Traefik OIDC Middleware

This middleware replaces the need for forward-auth and oauth2-proxy when using Traefik as a reverse proxy to support OpenID Connect (OIDC) authentication.

Overview

The Traefik OIDC middleware provides a complete OIDC authentication solution with features like:

• Token validation and verification
• Session management
• Domain restrictions
• Role-based access control
• Token caching and blacklisting
• Rate limiting
• Excluded paths (public URLs)

The middleware has been tested with Auth0 and Logto, but should work with any standard OIDC provider.

Traefik Version Compatibility

This middleware follows closely the current Traefik helm chart versions. If the plugin fails to load, it's time to update to the latest version of the Traefik helm chart.

Installation

As a Traefik Plugin

1. Enable the plugin in your Traefik static configuration:

# traefik.yml
experimental:
  plugins:
    traefikoidc:
      moduleName: github.com/lukaszraczylo/traefikoidc
      version: v0.2.1  # Use the latest version

2. Configure the middleware in your dynamic configuration (see examples below).

Local Development with Docker Compose

For local development or testing, you can use the provided Docker Compose setup:

cd docker
docker-compose up -d

This will start Traefik with the OIDC middleware and two test services.

Configuration Options

The middleware supports the following configuration options:

Required Parameters

Parameter	Description	Example
providerURL	The base URL of the OIDC provider	https://accounts.google.com
clientID	The OAuth 2.0 client identifier	1234567890.apps.googleusercontent.com
clientSecret	The OAuth 2.0 client secret	your-client-secret
sessionEncryptionKey	Key used to encrypt session data (must be at least 32 bytes long)	potato-secret-is-at-least-32-bytes-long
callbackURL	The path where the OIDC provider will redirect after authentication	/oauth2/callback

Optional Parameters

Parameter	Description	Default	Example
logoutURL	The path for handling logout requests	callbackURL + "/logout"	/oauth2/logout
postLogoutRedirectURI	The URL to redirect to after logout	/	/logged-out-page
scopes	The OAuth 2.0 scopes to request	["openid", "profile", "email"]	["openid", "email", "profile", "roles"]
logLevel	Sets the logging verbosity	info	debug, info, error
	forceHTTPS	Forces the use of HTTPS for all URLs	true
	rateLimit	Sets the maximum number of requests per second	100
	excludedURLs	Lists paths that bypass authentication	["/favicon"]
	allowedUserDomains	Restricts access to specific email domains	none
	allowedRolesAndGroups	Restricts access to users with specific roles or groups	none
	revocationURL	The endpoint for revoking tokens	auto-discovered
	oidcEndSessionURL	The provider's end session endpoint	auto-discovered
	enablePKCE	Enables PKCE (Proof Key for Code Exchange) for authorization code flow	false

Usage Examples

Basic Configuration

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-basic
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      scopes:
        - openid
        - email
        - profile

With Excluded URLs (Public Access Paths)

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-with-open-urls
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      scopes:
        - openid
        - email
        - profile
      excludedURLs:
        - /login        # covers /login, /login/me, /login/reminder etc.
        - /public-data
        - /health
        - /metrics

With Email Domain Restrictions

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-domain-restricted
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      scopes:
        - openid
        - email
        - profile
      allowedUserDomains:
        - company.com
        - subsidiary.com

With Role-Based Access Control

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-rbac
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      scopes:
        - openid
        - email
        - profile
        - roles     # Include this to get role information from the provider
      allowedRolesAndGroups:
        - admin
        - developer

With Custom Logging and Rate Limiting

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-custom-settings
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      logLevel: debug    # Options: debug, info, error (default: info)
      rateLimit: 500     # Requests per second (default: 100)
      forceHTTPS: false  # Default is true for security
      scopes:
        - openid
        - email
        - profile

With Custom Post-Logout Redirect

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-custom-logout
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      postLogoutRedirectURI: /logged-out-page  # Where to redirect after logout
      scopes:
        - openid
        - email
        - profile

With PKCE Enabled

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-with-pkce
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: https://accounts.google.com
      clientID: 1234567890.apps.googleusercontent.com
      clientSecret: your-client-secret
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      enablePKCE: true  # Enables PKCE for added security
      scopes:
        - openid
        - email
        - profile

Keeping Secrets Secret in Kubernetes

For Kubernetes environments, you can reference secrets instead of hardcoding sensitive values:

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: oidc-with-secrets
  namespace: traefik
spec:
  plugin:
    traefikoidc:
      providerURL: urn:k8s:secret:traefik-middleware-oidc:ISSUER
      clientID: urn:k8s:secret:traefik-middleware-oidc:CLIENT_ID
      clientSecret: urn:k8s:secret:traefik-middleware-oidc:SECRET
      sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
      callbackURL: /oauth2/callback
      logoutURL: /oauth2/logout
      scopes:
        - openid
        - email
        - profile

Don't forget to create the secret:

kubectl create secret generic traefik-middleware-oidc \
  --from-literal=ISSUER=https://accounts.google.com \
  --from-literal=CLIENT_ID=1234567890.apps.googleusercontent.com \
  --from-literal=SECRET=your-client-secret \
  -n traefik

Complete Docker Compose Example

Here's a complete example of using the middleware with Docker Compose:

version: "3.7"

services:
  traefik:
    image: traefik:v3.2.1
    command:
      - "--experimental.plugins.traefikoidc.modulename=github.com/lukaszraczylo/traefikoidc"
      - "--experimental.plugins.traefikoidc.version=v0.2.1"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - ./traefik-config/traefik.yml:/etc/traefik/traefik.yml
      - ./traefik-config/dynamic-configuration.yml:/etc/traefik/dynamic-configuration.yml
    labels:
      - "traefik.http.routers.dash.rule=Host(`dash.localhost`)"
      - "traefik.http.routers.dash.service=api@internal"
    ports:
      - "80:80"

  hello:
    image: containous/whoami
    labels:
      - traefik.enable=true
      - traefik.http.routers.hello.entrypoints=http
      - traefik.http.routers.hello.rule=Host(`hello.localhost`)
      - traefik.http.services.hello.loadbalancer.server.port=80
      - traefik.http.routers.hello.middlewares=my-plugin@file

  whoami:
    image: jwilder/whoami
    labels:
      - traefik.enable=true
      - traefik.http.routers.whoami.entrypoints=http
      - traefik.http.routers.whoami.rule=Host(`whoami.localhost`)
      - traefik.http.services.whoami.loadbalancer.server.port=8000
      - traefik.http.routers.whoami.middlewares=my-plugin@file

traefik-config/traefik.yml:

log:
  level: INFO

experimental:
  localPlugins:
    traefikoidc:
      moduleName: github.com/lukaszraczylo/traefikoidc

# API and dashboard configuration
api:
  dashboard: true
  insecure: true

entryPoints:
  http:
    address: ":80"
    forwardedHeaders:
      insecure: true

providers:
  docker:
    endpoint: "unix:///var/run/docker.sock"
    exposedByDefault: false
  file:
    filename: /etc/traefik/dynamic-configuration.yml

traefik-config/dynamic-configuration.yml:

http:
  middlewares:
    my-plugin:
      plugin:
        traefikoidc:
          providerURL: https://accounts.google.com
          clientID: 1234567890.apps.googleusercontent.com
          clientSecret: your-client-secret
          callbackURL: /oauth2/callback
          logoutURL: /oauth2/logout
          postLogoutRedirectURI: /logged-out-page
          sessionEncryptionKey: potato-secret-is-at-least-32-bytes-long
          scopes:
            - openid
            - email
            - profile
          allowedUserDomains:
            - company.com
          allowedRolesAndGroups:
            - admin
            - developer
          forceHTTPS: false
          logLevel: debug
          rateLimit: 100
          excludedURLs:
            - /login
            - /public
            - /health
            - /metrics

Advanced Configuration

Session Management

The middleware uses encrypted cookies to manage user sessions. The sessionEncryptionKey must be at least 32 bytes long and should be kept secret.

PKCE Support

The middleware supports PKCE (Proof Key for Code Exchange), which is an extension to the authorization code flow to prevent authorization code interception attacks. When enabled via the enablePKCE option, the middleware will generate a code verifier for each authentication request and derive a code challenge from it. The code verifier is stored in the user's session and sent during the token exchange process.

PKCE is recommended when:

• Your OIDC provider supports it (most modern providers do)
• You need an additional layer of security for the authorization code flow
• You're concerned about potential authorization code interception attacks

Note that not all OIDC providers support PKCE, so check your provider's documentation before enabling this feature.

Token Caching and Blacklisting

The middleware automatically caches validated tokens to improve performance and maintains a blacklist of revoked tokens.

Headers Set for Downstream Services

When a user is authenticated, the middleware sets the following headers for downstream services:

• X-Forwarded-User: The user's email address
• X-User-Groups: Comma-separated list of user groups (if available)
• X-User-Roles: Comma-separated list of user roles (if available)
• X-Auth-Request-Redirect: The original request URI
• X-Auth-Request-User: The user's email address
• X-Auth-Request-Token: The user's access token

Security Headers

The middleware also sets the following security headers:

• X-Frame-Options: DENY
• X-Content-Type-Options: nosniff
• X-XSS-Protection: 1; mode=block
• Referrer-Policy: strict-origin-when-cross-origin

Troubleshooting

Logging

Set the logLevel to debug to get more detailed logs:

logLevel: debug

Common Issues

1. Token verification failed: Check that your providerURL is correct and accessible.
2. Session encryption key too short: Ensure your sessionEncryptionKey is at least 32 bytes long.
3. No matching public key found: The JWKS endpoint might be unavailable or the token's key ID (kid) doesn't match any key in the JWKS.
4. Access denied: Your email domain is not allowed: The user's email domain is not in the allowedUserDomains list.
5. Access denied: You do not have any of the allowed roles or groups: The user doesn't have any of the roles or groups specified in allowedRolesAndGroups.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.