From: Florian Westphal <fw@strlen.de>
Date: Thu, 10 Mar 2016 00:56:23 +0000 (+0100)
Subject: netfilter: x_tables: check for size overflow
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=d157bd761585605b7882935ffb86286919f62ea1;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

netfilter: x_tables: check for size overflow

Ben Hawkes says:
 integer overflow in xt_alloc_table_info, which on 32-bit systems can
 lead to small structure allocation and a copy_from_user based heap
 corruption.

Reported-by: Ben Hawkes <hawkes@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index d0cd2b9bf844..582c9cfd6567 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -659,6 +659,9 @@ struct xt_table_info *xt_alloc_table_info(unsigned int size)
 	struct xt_table_info *info = NULL;
 	size_t sz = sizeof(*info) + size;
 
+	if (sz < sizeof(*info))
+		return NULL;
+
 	/* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
 	if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
 		return NULL;