From: Schichan Nicolas <nschichan@freebox.fr>
Date: Mon, 10 Dec 2012 13:49:40 +0000 (+0100)
Subject: ARM: 7598/1: net: bpf_jit_32: fix sp-relative load/stores offsets.
X-Git-Tag: omap-for-v3.8/fixes-for-merge-window-v4-signed~53^2~1^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe15f3f1067c56820da44aa92659f2f908fd3caa;p=pandora-kernel.git

ARM: 7598/1: net: bpf_jit_32: fix sp-relative load/stores offsets.

The offset must be multiplied by 4 to be sure to access the correct
32bit word in the stack scratch space.

For instance, a store at scratch memory cell #1 was generating the
following:

st	r4, [sp, #1]

While the correct code for this is:

st	r4, [sp, #4]

To reproduce the bug (assuming your system has a NIC with the mac
address 52:54:00:12:34:56):

echo 0 > /proc/sys/net/core/bpf_jit_enable
tcpdump -ni eth0 "ether[1] + ether[2] - ether[3] * ether[4] - ether[5] \
	== -0x3AA" # this will capture packets as expected

echo 1 > /proc/sys/net/core/bpf_jit_enable
tcpdump -ni eth0 "ether[1] + ether[2] - ether[3] * ether[4] - ether[5] \
	== -0x3AA" # this will not.

This bug was present since the original inclusion of bpf_jit for ARM
(ddecdfce: ARM: 7259/3: net: JIT compiler for packet filters).

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

Reading git-diff-tree failed