af-packet: fix oops when socket is not present
authorEric Leblond <eric@regit.org>
Tue, 6 Nov 2012 02:10:10 +0000 (02:10 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 17 Nov 2012 21:16:20 +0000 (13:16 -0800)
commit0f2835b0b762391fb8e1d1da3bdb8f1d90a5d53e
treedddb1503e28d2959af3202657f13a958e3da78f8
parentecdebbf0aedbedc96ee784046d06d0be8152d5a4
af-packet: fix oops when socket is not present

[ Upstream commit a3d744e995d2b936c500585ae39d99ee251c89b4 ]

Due to a NULL dereference, the following patch is causing oops
in normal trafic condition:

commit c0de08d04215031d68fa13af36f347a6cfa252ca
Author: Eric Leblond <eric@regit.org>
Date:   Thu Aug 16 22:02:58 2012 +0000

    af_packet: don't emit packet on orig fanout group

This buggy patch was a feature fix and has reached most stable
branches.

When skb->sk is NULL and when packet fanout is used, there is a
crash in match_fanout_group where skb->sk is accessed.
This patch fixes the issue by returning false as soon as the
socket is NULL: this correspond to the wanted behavior because
the kernel as to resend the skb to all the listening socket in
this case.

Signed-off-by: Eric Leblond <eric@regit.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/core/dev.c