3.2.43-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Hannes Frederic Sowa <han...@stressinduktion.org>

[ Upstream commit 1c4a154e5253687c51123956dfcee9e9dfa8542d ]

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.hu...@ericsson.com>
Cc: YOSHIFUJI Hideaki <yoshf...@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <han...@stressinduktion.org>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 net/ipv6/ip6_input.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 15295e9..6a4f4f3 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -111,6 +111,18 @@ 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

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