[SOLVED] MQTT block specific client from connecting via TLS

MQTT block specific client from connecting via TLS

I have MQTT (VerneMQ) setup with TLS authentication. Also I have setup frequent pulling CRL (certificate revocation list) from CA (Private). I am able to revoke the specific client certificate to blocking it from connecting to MQTT.

There is one certificate which is shared & I don't want to revoke but also don't want client to be able to authenticate with MQTT. Following is my configuration

DOCKER_VERNEMQ_ACCEPT_EULA = "yes"
MY_POD_NAME = "vernemq"
DOCKER_VERNEMQ_KUBERNETES_APP_LABEL = "vernemq"
DOCKER_VERNEMQ_LOG__CONSOLE__LEVEL = "debug"
DOCKER_VERNEMQ_KUBERNETES_LABEL_SELECTOR = "app=vernemq"
DOCKER_VERNEMQ_LISTENER__TCP__ALLOWED_PROTOCOL_VERSIONS = "3,4,5"
DOCKER_VERNEMQ_ALLOW_ANONYMOUS = "on"
DOCKER_VERNEMQ_KUBERNETES_INSECURE = "1"
DOCKER_VERNEMQ_MAX_ONLINE_MESSAGES = "-1"
DOCKER_VERNEMQ_MAX_OFFLINE_MESSAGES = "-1"
DOCKER_VERNEMQ_MAX_INFLIGHT_MESSAGES = "0"
DOCKER_VERNEMQ_LISTENER__TCP__DEFAULT = "0.0.0.0:1883"
DOCKER_VERNEMQ_LISTENER__SSL__DEFAULT = "0.0.0.0:8883"
DOCKER_VERNEMQ_LISTENER__WS__DEFAULT = "0.0.0.0:8080"
DOCKER_VERNEMQ_LISTENER__HTTP__METRICS = "0.0.0.0:8888"
DOCKER_VERNEMQ_LISTENER__HTTP__DEFAULT = "0.0.0.0:8888"
DOCKER_VERNEMQ_LISTENER__SSL__REQUIRE_CERTIFICATE = "on"
# DOCKER_VERNEMQ_LISTENER__SSL__USE_IDENTITY_AS_USERNAME = "on"
DOCKER_VERNEMQ_LISTENER__SSL__CAFILE = "/vernemq/cert/ca.crt"
DOCKER_VERNEMQ_LISTENER__SSL__CERTFILE = "/vernemq/cert/server.crt"
DOCKER_VERNEMQ_LISTENER__SSL__KEYFILE = "/vernemq/cert/server.key"
DOCKER_VERNEMQ_LISTENER__SSL__CRLFILE = "/tmp/shared/ca.crl"
DOCKER_VERNEMQ_ALLOW_REGISTER_DURING_NETSPLIT = "on"
DOCKER_VERNEMQ_ALLOW_PUBLISH_DURING_NETSPLIT = "on"
DOCKER_VERNEMQ_ALLOW_SUBSCRIBE_DURING_NETSPLIT = "on"
DOCKER_VERNEMQ_ALLOW_UNSUBSCRIBE_DURING_NETSPLIT = "on"

Any way I can block the specific client certificate ?

Solution

I'm not familiar with vernemq's specific options but why not just set up the ACL to block the user represented by that certificate from being able to subscribe or publish to any topics.

Clients would still be able to connect with that shared certificate, but would not be able to receive or publish any messages.

To make this work you would probably have to use the Certificate identity as the User name (but you appear to have commented that out of the env vars you have shown in the question)