From: Timo Teräs Date: Wed, 3 Mar 2010 04:01:13 +0000 (+0000) Subject: gre: fix hard header destination address checking X-Git-Tag: firefly_0821_release~9833^2~2199^2~325 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6d55cb91a0020ac0d78edcad61efd6c8cf5785a3;p=firefly-linux-kernel-4.4.55.git gre: fix hard header destination address checking ipgre_header() can be called with zero daddr when the gre device is configured as multipoint tunnel and still has the NOARP flag set (which is typically cleared by the userspace arp daemon). If the NOARP packets are not dropped, ipgre_tunnel_xmit() will take rt->rt_gateway (= NBMA IP) and use that for route look up (and may lead to bogus xfrm acquires). The multicast address check is removed as sending to multicast group should be ok. In fact, if gre device has a multicast address as destination ipgre_header is always called with multicast address. Signed-off-by: Timo Teras Signed-off-by: David S. Miller --- diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index c0c5274d0271..f47c9f76754b 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -1144,12 +1144,9 @@ static int ipgre_header(struct sk_buff *skb, struct net_device *dev, if (saddr) memcpy(&iph->saddr, saddr, 4); - - if (daddr) { + if (daddr) memcpy(&iph->daddr, daddr, 4); - return t->hlen; - } - if (iph->daddr && !ipv4_is_multicast(iph->daddr)) + if (iph->daddr) return t->hlen; return -t->hlen;