openid-connect

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

Name	Type	Required	Default	Valid values	Description
client_id	string	True			OAuth client ID.
client_secret	string	True			OAuth client secret.
discovery	string	True			Discovery endpoint URL of the identity server.
scope	string	False	"openid"		Scope used for authentication.
realm	string	False	"apisix"		Realm used for authentication.
bearer_only	boolean	False	false		When set to true, APISIX will only check if the authorization header in the request matches a bearer token.
logout_path	string	False	"/logout"		Path for logging out.
post_logout_redirect_uri	string	False			URL to redirect to after logging out.
redirect_uri	string	False	"ngx.var.request_uri"		URI to which the identity provider redirects back to.
timeout	integer	False	3	[1,...]	Request timeout time in seconds.
ssl_verify	boolean	False	false		When set to true, verifies the identity provider's SSL certificates.
introspection_endpoint	string	False			URL of the token verification endpoint of the identity server.
introspection_endpoint_auth_method	string	False	"client_secret_basic"		Authentication method name for token introspection.
token_endpoint_auth_method	string	False			Authentication method name for token endpoint. The default will get the first supported method specified by the OP.
public_key	string	False			Public key to verify the token.
use_jwks	boolean	False	false		When set to true, uses the JWKS endpoint of the identity server to verify the token.
use_pkce	boolean	False	false		when set to true, the "Proof Key for Code Exchange" as defined in RFC 7636 will be used.
token_signing_alg_values_expected	string	False			Algorithm used for signing the authentication token.
set_access_token_header	boolean	False	true		When set to true, sets the access token in a request header.
access_token_in_authorization_header	boolean	False	false		When set to true, sets the access token in the Authorization header. Otherwise, set the X-Access-Token header.
set_id_token_header	boolean	False	true		When set to true and the ID token is available, sets the ID token in the X-ID-Token request header.
set_userinfo_header	boolean	False	true		When set to true and the UserInfo object is available, sets it in the X-Userinfo request header.
set_refresh_token_header	boolean	False	false		When set to true and a refresh token object is available, sets it in the X-Refresh-Token request header.
session	object	False			When bearer_only is set to false, openid-connect will use Authorization Code flow to authenticate on the IDP, so you need to set the session-related configuration.
session.secret	string	True	Automatic generation	16 or more characters	The key used for session encrypt and HMAC operation.
unauth_action	string	False	"auth"		Specify the response type on unauthenticated requests. "auth" redirects to identity provider, "deny" results in a 401 response, "pass" will allow the request without authentication.

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:

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.