OAuth

Gloo Edge supports authentication via OpenID Connect (OIDC). OIDC is an identity layer on top of the OAuth 2.0 protocol. In OAuth 2.0 flows, authentication is performed by an external Identity Provider (IdP) which, in case of success, returns an Access Token representing the user identity. The protocol does not define the contents and structure of the Access Token, which greatly reduces the portability of OAuth 2.0 implementations.

The goal of OIDC is to address this ambiguity by additionally requiring Identity Providers to return a well-defined ID Token. OIDC ID tokens follow the JSON Web Token standard and contain specific fields that your applications can expect and handle. This standardization allows you to switch between Identity Providers - or support multiple ones at the same time - with minimal, if any, changes to your downstream services; it also allows you to consistently apply additional security measures like Role-based Access Control (RBAC) based on the identity of your users, i.e. the contents of their ID token (check out this guide for an example of how to use Gloo Edge to apply RBAC policies to JWTs).

In this guide, we will focus on the format of the Gloo Edge API for OIDC authentication.

Configuration format

Following is an example of an AuthConfig with an OIDC configuration (for more information on AuthConfig CRDs, see the main page of the authentication docs):

apiVersion: enterprise.gloo.solo.io/v1
kind: AuthConfig
metadata:
  name: oidc
  namespace: gloo-system
spec:
  configs:
  - oauth2:
      oidcAuthorizationCode:
        issuerUrl: theissuer.com
        appUrl: https://myapp.com
        authEndpoint_query_params:
          paramKey: paramValue
        callbackPath: /my/callback/path/
        clientId: myclientid
        clientSecretRef:
          name: my-oauth-secret
          namespace: gloo-system
        scopes:
        - email

The AuthConfig consists of a single config of type oauth. Let’s go through each of its attributes:

• issuer_url: The url of the OpenID Connect identity provider. Gloo Edge will automatically discover OpenID Connect configuration by querying the .well-known/openid-configuration endpoint on the issuer_url. For example, if you are using Google as an identity provider, Gloo Edge will expect to find OIDC discovery information at https://accounts.google.com/.well-known/openid-configuration.
• auth_endpoint_query_params: A map of query parameters appended to the issuer url in the form issuer_url?paramKey:paramValue. These query parameters are sent to the authorization endpoint when Gloo Edge initiates the OIDC flow. This can be useful when integrating Gloo Edge with some identity providers that require custom parameters to be sent to the authorization endpoint.
• app_url: This is the public URL of your application. It is used in combination with the callback_path attribute.
• callback_path: The callback path relative to the app_url. Once a user has been authenticated, the identity provider will redirect them to this URL. Gloo Edge will intercept requests with this path, exchange the authorization code received from the Identity Provider for an ID token, place the ID token in a cookie on the request, and forward the request to its original destination.

• client_id: This is the client id that you obtained when you registered your application with the identity provider.
• client_secret_ref: This is a reference to a Kubernetes secret containing the client secret that you obtained when you registered your application with the identity provider. The easiest way to create the Kubernetes secret in the expected format is to use glooctl, but you can also provide it by kubectl applying YAML to your cluster:
  • glooctl
  • kubectl

  
  glooctl create secret oauth --namespace gloo-system --name oidc --client-secret secretvalue
  

  
  apiVersion: v1
  kind: Secret
  type: extauth.solo.io/oauth
  metadata:
    name: oidc
    namespace: gloo-system
  data:
    # The value is a base64 encoding of the following YAML:
    # client_secret: secretvalue
    # Gloo Edge expects OAuth client secrets in this format.
    client-secret: Y2xpZW50U2VjcmV0OiBzZWNyZXR2YWx1ZQo=
  

• scopes: scopes to request in addition to the openid scope.

Cookie options

Use the cookieOptions field to customize cookie behavior:

• notSecure - Set the cookie to not secure. This is not recommended, but might be useful for demo/testing purposes.
• maxAge - The max age of the cookie in seconds. Leave unset for a default of 30 days (2592000 seconds). To disable cookie expiry, set explicitly to 0.
• path - The path of the cookie. If unset, it defaults to “/". Set it explicitly to "” to avoid setting a path.
• domain - The domain of the cookie. The default value is empty and matches only the originating request. This is fine for cases where the VirtualService matches the host value that is also the redirect target of the IdP. However, this value is critical if the OAuth provider is redirecting the request to another subdomain, for example. Consider a case where a VirtualService matches requests to *.example.com and the IdP redirects its auth requests to subdomain.example.com. With default settings for domain, if a request comes in on other.example.com, the operation fails. The user is directed to the IdP login as expected but auth fails because the token-bearing cookie is not sent back to the proxy, since the request originates from a different subdomain. However, if this domain property is set to example.com, then the operation succeeds because the cookie is sent to any subdomain of example.com.

Example configuration:

apiVersion: enterprise.gloo.solo.io/v1
kind: AuthConfig
metadata:
  name: oidc-dex
  namespace: gloo-system
spec:
  configs:
  - oauth2:
      oidcAuthorizationCode:
        appUrl: http://localhost:8080/
        callbackPath: /callback
        clientId: gloo
        clientSecretRef:
          name: oauth
          namespace: gloo-system
        issuerUrl: http://dex.gloo-system.svc.cluster.local:32000/
        scopes:
        - email
        session:
          cookieOptions:
            notSecure: true
            maxAge: 3600

Logout URL

Gloo also supports specifying a logout url. When specified, accessing this url will trigger a deletion of the user session and revoke the user’s access token. This action returns with an empty 200 HTTP response.

Example configuration:

apiVersion: enterprise.gloo.solo.io/v1
kind: AuthConfig
metadata:
  name: oidc-dex
  namespace: gloo-system
spec:
  configs:
  - oauth2:
      oidcAuthorizationCode:
        appUrl: http://localhost:8080/
        callbackPath: /callback
        clientId: gloo
        clientSecretRef:
          name: oauth
          namespace: gloo-system
        issuerUrl: http://dex.gloo-system.svc.cluster.local:32000/
        scopes:
        - email
        logoutPath: /logout

When this URL is accessed, the user session and cookie are deleted. The access token on the server is also revoked based on the discovered revocation endpoint. You can also override the revocation endpoint through the [DiscoveryOverride field] /gloo-edge/latest/reference/api/github.com/solo-io/gloo/projects/gloo/api/v1/enterprise/options/extauth/v1/extauth.proto.sk/#discoveryoverride ) in AuthConfig.

Sessions in Redis

By default, the tokens will be saved in a secure client side cookie. Gloo can instead use Redis to save the OIDC tokens, and set a randomly generated session id in the user’s cookie.

Example configuration:

apiVersion: enterprise.gloo.solo.io/v1
kind: AuthConfig
metadata:
  name: oidc-dex
  namespace: gloo-system
spec:
  configs:
  - oauth2:
      oidcAuthorizationCode:
        appUrl: http://localhost:8080/
        callbackPath: /callback
        clientId: gloo
        clientSecretRef:
          name: oauth
          namespace: gloo-system
        issuerUrl: http://dex.gloo-system.svc.cluster.local:32000/
        scopes:
        - email
        session:
          failOnFetchFailure: true
          redis:
            cookieName: session
            options:
              host: redis.gloo-system.svc.cluster.local:6379

Forwarding the ID token upstream

You can configure gloo to forward the id token to the upstream on successful authentication. To do that, set the headers section in the configuration.

Example configuration:

apiVersion: enterprise.gloo.solo.io/v1
kind: AuthConfig
metadata:
  name: oidc-dex
  namespace: gloo-system
spec:
  configs:
  - oauth2:
      oidcAuthorizationCode:
        appUrl: http://localhost:8080/
        callbackPath: /callback
        clientId: gloo
        clientSecretRef:
          name: oauth
          namespace: gloo-system
        issuerUrl: http://dex.gloo-system.svc.cluster.local:32000/
        scopes:
        - email
        headers:
          idTokenHeader: "x-token"

Examples

We have seen how a sample OIDC AuthConfig is structured. For complete examples of how to set up an OIDC flow with Gloo Edge, check out the following guides:

• Authenticate with Auth0: Integrating Gloo Edge and Auth0 for identity management

• Authenticate with Google: Setup OpenID Connect (OIDC) authentication with the Google identity provider.

• Authenticate with Okta: Integrating Gloo Edge and Okta Identity Cloud

• Authenticate with Dex: Integrating Gloo Edge and Dex Identity Provider

• Authenticate with an Access Token: Integrating Gloo Edge and Access Tokens