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Version: 8.x (Current)

Client Credentials Usage

In this section, we show you how to use the client-credentials service.

Endpoints

POST /oauth/token

In the login flow, you should call the /oauth/token endpoint with method POST.

note

There are two main types of authentication methods, which differ by the details employed to prove user identity. The secret basic is based on username and password, while the private key JWT requires as input a signed JWT.

Client secret basic

Request must have a body in x-www-form-urlencoded containing:

  • the grant_type=client_credentials
  • the audience (required only if the REQUIRED_AUDIENCE_IN_TOKEN_REQUEST environment variable is set to true)

and a basic authorization header set as Basic base64(clientId:clientSecret).

The client expected response is in application/json and contains:

  • access_token: jwt signed with private key;
  • expires_in: how many seconds the token is valid;
  • token_type: type of the token. It is Bearer.

In case the clientId and clientSecret pair does not exist on the database, it is returned an unauthorized error (HTTP code 401) with a brief explanation.

The returned access token is structured as follows:

  • the header contains, besides the algorithm adopted to generate the token and the token type, the kid field to address the correct signature key used in the token verification procedure.

    caution

    A token without the kid field is considered invalid.

  • the payload containing the following claims:

    • iss: the issuer of the token. Passed from env variable ISSUER_CLAIMS;
    • sub: the subject requesting the token. It is set to the clientId;
    • exp: the expiration unix timestamp in second of the token;
    • iat: the time at which the JWT was issued;
    • permissions: array of the permissions of the client which has issued the token;
    • jti: the id of the JWT;
    • aud: the audiences of the JWT.
  • its signature

Example CURL request:

curl --location \
--request POST 'http://client-credentials/oauth/token' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--header 'Authorization: Basic base64(client_id:client_secret)' \
--data-urlencode 'grant_type=client_credentials' \
--data-urlencode 'audience=aud1'

Example response:

{
"access_token": "eyJhbGciOiJSUzI1NiIsImtpZCI6ImtleUlEIiwidHlwIjoiSldUIn0.eyJleHAiOjE1OTE3OTg1OTYsImlhdCI6MTU5MTc5NDk5NiwiaXNzIjoidGVzdC1pc3N1ZXIiLCJzdWIiOiJjbGllbnQtaWQiLCJwZXJtaXNzaW9ucyI6W119.tfuIjL8ZN7dFmtT3n9NQLxY6Jhq1BoVZwb_LhTZS0zLNqxNQjQA-5-bN6-vne1ZJg9fBeRkq3aKxGjWCuruXTjYRfDLZwMSFoP3ki6NtUrdAqbse_c2J6DgI5m_F44NOZJFGZ8fbMydox5HV19swaozF32-aFN7UN53zZ7wV0tMdVXc-Nvf2WU8udGVXlqNtlMpQC2JZjSh8GeOljxZD4O6PDmp55ZoIcp7TscEzywT4yzUVJ78cLvMx1_rgZTto687XPJYdiqjdsI5kg7mSDH7_Bn9BfAR3Ln6qrPC_VieqAWf8-YmloyQNxx8dER8Yl-vDMCkHp3Z9Hla0XOrrm9F8IEyEQj5qmA_3TewppaDn3lu8Q4qYy_7v5lGSWTfx8PwaNHT5rRnDz10FI59KjM4WMzheTkqJ0Bw3dR-p1huF6iqoMsvnw5HfvdyyYP9_mMu0uw4JZiXInIR3qtmGZF6QGeeYK-l1atx1QRq-O5jvqZUy2hYFsJCLQEAHhF2jU5bWjbMjDsgSn1FHnzJY7IjRUNND6BuT4aBJzz0nspwy4fZhJTLrLLwFI3cjt17m5Ngrb9JY88dhGXLhAnWzjIDPWDM7Ao4YfQ2DHp2CM0P5OBB9sy8kXCgvv4ICAXv4cIEXIaMCE7QsPLHX8UqdwvP7-ygOyvCRRY_5seT70GQ",
"token_type": "Bearer",
"expires_in": 3600
}

Private key JWT

Request must have a body in x-www-form-urlencoded containing the follow parameters:

  • grant_type set to client_credentials
  • client_assertion_type set to urn:ietf:params:oauth:client-assertion-type:jwt-bearer
  • client_assertion set to the assertion JWT
  • client_id id of the client
  • token_endpoint_auth_method select which authentication method is adopted (in this case it should be set to private_key_jwt)

The assertion JWT must contain:

  • in the header the kid field, whose value has been defined during the registration phase

  • in the payload the claims specified by this spec:

    • iss (issuer): client_id of the oauth client;
    • sub (subject): client_id of the oauth client;
    • aud (audience): the issuer given to client credential;
    • jti (jwt id): a unique identifier of the token. The token must be used only once;
    • exp (expiration time): expiration time of the token, in unix timestamp;
    • iat (issued at): time at which the token is issued;
    • requested_audiences: an array of the requested audience.
caution

In case the assertion JWT does not contain all the detailed fields, it is considered invalid and the authentication is rejected with a forbidden error (code 403 HTTP)

Below is provided an example of assertion JWT components:

Header:

{
"alg": "RS256",
"kid": "kid-1",
"typ": "JWT"
}

Payload:

{
"iss": "<client-id>",
"sub": "<client-id>",
"aud": "test-issuer",
"jti": "0cda23a7b55ef6fa8afd01cbd1c7c70e",
"iat": "1604573964",
"exp": "1604577564",
"requested_audiences": [ "audience-1" ]
}

Example of CURL request:

curl --location \
--request POST 'http://client-credentials/oauth/token' \
--header 'Content-Type: application/x-www-form-urlencoded' \
--data-urlencode 'grant_type=client_credentials' \
--data-urlencode 'client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer' \
--data-urlencode 'client_assertion=<assertion-JWT>' \
--data-urlencode 'client_id=<client-id>' \
--data-urlencode 'token_endpoint_auth_method=private_key_jwt'

GET /.well-known/jwks.json

Client credentials service exposes an endpoint .well-known/jwks.json with an object with the key keys, containing an array of JWK values. Those JWKs could be used to verify the signature of the JWT.

The order of the keys in array has not a specific meaning.

The JWK contains:

  • kid: the key id. This key is set in JWT header. You must use the key with same kid of your JWT to verify the signature. It is not possible to have multiple key with the same kid;
  • use: use of the JWK. For this service all the keys will be sig (signature);
  • alg: algorithm used by the key. For this service is used RS256;
  • kty: key cryptographic name (RSA for RSA keys);
  • n: the modulus value of the RSA public key. It is represented as a Base64urlUInt-encoded value;
  • e: the exponent value for the RSA public key. It is represented as a Base64urlUInt-encoded value.

Example CURL request:

curl 'http://localhost:8080/.well-known/jwks.json'

Example response:

{
"keys": [
{
"kid": "kid",
"use": "sig",
"kty": "RSA",
"alg": "RSA256",
"n": "sR6WjRHDNXgzBTgYr-ayhSlxdt65FIrhTytZN9dZczDC8Uqt6Cynstq3eoAfLcrxKAyj4X3J4TRxSEOL78WUisLAADHU6oEsqeuB97kVN4PcPnd63H3naOiLioc2-9L1TtUMVB4H6G5ZkKQAgrwjpHSztJF0iYaXOQhEcBlCynltuEVuyK96tvnDVqXCfhsSFweP7KorcfMj4YYj5OT2ADlAFzBQ2qppd9BpJidHGD6auCsI7vjmNCEq49v9UOiQs2XbjN-ddr9nvNBBK5bVtjGkfUPNt6uAV1AWMboVjobcAnDH2AD8W--3JUl1ffguC_fsHpPjrNoH0hCbPFfEb2YK2DX1vKhYKX3u199gc4B1q0l1JTs8AJcFbf7d63FKa6O-5V97fLK9lJYd8adF8NZiJlXjFCR-LmAYmjxmsBmByImEenEzDxuuubitSWFt47L9eGV9eY7zmnD0FV_jbwXYCcod4R46vnjabzpUcnd3VqiruUwnquHNGgj2yJpT7CMCHpK9dVlMUY8cWIfYXn4si_RrRp_E2EIkWKkSyplBWMjIK_KhjuSi_YOYNSg3OKXOGmYMcCxXUnwPIIW5n-MdbO6WC8bqhpLU1_XisfaL-V8jEOjAs0dQ9dQyvvP9ckrC753FGARXtdqwnyb2d3r3r3cLh-eQo05TyLqHoEk",
"e": "AQAB"
}
]
}

It is important to emphasize that, as stated by RFC7517

The member names within a JWK Set MUST be unique; JWK Set parsers MUST either reject JWK Sets with duplicate member names or use a JSON parser that returns only the lexically last duplicate member name [...].

GET /tokeninfo

Calling this endpoint passing a valid Mia-Platform JWT, it returns 200 with the claims in an object. Here it is checked the validity of the JWT, if it is not passed or it is not valid this endpoint returns 401. If in the JWT is present an audience, it will be checked with the audience passed in ACCEPTED_AUDIENCES env variable.

Example CURL request:

curl --location --request GET 'http://client-credential-host/tokeninfo' \
--header 'Authorization: Bearer {{myJWT}}' \

Example response:

{
"exp": 1592233216,
"jti": "b29b64dd-1d62-461b-9be6-6efe3ff32237",
"iat": 1592229616,
"iss": "mia-issuer",
"sub": "rPxwZcgeFRJPgnnabMZrJWMemMBJjaSB",
"permissions": ["my permission 1", "my permission 2"],
"aud": ["my-aud"]
}

POST /register

The register endpoint has different auth method. The supported methods are client_secret_basic and private_key_jwt). One client has only one method possible.

The default method (if is not passed during registration) is the client_secret_basic.

Once called the endpoint, the client information will be saved in the CRUD with empty audience and permissions. You can add and change the fields manually on the CRUD or set up a CMS page and update them directly from the CMS.

Client secret basic

This endpoint generates a new client id and client secret pair with given applicationId. It follows the RFC to register to a client.

It returns 201 when credential pair and client is correctly generated, 401 otherwise.

curl --location --request POST 'http://client-credential-host/register' \
--header 'Content-Type: application/json' \
--data-raw '{
"client_name": "my client name"
}'

Example response:

{
"client_id": "rPxwZcgeFRJPgnnabMZrJWMemMBJjaSB",
"client_secret": "ugmWIVfZoTBKTXzADXJsJJexuMhCYxocxaKqkOlEYavgcEBr",
"client_secret_expires_at": 0,
"client_id_issued_at": 1592229239
}
note

Note that the client_secret field will only be available during registration so take care to save it locally.

Private key JWT

It is possible to pass the token_endpoint_auth_method parameter in input set to private_key_jwt.

note

You can use this guide to generate JWT public and private key suitable for this operation.

For this auth method, it is created a client. The client information are accessible from the CRUD, so it is possible to set a CMS page and change the permissions of the client directly from the CMS.

It returns 201 when client is correctly generated, 401 otherwise.

curl --location --request POST 'http://client-credential-host/register' \
--header 'Content-Type: application/json' \
--data-raw '{
"client_name": "my client name",
"token_endpoint_auth_method": "private_key_jwt",
"public_key": {
"kid": "kid",
"use": "sig",
"kty": "RSA",
"alg": "RSA256",
"n": "sR6WjRHDNXgzBTgYr-ayhSlxdt65FIrhTytZN9dZczDC8Uqt6Cynstq3eoAfLcrxKAyj4X3J4TRxSEOL78WUisLAADHU6oEsqeuB97kVN4PcPnd63H3naOiLioc2-9L1TtUMVB4H6G5ZkKQAgrwjpHSztJF0iYaXOQhEcBlCynltuEVuyK96tvnDVqXCfhsSFweP7KorcfMj4YYj5OT2ADlAFzBQ2qppd9BpJidHGD6auCsI7vjmNCEq49v9UOiQs2XbjN-ddr9nvNBBK5bVtjGkfUPNt6uAV1AWMboVjobcAnDH2AD8W--3JUl1ffguC_fsHpPjrNoH0hCbPFfEb2YK2DX1vKhYKX3u199gc4B1q0l1JTs8AJcFbf7d63FKa6O-5V97fLK9lJYd8adF8NZiJlXjFCR-LmAYmjxmsBmByImEenEzDxuuubitSWFt47L9eGV9eY7zmnD0FV_jbwXYCcod4R46vnjabzpUcnd3VqiruUwnquHNGgj2yJpT7CMCHpK9dVlMUY8cWIfYXn4si_RrRp_E2EIkWKkSyplBWMjIK_KhjuSi_YOYNSg3OKXOGmYMcCxXUnwPIIW5n-MdbO6WC8bqhpLU1_XisfaL-V8jEOjAs0dQ9dQyvvP9ckrC753FGARXtdqwnyb2d3r3r3cLh-eQo05TyLqHoEk",
"e": "AQAB"
}
}'

Example response:

{
"client_id": "rPxwZcgeFRJPgnnabMZrJWMemMBJjaSB",
"client_id_issued_at": 1592229239
}

Supported Authentication Flow

Below are reported the authentication flows that are supported by Client Credentials service. The flows are sequence diagrams descriptions.

Login flow

Below it is visible the sequence diagram of the login flow:

sequenceDiagram title: Login client credentials participant client participant clcr_service participant crud_service note over client: grant_type in body <br> client_id&client_secret in Basic header client->>clcr_service: POST /oauth/token clcr_service->>crud_service: GET {client_id,hash_client_secret} clcr_service->>clcr_service: generate Mia JWT note over clcr_service: iss: my-idp <br> sub: client-id <br> aud: permission <br> exp: expiration <br> iat: jwt issue date <br> jti: jwt id clcr_service->>client: {access_token, expires_in, token_type}

Authorization flow (internal client)

Below it is visible the sequence diagram of the authorization flow from internal client:

sequenceDiagram title: Authentication flow from a console project participant client participant api_gateway participant authorization_service participant clcr_service participant resource_owner client->>api_gateway: GET /foobar api_gateway->>authorization_service: /auth {client-type,isbackoffice,method,path} authorization_service->>clcr_service: /tokeninfo {authorization Bearer AT} clcr_service->>clcr_service: verify token expiration,signature opt if not logged clcr_service->>authorization_service: 401 with error authorization_service->>api_gateway: 401 with error api_gateway->>client: 401 with error end clcr_service->>authorization_service: 200 {aud or permission,sub} note over authorization_service: authorization_service handle <br> groups,client-type and isbackoffice in logical expression, <br> we should add permissions authorization_service->>authorization_service: evaluate permissions opt if have not the permission authorization_service->>api_gateway: 401 with error api_gateway->>client: 401 with error end authorization_service->>api_gateway: 200 <br> {miauserid,miausergroups,miauserproperties,client-type} api_gateway->>resource_owner: GET /foobar {Authorization Bearer AT} + platform headers

Authorization flow (external client)

Below it is visible the sequence diagram of the authorization flow from external client:

sequenceDiagram title: Authentication flow from external with an AT participant client participant resource_owner participant clcr_service client->>resource_owner: GET /foobar {Authorization Bearer AT} resource_owner->>resource_owner: Take AT from request opt if AT not in request resource_owner->>client: 401 end resource_owner->>clcr_service: GET /.well-known/jwks.json clcr_service->>resource_owner: [keys] resource_owner->>resource_owner: validate AT JWT {expire,signature,..} opt if AT not valid resource_owner->>client: 401 end resource_owner->>resource_owner: verify permission opt if not enough permission resource_owner->client: 403 end resource_owner->>resource_owner: make some stuff resource_owner->>client: ok

Tokeninfo

Below it is visible the sequence diagram to access to the JWT info:

sequenceDiagram title: Tokeninfo participant client participant clcr_service client->>clcr_service: GET /tokeninfo header Authorization Bearer AT clcr_service->>clcr_service: check expiration clcr_service->>clcr_service: check signature clcr_service->>clcr_service: decode jwt clcr_service->>client: {permission: []}