On Thu, Apr 25, 2019 at 09:43:53PM +0800, linmiaohe wrote:
> 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;
> + }
So, for the l3 device cases this makes:
#1 ip6_route_lookup() to fetch the route, using the device in xt_in()
(the _LOOSE flag is ignored for the l3 device case).
#2 If this is a l3dev master, then you make a global lookup for the
device using IP6CB(skb)->iif.
#3 You check if route matches with the device, using the new device
from the lookup:
if (rt->rt6i_idev->dev == dev ...
If there is no other way to fix this, OK, that's fair enough.
Still this fix looks a bit tricky to me.
And this assymmetric between the IPv4 and IPv6 codebase looks rare.
Probably someone can explain me this in more detail? I'd appreciate.
Thanks!
