fix: A certificate rejection does not crash the connection

Fixes moxxy/moxxyv2#137.

analysis_options.yaml

@@ -12,3 +12,4 @@ analyzer:
     - "**/*.g.dart"
     - "**/*.freezed.dart"
     - "test/"
+    - "integration_test/"

packages/moxxmpp/lib/src/connection.dart

@@ -796,6 +796,15 @@ class XmppConnection {
 
       _updateRoutingState(RoutingState.handleStanzas);
       await _onNegotiationsDone();
+    } else if (_currentNegotiator!.state == NegotiatorState.error) {
+      _log.severe('Negotiator returned an error');
+
+      _updateRoutingState(RoutingState.error);
+      await _setConnectionState(XmppConnectionState.error);
+      _connectionCompleter?.complete(const XmppConnectionResult(false));
+      _connectionCompleter = null;
+
+      _closeSocket();
     }
   }
 

packages/moxxmpp_socket_tcp/integration_test/badxmpp_certificate_test.dart

@@ -0,0 +1,64 @@
+import 'package:logging/logging.dart';
+import 'package:moxxmpp/moxxmpp.dart';
+import 'package:moxxmpp_socket_tcp/moxxmpp_socket_tcp.dart';
+import 'package:test/test.dart';
+
+Future<void> _runTest(String domain) async {
+  var gotTLSException = false;
+  final socket = TCPSocketWrapper(false);
+  final log = Logger('TestLogger');
+  socket.getEventStream().listen((event) {
+    if (event is XmppSocketTLSFailedEvent) {
+      log.info('Got XmppSocketTLSFailedEvent from socket');
+      gotTLSException = true;
+    }
+  });
+
+  final connection = XmppConnection(
+    ExponentialBackoffReconnectionPolicy(),
+    socket,
+  );
+  connection.registerFeatureNegotiators([
+    StartTlsNegotiator(),
+  ]);
+  connection.registerManagers([
+    DiscoManager(),
+    RosterManager(),
+    PingManager(),
+    MessageManager(),
+    PresenceManager('http://moxxmpp.example'),
+  ]);
+
+  connection.setConnectionSettings(
+    ConnectionSettings(
+      jid: JID.fromString('testuser@$domain'),
+      password: 'abc123',
+      useDirectTLS: true,
+      allowPlainAuth: true,
+    ),
+  );
+
+  final result = await connection.connectAwaitable();
+  expect(result.success, false);
+  expect(gotTLSException, true);
+}
+
+void main() {
+  Logger.root.level = Level.ALL;
+  Logger.root.onRecord.listen((record) {
+    print('${record.level.name}: ${record.time}: ${record.message}');
+  });
+
+  for (final domain in [
+    'self-signed.badxmpp.eu',
+    'expired.badxmpp.eu',
+    'wrong-name.badxmpp.eu',
+    'missing-chain.badxmpp.eu',
+    // TODO(Unknown): Technically, this one should not fail
+    //'ecdsa.badxmpp.eu',
+  ]) {
+    test('$domain with connectAwaitable', () async {
+      await _runTest(domain);
+    });
+  }
+}

packages/moxxmpp_socket_tcp/lib/moxxmpp_socket_tcp.dart

@@ -1,4 +1,5 @@
 library moxxmpp_socket_tcp;
 
+export 'src/events.dart';
 export 'src/record.dart';
 export 'src/socket.dart';

packages/moxxmpp_socket_tcp/lib/src/events.dart

@@ -0,0 +1,4 @@
+import 'package:moxxmpp/moxxmpp.dart';
+
+/// Triggered when TLS errors occur
+class XmppSocketTLSFailedEvent extends XmppSocketEvent {}

packages/moxxmpp_socket_tcp/lib/src/socket.dart

@@ -4,6 +4,7 @@ import 'dart:io';
 import 'package:logging/logging.dart';
 import 'package:meta/meta.dart';
 import 'package:moxxmpp/moxxmpp.dart';
+import 'package:moxxmpp_socket_tcp/src/events.dart';
 import 'package:moxxmpp_socket_tcp/src/record.dart';
 import 'package:moxxmpp_socket_tcp/src/rfc_2782.dart';
 
@@ -66,6 +67,7 @@ class TCPSocketWrapper extends BaseSocketWrapper {
       return false;
     }
 
+    var failedDueToTLS = false;
     results.sort(srvRecordSortComparator);
     for (final srv in results) {
       try {
@@ -91,11 +93,19 @@ class TCPSocketWrapper extends BaseSocketWrapper {
         _secure = true;
         _log.finest('Success!');
         return true;
-      } on SocketException catch(e) {
+      } on Exception catch(e) {
         _log.finest('Failure! $e');
         _ignoreSocketClosure = false;
+
+        if (e is HandshakeException) {
+          failedDueToTLS = true;
         }
       }
+    }
+
+    if (failedDueToTLS) {
+      _eventStream.add(XmppSocketTLSFailedEvent());
+    }
     
     return false;
   }
@@ -118,7 +128,7 @@ class TCPSocketWrapper extends BaseSocketWrapper {
         _ignoreSocketClosure = false;
         _log.finest('Success!');
         return true;
-      } on SocketException catch(e) {
+      } on Exception catch(e) {
         _log.finest('Failure! $e');
         _ignoreSocketClosure = false;
         continue;
@@ -142,7 +152,7 @@ class TCPSocketWrapper extends BaseSocketWrapper {
       );
       _log.finest('Success!');
       return true;
-    } on SocketException catch(e) {
+    } on Exception catch(e) {
       _log.finest('Failure! $e');
       _ignoreSocketClosure = false;
       return false;
@@ -183,8 +193,14 @@ class TCPSocketWrapper extends BaseSocketWrapper {
       _ignoreSocketClosure = false;
       _setupStreams();
       return true;
-    } on SocketException {
+    } on Exception catch (e) {
+      _log.severe('Failed to secure socket: $e');
       _ignoreSocketClosure = false;
+
+      if (e is HandshakeException) {
+        _eventStream.add(XmppSocketTLSFailedEvent());
+      }
+
       return false;
     }
   }
@@ -293,7 +309,7 @@ class TCPSocketWrapper extends BaseSocketWrapper {
 
     try {
       _socket!.write(data);
-    } on SocketException catch (e) {
+    } on Exception catch (e) {
       _log.severe(e);
       _eventStream.add(XmppSocketErrorEvent(e));
     }