Mqtt C client authentication

[Daniele Carvalho]

Hello!

I have installed mosquitto broker on my vps and I installed Certbot for Let's Encrypt Certificates form https://www.digitalocean.com/community/tutorials/how-to-install-and-secure-the-mosquitto-mqtt-messaging-broker-on-centos-7.

When I connect via websockets I can connect and send and recieve messages evething is ok.

But i have this development kit (samd21 + winc1500)  as a c client and i can't authenticate my connection...

Any advice?

My base code is the mqtt_chat_example project from Atmel Studio 7.

This function doesn't allow me to send a certificate. 

int mqtt_connect_broker (struct mqtt_module *const module, uint8_t clean_session, const char *id, const char *password, const char *client_id, const char *will_topic, const char *will_msg, uint32_t will_msg_len, uint8_t will_qos, uint8_t will_retain);

It was working before I installed Certbot for Let's Encrypt Certificates (without the authentication).

Thanks in advance.

Daniele

[Daniele Carvalho]

Mosquitto broker via Mqtt: (error)

1491560759: New connection from 89.114.125.123 on port 8883.
1491560759: OpenSSL Error: error:140940E5:SSL routines:SSL3_READ_BYTES:ssl handshake failure
1491560759: Socket error on client <unknown>, disconnecting.

Mosquitto broker via websockets: (success)

1491568948: New client connected from 89.114.125.123 as websocket_client_86f8624b (c1, k60, u'admin').
1491568948: Sending CONNACK to websocket_client_86f8624b (0, 0)
1491568948: Received SUBSCRIBE from websocket_client_86f8624b
1491568948:     tedayc/# (QoS 0)
1491568948: websocket_client_86f8624b 0 tedayc/#
1491568948: Sending SUBACK to websocket_client_86f8624b
1491568949: Received PUBLISH from websocket_client_86f8624b (d0, q0, r0, m0, 'tedayc/websocket_client_86f8624b', ... (9 bytes))
1491568949: Sending PUBLISH to websocket_client_86f8624b (d0, q0, r0, m0, 'tedayc/websocket_client_86f8624b', ... (9 bytes))

I think i need to send the ca certificate via mqtt but i dont have extra options or parameters to send it. My function only asks for the username and the password.

/**
 * \brief Send MQTT connect message to broker server with MQTT parameter.
 * If operation of this function is complete, MQTT_CALLBACK_CONNECTED event will be sent through MQTT callback.
 *
 * \param[in]  module_inst     Instance of MQTT module.
 * \param[in]  clean_session   If this value set to 1, Broker server store the previous subscribed informations after disconnected.
 * \param[in]  id              ID of user.
 * \param[in]  password        Password of user.
 * \param[in]  client_id       Client ID of this connection.
 * \param[in]  will_topic      A MQTT topic that will be sent to subscribers when this connection is disconnected.
 * \param[in]  will_msg        A MQTT payload that will be sent to subscribers when this connection is disconnected.
 * \param[in]  will_qos        QOS level of will message.
 * \param[in]  will_retain     Whether broker server will be store MQTT will message or not.
 *
 * \return     0               Function succeeded
 * \return     -ENOENT         No such address.
 * \return     -EINVAL         Invalid argument.
 * \return     -ENOSPC         No space left on device.
 * \return     -EIO            Device was occurred error due to unknown exception.
 * \return     -EDESTADDRREQ   Destination address required.
 * \return     -ECONNRESET     Connection reset by peer.
 * \return     -EAGAIN         Try again.
 * \return     -EBUSY          Device or resource busy.
 * \return     -EADDRINUSE     Address already in use.
 * \return     -EALREADY       Socket already connected.
 * \return     -ENOTCONN       Service in bad state.
 * \return     -ECONNREFUSED   Connection refused.
 * \return     -EOVERFLOW      Value too large for defined data type.
 * \return     -EBADMSG        Not a data message.
 */

int mqtt_connect_broker (struct mqtt_module *const module, uint8_t clean_session, const char *id, const char *password, const char *client_id, const char *will_topic, const char *will_msg, uint32_t will_msg_len, uint8_t will_qos, uint8_t will_retain);

mqtt_connect_broker(&module_inst, 1, MAIN_MQTT_USERNAME, MAIN_MQTT_PASSWORD, mqtt_user, NULL, NULL, 0, 0, 0);

[Filipe Nicoli]

You may need to implement authentication by yourself modifying your library.

You can use this as an example or try to port it to your architecture.