netdev - [PATCH 2/2] netfilter: cttimeout: fix buffer overflow

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Date:	Thu, 22 Nov 2012 10:10:52 +0100
From:	pablo@...filter.org
To:	netfilter-devel@...r.kernel.org
Cc:	davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 2/2] netfilter: cttimeout: fix buffer overflow

From: Florian Westphal <fw@...len.de>

Chen Gang reports:
the length of nla_data(cda[CTA_TIMEOUT_NAME]) is not limited in server side.

And indeed, its used to strcpy to a fixed-sized buffer.

Fortunately, nfnetlink users need CAP_NET_ADMIN.

Reported-by: Chen Gang <gang.chen@...anux.com>
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nfnetlink_cttimeout.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c
index 8847b4d..701c88a 100644
--- a/net/netfilter/nfnetlink_cttimeout.c
+++ b/net/netfilter/nfnetlink_cttimeout.c
@@ -41,7 +41,8 @@ MODULE_DESCRIPTION("cttimeout: Extended Netfilter Connection Tracking timeout tu
 static LIST_HEAD(cttimeout_list);
 
 static const struct nla_policy cttimeout_nla_policy[CTA_TIMEOUT_MAX+1] = {
-	[CTA_TIMEOUT_NAME]	= { .type = NLA_NUL_STRING },
+	[CTA_TIMEOUT_NAME]	= { .type = NLA_NUL_STRING,
+				    .len  = CTNL_TIMEOUT_NAME_MAX - 1},
 	[CTA_TIMEOUT_L3PROTO]	= { .type = NLA_U16 },
 	[CTA_TIMEOUT_L4PROTO]	= { .type = NLA_U8 },
 	[CTA_TIMEOUT_DATA]	= { .type = NLA_NESTED },
-- 
1.7.10.4

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