net: setsockopt: fix IPV6_UNICAST_IF option for connected sockets

[ Upstream commit 526682b458b1b56d2e0db027df535cb5cdcfde59 ]

Change the behaviour of ip6_datagram_connect to consider the interface
set by the IPV6_UNICAST_IF socket option, similarly to udpv6_sendmsg.

This change is the IPv6 counterpart of the fix for IP_UNICAST_IF.
The tests introduced by that patch showed that the incorrect
behavior is present in IPv6 as well.
This patch fixes the broken test.

Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/r/202210062117.c7eef1a3-oliver.sang@intel.com
Fixes: 0e4d354762ce ("net-next: Fix IP_UNICAST_IF option behavior for connected sockets")

Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 5ecb565..ba28aeb 100644 (file)
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -42,24 +42,29 @@ static void ip6_datagram_flow_key_init(struct flowi6 *fl6, struct sock *sk)
 {
        struct inet_sock *inet = inet_sk(sk);
        struct ipv6_pinfo *np = inet6_sk(sk);
+       int oif = sk->sk_bound_dev_if;
 
        memset(fl6, 0, sizeof(*fl6));
        fl6->flowi6_proto = sk->sk_protocol;
        fl6->daddr = sk->sk_v6_daddr;
        fl6->saddr = np->saddr;
-       fl6->flowi6_oif = sk->sk_bound_dev_if;
        fl6->flowi6_mark = sk->sk_mark;
        fl6->fl6_dport = inet->inet_dport;
        fl6->fl6_sport = inet->inet_sport;
        fl6->flowlabel = np->flow_label;
        fl6->flowi6_uid = sk->sk_uid;
 
-       if (!fl6->flowi6_oif)
-               fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
+       if (!oif)
+               oif = np->sticky_pktinfo.ipi6_ifindex;
 
-       if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr))
-               fl6->flowi6_oif = np->mcast_oif;
+       if (!oif) {
+               if (ipv6_addr_is_multicast(&fl6->daddr))
+                       oif = np->mcast_oif;
+               else
+                       oif = np->ucast_oif;
+       }
 
+       fl6->flowi6_oif = oif;
        security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
 }