From a858bb28dcb30932271c46db3615a50075c1fba9 Mon Sep 17 00:00:00 2001 From: Vincent Bernat Date: Sun, 20 May 2018 13:03:38 +0200 Subject: [PATCH] netfilter: ip6t_rpfilter: provide input interface for route lookup BugLink: http://bugs.launchpad.net/bugs/1808185 commit cede24d1b21d68d84ac5a36c44f7d37daadcc258 upstream. In commit 47b7e7f82802, this bit was removed at the same time the RT6_LOOKUP_F_IFACE flag was removed. However, it is needed when link-local addresses are used, which is a very common case: when packets are routed, neighbor solicitations are done using link-local addresses. For example, the following neighbor solicitation is not matched by "-m rpfilter": IP6 fe80::5254:33ff:fe00:1 > ff02::1:ff00:3: ICMP6, neighbor solicitation, who has 2001:db8::5254:33ff:fe00:3, length 32 Commit 47b7e7f82802 doesn't quite explain why we shouldn't use RT6_LOOKUP_F_IFACE in the rpfilter case. I suppose the interface check later in the function would make it redundant. However, the remaining of the routing code is using RT6_LOOKUP_F_IFACE when there is no source address (which matches rpfilter's case with a non-unicast destination, like with neighbor solicitation). Signed-off-by: Vincent Bernat Fixes: 47b7e7f82802 ("netfilter: don't set F_IFACE on ipv6 fib lookups") Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Khalid Elmously --- net/ipv6/netfilter/ip6t_rpfilter.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/netfilter/ip6t_rpfilter.c b/net/ipv6/netfilter/ip6t_rpfilter.c index 3119e720a6c8..1c4a5de3f301 100644 --- a/net/ipv6/netfilter/ip6t_rpfilter.c +++ b/net/ipv6/netfilter/ip6t_rpfilter.c @@ -48,6 +48,8 @@ static bool rpfilter_lookup_reverse6(struct net *net, const struct sk_buff *skb, } fl6.flowi6_mark = flags & XT_RPFILTER_VALID_MARK ? skb->mark : 0; + if ((flags & XT_RPFILTER_LOOSE) == 0) + fl6.flowi6_oif = dev->ifindex; rt = (void *) ip6_route_lookup(net, &fl6, lookup_flags); if (rt->dst.error) -- 2.39.2