4.18-stable review patch. If anyone has any objections, please let me know.
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From: Florian Westphal fw@strlen.de
[ Upstream commit da786717e0894886301ed2536843c13f9e8fd53e ]
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 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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/netfilter/ip6t_rpfilter.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
--- a/net/ipv6/netfilter/ip6t_rpfilter.c +++ b/net/ipv6/netfilter/ip6t_rpfilter.c @@ -26,6 +26,12 @@ static bool rpfilter_addr_unicast(const 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(str }
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);