Do not let lanlink connections stay open for long without authenticating

If there's no information received, close the socket to try again.

Thanks Matthias Gerstner <mgerstner@suse.de> for reporting this.

core/backends/lan/lanlinkprovider.cpp

@@ -392,6 +392,16 @@ void LanLinkProvider::newConnection()
         connect(socket, &QIODevice::readyRead,
                 this, &LanLinkProvider::dataReceived);
 
+        QTimer* timer = new QTimer(socket);
+        timer->setSingleShot(true);
+        timer->setInterval(1000);
+        connect(socket, &QSslSocket::encrypted,
+                timer, &QObject::deleteLater);
+        connect(timer, &QTimer::timeout, socket, [socket] {
+            qCWarning(KDECONNECT_CORE) << "LanLinkProvider/newConnection: Host timed out without sending any identity." << socket->peerAddress();
+            socket->disconnectFromHost();
+        });
+        timer->start();
     }
 }