ipv4: Restore accept_local behaviour in fib_validate_source()
Commit 7a9bc9b8 ("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 7a9bc9b8 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>
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