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Commit 0aa8c13e authored by Florian Westphal's avatar Florian Westphal Committed by David S. Miller
Browse files

ipv6: drop non loopback packets claiming to originate from ::1 



We lack a saddr check for ::1. This causes security issues e.g. with acls
permitting connections from ::1 because of assumption that these originate
from local machine.

Assuming a source address of ::1 is local seems reasonable.
RFC4291 doesn't allow such a source address either, so drop such packets.

Reported-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 71947f0f

net/ipv6/ip6_input.c

+5 −2
Original line number Diff line number Diff line
@@ -122,11 +122,14 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt 
			max_t(unsigned short, 1, skb_shinfo(skb)->gso_segs));

	/*

	 * RFC4291 2.5.3

	 * The loopback address must not be used as the source address in IPv6

	 * packets that are sent outside of a single node. [..]

	 * A packet received on an interface with a destination address

	 * of loopback must be dropped.

	 */

	if (!(dev->flags & IFF_LOOPBACK) &&

	    ipv6_addr_loopback(&hdr->daddr))

	if ((ipv6_addr_loopback(&hdr->saddr) ||

	     ipv6_addr_loopback(&hdr->daddr)) &&

	     !(dev->flags & IFF_LOOPBACK))

		goto err;



	/* RFC4291 Errata ID: 3480