feat: Implement acknowledging ratchet sessions

This commit is contained in:
PapaTutuWawa 2022-08-16 14:02:04 +02:00
parent 800b53b11f
commit fda06cef55
3 changed files with 81 additions and 0 deletions

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@ -67,6 +67,7 @@ class OmemoDoubleRatchet {
this.ik,
this.sessionAd,
this.mkSkipped, // MKSKIPPED
this.acknowledged,
);
factory OmemoDoubleRatchet.fromJson(Map<String, dynamic> data) {
@ -83,6 +84,7 @@ class OmemoDoubleRatchet {
'pn': 0,
'ik_pub': 'base/64/encoded',
'session_ad': 'base/64/encoded',
'acknowledged': true | false,
'mkskipped': [
{
'key': 'base/64/encoded',
@ -117,6 +119,7 @@ class OmemoDoubleRatchet {
),
base64.decode(data['session_ad']! as String),
mkSkipped,
data['acknowledged']! as bool,
);
}
@ -148,6 +151,10 @@ class OmemoDoubleRatchet {
final Map<SkippedKey, List<int>> mkSkipped;
/// Indicates whether we received an empty OMEMO message after building a session with
/// the device.
bool acknowledged;
/// Create an OMEMO session using the Signed Pre Key [spk], the shared secret [sk] that
/// was obtained using a X3DH and the associated data [ad] that was also obtained through
/// a X3DH. [ik] refers to Bob's (the receiver's) IK public key.
@ -169,6 +176,7 @@ class OmemoDoubleRatchet {
ik,
ad,
{},
false,
);
}
@ -189,6 +197,7 @@ class OmemoDoubleRatchet {
ik,
ad,
{},
true,
);
}
@ -214,6 +223,7 @@ class OmemoDoubleRatchet {
'ik_pub': base64.encode(await ik.getBytes()),
'session_ad': base64.encode(sessionAd),
'mkskipped': mkSkippedSerialised,
'acknowledged': acknowledged,
};
}

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@ -430,6 +430,33 @@ class OmemoSessionManager {
_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 {
final ret = List<int>.empty(growable: true);
await _lock.synchronized(() async {
final devices = _deviceMap[jid]!;
for (final device in devices) {
final ratchet = _ratchetMap[RatchetMapKey(jid, device)]!;
if (!ratchet.acknowledged) ret.add(device);
}
});
return ret;
}
/// Mark the ratchet for device [deviceId] from [jid] as acked.
Future<void> ratchetAcknowledged(String jid, int deviceId) async {
await _lock.synchronized(() async {
final ratchet = _ratchetMap[RatchetMapKey(jid, deviceId)]!
..acknowledged = true;
// Commit it
_eventStreamController.add(RatchetModifiedEvent(jid, deviceId, ratchet));
});
}
@visibleForTesting
OmemoDoubleRatchet getRatchet(String jid, int deviceId) => _ratchetMap[RatchetMapKey(jid, deviceId)]!;

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@ -499,4 +499,48 @@ void main() {
expect(deviceMap.containsKey(bobJid), false);
});
});
test('Test acknowledging a ratchet', () 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: 1,
);
// Alice sends Bob a message
await aliceSession.encryptToJid(
bobJid,
'Hallo Welt',
newSessions: [
await (await bobSession.getDevice()).toBundle(),
],
);
expect(
await aliceSession.getUnacknowledgedRatchets(bobJid),
[
(await bobSession.getDevice()).id,
],
);
// Bob sends alice an empty message
// ...
// Alice decrypts it
// ...
// Alice marks the ratchet as acknowledged
await aliceSession.ratchetAcknowledged(bobJid, (await bobSession.getDevice()).id);
expect(
(await aliceSession.getUnacknowledgedRatchets(bobJid)).isEmpty,
true,
);
});
}