tcp: bind() fix when many ports are bound

Port autoselection done by kernel only works when number of bound
sockets is under a threshold (typically 30000).

When this threshold is over, we must check if there is a conflict before
exiting first loop in inet_csk_get_port()

Change inet_csk_bind_conflict() to forbid two reuse-enabled sockets to
bind on same (address,port) tuple (with a non ANY address)

Same change for inet6_csk_bind_conflict()

Reported-by: Gaspar Chilingarov <gasparch@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 5 deletions

diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index 628db24bcf22..b4b7d40a9c95 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -42,11 +42,16 @@ int inet6_csk_bind_conflict(const struct sock *sk,
                 if (sk != sk2 &&
                     (!sk->sk_bound_dev_if ||
                      !sk2->sk_bound_dev_if ||
-                     sk->sk_bound_dev_if == sk2->sk_bound_dev_if) &&
-                    (!sk->sk_reuse || !sk2->sk_reuse ||
-                     sk2->sk_state == TCP_LISTEN) &&
-                     ipv6_rcv_saddr_equal(sk, sk2))
-                        break;
+                     sk->sk_bound_dev_if == sk2->sk_bound_dev_if)) {
+                        if ((!sk->sk_reuse || !sk2->sk_reuse ||
+                             sk2->sk_state == TCP_LISTEN) &&
+                             ipv6_rcv_saddr_equal(sk, sk2))
+                                break;
+                        else if (sk->sk_reuse && sk2->sk_reuse &&
+                                !ipv6_addr_any(inet6_rcv_saddr(sk2)) &&
+                                ipv6_rcv_saddr_equal(sk, sk2))
+                                break;
+                }
         }
 
         return node != NULL;