From: Andrey Konovalov <andreyknvl@google.com>
Date: Wed, 29 Mar 2017 14:11:22 +0000 (+0200)
Subject: net/packet: fix overflow in check for tp_reserve
X-Git-Tag: v4.1.12-102.0.20170601_1400~241
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=215eb22368830bb78f9fe41b5d6d24176529bf1e;p=users%2Fjedix%2Flinux-maple.git

net/packet: fix overflow in check for tp_reserve

Orabug: 25813773
CVE: CVE-2017-7308

When calculating po->tp_hdrlen + po->tp_reserve the result can overflow.

Fix by checking that tp_reserve <= INT_MAX on assign.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit bcc5364bdcfe131e6379363f089e7b4108d35b70)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
---

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index cd4af1d1a58ca..282506cffa424 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3373,6 +3373,8 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
 			return -EBUSY;
 		if (copy_from_user(&val, optval, sizeof(val)))
 			return -EFAULT;
+		if (val > INT_MAX)
+			return -EINVAL;
 		po->tp_reserve = val;
 		return 0;
 	}