From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hangbin Liu Subject: [PATCH net] ipv6: Fix MLD Query message check Date: Tue, 24 Jun 2014 19:50:28 +0800 Message-ID: <1403610628-19676-1-git-send-email-liuhangbin@gmail.com> Cc: David Miller , Hangbin Liu To: network dev Return-path: Received: from mail-pa0-f52.google.com ([209.85.220.52]:38622 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751859AbaFXLu7 (ORCPT ); Tue, 24 Jun 2014 07:50:59 -0400 Received: by mail-pa0-f52.google.com with SMTP id eu11so159211pac.25 for ; Tue, 24 Jun 2014 04:50:58 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: 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 --- net/ipv6/mcast.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 08b367c..fdf7455 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1301,8 +1301,18 @@ 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 || + ipv6_hdr(skb)->nexthdr != NEXTHDR_HOP || + !(IP6CB(skb)->flags & IP6SKB_ROUTERALERT) || + IP6CB(skb)->ra != htons(IPV6_OPT_ROUTERALERT_MLD)) return -EINVAL; idev = __in6_dev_get(skb->dev); -- 1.8.1.4