From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Date: Wed, 12 Jan 2011 08:34:08 +0000 (+0000)
Subject: inet6: prevent network storms caused by linux IPv6 routers
X-Git-Tag: v2.6.37.1~134
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3e7e81d9e842ba49fbe4abdc173fac61c9b14181;p=karo-tx-linux.git

inet6: prevent network storms caused by linux IPv6 routers

[ Upstream commit 72b43d0898e97f588293b4a24b33c58c46633d81 ]

Linux IPv6 forwards unicast packets, which are link layer multicasts...
The hole was present since day one. I was 100% this check is there, but it is not.

The problem shows itself, f.e. when Microsoft Network Load Balancer runs on a network.
This software resolves IPv6 unicast addresses to multicast MAC addresses.

Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 94b5bf132b2e..5f8d242be3f3 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -401,6 +401,9 @@ int ip6_forward(struct sk_buff *skb)
 		goto drop;
 	}
 
+	if (skb->pkt_type != PACKET_HOST)
+		goto drop;
+
 	skb_forward_csum(skb);
 
 	/*