ipv6:introduce function to find route for redirect

RFC 4861 says that the IP source address of the Redirect is the
same as the current first-hop router for the specified ICMP
Destination Address, so the gateway should be taken into
consideration when we find the route for redirect.

There was once a check in commit
a6279458c5 ("NDISC: Search over
all possible rules on receipt of redirect.") and the check
went away in commit b94f1c0904
("ipv6: Use icmpv6_notify() to propagate redirect, instead of
rt6_redirect()").

The bug is only "exploitable" on layer-2 because the source
address of the redirect is checked to be a valid link-local
address but it makes spoofing a lot easier in the same L2
domain nonetheless.

Thanks very much for Hannes's help.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Duan Jiong
2013-09-04 19:44:21 +08:00
committed by David S. Miller
parent 60cad4e67b
commit b55b76b221
6 changed files with 81 additions and 11 deletions

View File

@@ -447,7 +447,7 @@ static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
return;
if (type == NDISC_REDIRECT)
ip6_redirect(skb, net, 0, 0);
ip6_redirect(skb, net, skb->dev->ifindex, 0);
else
ip6_update_pmtu(skb, net, info, 0, 0);
xfrm_state_put(x);