[PATCH 5.15 145/177] netfilter: Update ip6_route_me_harder to consider L3 domain

Greg Kroah-Hartman
2022-05-04T17:40:09Z

From: Martin Willi <martin@strongswan.org>

commit 8ddffdb9442a9d60b4a6e679ac48d7d21403a674 upstream.

The commit referenced below fixed packet re-routing if Netfilter mangles
a routing key property of a packet and the packet is routed in a VRF L3
domain. The fix, however, addressed IPv4 re-routing, only.

This commit applies the same behavior for IPv6. While at it, untangle
the nested ternary operator to make the code more readable.

Fixes: 6d8b49c3a3a3 ("netfilter: Update ip_route_me_harder to consider L3 domain")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Willi <martin@strongswan.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/netfilter.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -24,14 +24,13 @@ int ip6_route_me_harder(struct net *net,
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
struct sock *sk = sk_to_full_sk(sk_partial);
+ struct net_device *dev = skb_dst(skb)->dev;
struct flow_keys flkeys;
unsigned int hh_len;
struct dst_entry *dst;
int strict = (ipv6_addr_type(&iph->daddr) &
(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL));
struct flowi6 fl6 = {
- .flowi6_oif = sk && sk->sk_bound_dev_if ? sk->sk_bound_dev_if :
- strict ? skb_dst(skb)->dev->ifindex : 0,
.flowi6_mark = skb->mark,
.flowi6_uid = sock_net_uid(net, sk),
.daddr = iph->daddr,
@@ -39,6 +38,13 @@ int ip6_route_me_harder(struct net *net,
};
int err;

+ if (sk && sk->sk_bound_dev_if)
+ fl6.flowi6_oif = sk->sk_bound_dev_if;
+ else if (strict)
+ fl6.flowi6_oif = dev->ifindex;
+ else
+ fl6.flowi6_oif = l3mdev_master_ifindex(dev);
+
fib6_rules_early_flow_dissect(net, skb, &fl6, &flkeys);
dst = ip6_route_output(net, sk, &fl6);
err = dst->error;