From: Willem de Bruijn <willemb@google.com>
Date: Wed, 17 Jun 2015 19:59:34 +0000 (-0400)
Subject: packet: avoid out of bounds read in round robin fanout
X-Git-Tag: omap-for-v4.2/fixes-rc1^2~134^2~2^2~10
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=468479e6043c84f5a65299cc07cb08a22a28c2b1;p=pandora-kernel.git

packet: avoid out of bounds read in round robin fanout

PACKET_FANOUT_LB computes f->rr_cur such that it is modulo
f->num_members. It returns the old value unconditionally, but
f->num_members may have changed since the last store. Ensure
that the return value is always < num.

When modifying the logic, simplify it further by replacing the loop
with an unconditional atomic increment.

Fixes: dc99f600698d ("packet: Add fanout support.")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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