It was possible to use a negative offset in a u32 match to reference the ethernet header or other parts of the link layer header. This fixes the regression caused by: commit fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d Author: Changli Gao Date: Wed Jun 2 07:32:42 2010 -0700 cls_u32: use skb_header_pointer() to dereference data safely Signed-off-by: Stephen Hemminger --- a/net/sched/cls_u32.c 2010-08-01 09:26:20.734923805 -0700 +++ b/net/sched/cls_u32.c 2010-08-01 09:27:09.099851764 -0700 @@ -134,10 +134,9 @@ next_knode: #endif for (i = n->sel.nkeys; i>0; i--, key++) { - unsigned int toff; + int toff = off + key->off + (off2 & key->offmask); __be32 *data, _data; - - toff = off + key->off + (off2 & key->offmask); + data = skb_header_pointer(skb, toff, 4, &_data); if (!data) goto out; -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html