From 51df784ed739246a3774b300e5f536e17bec36ed Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Wed, 9 Nov 2005 12:59:41 -0800
Subject: [NETFILTER] ctnetlink: check if protoinfo is present

This fixes an oops triggered from userspace. If we don't pass information
about the private protocol info, the reference to attr will be NULL. This is
likely to happen in update messages.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/netfilter/ip_conntrack_proto_tcp.c b/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
index 6ea4b22..468c600 100644
--- a/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
+++ b/net/ipv4/netfilter/ip_conntrack_proto_tcp.c
@@ -362,6 +362,11 @@ static int nfattr_to_tcp(struct nfattr *cda[], struct ip_conntrack *ct)
 	struct nfattr *attr = cda[CTA_PROTOINFO_TCP-1];
 	struct nfattr *tb[CTA_PROTOINFO_TCP_MAX];
 
+	/* updates could not contain anything about the private
+	 * protocol info, in that case skip the parsing */
+	if (!attr)
+		return 0;
+
         nfattr_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr);
 
 	if (!tb[CTA_PROTOINFO_TCP_STATE-1])
-- 
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