private async Task buildSessionForDevicesAsync(Dictionary <uint, SessionCipher> sessions, IList <SignalProtocolAddress> devices)
{
if (devices.Count <= 0)
{
return;
}
SignalProtocolAddress device = devices[0];
devices.RemoveAt(0);
// Check if there exists already a session for this device:
if (OMEMO_HELPER.OMEMO_STORE.ContainsSession(device))
{
// If yes, the load it:
SessionCipher cipher = OMEMO_HELPER.loadCipher(device);
sessions.Add(device.getDeviceId(), cipher);
Logger.Info("[OmemoSessionBuildHelper] Session for " + device.ToString() + " loaded from cache.");
}
else
{
// Else try to build a new one by requesting the devices bundle information:
OmemoBundleInformationResultMessage bundleMsg = await requestBundleInformationAsync(device);
if (!(bundleMsg is null))
{
SignalProtocolAddress address = OMEMO_HELPER.newSession(CHAT_JID, bundleMsg);
SessionCipher cipher = OMEMO_HELPER.loadCipher(address);
sessions.Add(device.getDeviceId(), cipher);
Logger.Info("[OmemoSessionBuildHelper] Session with " + device.ToString() + " established.");
}
private bool onRequestBundleInformationMessage(IQMessage msg)
{
if (STATE != OmemoSessionBuildHelperState.REQUESTING_BUNDLE_INFORMATION)
{
return(true);
}
if (msg is OmemoBundleInformationResultMessage bundleMsg)
{
Logger.Info("[OmemoSessionBuildHelper] Session with " + curAddress.getName() + ':' + curAddress.getDeviceId() + " established.");
SignalProtocolAddress address = OMEMO_HELPER.newSession(CHAT_JID, bundleMsg);
SessionCipher cipher = OMEMO_HELPER.loadCipher(address);
SESSION.DEVICE_SESSIONS.Add(curAddress.getDeviceId(), cipher);
createSessionForNextDevice();
return(true);
}
else if (msg is IQErrorMessage errMsg)
{
if (errMsg.ERROR_OBJ.ERROR_NAME == ErrorName.ITEM_NOT_FOUND)
{
Logger.Error("[OmemoSessionBuildHelper] Failed to establish session - " + curAddress.getName() + ':' + curAddress.getDeviceId() + " doesn't support OMEMO: " + errMsg.ERROR_OBJ.ToString());
setState(OmemoSessionBuildHelperState.ERROR);
ON_SESSION_RESULT(this, new OmemoSessionBuildResult(OmemoSessionBuildError.TARGET_DOES_NOT_SUPPORT_OMEMO));
}
else
{
Logger.Error("[OmemoSessionBuildHelper] Failed to establish session - request bundle info failed(" + curAddress.getName() + ':' + curAddress.getDeviceId() + "): " + errMsg.ERROR_OBJ.ToString());
setState(OmemoSessionBuildHelperState.ERROR);
ON_SESSION_RESULT(this, new OmemoSessionBuildResult(OmemoSessionBuildError.REQUEST_BUNDLE_INFORMATION_IQ_ERROR));
}
return(true);
}
return(false);
}
private async Task buildSessionForDevicesAsync(Dictionary <uint, SessionCipher> sessions, IList <SignalProtocolAddress> devices)
{
if (devices.Count <= 0)
{
return;
}
SignalProtocolAddress device = devices[0];
devices.RemoveAt(0);
// Validate the device fingerprint:
OmemoFingerprint fingerprint = OMEMO_HELPER.OMEMO_STORE.LoadFingerprint(device);
if (!(fingerprint is null) && !OMEMO_HELPER.OMEMO_STORE.IsFingerprintTrusted(fingerprint))
{
Logger.Warn("[OmemoSessionBuildHelper] Not building a session with " + device.ToString() + " - key not trusted.");
await buildSessionForDevicesAsync(sessions, devices);
return;
}
// Check if there exists already a session for this device:
if (OMEMO_HELPER.OMEMO_STORE.ContainsSession(device))
{
// If yes, the load it:
SessionCipher cipher = OMEMO_HELPER.loadCipher(device);
sessions.Add(device.getDeviceId(), cipher);
Logger.Info("[OmemoSessionBuildHelper] Session for " + device.ToString() + " loaded from cache.");
}
else
{
// Else try to build a new one by requesting the devices bundle information:
OmemoBundleInformationResultMessage bundleMsg = await requestBundleInformationAsync(device);
if (!(bundleMsg is null))
{
OMEMO_HELPER.newSession(device.getName(), bundleMsg);
// Validate fingerprints:
if (fingerprint is null)
{
fingerprint = new OmemoFingerprint(bundleMsg.BUNDLE_INFO.PUBLIC_IDENTITY_KEY, device);
OMEMO_HELPER.OMEMO_STORE.StoreFingerprint(fingerprint);
}
else
{
OmemoFingerprint receivedFingerprint = new OmemoFingerprint(bundleMsg.BUNDLE_INFO.PUBLIC_IDENTITY_KEY, device);
// Make sure the fingerprint did not change or somebody is doing an attack:
if (!fingerprint.checkIdentityKey(receivedFingerprint.IDENTITY_PUB_KEY))
{
Logger.Warn("[OmemoSessionBuildHelper] Unable to establish session with " + device.ToString() + " - other fingerprint received than stored locally.");
await buildSessionForDevicesAsync(sessions, devices);
return;
}
}
// Check if the fingerprint is trusted:
if (OMEMO_HELPER.OMEMO_STORE.IsFingerprintTrusted(fingerprint))
{
SessionCipher cipher = OMEMO_HELPER.loadCipher(device);
sessions.Add(device.getDeviceId(), cipher);
Logger.Info("[OmemoSessionBuildHelper] Session with " + device.ToString() + " established.");
}
else
{
Logger.Warn("[OmemoSessionBuildHelper] Unable to establish session with " + device.ToString() + " - key not trusted.");
}
}