netdev - Re: [PATCH v2] netfilter: SYNPROXY: fix process non tcp packet bug in {ipv4,ipv6}_synproxy

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Message-ID: <20171003133206.GA19459@salvia>
Date:   Tue, 3 Oct 2017 15:32:06 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     Lin Zhang <xiaolou4617@...il.com>
Cc:     kadlec@...ckhole.kfki.hu, fw@...len.de, davem@...emloft.net,
        kuznet@....inr.ac.ru, yoshfuji@...ux-ipv6.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH v2] netfilter: SYNPROXY: fix process non tcp packet bug
 in {ipv4,ipv6}_synproxy_hook

On Tue, Oct 03, 2017 at 03:28:25PM +0200, Pablo Neira Ayuso wrote:
> On Sat, Sep 30, 2017 at 06:25:15PM +0800, Lin Zhang wrote:
> > In function {ipv4,ipv6}_synproxy_hook we expect a normal tcp packet,
> > but the real server maybe reply an icmp error packet related to the 
> > exist tcp conntrack, so we will access wrong tcp data.
> > 
> > For fix it, check for the protocol field and only process tcp traffic.
> 
> Applied, thanks.
> 
> I have made minor comestic changes to patch title:
> 
> netfilter: SYNPROXY: skip non-TCP packets from {ipv4,ipv6}_synproxy_hook
> 
> for the record.

I have to keep this back, sorry.

This has been not compiled tested.

net/ipv6/netfilter/ip6t_SYNPROXY.c: In function ‘ipv6_synproxy_hook’:
net/ipv6/netfilter/ip6t_SYNPROXY.c:351:19: error: ‘struct ipv6hdr’ has
no member named ‘protocol’
      ipv6_hdr(skb)->protocol != IPPROTO_TCP)
                   ^