Authentication with Mainflux keys#

By default, Mainflux uses Mainflux keys for authentication. The –úainflux key is a secret key that's generated at the Thing creation. In order to authenticate, the Thing needs to send its key with the message. The way the key is passed depends on the protocol used to send a message and differs from adapter to adapter. For more details on how this key is passed around, please check out messaging section. This is the default Mainflux authentication mechanism and this method is used if the composition is started using the following command:

docker-compose -f docker/docker-compose.yml up

Mutual TLS Authentication with X.509 Certificates#

In most of the cases, HTTPS, WSS, MQTTS or secure CoAP are secure enough. However, sometimes you might need an even more secure connection. Mainflux supports mutual TLS authentication (mTLS) based on X.509 certificates. By default, the TLS protocol only proves the identity of the server to the client using the X.509 certificate and the authentication of the client to the server is left to the application layer. TLS also offers client-to-server authentication using client-side X.509 authentication. This is called two-way or mutual authentication. Mainflux currently supports mTLS over HTTP, WS, and MQTT protocols. In order to run Docker composition with mTLS turned on, you can execute the following command from the project root:

AUTH=x509 docker-compose -f docker/docker-compose.yml up -d

Mutual authentication includes client-side certificates. Certificates can be generated using the simple script provided here. In order to create a valid certificate, you need to create Mainflux thing using the process described in the provisioning section. After that, you need to fetch created thing key. Thing key will be used to create x.509 certificate for the corresponding thing. To create a certificate, execute the following commands:

cd docker/ssl
make ca
make server_cert
make thing_cert KEY=<thing_key> CRT_FILE_NAME=<cert_name>

These commands use OpenSSL tool, so please make sure that you have it installed and set up before running these commands.

- Command `make ca` will generate a self-signed certificate that will later be used as a CA to sign other generated certificates. CA will expire in 3 years.
- Command `make server_cert` will generate and sign (with previously created CA) server cert, which will expire after 1000 days. This cert is used as a Mainflux server-side certificate in usual TLS flow to establish HTTPS, WSS, or MQTTS connection.
- Command `make thing_cert` will finally generate and sign a client-side certificate and private key for the thing.

In this example <thing_key> represents key of the thing, and <cert_name> represents the name of the certificate and key file which will be saved in docker/ssl/certs directory. Generated Certificate will expire after 2 years. The key must be stored in the x.509 certificate CN field. This script is created for testing purposes and is not meant to be used in production. We strongly recommend avoiding self-signed certificates and using a certificate management tool such as Vault for the production.

Once you have created CA and server-side cert, you can spin the composition using:

AUTH=x509 docker-compose -f docker/docker-compose.yml up -d

Then, you can create user and provision things and channels. Now, in order to send a message from the specific thing to the channel, you need to connect thing to the channel and generate corresponding client certificate using aforementioned commands. To publish a message to the channel, thing should send following request:

HTTPS#

curl -s -S -i --cacert docker/ssl/certs/ca.crt --cert docker/ssl/certs/<thing_cert_name>.crt --key docker/ssl/certs/<thing_cert_key>.key --insecure -X POST -H "Content-Type: application/senml+json" https://localhost/http/channels/<channel_id>/messages -d '[{"bn":"some-base-name:","bt":1.276020076001e+09, "bu":"A","bver":5, "n":"voltage","u":"V","v":120.1}, {"n":"current","t":-5,"v":1.2}, {"n":"current","t":-4,"v":1.3}]'

MQTTS#

Publish#

mosquitto_pub -u <thing_id> -P <thing_key> -t channels/<channel_id>/messages -h localhost -p 8883  --cafile docker/ssl/certs/ca.crt --cert docker/ssl/certs/<thing_cert_name>.crt --key docker/ssl/certs/<thing_cert_key>.key -m '[{"bn":"some-base-name:","bt":1.276020076001e+09, "bu":"A","bver":5, "n":"voltage","u":"V","v":120.1}, {"n":"current","t":-5,"v":1.2}, {"n":"current","t":-4,"v":1.3}]'

Subscribe#

mosquitto_sub -u <thing_id> -P <thing_key> --cafile docker/ssl/certs/ca.crt --cert docker/ssl/certs/<thing_cert_name>.crt --key docker/ssl/certs/<thing_cert_key>.key -t channels/<channel_id>/messages -h localhost -p 8883

WSS#

const WebSocket = require('ws');

// Do not verify self-signed certificates if you are using one.
process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0'

// Replace <channel_id> and <thing_key> with real values.
const ws = new WebSocket('wss://localhost/ws/channels/<channel_id>/messages?authorization=<thing_key>',
// This is ClientOptions object that contains client cert and client key in the form of string. You can easily load these strings from cert and key files.
{
    cert: `-----BEGIN CERTIFICATE-----....`,
    key: `-----BEGIN RSA PRIVATE KEY-----.....`
})

ws.on('open', () => {
    ws.send('something')
})

ws.on('message', (data) => {
    console.log(data)
})
ws.on('error', (e) => {
    console.log(e)
})

As you can see, Authorization header does not have to be present in the HTTP request, since the key is present in the certificate. However, if you pass Authorization header, it must be the same as the key in the cert. In the case of MQTTS, password filed in CONNECT message must match the key from the certificate. In the case of WSS, Authorization header or authorization query parameter must match cert key.