Subject: [PATCH 3/3] Prevent from passing NULL pointer to tcp_v6_md5_do_lookup()

From: Gui Jianfeng <[email-masked]>
Date: Tue, 05 Aug 2008 17:24:39 +0800

If skb->sk == NULL when calling tcp_v6_md5_do_lookup(), kernel
will panic. Don't let this thing happen.

Signed-off-by: Gui Jianfeng <[email-masked]>
---
 net/ipv6/tcp_ipv6.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 78185a4..5b90b36 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -69,7 +69,8 @@
 #include <linux/scatterlist.h>
 
 static void	tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
-static void	tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req);
+static void	tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+				      struct request_sock *req);
 
 static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
 
@@ -1138,10 +1139,11 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 	inet_twsk_put(tw);
 }
 
-static void tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req)
+static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
+				  struct request_sock *req)
 {
 	tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
-			tcp_v6_md5_do_lookup(skb->sk, &ipv6_hdr(skb)->daddr));
+			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr));
 }

-- 
1.5.3