feat(xep): Allow inline enablement of carbons

packages/moxxmpp/lib/src/negotiators/namespaces.dart

@@ -10,3 +10,4 @@ const startTlsNegotiator = 'im.moxxmpp.core.starttls';
 const sasl2Negotiator = 'org.moxxmpp.sasl.sasl2';
 const bind2Negotiator = 'org.moxxmpp.bind2';
 const saslFASTNegotiator = 'org.moxxmpp.sasl.fast';
+const carbonsNegotiator = 'org.moxxmpp.bind2.carbons';

packages/moxxmpp/lib/src/xeps/xep_0280.dart

@@ -1,3 +1,4 @@
+import 'package:logging/logging.dart';
 import 'package:meta/meta.dart';
 import 'package:moxxmpp/src/connection.dart';
 import 'package:moxxmpp/src/events.dart';
@@ -7,10 +8,15 @@ import 'package:moxxmpp/src/managers/data.dart';
 import 'package:moxxmpp/src/managers/handlers.dart';
 import 'package:moxxmpp/src/managers/namespaces.dart';
 import 'package:moxxmpp/src/namespaces.dart';
+import 'package:moxxmpp/src/negotiators/namespaces.dart';
+import 'package:moxxmpp/src/negotiators/negotiator.dart';
+import 'package:moxxmpp/src/negotiators/sasl2.dart';
 import 'package:moxxmpp/src/stanza.dart';
 import 'package:moxxmpp/src/stringxml.dart';
+import 'package:moxxmpp/src/types/result.dart';
 import 'package:moxxmpp/src/xeps/xep_0030/xep_0030.dart';
 import 'package:moxxmpp/src/xeps/xep_0297.dart';
+import 'package:moxxmpp/src/xeps/xep_0386.dart';
 
 /// This manager class implements support for XEP-0280.
 class CarbonsManager extends XmppManagerBase {
@@ -173,6 +179,16 @@ class CarbonsManager extends XmppManagerBase {
     _isEnabled = true;
   }
 
+  @internal
+  void setEnabled() {
+    _isEnabled = true;
+  }
+
+  @internal
+  void setDisabled() {
+    _isEnabled = false;
+  }
+
   /// Checks if a carbon sent by [senderJid] is valid to prevent vulnerabilities like
   /// the ones listed at https://xmpp.org/extensions/xep-0280.html#security.
   ///
@@ -185,3 +201,82 @@ class CarbonsManager extends XmppManagerBase {
             );
   }
 }
+
+class CarbonsNegotiator extends Sasl2FeatureNegotiator
+    implements Bind2FeatureNegotiator {
+  CarbonsNegotiator() : super(0, false, carbonsXmlns, carbonsNegotiator);
+
+  /// Flag indicating whether we requested to enable carbons inline (true) or not
+  /// (false).
+  bool _requestedEnablement = false;
+
+  /// Logger
+  final Logger _log = Logger('CarbonsNegotiator');
+
+  @override
+  bool canInlineFeature(List<XMLNode> features) => true;
+
+  @override
+  Future<List<XMLNode>> onSasl2FeaturesReceived(XMLNode sasl2Features) async {
+    return [];
+  }
+
+  @override
+  Future<Result<bool, NegotiatorError>> onSasl2Success(XMLNode response) async {
+    if (_requestedEnablement) {
+      final enabled = response
+          .firstTag('bound', xmlns: bind2Xmlns)
+          ?.firstTag('enabled', xmlns: carbonsXmlns);
+      final cm = attributes.getManagerById<CarbonsManager>(carbonsManager)!;
+      if (enabled != null) {
+        _log.finest('Successfully enabled Message Carbons inline');
+        cm.setEnabled();
+      } else {
+        _log.warning('Failed to enable Message Carbons inline');
+        cm.setDisabled();
+      }
+    }
+
+    return const Result(true);
+  }
+
+  @override
+  Future<Result<NegotiatorState, NegotiatorError>> negotiate(
+    XMLNode nonza,
+  ) async {
+    return const Result(NegotiatorState.done);
+  }
+
+  @override
+  Future<List<XMLNode>> onBind2FeaturesReceived(
+      List<String> bind2Features) async {
+    if (!bind2Features.contains(carbonsXmlns)) {
+      return [];
+    }
+
+    _requestedEnablement = true;
+    return [
+      XMLNode.xmlns(
+        tag: 'enable',
+        xmlns: carbonsXmlns,
+      ),
+    ];
+  }
+
+  @override
+  Future<void> postRegisterCallback() async {
+    attributes
+        .getNegotiatorById<Sasl2Negotiator>(sasl2Negotiator)
+        ?.registerNegotiator(this);
+    attributes
+        .getNegotiatorById<Bind2Negotiator>(bind2Negotiator)
+        ?.registerNegotiator(this);
+  }
+
+  @override
+  void reset() {
+    _requestedEnablement = false;
+
+    super.reset();
+  }
+}

packages/moxxmpp/test/xeps/xep_0280_test.dart

@@ -1,8 +1,11 @@
 import 'package:moxxmpp/moxxmpp.dart';
 import 'package:test/test.dart';
+import '../helpers/logging.dart';
 import '../helpers/xmpp.dart';
 
 void main() {
+  initLogger();
+
   test("Test if we're vulnerable against CVE-2020-26547 style vulnerabilities",
       () async {
     final attributes = XmppManagerAttributes(
@@ -52,4 +55,92 @@ void main() {
       false,
     );
   });
+
+  test('Test enabling message carbons inline with Bind2', () async {
+    final fakeSocket = StubTCPSocket([
+      StringExpectation(
+        "<stream:stream xmlns='jabber:client' version='1.0' xmlns:stream='http://etherx.jabber.org/streams' to='test.server' xml:lang='en'>",
+        '''
+<stream:stream
+    xmlns="jabber:client"
+    version="1.0"
+    xmlns:stream="http://etherx.jabber.org/streams"
+    from="test.server"
+    xml:lang="en">
+  <stream:features xmlns="http://etherx.jabber.org/streams">
+    <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
+      <mechanism>PLAIN</mechanism>
+    </mechanisms>
+    <authentication xmlns='urn:xmpp:sasl:2'>
+      <mechanism>PLAIN</mechanism>
+      <inline>
+        <resume xmlns="urn:xmpp:sm:3" />
+        <bind xmlns="urn:xmpp:bind:0">
+          <inline>
+            <feature var="urn:xmpp:sm:3" />
+            <feature var="urn:xmpp:carbons:2" />
+          </inline>
+        </bind>
+      </inline>
+    </authentication>
+    <bind xmlns="urn:ietf:params:xml:ns:xmpp-bind">
+      <required/>
+    </bind>
+  </stream:features>''',
+      ),
+      StanzaExpectation(
+        "<authenticate xmlns='urn:xmpp:sasl:2' mechanism='PLAIN'><user-agent id='d4565fa7-4d72-4749-b3d3-740edbf87770'><software>moxxmpp</software><device>PapaTutuWawa's awesome device</device></user-agent><initial-response>AHBvbHlub21kaXZpc2lvbgBhYWFh</initial-response><bind xmlns='urn:xmpp:bind:0'><enable xmlns='urn:xmpp:carbons:2' /></bind></authenticate>",
+        '''
+<success xmlns='urn:xmpp:sasl:2'>
+  <authorization-identifier>polynomdivision@test.server/test-resource</authorization-identifier>
+  <bound xmlns='urn:xmpp:bind:0'>
+    <enabled xmlns='urn:xmpp:carbons:2' />
+  </bound>
+</success>
+        ''',
+      ),
+    ]);
+    final conn = XmppConnection(
+      TestingReconnectionPolicy(),
+      AlwaysConnectedConnectivityManager(),
+      fakeSocket,
+    )
+      ..setConnectionSettings(
+        ConnectionSettings(
+          jid: JID.fromString('polynomdivision@test.server'),
+          password: 'aaaa',
+          useDirectTLS: true,
+        ),
+      )
+      ..setResource('test-resource', triggerEvent: false);
+    await conn.registerManagers([
+      RosterManager(TestingRosterStateManager('', [])),
+      DiscoManager([]),
+      CarbonsManager(),
+    ]);
+
+    await conn.registerFeatureNegotiators([
+      SaslPlainNegotiator(),
+      ResourceBindingNegotiator(),
+      CarbonsNegotiator(),
+      Bind2Negotiator(),
+      Sasl2Negotiator(
+        userAgent: const UserAgent(
+          id: 'd4565fa7-4d72-4749-b3d3-740edbf87770',
+          software: 'moxxmpp',
+          device: "PapaTutuWawa's awesome device",
+        ),
+      ),
+    ]);
+
+    final result = await conn.connect(
+      waitUntilLogin: true,
+      shouldReconnect: false,
+      enableReconnectOnSuccess: false,
+    );
+    expect(result.isType<NegotiatorError>(), false);
+    expect(conn.resource, 'test-resource');
+    expect(
+        conn.getManagerById<CarbonsManager>(carbonsManager)!.isEnabled, true);
+  });
 }