Commit 1c4a154e authored Mar 26, 2013 by Hannes Frederic Sowa Committed by David S. Miller Mar 29, 2013

ipv6: don't accept node local multicast traffic from the wire

Erik Hugne's errata proposal (Errata ID: 3480) to RFC4291 has been
verified: http://www.rfc-editor.org/errata_search.php?eid=3480



We have to check for pkt_type and loopback flag because either the
packets are allowed to travel over the loopback interface (in which case
pkt_type is PACKET_HOST and IFF_LOOPBACK flag is set) or they travel
over a non-loopback interface back to us (in which case PACKET_TYPE is
PACKET_LOOPBACK and IFF_LOOPBACK flag is not set).

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

parent 74f9f42c

net/ipv6/ip6_input.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -118,6 +118,18 @@ int ipv6_rcv(struct sk_buff skb, struct net_device dev, struct packet_type *pt
		ipv6_addr_loopback(&hdr->daddr))
		goto err;

		/* RFC4291 Errata ID: 3480
		* Interface-Local scope spans only a single interface on a
		* node and is useful only for loopback transmission of
		* multicast. Packets with interface-local scope received
		* from another node must be discarded.
		*/
		if (!(skb->pkt_type == PACKET_LOOPBACK \|\|
		dev->flags & IFF_LOOPBACK) &&
		ipv6_addr_is_multicast(&hdr->daddr) &&
		IPV6_ADDR_MC_SCOPE(&hdr->daddr) == 1)
		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