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From: jamal <hadi@cyberus.ca>
To: Changli Gao <xiaosuo@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH] cls_u32: use skb_copy_bits() to dereference data safely
Date: Wed, 02 Jun 2010 08:25:38 -0400	[thread overview]
Message-ID: <1275481538.14363.10.camel@bigi> (raw)
In-Reply-To: <1275481219.14363.6.camel@bigi>

On Wed, 2010-06-02 at 08:21 -0400, jamal wrote:

> Can we make the fix very simple please? i.e no copy bits, this is the
> fast path.

Example, something along lines of:

---
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 9627542..dde7a23 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -135,6 +135,9 @@ next_knode:
 
 for (i = n->sel.nkeys; i>0; i--, key++) {
 
+        int toff = key->off+(off2&key->offmask)- 4;
+        if (unlikely(toff > skb->len))
+              /* bailout here - needs some thought */
         if ((*(__be32*)(ptr+key->off+(off2&key->offmask))^key->v
             n = n->next;
             goto next_knode;
----


cheers,
jamal


  reply	other threads:[~2010-06-02 12:25 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-31  2:24 [PATCH] cls_u32: use skb_copy_bits() to dereference data safely Changli Gao
2010-06-01 12:34 ` jamal
2010-06-01 17:47   ` Changli Gao
2010-06-02 12:20     ` jamal
2010-06-02 12:25       ` jamal [this message]
2010-06-02 12:45         ` David Miller
2010-06-02 13:14           ` Changli Gao
2010-06-02 13:27             ` David Miller
2010-06-02 13:36             ` jamal
2010-06-02 13:43               ` Changli Gao
2010-06-02 13:48                 ` jamal
2010-06-02 13:43               ` David Miller
2010-06-02 13:47                 ` jamal
2010-06-02 12:47       ` David Miller
2010-06-02 13:17       ` Changli Gao

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