#random (2023-05)

Sudhish KR’s personal website

title: openid-connect
keywords:

• Apache APISIX • API Gateway • OpenID Connect • OIDC
description: OpenID Connect allows the client to obtain user information from the identity providers, such as Keycloak, Ory Hydra, Okta, Auth0, etc. API Gateway APISIX supports to integrate with the above identity providers to protect your APIs.

Description

OpenID Connect (OIDC) is an authentication protocol based on the OAuth 2.0. It allows the client to obtain user information from the identity provider (IdP), e.g., Keycloak, Ory Hydra, Okta, Auth0, etc. API Gateway Apache APISIX supports to integrate with the above identity providers to protect your APIs.

Attributes

NOTE: encrypt_fields = {"client_secret"} is also defined in the schema, which means that the field will be stored encrypted in etcd. See encrypted storage fields.

Scenarios

:::tip

Tutorial: Use Keycloak with API Gateway to secure APIs

:::

This plugin offers two scenorios:

1. Authentication between Services: Set bearer_only to true and configure the introspection_endpoint or public_key attribute. In this scenario, APISIX will reject requests without a token or invalid token in the request header.
2. Authentication between Browser and Identity Providers: Set bearer_only to false. After successful authentication, this plugin can obtain and manage the token in the cookie, and subsequent requests will use the token. In this mode, the user session will be stored in the browser as a cookie and this data is encrypted, so you have to set a key for encryption via session.secret.

Token introspection

Token introspection validates a request by verifying the token with an OAuth 2.0 authorization server.

You should first create a trusted client in the identity server and generate a valid JWT token for introspection.

The image below shows an example token introspection flow via a Gateway:

token introspection

The example below shows how you can enable the Plugin on Route. The Route below will protect the Upstream by introspecting the token provided in the request header:

curl <http://127.0.0.1:9180/apisix/admin/routes/5> -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "uri": "/get",
  "plugins":{
    "openid-connect":{
      "client_id": "${CLIENT_ID}",
      "client_secret": "${CLIENT_SECRET}",
      "discovery": "${DISCOVERY_ENDPOINT}",
      "introspection_endpoint": "${INTROSPECTION_ENDPOINT}",
      "bearer_only": true,
      "realm": "master",
      "introspection_endpoint_auth_method": "client_secret_basic"
    }
  },
  "upstream":{
    "type": "roundrobin",
    "nodes":{
      "httpbin.org:443":1
    }
  }
}'

Now, to access the Route:

curl -i -X GET <http://127.0.0.1:9080/get> -H "Host: httpbin.org" -H "Authorization: Bearer {JWT_TOKEN}"

In this example, the Plugin enforces that the access token and the Userinfo object be set in the request headers.

When the OAuth 2.0 authorization server returns an expire time with the token, it is cached in APISIX until expiry. For more details, read:

1. lua-resty-openidc’s documentation and source code.
2. exp field in the RFC’s Introspection Response section.

Introspecting with public key

You can also provide the public key of the JWT token for verification. If you have provided a public key and a token introspection endpoint, the public key workflow will be executed instead of verification through an identity server. This is useful if you want to reduce network calls and speedup the process.

The example below shows how you can add public key introspection to a Route:

curl <http://127.0.0.1:9180/apisix/admin/routes/5> -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "uri": "/get",
  "plugins":{
    "openid-connect":{
      "client_id": "${CLIENT_ID}",
      "client_secret": "${CLIENT_SECRET}",
      "discovery": "${DISCOVERY_ENDPOINT}",
      "bearer_only": true,
      "realm": "master",
      "token_signing_alg_values_expected": "RS256",
      "public_key": "-----BEGIN PUBLIC KEY-----
      {public_key}
      -----END PUBLIC KEY-----"
    }
  },
  "upstream":{
    "type": "roundrobin",
    "nodes":{
      "httpbin.org:443":1
    }
  }
}'

In this example, the Plugin can only enforce that the access token should be set in the request headers.

Authentication through OIDC Relying Party flow

When an incoming request does not contain an access token in its header nor in an appropriate session cookie, the Plugin can act as an OIDC Relying Party and redirect to the authorization endpoint of the identity provider to go through the OIDC authorization code flow.

Once the user has authenticated with the identity provider, the Plugin will obtain and manage the access token and further interaction with the identity provider. The access token will be stored in a session cookie.

The example below adds the Plugin with this mode of operation to the Route:

curl <http://127.0.0.1:9180/apisix/admin/routes/5> -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "uri": "/get",
  "plugins": {
    "openid-connect": {
      "client_id": "${CLIENT_ID}",
      "client_secret": "${CLIENT_SECRET}",
      "discovery": "${DISCOVERY_ENDPOINT}",
      "bearer_only": false,
      "realm": "master"
    }
  },
  "upstream": {
    "type": "roundrobin",
    "nodes": {
      "httpbin.org:443": 1
    }
  }
}'

In this example, the Plugin can enforce that the access token, the ID token, and the UserInfo object to be set in the request headers.

Troubleshooting

1. If APISIX cannot resolve/connect to the identity provider (e.g., Okta, Keycloak, Authing), check/modify the DNS settings in your configuration file (conf/config.yaml).
2. If you encounter the error the error request to the redirect_uri path, but there's no session state found, please confirm whether the currently accessed URL carries code and state, and do not directly access redirect_uri.
3. If you encounter the error the error request to the redirect_uri path, but there's no session state found, please check the redirect_uri attribute : APISIX will initiate an authentication request to the identity provider, after the authentication service completes the authentication and authorization logic, it will redirect to the address configured by redirect_uri (e.g., <http://127.0.0.1:9080/callback>) with ID Token and AccessToken, and then enter APISIX again and complete the function of token exchange in OIDC logic. The redirect_uri attribute needs to meet the following conditions:

• redirect_uri needs to be captured by the route where the current APISIX is located. For example, the uri of the current route is /api/v1/*, redirect_uri can be filled in as /api/v1/callback; • scheme and host of redirect_uri (scheme:host) are the values required to access APISIX from the perspective of the identity provider.

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