From fbe0e839d1e22d88810f3ee3e2f1479be4c0aa4a Mon Sep 17 00:00:00 2001 From: Li Jinyue Date: Thu, 14 Dec 2017 17:04:54 +0800 Subject: [PATCH] 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. Signed-off-by: Li Jinyue Signed-off-by: Thomas Gleixner 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 --- kernel/futex.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/futex.c b/kernel/futex.c index 9e69589b9248..8c5424dd5924 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1878,6 +1878,9 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags, struct futex_q *this, *next; DEFINE_WAKE_Q(wake_q); + if (nr_wake < 0 || nr_requeue < 0) + return -EINVAL; + /* * When PI not supported: return -ENOSYS if requeue_pi is true, * consequently the compiler knows requeue_pi is always false past -- 2.30.2