fix: Enabling carbons crashes

packages/moxxmpp/lib/src/jid.dart

@@ -1,10 +1,11 @@
 import 'package:meta/meta.dart';
 
+/// Represents a Jabber ID in parsed form.
 @immutable
 class JID {
-
   const JID(this.local, this.domain, this.resource);
 
+  /// Parses the string [jid] into a JID instance.
   factory JID.fromString(String jid) {
     // Algorithm taken from here: https://blog.samwhited.com/2021/02/xmpp-addresses/
     var localPart = '';
@@ -43,12 +44,29 @@ class JID {
   final String domain;
   final String resource;
 
+  /// Returns true if the JID is bare.
   bool isBare() => resource.isEmpty;
+
+  /// Returns true if the JID is full.
   bool isFull() => resource.isNotEmpty;
 
+  /// Converts the JID into a bare JID.
   JID toBare() => JID(local, domain, '');
+
+  /// Converts the JID into one with a resource part of [resource].
   JID withResource(String resource) => JID(local, domain, resource);
 
+  /// Compares the JID with [other]. This function assumes that JID and [other]
+  /// are bare, i.e. only the domain- and localparts are compared. If [ensureBare]
+  /// is optionally set to true, then [other] MUST be bare. Otherwise, false is returned.
+  bool bareCompare(JID other, { bool ensureBare = false }) {
+    if (ensureBare && !other.isBare()) return false;
+
+    return local == other.local && domain == other.domain;
+  }
+  
+  /// Converts to JID instance into its string representation of
+  /// localpart@domainpart/resource.
   @override
   String toString() {
     var result = '';

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

@@ -12,10 +12,17 @@ import 'package:moxxmpp/src/stringxml.dart';
 import 'package:moxxmpp/src/xeps/xep_0030/xep_0030.dart';
 import 'package:moxxmpp/src/xeps/xep_0297.dart';
 
+/// This manager class implements support for XEP-0280.
 class CarbonsManager extends XmppManagerBase {
   CarbonsManager() : super();
+
+  /// Indicates that message carbons are enabled.
   bool _isEnabled = false;
+
+  /// Indicates that the server supports message carbons.
   bool _supported = false;
+
+  /// Indicates that we know that [CarbonsManager._supported] is accurate.
   bool _gotSupported = false;
   
   @override
@@ -102,9 +109,14 @@ class CarbonsManager extends XmppManagerBase {
     );
   }
 
+  /// Send a request to the server, asking it to enable Message Carbons.
+  ///
+  /// Returns true if carbons were enabled. False, if not.
   Future<bool> enableCarbons() async {
-    final result = await getAttributes().sendStanza(
+    final attrs = getAttributes();
+    final result = await attrs.sendStanza(
       Stanza.iq(
+        to: attrs.getFullJID().toBare().toString(),
         type: 'set',
         children: [
           XMLNode.xmlns(
@@ -129,6 +141,9 @@ class CarbonsManager extends XmppManagerBase {
     return true;
   }
 
+  /// Send a request to the server, asking it to disable Message Carbons.
+  ///
+  /// Returns true if carbons were disabled. False, if not.
   Future<bool> disableCarbons() async {
     final result = await getAttributes().sendStanza(
       Stanza.iq(
@@ -164,7 +179,14 @@ class CarbonsManager extends XmppManagerBase {
     _isEnabled = true;
   }
 
+  /// 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.
+  ///
+  /// Returns true if the carbon is valid. Returns false if not.
   bool isCarbonValid(JID senderJid) {
-    return _isEnabled && senderJid == getAttributes().getConnectionSettings().jid.toBare();
+    return _isEnabled && getAttributes().getFullJID().bareCompare(
+      senderJid,
+      ensureBare: true,
+    );
   }
 }

packages/moxxmpp/test/jid_test.dart

@@ -1,6 +1,5 @@
 import 'package:moxxmpp/moxxmpp.dart';
 import 'package:test/test.dart';
-
 void main() {
   test('Parse a full JID', () {
     final jid = JID.fromString('test@server/abc');
@@ -42,4 +41,15 @@ void main() {
   test('Parse resource with a slash', () {
     expect(JID.fromString('hallo@welt.example./test/welt') == JID('hallo', 'welt.example', 'test/welt'), true);
   });
+
+  test('bareCompare', () {
+    final jid1 = JID('hallo', 'welt', 'lol');
+    final jid2 = JID('hallo', 'welt', '');
+    final jid3 = JID('hallo', 'earth', 'true');
+
+    expect(jid1.bareCompare(jid2), true);
+    expect(jid2.bareCompare(jid1), true);
+    expect(jid2.bareCompare(jid1, ensureBare: true), false);
+    expect(jid2.bareCompare(jid3), false);
+  });
 }

packages/moxxmpp/test/xeps/xep_0280_test.dart

@@ -4,33 +4,33 @@ import '../helpers/xmpp.dart';
 
 void main() {
   test("Test if we're vulnerable against CVE-2020-26547 style vulnerabilities", () async {
-      final attributes = XmppManagerAttributes(
-        sendStanza: (stanza, { StanzaFromType addFrom = StanzaFromType.full, bool addId = true, bool retransmitted = false, bool awaitable = true, bool encrypted = false }) async {
-          // ignore: avoid_print
-          print('==> ${stanza.toXml()}');
-          return XMLNode(tag: 'iq', attributes: { 'type': 'result' });
-        },
-        sendNonza: (nonza) {},
-        sendEvent: (event) {},
-        getManagerById: getManagerNullStub,
-        getConnectionSettings: () => ConnectionSettings(
-          jid: JID.fromString('bob@xmpp.example'),
-          password: 'password',
-          useDirectTLS: true,
-          allowPlainAuth: false,
-        ),
-        isFeatureSupported: (_) => false,
-        getFullJID: () => JID.fromString('bob@xmpp.example/uwu'),
-        getSocket: () => StubTCPSocket(play: []),
-        getConnection: () => XmppConnection(TestingReconnectionPolicy(), StubTCPSocket(play: [])),
-        getNegotiatorById: getNegotiatorNullStub,
-      );
-      final manager = CarbonsManager();
-      manager.register(attributes);
-      await manager.enableCarbons();
+    final attributes = XmppManagerAttributes(
+      sendStanza: (stanza, { StanzaFromType addFrom = StanzaFromType.full, bool addId = true, bool retransmitted = false, bool awaitable = true, bool encrypted = false }) async {
+        // ignore: avoid_print
+        print('==> ${stanza.toXml()}');
+        return XMLNode(tag: 'iq', attributes: { 'type': 'result' });
+      },
+      sendNonza: (nonza) {},
+      sendEvent: (event) {},
+      getManagerById: getManagerNullStub,
+      getConnectionSettings: () => ConnectionSettings(
+        jid: JID.fromString('bob@xmpp.example'),
+        password: 'password',
+        useDirectTLS: true,
+        allowPlainAuth: false,
+      ),
+      isFeatureSupported: (_) => false,
+      getFullJID: () => JID.fromString('bob@xmpp.example/uwu'),
+      getSocket: () => StubTCPSocket(play: []),
+      getConnection: () => XmppConnection(TestingReconnectionPolicy(), StubTCPSocket(play: [])),
+      getNegotiatorById: getNegotiatorNullStub,
+    );
+    final manager = CarbonsManager();
+    manager.register(attributes);
+    await manager.enableCarbons();
 
-      expect(manager.isCarbonValid(JID.fromString('mallory@evil.example')), false);
-      expect(manager.isCarbonValid(JID.fromString('bob@xmpp.example')), true);
-      expect(manager.isCarbonValid(JID.fromString('bob@xmpp.example/abc')), false);
+    expect(manager.isCarbonValid(JID.fromString('mallory@evil.example')), false);
+    expect(manager.isCarbonValid(JID.fromString('bob@xmpp.example')), true);
+    expect(manager.isCarbonValid(JID.fromString('bob@xmpp.example/abc')), false);
   });
 }