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-rw-r--r--net/ipv6/mcast.c13
1 files 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);