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/futex.c b/kernel/futex.c
index a03c776..0d21619 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1705,6 +1705,9 @@
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
