ksmbd: off ipv6only for both ipv4/ipv6 binding

ΕΛΕΝΗ reported that ksmbd binds to the IPV6 wildcard (::) by default for
ipv4 and ipv6 binding. So IPV4 connections are successful only when
the Linux system parameter bindv6only is set to 0 [default value].
If this parameter is set to 1, then the ipv6 wildcard only represents
any IPV6 address. Samba creates different sockets for ipv4 and ipv6
by default. This patch off sk_ipv6only to support IPV4/IPV6 connections
without creating two sockets.

Cc: stable@vger.kernel.org
Reported-by: ΕΛΕΝΗ ΤΖΑΒΕΛΛΑ <helentzavellas@yahoo.gr>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/transport_tcp.c

@@ -448,6 +448,10 @@ static int create_socket(struct interface *iface)
 		sin6.sin6_family = PF_INET6;
 		sin6.sin6_addr = in6addr_any;
 		sin6.sin6_port = htons(server_conf.tcp_port);
+
+		lock_sock(ksmbd_socket->sk);
+		ksmbd_socket->sk->sk_ipv6only = false;
+		release_sock(ksmbd_socket->sk);
 	}
 
 	ksmbd_tcp_nodelay(ksmbd_socket);