From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 20 Mar 2011 14:40:06 +0000 (+0100)
Subject: netfilter: xtables: fix reentrancy
X-Git-Tag: v2.6.39-rc1~390^2~13^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=db856674ac69e31946e56085239757cca3f7655f;p=pandora-kernel.git

netfilter: xtables: fix reentrancy

commit f3c5c1bfd4308 (make ip_tables reentrant) introduced a race in
handling the stackptr restore, at the end of ipt_do_table()

We should do it before the call to xt_info_rdunlock_bh(), or we allow
cpu preemption and another cpu overwrites stackptr of original one.

A second fix is to change the underflow test to check the origptr value
instead of 0 to detect underflow, or else we allow a jump from different
hooks.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
---

Reading git-diff-tree failed