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

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Message-ID: <daa9f83eaeba2ce41a72ac2fa23e24817ef3d4a1.camel@linux.ibm.com>
Date:   Fri, 30 Aug 2019 11:15:22 -0300
From:   Leonardo Bras <leonardo@...ux.ibm.com>
To:     Florian Westphal <fw@...len.de>
Cc:     Pablo Neira Ayuso <pablo@...filter.org>,
        "David S. Miller" <davem@...emloft.net>,
        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 22:58 +0200, Florian Westphal wrote:
> In any case your patch looks ok to me.

Great! Please give your feedback on v3: 
http://patchwork.ozlabs.org/patch/1154040/

[...]
> 
> Even if we disable call-ip6tables in br_netfilter we will at least
> in addition need a patch for nft_fib_netdev.c.
> 
> From a "avoid calls to ipv6 stack when its disabled" standpoint,
> the safest fix is to disable call-ip6tables functionality if ipv6
> module is off *and* fix nft_fib_netdev.c to BREAK in ipv6 is off case.
> 
> I started to place a list of suspicous modules here, but that got out
> of hand quickly.
> 
> So, given I don't want to plaster ipv6_mod_enabled() everywhere, I
> would suggest this course of action:
> 
> 1. add a patch to BREAK in nft_fib_netdev.c for !ipv6_mod_enabled()
> 2. change net/bridge/br_netfilter_hooks.c, br_nf_pre_routing() to
>    make sure ipv6_mod_enabled() is true before doing the ipv6 stack
>    "emulation".
> 
> Makes sense?
IMHO sure.

Shortly, I will send a couple patches proposing the above changes.
(Or my best understanding about them :) ) 

> 
> Thanks,
> Florian

Thank you,
Leonardo Bras

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