ipv6: don't accept multicast traffic with scope 0

v2:
a) moved before multicast source address check
b) changed comment to netdev style

Cc: Erik Hugne <erik.hugne@ericsson.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 4ac5bf3..5b10414 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -118,6 +118,15 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
            ipv6_addr_loopback(&hdr->daddr))
                goto err;
 
+       /* RFC4291 2.7
+        * Nodes must not originate a packet to a multicast address whose scope
+        * field contains the reserved value 0; if such a packet is received, it
+        * must be silently dropped.
+        */
+       if (ipv6_addr_is_multicast(&hdr->daddr) &&
+           IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 0)
+               goto err;
+
        /*
         * RFC4291 2.7
         * Multicast addresses must not be used as source addresses in IPv6