From: Florian Westphal <fw@strlen.de>
Date: Tue, 30 Aug 2016 04:35:04 +0000 (-0400)
Subject: netfilter: x_tables: check for size overflow
X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~53
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=61610c63fa1025468c82be975e7d574e847d00de;p=firefly-linux-kernel-4.4.55.git

netfilter: x_tables: check for size overflow

[ Upstream commit d157bd761585605b7882935ffb86286919f62ea1 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index c7b7cecb5bd1..2fc6ca9d1286 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -897,6 +897,9 @@ 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;
+
 	if (sz < sizeof(*info))
 		return NULL;