10 changed files with 32 additions and 412 deletions
--- a/lib/src/omemo/ratchet_map_key.dart
+++ b/lib/src/omemo/ratchet_map_key.dart
@ -4,24 +4,9 @@ import 'package:meta/meta.dart';
 class RatchetMapKey {

  const RatchetMapKey(this.jid, this.deviceId);
-
-  factory RatchetMapKey.fromJsonKey(String key) {
-    final parts = key.split(':');
-    final deviceId = int.parse(parts.first);
-
-    return RatchetMapKey(
-      parts.sublist(1).join(':'),
-      deviceId,
-    );
-  }
-
  final String jid;
  final int deviceId;

-  String toJsonKey() {
-    return '$deviceId:$jid';
-  }
-  
  @override
  bool operator ==(Object other) {
    return other is RatchetMapKey && jid == other.jid && deviceId == other.deviceId;
--- a/lib/src/omemo/sessionmanager.dart
+++ b/lib/src/omemo/sessionmanager.dart
@ -177,17 +177,15 @@ class OmemoSessionManager {
    // Pick the correct SPK
    final device = await getDevice();
    OmemoKeyPair? spk;
-
-    await _lock.synchronized(() async {
-      if (kex.spkId == _device.spkId) {
-        spk = _device.spk;
-      } else if (kex.spkId == _device.oldSpkId) {
-        spk = _device.oldSpk;
-      }
-    });
-    if (spk == null) {
+    if (kex.spkId == device.spkId) {
+      spk = device.spk;
+    } else if (kex.spkId == device.oldSpkId) {
+      spk = device.oldSpk;
+    } else {
      throw UnknownSignedPrekeyException();
    }
+
+    assert(spk != null, 'The used SPK must be found');
    
    final kexResult = await x3dhFromInitialMessage(
      X3DHMessage(
@ -200,7 +198,7 @@ class OmemoSessionManager {
      device.ik,
    );
    final ratchet = await OmemoDoubleRatchet.acceptNewSession(
-      spk!,
+      spk,
      OmemoPublicKey.fromBytes(kex.ik!, KeyPairType.ed25519),
      kexResult.sk,
      kexResult.ad,
@ -299,25 +297,6 @@ class OmemoSessionManager {
    );
  }

-  /// In case a decryption error occurs, the Double Ratchet spec says to just restore
-  /// the ratchet to its old state. As such, this function restores the ratchet at
-  /// [mapKey] with [oldRatchet].
-  Future<void> _restoreRatchet(RatchetMapKey mapKey, OmemoDoubleRatchet oldRatchet) async {
-    await _lock.synchronized(() {
-      print('RESTORING RATCHETS');
-      _ratchetMap[mapKey] = oldRatchet;
-
-      // Commit the ratchet
-      _eventStreamController.add(
-        RatchetModifiedEvent(
-          mapKey.jid,
-          mapKey.deviceId,
-          oldRatchet,
-        ),
-      );
-    });
-  }
-  
  /// Attempt to decrypt [ciphertext]. [keys] refers to the <key /> elements inside the
  /// <keys /> element with a "jid" attribute matching our own. [senderJid] refers to the
  /// bare Jid of the sender. [senderDeviceId] refers to the "sid" attribute of the
@ -335,15 +314,9 @@ class OmemoSessionManager {
      throw NotEncryptedForDeviceException();
    }

-    final ratchetKey = RatchetMapKey(senderJid, senderDeviceId);
    final decodedRawKey = base64.decode(rawKey.value);
    OmemoAuthenticatedMessage authMessage;
-    OmemoDoubleRatchet? oldRatchet;
    if (rawKey.kex) {
-      // If the ratchet already existed, we store it. If it didn't, oldRatchet will stay
-      // null.
-      oldRatchet = await _getRatchet(ratchetKey);
-
      // TODO(PapaTutuWawa): Only do this when we should
      final kex = OmemoKeyExchange.fromBuffer(decodedRawKey);
      await _addSessionFromKeyExchange(
@ -374,38 +347,31 @@ class OmemoSessionManager {
    }

    final message = OmemoMessage.fromBuffer(authMessage.message!);
+    final ratchetKey = RatchetMapKey(senderJid, senderDeviceId);
    List<int>? keyAndHmac;
-    // We can guarantee that the ratchet exists at this point in time
-    final ratchet = (await _getRatchet(ratchetKey))!;
-    oldRatchet ??= ratchet ;
-
-    try {
+    await _lock.synchronized(() async {
+      final ratchet = _ratchetMap[ratchetKey]!;
      if (rawKey.kex) {
        keyAndHmac = await ratchet.ratchetDecrypt(message, authMessage.writeToBuffer());
      } else {
        keyAndHmac = await ratchet.ratchetDecrypt(message, decodedRawKey);
      }
-    } on InvalidMessageHMACException {
-      await _restoreRatchet(ratchetKey, oldRatchet);
-      rethrow;
-    }

-    // Commit the ratchet
-    _eventStreamController.add(RatchetModifiedEvent(senderJid, senderDeviceId, ratchet));
+      // Commit the ratchet
+      _eventStreamController.add(RatchetModifiedEvent(senderJid, senderDeviceId, ratchet));
+    });

    // Empty OMEMO messages should just have the key decrypted and/or session set up.
    if (ciphertext == null) {
      return null;
    }
    
-    final key = keyAndHmac.sublist(0, 32);
-    final hmac = keyAndHmac.sublist(32, 48);
+    final key = keyAndHmac!.sublist(0, 32);
+    final hmac = keyAndHmac!.sublist(32, 48);
    final derivedKeys = await deriveEncryptionKeys(key, omemoPayloadInfoString);

    final computedHmac = await truncatedHmac(ciphertext, derivedKeys.authenticationKey);
    if (!listsEqual(hmac, computedHmac)) {
-      // TODO(PapaTutuWawa): I am unsure if we should restore the ratchet here
-      await _restoreRatchet(ratchetKey, oldRatchet);
      throw InvalidMessageHMACException();
    }
    
@ -475,24 +441,6 @@ class OmemoSessionManager {
    });
  }

-  /// Removes all ratchets for Jid [jid]. Triggers a DeviceMapModified event at the end and an
-  /// RatchetRemovedEvent for each ratchet.
-  Future<void> removeAllRatchets(String jid) async {
-    await _lock.synchronized(() async {
-      for (final deviceId in _deviceMap[jid]!) {
-        // Remove the ratchet
-        _ratchetMap.remove(RatchetMapKey(jid, deviceId));
-        // Commit it
-        _eventStreamController.add(RatchetRemovedEvent(jid, deviceId));
-      }
-
-      // Remove the device from jid
-      _deviceMap.remove(jid);
-      // Commit it
-      _eventStreamController.add(DeviceMapModifiedEvent(_deviceMap));
-    });
-  }
-  
  /// Returns the list of device identifiers belonging to [jid] that are yet unacked, i.e.
  /// we have not yet received an empty OMEMO message from.
  Future<List<int>?> getUnacknowledgedRatchets(String jid) async {
@ -548,12 +496,6 @@ class OmemoSessionManager {
      _eventStreamController.add(DeviceModifiedEvent(_device));
    });
  }
-
-  Future<OmemoDoubleRatchet?> _getRatchet(RatchetMapKey key) async {
-    return _lock.synchronized(() async {
-      return _ratchetMap[key];
-    });
-  }
  
  @visibleForTesting
  OmemoDoubleRatchet getRatchet(String jid, int deviceId) => _ratchetMap[RatchetMapKey(jid, deviceId)]!;
--- a/lib/src/protobuf/protobuf.dart
+++ b/lib/src/protobuf/protobuf.dart
@ -46,18 +46,21 @@ List<int> encodeVarint(int i) {
  assert(i >= 0, "Two's complement is not implemented");
  final ret = List<int>.empty(growable: true);

-  // Thanks to https://github.com/hathibelagal-dev/LEB128 for the trick with toRadixString!
-  final numSevenBlocks = (i.toRadixString(2).length / 7).ceil();
-  for (var j = 0; j < numSevenBlocks; j++) {
+  var j = 0;
+  while (true) {
    // The 7 LSB of the byte we're creating
    final x = (i & (lsb7Mask << j * 7)) >> j * 7;
+    // The next bits
+    final next = i & (lsb7Mask << (j + 1) * 7);

-    if (j == numSevenBlocks - 1) {
+    if (next == 0) {
      // If we were to shift further, we only get zero, so we're at the end
      ret.add(x);
+      break;
    } else {
      // We still have at least one bit more to go, so set the MSB to 1
      ret.add(x + msb);
+      j++;
    }
  }

--- a/lib/src/trust/always.dart
+++ b/lib/src/trust/always.dart
@ -17,7 +17,4 @@ class AlwaysTrustingTrustManager extends TrustManager {

  @override
  Future<void> setEnabled(String jid, int deviceId, bool enabled) async {}
-
-  @override
-  Future<Map<String, dynamic>> toJson() async => <String, dynamic>{};
 }
--- a/lib/src/trust/base.dart
+++ b/lib/src/trust/base.dart
@ -16,7 +16,4 @@ abstract class TrustManager {
  /// Mark the device with id [deviceId] of Jid [jid] as enabled if [enabled] is true or as disabled
  /// if [enabled] is false.
  Future<void> setEnabled(String jid, int deviceId, bool enabled);
-
-  /// Serialize the trust manager to JSON.
-  Future<Map<String, dynamic>> toJson();
 }
--- a/lib/src/trust/btbv.dart
+++ b/lib/src/trust/btbv.dart
@ -8,52 +8,29 @@ import 'package:synchronized/synchronized.dart';
 /// - blindTrust: The fingerprint is not verified using OOB means
 /// - verified: The fingerprint has been verified using OOB means
 enum BTBVTrustState {
-  notTrusted, // = 1
-  blindTrust, // = 2
-  verified,   // = 3
-}
-
-int _trustToInt(BTBVTrustState state) {
-  switch (state) {
-    case BTBVTrustState.notTrusted: return 1;
-    case BTBVTrustState.blindTrust: return 2;
-    case BTBVTrustState.verified:   return 3;
-  }
-}
-
-BTBVTrustState _trustFromInt(int i) {
-  switch (i) {
-    case 1: return BTBVTrustState.notTrusted;
-    case 2: return BTBVTrustState.blindTrust;
-    case 3: return BTBVTrustState.verified;
-    default: return BTBVTrustState.notTrusted;
-  }
+  notTrusted,
+  blindTrust,
+  verified,
 }

 /// A TrustManager that implements the idea of Blind Trust Before Verification.
 /// See https://gultsch.de/trust.html for more details.
 abstract class BlindTrustBeforeVerificationTrustManager extends TrustManager {
-  BlindTrustBeforeVerificationTrustManager({
-    Map<RatchetMapKey, BTBVTrustState>? trustCache,
-    Map<RatchetMapKey, bool>? enablementCache,
-    Map<String, List<int>>? devices,
-  }) : trustCache = trustCache ?? {},
-       enablementCache = enablementCache ?? {},
-       devices = devices ?? {},
-       _lock = Lock();
+  BlindTrustBeforeVerificationTrustManager()
+    : trustCache = {},
+      enablementCache = {},
+      devices = {},
+      _lock = Lock();

  /// The cache for mapping a RatchetMapKey to its trust state
-  @visibleForTesting
  @protected
  final Map<RatchetMapKey, BTBVTrustState> trustCache;

  /// The cache for mapping a RatchetMapKey to whether it is enabled or not
-  @visibleForTesting
  @protected
  final Map<RatchetMapKey, bool> enablementCache;
  
  /// Mapping of Jids to their device identifiers
-  @visibleForTesting
  @protected
  final Map<String, List<int>> devices;

@ -164,50 +141,6 @@ abstract class BlindTrustBeforeVerificationTrustManager extends TrustManager {
    // Commit the state
    await commitState();
  }
-
-  @override
-  Future<Map<String, dynamic>> toJson() async {
-    return {
-      'devices': devices,
-      'trust': trustCache.map((key, value) => MapEntry(
-        key.toJsonKey(), _trustToInt(value),
-      ),),
-      'enable': enablementCache.map((key, value) => MapEntry(key.toJsonKey(), value)),
-    };
-  }
-
-  /// From a serialized version of a BTBV trust manager, extract the device list.
-  /// NOTE: This is needed as Dart cannot just cast a List<dynamic> to List<int> and so on.
-  static Map<String, List<int>> deviceListFromJson(Map<String, dynamic> json) {
-    return (json['devices']! as Map<String, dynamic>).map<String, List<int>>(
-      (key, value) => MapEntry(
-        key,
-        (value as List<dynamic>).map<int>((i) => i as int).toList(),
-      ),
-    );
-  }
-
-  /// From a serialized version of a BTBV trust manager, extract the trust cache.
-  /// NOTE: This is needed as Dart cannot just cast a List<dynamic> to List<int> and so on.
-  static Map<RatchetMapKey, BTBVTrustState> trustCacheFromJson(Map<String, dynamic> json) {
-    return (json['trust']! as Map<String, dynamic>).map<RatchetMapKey, BTBVTrustState>(
-      (key, value) => MapEntry(
-        RatchetMapKey.fromJsonKey(key),
-        _trustFromInt(value as int),
-      ),
-    );
-  }
-
-  /// From a serialized version of a BTBV trust manager, extract the enable cache.
-  /// NOTE: This is needed as Dart cannot just cast a List<dynamic> to List<int> and so on.
-  static Map<RatchetMapKey, bool> enableCacheFromJson(Map<String, dynamic> json) {
-    return (json['enable']! as Map<String, dynamic>).map<RatchetMapKey, bool>(
-      (key, value) => MapEntry(
-        RatchetMapKey.fromJsonKey(key),
-        value as bool,
-      ),
-    );
-  }
  
  /// Called when the state of the trust manager has been changed. Allows the user to
  /// commit the trust state to persistent storage.
--- a/lib/src/trust/never.dart
+++ b/lib/src/trust/never.dart
@ -17,7 +17,4 @@ class NeverTrustingTrustManager extends TrustManager {

  @override
  Future<void> setEnabled(String jid, int deviceId, bool enabled) async {}
-
-  @override
-  Future<Map<String, dynamic>> toJson() async => <String, dynamic>{};
 }
--- a/test/omemo_test.dart
+++ b/test/omemo_test.dart
@ -220,7 +220,7 @@ void main() {
    expect(messagePlaintext, aliceMessage2);
  });

-  test('Test sending empty OMEMO messages', () async {
+  test('Test using sending empty OMEMO messages', () async {
    const aliceJid = 'alice@server.example';
    const bobJid = 'bob@other.server.example';
      
@ -614,145 +614,4 @@ void main() {
    expect(await aliceRatchet1.equals(aliceRatchet2), false);
    expect(await bobRatchet1.equals(bobRatchet2), false);
  });
-
-  test('Test receiving an old message that contains a KEX', () async {
-    const aliceJid = 'alice@server.example';
-    const bobJid = 'bob@other.server.example';
-    // Alice and Bob generate their sessions
-    final aliceSession = await OmemoSessionManager.generateNewIdentity(
-      aliceJid,
-      AlwaysTrustingTrustManager(),
-      opkAmount: 1,
-    );
-    final bobSession = await OmemoSessionManager.generateNewIdentity(
-      bobJid,
-      AlwaysTrustingTrustManager(),
-      opkAmount: 2,
-    );
-
-    // Alice sends Bob a message
-    final msg1 = await aliceSession.encryptToJid(
-      bobJid,
-      'Hallo Welt',
-      newSessions: [
-        await bobSession.getDeviceBundle(),
-      ],
-    );
-
-    await bobSession.decryptMessage(
-      msg1.ciphertext,
-      aliceJid,
-      await aliceSession.getDeviceId(),
-      msg1.encryptedKeys,
-    );
-
-    // Bob responds
-    final msg2 = await bobSession.encryptToJid(
-      aliceJid,
-      'Hello!',
-    );
-    await aliceSession.decryptMessage(
-      msg2.ciphertext,
-      bobJid,
-      await bobSession.getDeviceId(),
-      msg2.encryptedKeys,
-    );
-
-    // Due to some issue with the transport protocol, the first message Bob received is
-    // received again
-    try {
-      await bobSession.decryptMessage(
-        msg1.ciphertext,
-        aliceJid,
-        await aliceSession.getDeviceId(),
-        msg1.encryptedKeys,
-      );
-      expect(true, false);
-    } on InvalidMessageHMACException {
-      // NOOP
-    }
-
-    final msg3 = await aliceSession.encryptToJid(
-      bobJid,
-      'Are you okay?',
-    );
-    final result = await bobSession.decryptMessage(
-      msg3.ciphertext,
-      aliceJid,
-      await aliceSession.getDeviceId(),
-      msg3.encryptedKeys,
-    );
-
-    expect(result, 'Are you okay?');
-  });
-
-  test('Test receiving an old message that does not contain a KEX', () async {
-    const aliceJid = 'alice@server.example';
-    const bobJid = 'bob@other.server.example';
-    // Alice and Bob generate their sessions
-    final aliceSession = await OmemoSessionManager.generateNewIdentity(
-      aliceJid,
-      AlwaysTrustingTrustManager(),
-      opkAmount: 1,
-    );
-    final bobSession = await OmemoSessionManager.generateNewIdentity(
-      bobJid,
-      AlwaysTrustingTrustManager(),
-      opkAmount: 2,
-    );
-
-    // Alice sends Bob a message
-    final msg1 = await aliceSession.encryptToJid(
-      bobJid,
-      'Hallo Welt',
-      newSessions: [
-        await bobSession.getDeviceBundle(),
-      ],
-    );
-    await bobSession.decryptMessage(
-      msg1.ciphertext,
-      aliceJid,
-      await aliceSession.getDeviceId(),
-      msg1.encryptedKeys,
-    );
-
-    // Bob responds
-    final msg2 = await bobSession.encryptToJid(
-      aliceJid,
-      'Hello!',
-    );
-    await aliceSession.decryptMessage(
-      msg2.ciphertext,
-      bobJid,
-      await bobSession.getDeviceId(),
-      msg2.encryptedKeys,
-    );
-
-    // Due to some issue with the transport protocol, the first message Alice received is
-    // received again.
-    try {
-      await aliceSession.decryptMessage(
-        msg2.ciphertext,
-        bobJid,
-        await bobSession.getDeviceId(),
-        msg2.encryptedKeys,
-      );
-      expect(true, false);
-    } catch (_) {
-      // NOOP
-    }
-
-    final msg3 = await aliceSession.encryptToJid(
-      bobJid,
-      'Are you okay?',
-    );
-    final result = await bobSession.decryptMessage(
-      msg3.ciphertext,
-      aliceJid,
-      await aliceSession.getDeviceId(),
-      msg3.encryptedKeys,
-    );
-
-    expect(result, 'Are you okay?');
-  });
 }
--- a/test/protobuf_test.dart
+++ b/test/protobuf_test.dart
@ -48,10 +48,6 @@ void main() {
        <int>[172, 2],
      );
    });
-
-    test('Test some special cases', () {
-      expect(decodeVarint(encodeVarint(1042464893), 0).n, 1042464893);
-    });
  });

  group('OMEMOMessage', () {
@ -174,13 +170,5 @@ void main() {
      expect(decoded.message!.mac, <int>[5, 6, 8, 0]);
      expect(decoded.message!.message, <int>[4, 5, 7, 3, 2]);
    });
-    test('Test decoding an issue', () {
-      /*
-      final data = 'CAAQfRogc2GwslU219dUkrMHNM4KdZRmuFnBTae+bQaJ+55IsAMiII7aZKj2sUpb6xR/3Ari7WZUmKFV0G6czUc4NMvjKDBaKnwKEM2ZpI8X3TgcxhxwENANnlsSaAgAEAAaICy8T9WPgLb7RdYd8/4JkrLF0RahEkC3ZaEfk5jw3dsLIkBMILzLyByweLgF4lCn0oNea+kbdrFr6rY7r/7WyI8hXEQz38QpnN+jyGGwC7Ga0dq70WuyqE7VpiFArQwqZh2G';
-      final kex = OmemoKeyExchange.fromBuffer(base64Decode(data));
-
-      expect(kex.spkId!, 1042464893);
-      */
-    });
  });
 }
--- a/test/serialisation_test.dart
+++ b/test/serialisation_test.dart
@ -1,4 +1,3 @@
-import 'dart:convert';
 import 'package:omemo_dart/omemo_dart.dart';
 import 'package:omemo_dart/src/trust/always.dart';
 import 'package:test/test.dart';
@ -105,84 +104,4 @@ void main() {
      expect(await oldRatchet.equals(newRatchet), true);
    }
  });
-
-  test('Test serialising and deserialising the BlindTrustBeforeVerificationTrustManager', () async {
-    // Caroline's BTBV manager
-    final btbv = MemoryBTBVTrustManager();
-    // Example data
-    const aliceJid = 'alice@some.server';
-    const bobJid = 'bob@other.server';
-    
-    // Caroline starts a chat a device from Alice
-    await btbv.onNewSession(aliceJid, 1);
-    expect(await btbv.isTrusted(aliceJid, 1), true);
-    expect(await btbv.isEnabled(aliceJid, 1), true);
-
-    // Caroline meets with Alice and verifies her fingerprint
-    await btbv.setDeviceTrust(aliceJid, 1, BTBVTrustState.verified);
-    expect(await btbv.isTrusted(aliceJid, 1), true);
-
-    // Alice adds a new device
-    await btbv.onNewSession(aliceJid, 2);
-    expect(await btbv.isTrusted(aliceJid, 2), false);
-    expect(btbv.getDeviceTrust(aliceJid, 2), BTBVTrustState.notTrusted);
-    expect(await btbv.isEnabled(aliceJid, 2), false);
-
-    // Caronline starts a chat with Bob but since they live far apart, Caroline cannot
-    // verify his fingerprint.
-    await btbv.onNewSession(bobJid, 3);
-
-    // Bob adds a new device
-    await btbv.onNewSession(bobJid, 4);
-    expect(await btbv.isTrusted(bobJid, 3), true);
-    expect(await btbv.isTrusted(bobJid, 4), true);
-    expect(btbv.getDeviceTrust(bobJid, 3), BTBVTrustState.blindTrust);
-    expect(btbv.getDeviceTrust(bobJid, 4), BTBVTrustState.blindTrust);
-    expect(await btbv.isEnabled(bobJid, 3), true);
-    expect(await btbv.isEnabled(bobJid, 4), true);
-  });
-
-  test('Test serializing and deserializing RatchetMapKey', () {
-    const test1 = RatchetMapKey('user@example.org', 1234);
-    final result1 = RatchetMapKey.fromJsonKey(test1.toJsonKey());
-    expect(result1.jid, test1.jid);
-    expect(result1.deviceId, test1.deviceId);
-
-    const test2 = RatchetMapKey('user@example.org/hallo:welt', 3333);
-    final result2 = RatchetMapKey.fromJsonKey(test2.toJsonKey());
-    expect(result2.jid, test2.jid);
-    expect(result2.deviceId, test2.deviceId);
-  });
-
-  test('Test serializing and deserializing the components of the BTBV manager', () async {
-    // Caroline's BTBV manager
-    final btbv = MemoryBTBVTrustManager();
-    // Example data
-    const aliceJid = 'alice@some.server';
-    const bobJid = 'bob@other.server';
-    
-    await btbv.onNewSession(aliceJid, 1);
-    await btbv.setDeviceTrust(aliceJid, 1, BTBVTrustState.verified);
-    await btbv.onNewSession(aliceJid, 2);
-    await btbv.onNewSession(bobJid, 3);
-    await btbv.onNewSession(bobJid, 4);
-
-    final managerJson = await btbv.toJson();
-    final managerString = jsonEncode(managerJson);
-    final managerPostJson = jsonDecode(managerString) as Map<String, dynamic>;
-    final deviceList = BlindTrustBeforeVerificationTrustManager.deviceListFromJson(
-      managerPostJson,
-    );
-    expect(btbv.devices, deviceList);
-
-    final trustCache = BlindTrustBeforeVerificationTrustManager.trustCacheFromJson(
-      managerPostJson,
-    );
-    expect(btbv.trustCache, trustCache);
-
-    final enableCache = BlindTrustBeforeVerificationTrustManager.enableCacheFromJson(
-      managerPostJson,
-    );
-    expect(btbv.enablementCache, enableCache);
-  });
 }