V5 connection connack missing authentication method

[michaelg9]

Expected behavior

The CONNACK packet sent by the broker in response to a successful v5 client authentication request must contain the same authentication method value as specified by the CONNECT packet, as specified in the MQTTv5 protocol specification:
If the initial CONNECT packet included an Authentication Method property then all AUTH packets, and any successful CONNACK packet MUST include an Authentication Method Property with the same value as in the CONNECT packet [MQTT-4.12.0-5].

Actual behavior

At the moment the v5 CONNACK is always sent with an empty authentication method field

To Reproduce

Steps

Use a v5 client (hivemq client works as well) to authenticate with the broker using an extended authentication method (in my case it's an extension of SimpleAuthenticator). The broker successfully authenticates the client and sends a CONNACK but the client rejects the connection because of this

Details

• Affected HiveMQ CE version(s): latest
• Used JVM version: 11

Proposed bugfix:

In ConnectHandler.java, method buildMqtt5Connack:

        final CONNACK.Mqtt5Builder builder = new CONNACK.Mqtt5Builder()
                .withSessionPresent(sessionPresent)
                .withReasonCode(Mqtt5ConnAckReasonCode.SUCCESS)
                .withReceiveMaximum(configurationService.mqttConfiguration().serverReceiveMaximum())
                .withSubscriptionIdentifierAvailable(configurationService.mqttConfiguration().subscriptionIdentifierEnabled())
                .withMaximumPacketSize(configurationService.mqttConfiguration().maxPacketSize())
                .withWildcardSubscriptionAvailable(configurationService.mqttConfiguration().wildcardSubscriptionsEnabled())
                .withSharedSubscriptionAvailable(configurationService.mqttConfiguration().sharedSubscriptionsEnabled())
                .withMaximumQoS(configurationService.mqttConfiguration().maximumQos())
                .withRetainAvailable(configurationService.mqttConfiguration().retainedMessagesEnabled());

A .withAuthMethod(msg.getAuthMethod()); is missing from there

[SgtSilvio]

Hi @michaelg9
This issue will be solved when enhanced authentication is exposed to the extension SDK.
Enhanced authentication will be implemented soon. We will then link and close this ticket.

[michaelg9]

Hi
When will this feature be published to the SDK repo?