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Date:   Thu, 28 Feb 2019 13:02:13 -0800 (PST)
Message-Id: <20190228.130213.1481374802407995712.davem@davemloft.net>
To:     fruggeri@arista.com
Cc:     yoshfuji@linux-ipv6.org, kuznet@ms2.inr.ac.ru, maxim@arista.com,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH] net: ipv6: check net in ip6_call_ra_chain
From:   David Miller <davem@davemloft.net>
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From: fruggeri@arista.com (Francesco Ruggeri)
Date: Thu, 28 Feb 2019 11:01:46 -0800

> ip6_call_ra_chain is called when IPv6 packet with Router Alert option
> is forwarded.
> It needs to check if the net of the socket is the same as the net of the
> input device, otherwise the packet gets delivered to every IPv6 socket
> listening for Router Alerts, no matter which network namespace it is in.
> 
> Suggested-by: Maxim Martynov <maxim@arista.com>
> Signed-off-by: Maxim Martynov <maxim@arista.com>
> Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>

Right now someone using such a tool does get all RAs in the system.

Your change not only breaks them, but also gives them no method by
which to keep obtaining the same behavior.

I don't know what to do or suggest in this situation, but right now
I'm putting this patch on hold.