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

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Message-ID: <1365346942.3887.6.camel@edumazet-glaptop>
Date:	Sun, 07 Apr 2013 08:02:22 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Christoph Paasch <christoph.paasch@...ouvain.be>
Cc:	netdev@...r.kernel.org, David Miller <davem@...emloft.net>,
	djduanjiong@...il.com, steffen.klassert@...unet.com,
	Neal Cardwell <ncardwell@...gle.com>,
	Hannes Frederic Sowa <hannes@...essinduktion.org>
Subject: Re: [PATCH v2] ipv6/tcp: Stop processing ICMPv6 redirect messages

On Sun, 2013-04-07 at 16:53 +0200, Christoph Paasch wrote:
> 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) {


Thanks for sorting this out.

Acked-by: Eric Dumazet <edumazet@...gle.com>




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