From e940f5d6ba6a01f8dbb870854d5205d322452730 Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Fri, 27 Jun 2014 09:57:53 +0800 Subject: [PATCH] ipv6: Fix MLD Query message check Based on RFC3810 6.2, we also need to check the hop limit and router alert option besides source address. Signed-off-by: Hangbin Liu Acked-by: YOSHIFUJI Hideaki Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv6/mcast.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 08b367c6b9cf..617f0958e164 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1301,8 +1301,17 @@ int igmp6_event_query(struct sk_buff *skb) len = ntohs(ipv6_hdr(skb)->payload_len) + sizeof(struct ipv6hdr); len -= skb_network_header_len(skb); - /* Drop queries with not link local source */ - if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) + /* RFC3810 6.2 + * Upon reception of an MLD message that contains a Query, the node + * checks if the source address of the message is a valid link-local + * address, if the Hop Limit is set to 1, and if the Router Alert + * option is present in the Hop-By-Hop Options header of the IPv6 + * packet. If any of these checks fails, the packet is dropped. + */ + if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL) || + ipv6_hdr(skb)->hop_limit != 1 || + !(IP6CB(skb)->flags & IP6SKB_ROUTERALERT) || + IP6CB(skb)->ra != htons(IPV6_OPT_ROUTERALERT_MLD)) return -EINVAL; idev = __in6_dev_get(skb->dev); -- 2.20.1