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Date:	Thu, 13 Dec 2007 10:49:18 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	David Miller <davem@...emloft.net>, ilpo.jarvinen@...sinki.fi,
	netdev@...r.kernel.org
Subject: Re: [IPSEC]: Fix reversed ICMP6 policy check

On Thu, Dec 13, 2007 at 09:58:56AM +0800, Herbert Xu wrote:
>
> [IPSEC]: Fix reversed ICMP6 policy check

While that won't crash anymore, it's still logically wrong.

Here's a more complete fix.

[IPSEC]: Fix reversed ICMP6 policy check

The policy check I added for ICMP on IPv6 is reversed.  We were also
letting packets through incorrectly if the ICMP flag isn't set.  This
patch fixes that.

It also adds an skb->sp check so that unprotected packets that
fail the policy check do not crash the machine.

Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 4e3bfcd..ccdef9a 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -978,10 +978,13 @@ int icmp_rcv(struct sk_buff *skb)
 	struct icmphdr *icmph;
 	struct rtable *rt = (struct rtable *)skb->dst;
 
-	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb) &&
-	    skb->sp->xvec[skb->sp->len - 1]->props.flags & XFRM_STATE_ICMP) {
+	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 		int nh;
 
+		if (!(skb->sp && skb->sp->xvec[skb->sp->len - 1]->props.flags &
+				 XFRM_STATE_ICMP))
+			goto drop;
+
 		if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
 			goto drop;
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 478ee77..bbf4162 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -646,10 +646,13 @@ static int icmpv6_rcv(struct sk_buff *skb)
 	struct icmp6hdr *hdr;
 	int type;
 
-	if (xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb) &&
-	    skb->sp->xvec[skb->sp->len - 1]->props.flags & XFRM_STATE_ICMP) {
+	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 		int nh;
 
+		if (!(skb->sp && skb->sp->xvec[skb->sp->len - 1]->props.flags &
+				 XFRM_STATE_ICMP))
+			goto drop_no_count;
+
 		if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(*orig_hdr)))
 			goto drop_no_count;
 

Thanks,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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