From f668f5f7e0861087ef9d64d473a9c1399fc25471 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Thu, 5 Nov 2015 11:34:06 -0800
Subject: ipv4: use sk_fullsock() in ipv4_conntrack_defrag()

Before converting a 'socket pointer' into inet socket,
use sk_fullsock() to detect timewait or request sockets.

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/netfilter/nf_defrag_ipv4.c b/net/ipv4/netfilter/nf_defrag_ipv4.c
index 0e5591c..6fb869f6 100644
--- a/net/ipv4/netfilter/nf_defrag_ipv4.c
+++ b/net/ipv4/netfilter/nf_defrag_ipv4.c
@@ -67,10 +67,9 @@ static unsigned int ipv4_conntrack_defrag(void *priv,
 					  const struct nf_hook_state *state)
 {
 	struct sock *sk = skb->sk;
-	struct inet_sock *inet = inet_sk(skb->sk);
 
-	if (sk && (sk->sk_family == PF_INET) &&
-	    inet->nodefrag)
+	if (sk && sk_fullsock(sk) && (sk->sk_family == PF_INET) &&
+	    inet_sk(sk)->nodefrag)
 		return NF_ACCEPT;
 
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
-- 
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