471 lines
15 KiB
Dart
471 lines
15 KiB
Dart
/*
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* Famedly Matrix SDK
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* Copyright (C) 2020, 2021 Famedly GmbH
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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import 'dart:convert';
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import 'package:canonical_json/canonical_json.dart';
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import 'package:famedlysdk/famedlysdk.dart';
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import 'package:olm/olm.dart' as olm;
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import '../../encryption.dart';
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import '../client.dart';
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import '../database/database.dart'
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show DbUserDeviceKey, DbUserDeviceKeysKey, DbUserCrossSigningKey;
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import '../event.dart';
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import '../room.dart';
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import '../user.dart';
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enum UserVerifiedStatus { verified, unknown, unknownDevice }
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class DeviceKeysList {
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Client client;
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String userId;
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bool outdated = true;
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Map<String, DeviceKeys> deviceKeys = {};
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Map<String, CrossSigningKey> crossSigningKeys = {};
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SignableKey getKey(String id) {
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if (deviceKeys.containsKey(id)) {
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return deviceKeys[id];
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}
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if (crossSigningKeys.containsKey(id)) {
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return crossSigningKeys[id];
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}
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return null;
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}
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CrossSigningKey getCrossSigningKey(String type) => crossSigningKeys.values
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.firstWhere((k) => k.usage.contains(type), orElse: () => null);
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CrossSigningKey get masterKey => getCrossSigningKey('master');
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CrossSigningKey get selfSigningKey => getCrossSigningKey('self_signing');
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CrossSigningKey get userSigningKey => getCrossSigningKey('user_signing');
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UserVerifiedStatus get verified {
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if (masterKey == null) {
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return UserVerifiedStatus.unknown;
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}
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if (masterKey.verified) {
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for (final key in deviceKeys.values) {
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if (!key.verified) {
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return UserVerifiedStatus.unknownDevice;
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}
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}
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return UserVerifiedStatus.verified;
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} else {
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for (final key in deviceKeys.values) {
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if (!key.verified) {
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return UserVerifiedStatus.unknown;
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}
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}
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return UserVerifiedStatus.verified;
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}
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}
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Future<KeyVerification> startVerification() async {
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if (userId != client.userID) {
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// in-room verification with someone else
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final roomId =
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await User(userId, room: Room(client: client)).startDirectChat();
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if (roomId == null) {
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throw Exception('Unable to start new room');
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}
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final room =
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client.getRoomById(roomId) ?? Room(id: roomId, client: client);
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final request = KeyVerification(
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encryption: client.encryption, room: room, userId: userId);
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await request.start();
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// no need to add to the request client object. As we are doing a room
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// verification request that'll happen automatically once we know the transaction id
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return request;
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} else {
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// broadcast self-verification
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final request = KeyVerification(
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encryption: client.encryption, userId: userId, deviceId: '*');
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await request.start();
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client.encryption.keyVerificationManager.addRequest(request);
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return request;
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}
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}
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DeviceKeysList.fromDb(
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DbUserDeviceKey dbEntry,
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List<DbUserDeviceKeysKey> childEntries,
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List<DbUserCrossSigningKey> crossSigningEntries,
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Client cl) {
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client = cl;
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userId = dbEntry.userId;
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outdated = dbEntry.outdated;
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deviceKeys = {};
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for (final childEntry in childEntries) {
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final entry = DeviceKeys.fromDb(childEntry, client);
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if (entry.isValid) {
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deviceKeys[childEntry.deviceId] = entry;
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} else {
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outdated = true;
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}
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}
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for (final crossSigningEntry in crossSigningEntries) {
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final entry = CrossSigningKey.fromDb(crossSigningEntry, client);
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if (entry.isValid) {
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crossSigningKeys[crossSigningEntry.publicKey] = entry;
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} else {
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outdated = true;
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}
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}
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}
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DeviceKeysList(this.userId, this.client);
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}
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abstract class SignableKey extends MatrixSignableKey {
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Client client;
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Map<String, dynamic> validSignatures;
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bool _verified;
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bool blocked;
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String get ed25519Key => keys['ed25519:$identifier'];
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bool get verified => (directVerified || crossVerified) && !blocked;
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bool get encryptToDevice =>
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!blocked &&
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(client.userDeviceKeys[userId]?.masterKey?.verified ?? false
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? verified
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: true);
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void setDirectVerified(bool v) {
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_verified = v;
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}
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bool get directVerified => _verified;
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bool get crossVerified => hasValidSignatureChain();
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bool get signed => hasValidSignatureChain(verifiedOnly: false);
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SignableKey.fromJson(Map<String, dynamic> json, Client cl)
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: client = cl,
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super.fromJson(json) {
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_verified = false;
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blocked = false;
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}
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MatrixSignableKey cloneForSigning() {
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final newKey = MatrixSignableKey.fromJson(toJson().copy());
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newKey.identifier = identifier;
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newKey.signatures ??= <String, Map<String, String>>{};
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newKey.signatures.clear();
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return newKey;
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}
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String get signingContent {
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final data = super.toJson().copy();
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// some old data might have the custom verified and blocked keys
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data.remove('verified');
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data.remove('blocked');
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// remove the keys not needed for signing
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data.remove('unsigned');
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data.remove('signatures');
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return String.fromCharCodes(canonicalJson.encode(data));
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}
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bool _verifySignature(String pubKey, String signature,
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{bool isSignatureWithoutLibolmValid = false}) {
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olm.Utility olmutil;
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try {
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olmutil = olm.Utility();
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} catch (e) {
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// if no libolm is present we land in this catch block, and return the default
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// set if no libolm is there. Some signatures should be assumed-valid while others
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// should be assumed-invalid
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return isSignatureWithoutLibolmValid;
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}
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var valid = false;
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try {
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olmutil.ed25519_verify(pubKey, signingContent, signature);
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valid = true;
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} catch (_) {
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// bad signature
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valid = false;
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} finally {
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olmutil.free();
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}
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return valid;
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}
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bool hasValidSignatureChain(
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{bool verifiedOnly = true,
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Set<String> visited,
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Set<String> onlyValidateUserIds}) {
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if (!client.encryptionEnabled) {
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return false;
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}
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visited ??= <String>{};
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onlyValidateUserIds ??= <String>{};
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final setKey = '$userId;$identifier';
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if (visited.contains(setKey) ||
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(onlyValidateUserIds.isNotEmpty &&
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!onlyValidateUserIds.contains(userId))) {
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return false; // prevent recursion & validate hasValidSignatureChain
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}
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visited.add(setKey);
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if (signatures == null) return false;
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for (final signatureEntries in signatures.entries) {
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final otherUserId = signatureEntries.key;
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if (!(signatureEntries.value is Map) ||
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!client.userDeviceKeys.containsKey(otherUserId)) {
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continue;
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}
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// we don't allow transitive trust unless it is for ourself
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if (otherUserId != userId && otherUserId != client.userID) {
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continue;
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}
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for (final signatureEntry in signatureEntries.value.entries) {
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final fullKeyId = signatureEntry.key;
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final signature = signatureEntry.value;
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if (!(fullKeyId is String) || !(signature is String)) {
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continue;
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}
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final keyId = fullKeyId.substring('ed25519:'.length);
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// we ignore self-signatures here
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if (otherUserId == userId && keyId == identifier) {
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continue;
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}
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SignableKey key;
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if (client.userDeviceKeys[otherUserId].deviceKeys.containsKey(keyId)) {
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key = client.userDeviceKeys[otherUserId].deviceKeys[keyId];
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} else if (client.userDeviceKeys[otherUserId].crossSigningKeys
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.containsKey(keyId)) {
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key = client.userDeviceKeys[otherUserId].crossSigningKeys[keyId];
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} else {
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continue;
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}
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if (onlyValidateUserIds.isNotEmpty &&
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!onlyValidateUserIds.contains(key.userId)) {
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// we don't want to verify keys from this user
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continue;
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}
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if (key.blocked) {
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continue; // we can't be bothered about this keys signatures
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}
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var haveValidSignature = false;
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var gotSignatureFromCache = false;
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if (validSignatures != null &&
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validSignatures.containsKey(otherUserId) &&
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validSignatures[otherUserId].containsKey(fullKeyId)) {
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if (validSignatures[otherUserId][fullKeyId] == true) {
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haveValidSignature = true;
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gotSignatureFromCache = true;
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} else if (validSignatures[otherUserId][fullKeyId] == false) {
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haveValidSignature = false;
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gotSignatureFromCache = true;
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}
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}
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if (!gotSignatureFromCache) {
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// validate the signature manually
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haveValidSignature = _verifySignature(key.ed25519Key, signature);
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validSignatures ??= <String, dynamic>{};
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if (!validSignatures.containsKey(otherUserId)) {
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validSignatures[otherUserId] = <String, dynamic>{};
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}
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validSignatures[otherUserId][fullKeyId] = haveValidSignature;
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}
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if (!haveValidSignature) {
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// no valid signature, this key is useless
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continue;
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}
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if ((verifiedOnly && key.directVerified) ||
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(key is CrossSigningKey &&
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key.usage.contains('master') &&
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key.directVerified &&
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key.userId == client.userID)) {
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return true; // we verified this key and it is valid...all checks out!
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}
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// or else we just recurse into that key and chack if it works out
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final haveChain = key.hasValidSignatureChain(
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verifiedOnly: verifiedOnly,
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visited: visited,
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onlyValidateUserIds: onlyValidateUserIds);
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if (haveChain) {
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return true;
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}
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}
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}
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return false;
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}
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Future<void> setVerified(bool newVerified, [bool sign = true]) async {
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_verified = newVerified;
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if (newVerified &&
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sign &&
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client.encryptionEnabled &&
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client.encryption.crossSigning.signable([this])) {
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// sign the key!
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// ignore: unawaited_futures
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client.encryption.crossSigning.sign([this]);
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}
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}
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Future<void> setBlocked(bool newBlocked);
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@override
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Map<String, dynamic> toJson() {
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final data = super.toJson().copy();
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// some old data may have the verified and blocked keys which are unneeded now
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data.remove('verified');
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data.remove('blocked');
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return data;
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}
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@override
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String toString() => json.encode(toJson());
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}
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class CrossSigningKey extends SignableKey {
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String get publicKey => identifier;
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List<String> usage;
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bool get isValid =>
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userId != null && publicKey != null && keys != null && ed25519Key != null;
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@override
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Future<void> setVerified(bool newVerified, [bool sign = true]) async {
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await super.setVerified(newVerified, sign);
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return client.database?.setVerifiedUserCrossSigningKey(
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newVerified, client.id, userId, publicKey);
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}
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@override
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Future<void> setBlocked(bool newBlocked) {
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blocked = newBlocked;
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return client.database?.setBlockedUserCrossSigningKey(
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newBlocked, client.id, userId, publicKey);
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}
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CrossSigningKey.fromMatrixCrossSigningKey(MatrixCrossSigningKey k, Client cl)
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: super.fromJson(k.toJson().copy(), cl) {
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final json = toJson();
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identifier = k.publicKey;
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usage = json['usage'].cast<String>();
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}
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CrossSigningKey.fromDb(DbUserCrossSigningKey dbEntry, Client cl)
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: super.fromJson(Event.getMapFromPayload(dbEntry.content), cl) {
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final json = toJson();
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identifier = dbEntry.publicKey;
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usage = json['usage'].cast<String>();
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_verified = dbEntry.verified;
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blocked = dbEntry.blocked;
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}
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CrossSigningKey.fromJson(Map<String, dynamic> json, Client cl)
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: super.fromJson(json.copy(), cl) {
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final json = toJson();
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usage = json['usage'].cast<String>();
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if (keys != null && keys.isNotEmpty) {
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identifier = keys.values.first;
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}
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}
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}
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class DeviceKeys extends SignableKey {
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String get deviceId => identifier;
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List<String> algorithms;
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DateTime lastActive;
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String get curve25519Key => keys['curve25519:$deviceId'];
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String get deviceDisplayName =>
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unsigned != null ? unsigned['device_display_name'] : null;
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bool _validSelfSignature;
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bool get selfSigned =>
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_validSelfSignature ??
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(_validSelfSignature = (signatures
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?.tryGet<Map<String, dynamic>>(userId)
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?.tryGet<String>('ed25519:$deviceId') ==
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null
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? false
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// without libolm we still want to be able to add devices. In that case we ofc just can't
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// verify the signature
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: _verifySignature(
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ed25519Key, signatures[userId]['ed25519:$deviceId'],
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isSignatureWithoutLibolmValid: true)));
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@override
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bool get blocked => super.blocked || !selfSigned;
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bool get isValid =>
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userId != null &&
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deviceId != null &&
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keys != null &&
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curve25519Key != null &&
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ed25519Key != null &&
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selfSigned;
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@override
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Future<void> setVerified(bool newVerified, [bool sign = true]) async {
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await super.setVerified(newVerified, sign);
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return client?.database
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?.setVerifiedUserDeviceKey(newVerified, client.id, userId, deviceId);
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}
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@override
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Future<void> setBlocked(bool newBlocked) {
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blocked = newBlocked;
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return client?.database
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?.setBlockedUserDeviceKey(newBlocked, client.id, userId, deviceId);
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}
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DeviceKeys.fromMatrixDeviceKeys(MatrixDeviceKeys k, Client cl,
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[DateTime lastActiveTs])
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: super.fromJson(k.toJson().copy(), cl) {
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final json = toJson();
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identifier = k.deviceId;
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algorithms = json['algorithms'].cast<String>();
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lastActive = lastActiveTs ?? DateTime.now();
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}
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DeviceKeys.fromDb(DbUserDeviceKeysKey dbEntry, Client cl)
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: super.fromJson(Event.getMapFromPayload(dbEntry.content), cl) {
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final json = toJson();
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identifier = dbEntry.deviceId;
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algorithms = json['algorithms'].cast<String>();
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_verified = dbEntry.verified;
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blocked = dbEntry.blocked;
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lastActive = DateTime.fromMillisecondsSinceEpoch(dbEntry.lastActive ?? 0);
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}
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DeviceKeys.fromJson(Map<String, dynamic> json, Client cl)
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: super.fromJson(json.copy(), cl) {
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final json = toJson();
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identifier = json['device_id'];
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algorithms = json['algorithms'].cast<String>();
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lastActive = DateTime.fromMillisecondsSinceEpoch(0);
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}
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KeyVerification startVerification() {
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final request = KeyVerification(
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encryption: client.encryption, userId: userId, deviceId: deviceId);
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request.start();
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client.encryption.keyVerificationManager.addRequest(request);
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return request;
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}
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}
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