netfilter: ip6t_rpfilter: set F_IFACE for linklocal addresses

Roman reports that DHCPv6 client no longer sees replies from server
due to

ip6tables -t raw -A PREROUTING -m rpfilter --invert -j DROP

rule.  We need to set the F_IFACE flag for linklocal addresses, they
are scoped per-device.

Fixes: 47b7e7f828 ("netfilter: don't set F_IFACE on ipv6 fib lookups")
Reported-by: Roman Mamedov <rm@romanrm.net>
Tested-by: Roman Mamedov <rm@romanrm.net>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Florian Westphal 2018-07-25 21:38:43 +02:00 committed by Pablo Neira Ayuso
parent b71ed54dc2
commit da786717e0

View File

@ -26,6 +26,12 @@ static bool rpfilter_addr_unicast(const struct in6_addr *addr)
return addr_type & IPV6_ADDR_UNICAST;
}
static bool rpfilter_addr_linklocal(const struct in6_addr *addr)
{
int addr_type = ipv6_addr_type(addr);
return addr_type & IPV6_ADDR_LINKLOCAL;
}
static bool rpfilter_lookup_reverse6(struct net *net, const struct sk_buff *skb,
const struct net_device *dev, u8 flags)
{
@ -48,7 +54,11 @@ 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)
if (rpfilter_addr_linklocal(&iph->saddr)) {
lookup_flags |= RT6_LOOKUP_F_IFACE;
fl6.flowi6_oif = dev->ifindex;
} else if ((flags & XT_RPFILTER_LOOSE) == 0)
fl6.flowi6_oif = dev->ifindex;
rt = (void *)ip6_route_lookup(net, &fl6, skb, lookup_flags);