[PATCH 4.14 40/61] netfilter: dont set F_IFACE on ipv6 fib lookups

From: Greg Kroah-Hartman
Date: Fri Jul 06 2018 - 01:57:28 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Florian Westphal <fw@xxxxxxxxx>

commit 47b7e7f82802dced3ac73658bf4b77584a63063f upstream.

"fib" starts to behave strangely when an ipv6 default route is
added - the FIB lookup returns a route using 'oif' in this case.

This behaviour was inherited from ip6tables rpfilter so change
this as well.

Bugzilla: https://bugzilla.netfilter.org/show_bug.cgi?id=1221
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/ipv6/netfilter/ip6t_rpfilter.c | 4 ----
net/ipv6/netfilter/nft_fib_ipv6.c | 12 ++----------
2 files changed, 2 insertions(+), 14 deletions(-)

--- a/net/ipv6/netfilter/ip6t_rpfilter.c
+++ b/net/ipv6/netfilter/ip6t_rpfilter.c
@@ -48,10 +48,6 @@ static bool rpfilter_lookup_reverse6(str
}

fl6.flowi6_mark = flags & XT_RPFILTER_VALID_MARK ? skb->mark : 0;
- if ((flags & XT_RPFILTER_LOOSE) == 0) {
- fl6.flowi6_oif = dev->ifindex;
- lookup_flags |= RT6_LOOKUP_F_IFACE;
- }

rt = (void *) ip6_route_lookup(net, &fl6, lookup_flags);
if (rt->dst.error)
--- a/net/ipv6/netfilter/nft_fib_ipv6.c
+++ b/net/ipv6/netfilter/nft_fib_ipv6.c
@@ -182,7 +182,6 @@ void nft_fib6_eval(const struct nft_expr
}

*dest = 0;
- again:
rt = (void *)ip6_route_lookup(nft_net(pkt), &fl6, lookup_flags);
if (rt->dst.error)
goto put_rt_err;
@@ -191,15 +190,8 @@ void nft_fib6_eval(const struct nft_expr
if (rt->rt6i_flags & (RTF_REJECT | RTF_ANYCAST | RTF_LOCAL))
goto put_rt_err;

- if (oif && oif != rt->rt6i_idev->dev) {
- /* multipath route? Try again with F_IFACE */
- if ((lookup_flags & RT6_LOOKUP_F_IFACE) == 0) {
- lookup_flags |= RT6_LOOKUP_F_IFACE;
- fl6.flowi6_oif = oif->ifindex;
- ip6_rt_put(rt);
- goto again;
- }
- }
+ if (oif && oif != rt->rt6i_idev->dev)
+ goto put_rt_err;

switch (priv->result) {
case NFT_FIB_RESULT_OIF: