netdev - [PATCH v2] ipv6/tcp: Stop processing ICMPv6 redirect messages

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Date:	Sun,  7 Apr 2013 16:53:15 +0200
From:	Christoph Paasch <christoph.paasch@...ouvain.be>
To:	netdev@...r.kernel.org
Cc:	David Miller <davem@...emloft.net>,
	Eric Dumazet <eric.dumazet@...il.com>, djduanjiong@...il.com,
	steffen.klassert@...unet.com, Neal Cardwell <ncardwell@...gle.com>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>
Subject: [PATCH v2] ipv6/tcp: Stop processing ICMPv6 redirect messages

Tetja Rediske found that if the host receives an ICMPv6 redirect message
after sending a SYN+ACK, the connection will be reset.

He bisected it down to 093d04d (ipv6: Change skb->data before using
icmpv6_notify() to propagate redirect), but the origin of the bug comes
from ec18d9a26 (ipv6: Add redirect support to all protocol icmp error
handlers.). The bug simply did not trigger prior to 093d04d, because
skb->data did not point to the inner IP header and thus icmpv6_notify
did not call the correct err_handler.

This patch adds the missing "goto out;" in tcp_v6_err. After receiving
an ICMPv6 Redirect, we should not continue processing the ICMP in
tcp_v6_err, as this may trigger the removal of request-socks or setting
sk_err(_soft).

Reported-by: Tetja Rediske <tetja@...ja.de>
Signed-off-by: Christoph Paasch <christoph.paasch@...ouvain.be>
---
v2: Removed code-cleanup from the patch and improved the commit-message upon 
suggestion from Eric Dumazet.

 net/ipv6/tcp_ipv6.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 1033d2b..e51bd1a 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -386,6 +386,7 @@ static void tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,

 		if (dst)
 			dst->ops->redirect(dst, sk, skb);
+		goto out;
 	}

 	if (type == ICMPV6_PKT_TOOBIG) {
-- 
1.8.1.227.g44fe835

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