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From: Changli Gao <xiaosuo@gmail.com>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH 4/4] u32: use get_unaligned_be32
Date: Tue, 3 Aug 2010 06:34:59 +0800	[thread overview]
Message-ID: <AANLkTimNBA4E0-iX6fesYPch-N1TDgg2kD0r-tK5Mq7A@mail.gmail.com> (raw)
In-Reply-To: <20100802220113.821018357@vyatta.com>

On Tue, Aug 3, 2010 at 6:00 AM, Stephen Hemminger <shemminger@vyatta.com> 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       2010-08-01 11:21:06.945820852 -0700
> +++ b/net/sched/cls_u32.c       2010-08-01 11:24:55.257793848 -0700
> @@ -41,6 +41,7 @@
>  #include <net/netlink.h>
>  #include <net/act_api.h>
>  #include <net/pkt_cls.h>
> +#include <asm/unaligned.h>
>
>  struct tc_u_knode
>  {
> @@ -140,7 +141,7 @@ next_knode:
>                        data = skb_header_pointer(skb, toff, 4, &_data);
>                        if (!data)
>                                goto out;
> -                       if ((*data ^ key->val) & key->mask) {
> +                       if ((get_unaligned_be32(data) ^ key->val) & key->mask) {

be32()? I think it may break configuration.

>                                n = n->next;
>                                goto next_knode;
>                        }
>
>

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.


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

  reply	other threads:[~2010-08-02 22:35 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-02 22:00 [PATCH 0/4] u32 classifier fixes Stephen Hemminger
2010-08-02 22:00 ` [PATCH 1/4] net: check for reference outside of skb Stephen Hemminger
2010-08-02 22:59   ` David Miller
2010-08-02 23:11   ` Changli Gao
2010-08-02 23:21     ` Stephen Hemminger
2010-08-02 23:25       ` Changli Gao
2010-08-02 22:00 ` [PATCH 2/4] net: add likely/unlikely to skb_header_pointer Stephen Hemminger
2010-08-02 22:00 ` [PATCH 3/4] u32: allow negative offset Stephen Hemminger
2010-08-02 22:00 ` [PATCH 4/4] u32: use get_unaligned_be32 Stephen Hemminger
2010-08-02 22:34   ` Changli Gao [this message]
2010-08-02 22:45     ` Stephen Hemminger
2010-08-02 22:55       ` Ben Hutchings
2010-08-02 23:01         ` Changli Gao
2010-08-02 23:44 ` [PATCH] u32: negative offset fix Stephen Hemminger
2010-08-03  5:08   ` David Miller

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