From: Florian Westphal Date: Wed, 25 Jul 2018 19:38:43 +0000 (+0200) Subject: netfilter: ip6t_rpfilter: set F_IFACE for linklocal addresses X-Git-Tag: v4.19-rc1~86^2~7^2~11 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=da786717e0894886301ed2536843c13f9e8fd53e;p=thirdparty%2Fkernel%2Flinux.git 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: 47b7e7f82802 ("netfilter: don't set F_IFACE on ipv6 fib lookups") Reported-by: Roman Mamedov Tested-by: Roman Mamedov Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- diff --git a/net/ipv6/netfilter/ip6t_rpfilter.c b/net/ipv6/netfilter/ip6t_rpfilter.c index 0fe61ede77c67..c3c6b09acdc4f 100644 --- a/net/ipv6/netfilter/ip6t_rpfilter.c +++ b/net/ipv6/netfilter/ip6t_rpfilter.c @@ -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);