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>

1 files changed, 9 insertions, 0 deletions

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 4ac5bf30e16a..5b10414e619e 100644
--- 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