[Devel] [PATCH RHEL7 COMMIT] netfilter: don't set F_IFACE on ipv6 fib lookups

[Vasily Averin]

The commit is pushed to "branch-rh7-3.10.0-1160.11.1.vz7.172.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.11.1.vz7.172.12
------>
commit 9605fb3a1d1fc56c3c18a02972a224ed301bdb17
Author: Florian Westphal <fw at strlen.de>
Date:   Fri Feb 5 14:32:34 2021 +0300

    netfilter: don't set F_IFACE on ipv6 fib lookups
    
    "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 at strlen.de>
    Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
    
    https://jira.sw.ru/browse/PSBM-125002
    (cherry picked from commit 47b7e7f82802dced3ac73658bf4b77584a63063f)
    Signed-off-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>
---
 net/ipv6/netfilter/ip6t_rpfilter.c |  4 ----
 net/ipv6/netfilter/nft_fib_ipv6.c  | 12 ++----------
 2 files changed, 2 insertions(+), 14 deletions(-)

diff --git a/net/ipv6/netfilter/ip6t_rpfilter.c b/net/ipv6/netfilter/ip6t_rpfilter.c
index 498e4b4..151aec2 100644
--- a/net/ipv6/netfilter/ip6t_rpfilter.c
+++ b/net/ipv6/netfilter/ip6t_rpfilter.c
@@ -47,10 +47,6 @@ 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) {
-		fl6.flowi6_oif = dev->ifindex;
-		lookup_flags |= RT6_LOOKUP_F_IFACE;
-	}
 
 	rt = (void *) ip6_route_lookup(net, &fl6, lookup_flags);
 	if (rt->dst.error)
diff --git a/net/ipv6/netfilter/nft_fib_ipv6.c b/net/ipv6/netfilter/nft_fib_ipv6.c
index 15af254..7f4a398 100644
--- 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 *expr, struct nft_regs *regs,
 	}
 
 	*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 *expr, struct nft_regs *regs,
 	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: