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authorFlorian Westphal <fw@strlen.de>2017-04-14 20:22:43 +0200
committerDavid S. Miller <davem@davemloft.net>2017-04-17 15:09:23 -0400
commit0aa8c13eb512823bc4d60397d666a6b6260bb965 (patch)
treecb0a1a2dd8d48965f34613646c4d5b3a52c59e03
parent71947f0f91ad9c995e11c671d24bd4da5d11c0cb (diff)
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: Eric Dumazet <edumazet@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Eric Dumazet <edumazet@google.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv6/ip6_input.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index aacfb4bce153..c45b12b4431c 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -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