linux-kernel - Re: [PATCH v2 1/1] netfilter: nf_tables: fib: Drop IPV6 packages if IPv6 is disabled on boot

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Date:   Thu, 29 Aug 2019 17:29:51 -0300
From:   Leonardo Bras <leonardo@...ux.ibm.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>
Cc:     netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jozsef Kadlecsik <kadlec@...filter.org>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>
Subject: Re: [PATCH v2 1/1] netfilter: nf_tables: fib: Drop IPV6 packages if
 IPv6 is disabled on boot

On Thu, 2019-08-29 at 17:04 -0300, Leonardo Bras wrote:
> > Thats a good point -- Leonardo, is the
> > "net.bridge.bridge-nf-call-ip6tables" sysctl on?
> 
> Running
> # sudo sysctl -a
> I can see:
> net.bridge.bridge-nf-call-ip6tables = 1

Also, doing
# echo 0 >  /proc/sys/net/bridge/bridge-nf-call-ip6tables 
And then trying to boot the guest will not crash the host.

Which would make sense, since host iptables is not dealing with guest
IPv6 packets.

So, the real cause of this bug is the bridge making host ip6tables deal
with guest IPv6 packets ? 
If so, would it be ok if write a patch testing ipv6_mod_enabled()
before passing guest ipv6 packets to host ip6tables? 


Best regards,

>  
> So this packets are sent to host iptables for processing?
> 
> 
> (Sorry for the delay, I did not received the previous e-mails.
> Please include me in to/cc.)

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