[PATCH v3 net] net: ipv6: reset daddr and dport in sk if connect() fails

[Wei Wang]

From: Wei Wang <wei...@google.com>

In __ip6_datagram_connect(), reset sk->sk_v6_daddr and inet->dport if
error occurs.
In udp_v6_early_demux(), check for sk_state to make sure it is in
TCP_ESTABLISHED state.
Together, it makes sure unconnected UDP socket won't be considered as a
valid candidate for early demux.

Fixes: 5425077d73e0 ("net: ipv6: Add early demux handler for UDP unicast")

v3: add TCP_ESTABLISHED state check in udp_v6_early_demux()
v2: fix compilation error

Signed-off-by: Wei Wang <wei...@google.com>
Acked-by: Maciej Żenczykowski <m...@google.com>
---
 net/ipv6/datagram.c | 8 +++++++-
 net/ipv6/udp.c      | 3 ++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index e011122ebd43..5c786f5ab961 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -250,8 +250,14 @@ int __ip6_datagram_connect(struct sock *sk, struct 
sockaddr *uaddr,
         */
 
        err = ip6_datagram_dst_update(sk, true);
-       if (err)
+       if (err) {
+               /* Reset daddr and dport so that udp_v6_early_demux()
+                * fails to find this socket
+                */
+               memset(&sk->sk_v6_daddr, 0, sizeof(sk->sk_v6_daddr));
+               inet->inet_dport = 0;
                goto out;
+       }
 
        sk->sk_state = TCP_ESTABLISHED;
        sk_set_txhash(sk);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 2b33847bf931..d494b2621b11 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -880,7 +880,8 @@ static struct sock *__udp6_lib_demux_lookup(struct net *net,
        struct sock *sk;
 
        udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
-               if (INET6_MATCH(sk, net, rmt_addr, loc_addr, ports, dif))
+               if (sk->sk_state == TCP_ESTABLISHED &&
+                   INET6_MATCH(sk, net, rmt_addr, loc_addr, ports, dif))
                        return sk;
                /* Only check first socket in chain */
                break;
-- 
2.13.1.611.g7e3b11ae1-goog