Re: [PATCH net-next v2] ipv4: Restore accept_local behaviour in fib_validate_source()

[David Miller <davem@davemloft.net>]

From: Sébastien Barré <sebastien.barre@uclouvain.be>
Date: Sun, 17 Aug 2014 09:19:54 +0200

> Commit 7a9bc9b81a5b ("ipv4: Elide fib_validate_source() completely when possible.")
> introduced a short-circuit to avoid calling fib_validate_source when not
> needed. That change took rp_filter into account, but not accept_local.
> This resulted in a change of behaviour: with rp_filter and accept_local
> off, incoming packets with a local address in the source field should be
> dropped.
> 
> Here is how to reproduce the change pre/post 7a9bc9b81a5b commit:
> -configure the same IPv4 address on hosts A and B.
> -try to send an ARP request from B to A.
> -The ARP request will be dropped before that commit, but accepted and answered
> after that commit.
> 
> This adds a check for ACCEPT_LOCAL, to maintain full
> fib validation in case it is 0. We also leave __fib_validate_source() earlier
> when possible, based on the same check as fib_validate_source(), once the
> accept_local stuff is verified.
> 
> Cc: Gregory Detal <gregory.detal@uclouvain.be>
> Cc: Christoph Paasch <christoph.paasch@uclouvain.be>
> Cc: Hannes Frederic Sowa <hannes@redhat.com>
> Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> Signed-off-by: Sébastien Barré <sebastien.barre@uclouvain.be>

Applied.