From 1dced6a854827eb5683f3c57ddbb4595daf145e4 Mon Sep 17 00:00:00 2001
From: =?utf8?q?S=C3=A9bastien=20Barr=C3=A9?= <sebastien.barre@uclouvain.be>
Date: Sun, 17 Aug 2014 09:19:54 +0200
Subject: [PATCH] ipv4: Restore accept_local behaviour in fib_validate_source()
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
Reading git-format-patch failed