From: Li Jinyue Date: Thu, 14 Dec 2017 09:04:54 +0000 (+0800) Subject: futex: Prevent overflow by strengthen input validation X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=9d4265fc8f485089645dca8c688eedd890a165af 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 Signed-off-by: Thomas Gleixner Cc: peterz@infradead.org Cc: dvhart@infradead.org Link: https://lkml.kernel.org/r/1513242294-31786-1-git-send-email-lijinyue@huawei.com [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- diff --git a/kernel/futex.c b/kernel/futex.c index 3854e754f641..5e483785d43f 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1376,6 +1376,9 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags, struct plist_head *head1; 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