[PATCH v3] net: netfilter: Fix rpfilter dropping vrf packets by mistake

[linmiaohe]

From: Miaohe Lin <linmiaohe@xxxxxxxxxx>

When firewalld is enabled with ipv4/ipv6 rpfilter, vrf
ipv4/ipv6 packets will be dropped because in device is
vrf but out device is an enslaved device. So failed with
the check of the rpfilter.

Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
 net/ipv4/netfilter/ipt_rpfilter.c  |  1 +
 net/ipv6/netfilter/ip6t_rpfilter.c | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c
index 0b10d8812828..6e07cd0ecbec 100644
--- a/net/ipv4/netfilter/ipt_rpfilter.c
+++ b/net/ipv4/netfilter/ipt_rpfilter.c
@@ -81,6 +81,7 @@ static bool rpfilter_mt(const struct sk_buff *skb, struct xt_action_param *par)
 	flow.flowi4_mark = info->flags & XT_RPFILTER_VALID_MARK ? skb->mark : 0;
 	flow.flowi4_tos = RT_TOS(iph->tos);
 	flow.flowi4_scope = RT_SCOPE_UNIVERSE;
+	flow.flowi4_oif = l3mdev_master_ifindex_rcu(xt_in(par));

 	return rpfilter_lookup_reverse(xt_net(par), &flow, xt_in(par), info->flags) ^ invert;
 }
diff --git a/net/ipv6/netfilter/ip6t_rpfilter.c b/net/ipv6/netfilter/ip6t_rpfilter.c
index c3c6b09acdc4..a28c81322148 100644
--- a/net/ipv6/netfilter/ip6t_rpfilter.c
+++ b/net/ipv6/netfilter/ip6t_rpfilter.c
@@ -58,7 +58,9 @@ static bool rpfilter_lookup_reverse6(struct net *net, const struct sk_buff *skb,
 	if (rpfilter_addr_linklocal(&iph->saddr)) {
 		lookup_flags |= RT6_LOOKUP_F_IFACE;
 		fl6.flowi6_oif = dev->ifindex;
-	} else if ((flags & XT_RPFILTER_LOOSE) == 0)
+	} else if (((flags & XT_RPFILTER_LOOSE) == 0) ||
+		   (netif_is_l3_master(dev)) ||
+		   (netif_is_l3_slave(dev)))
 		fl6.flowi6_oif = dev->ifindex;

 	rt = (void *)ip6_route_lookup(net, &fl6, skb, lookup_flags);
@@ -73,6 +75,12 @@ static bool rpfilter_lookup_reverse6(struct net *net, const struct sk_buff *skb,
 		goto out;
 	}

+	if (netif_is_l3_master(dev)) {
+		dev = dev_get_by_index_rcu(dev_net(dev), IP6CB(skb)->iif);
+		if (!dev)
+			goto out;
+	}
+
 	if (rt->rt6i_idev->dev == dev || (flags & XT_RPFILTER_LOOSE))
 		ret = true;
  out:
-- 
2.19.1