Commit 66d50d25 authored Aug 02, 2010 by stephen hemminger Committed by David S. Miller Aug 02, 2010

u32: negative offset fix



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 fbc2e7d9
Author: Changli Gao <xiaosuo@gmail.com>
Date:   Wed Jun 2 07:32:42 2010 -0700

    cls_u32: use skb_header_pointer() to dereference data safely

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent eabd8ba9

net/sched/cls_u32.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -134,10 +134,12 @@ static int u32_classify(struct sk_buff skb, struct tcf_proto tp, struct tcf_re
		#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);
		if (skb_headroom(skb) + toff < 0)
		goto out;

		data = skb_header_pointer(skb, toff, 4, &_data);
		if (!data)
		goto out;