From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934586Ab3DGW4x (ORCPT ); Sun, 7 Apr 2013 18:56:53 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46341 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934525Ab3DGWz7 (ORCPT ); Sun, 7 Apr 2013 18:55:59 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Erik Hugne" , "YOSHIFUJI Hideaki" , "David S. Miller" , "Hannes Frederic Sowa" Date: Sun, 07 Apr 2013 23:45:43 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [68/74] ipv6: don't accept node local multicast traffic from the wire In-Reply-To: X-SA-Exim-Connect-IP: 2001:470:1f08:1539:b4b3:7e2a:e2d0:3478 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.43-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Hannes Frederic Sowa [ 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 Cc: YOSHIFUJI Hideaki Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- 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