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ipv6: drop packets when source address is multicast

PATCH Applied Brian Haley 2 participants 2 messages Nov 8, 2011

Subsystems (3)
Networking Network drivers IPv4/IPv6
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Brian Haley

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PATCH 1/1 ipv6: drop packets when source address is multicast

RFC 4291 Section 2.7 says Multicast addresses must not be used as source addresses in IPv6 packets - drop them on input so we don't process the packet further.

Signed-off-by Brian Haley <[email protected]>
Reported-and-Tested-by Kumar Sanghvi <[email protected]>
net/ipv6/ip6_input.c +8 -0
index 027c7ff..a46c64e 100644
@@ -111,6 +111,14 @@ 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
+	 * Multicast addresses must not be used as source addresses in IPv6
+	 * packets or appear in any Routing header.
+	 */
+	if (ipv6_addr_is_multicast(&hdr->saddr))
+		goto err;
+
 	skb->transport_header = skb->network_header + sizeof(*hdr);
 	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);