From mboxrd@z Thu Jan  1 00:00:00 1970
From: Changli Gao <xiaosuo@gmail.com>
Subject: Re: [PATCH 4/4] u32: use get_unaligned_be32
Date: Tue, 3 Aug 2010 06:34:59 +0800
Message-ID: <AANLkTimNBA4E0-iX6fesYPch-N1TDgg2kD0r-tK5Mq7A@mail.gmail.com>
References: <20100802220030.991706005@vyatta.com> <20100802220113.821018357@vyatta.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
To: Stephen Hemminger <shemminger@vyatta.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from mail-ww0-f42.google.com ([74.125.82.42]:48175 "EHLO
	mail-ww0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753109Ab0HBWfV convert rfc822-to-8bit (ORCPT
	<rfc822;netdev@vger.kernel.org>); Mon, 2 Aug 2010 18:35:21 -0400
Received: by wwf26 with SMTP id 26so212888wwf.1
        for <netdev@vger.kernel.org>; Mon, 02 Aug 2010 15:35:19 -0700 (PDT)
In-Reply-To: <20100802220113.821018357@vyatta.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

On Tue, Aug 3, 2010 at 6:00 AM, Stephen Hemminger <shemminger@vyatta.co=
m> wrote:
> U32 classifier reads data from packet at a offset passed in from
> user space. The offset should be aligned, but it is unsafe practice
> to depend on values from userspace.
>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> --- a/net/sched/cls_u32.c =A0 =A0 =A0 2010-08-01 11:21:06.945820852 -=
0700
> +++ b/net/sched/cls_u32.c =A0 =A0 =A0 2010-08-01 11:24:55.257793848 -=
0700
> @@ -41,6 +41,7 @@
> =A0#include <net/netlink.h>
> =A0#include <net/act_api.h>
> =A0#include <net/pkt_cls.h>
> +#include <asm/unaligned.h>
>
> =A0struct tc_u_knode
> =A0{
> @@ -140,7 +141,7 @@ next_knode:
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0data =3D skb_header_po=
inter(skb, toff, 4, &_data);
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0if (!data)
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0goto o=
ut;
> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if ((*data ^ key->val) =
& key->mask) {
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if ((get_unaligned_be32=
(data) ^ key->val) & key->mask) {

be32()? I think it may break configuration.

> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0n =3D =
n->next;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0goto n=
ext_knode;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0}
>
>

Please refer to the comment from David about get_unaligned()
http://www.spinics.net/lists/netdev/msg131765.html .  And there are
more than one get_unaligned() needed. Thanks.


--=20
Regards,
Changli Gao(xiaosuo@gmail.com)