[ 164/171 ] ipv6: dont accept multicast traffic with scope 0

[Steven Rostedt]

3.6.11.2 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit 20314092c1b41894d8c181bf9aa6f022be2416aa ]

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

Cc: Erik Hugne <erik.hugne@xxxxxxxxxxxx>
Cc: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 net/ipv6/ip6_input.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index b196852..db70b88 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
-- 
1.7.10.4


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