fixup! Add ability to set cookie prefix for session cookies ( #87 )

.traefik.yml

@@ -109,6 +109,7 @@ testData:
   oidcEndSessionURL: https://accounts.google.com/logout # Provider's end session endpoint
   enablePKCE: false # Enables PKCE (Proof Key for Code Exchange) for additional security
   cookieDomain: "" # Explicit domain for session cookies (e.g., ".example.com" for multi-subdomain setups)
+  cookiePrefix: "" # Custom prefix for cookie names (e.g., "_oidc_myapp_" for session isolation between middleware instances)
   overrideScopes: false # When true, replaces default scopes instead of appending (default: false)
   refreshGracePeriodSeconds: 60 # Seconds before token expiry to attempt proactive refresh (default: 60)
 
@@ -658,6 +659,40 @@ configuration:
       Default: "" (auto-detected from request headers)
     required: false
 
+  cookiePrefix:
+    type: string
+    description: |
+      Custom prefix for session cookie names. This is essential for running multiple
+      middleware instances with different authorization requirements on the same domain.
+
+      By default, all middleware instances use the same cookie names (_oidc_raczylo_m,
+      _oidc_raczylo_a, etc.), which means they share session state. When you have
+      multiple instances with different access restrictions (e.g., one for general users
+      and one for admins), this session sharing can lead to authorization bypass issues.
+
+      Setting a unique cookiePrefix for each middleware instance ensures complete
+      session isolation, preventing users authenticated via one middleware from
+      automatically gaining access to routes protected by a different middleware.
+
+      The prefix is prepended to all session cookie names:
+      - Main session cookie: {prefix}m
+      - Access token cookie: {prefix}a
+      - Refresh token cookie: {prefix}r
+      - ID token cookie: {prefix}id
+
+      Examples:
+      - "_oidc_userauth_" - For general user authentication middleware
+      - "_oidc_adminauth_" - For admin-only authentication middleware
+      - "_oidc_api_" - For API-specific authentication middleware
+
+      Security Note: Use different cookie prefixes AND different sessionEncryptionKey
+      values for each middleware instance to ensure complete isolation.
+
+      Default: "_oidc_raczylo_" (standard prefix for backward compatibility)
+
+      See: https://github.com/lukaszraczylo/traefikoidc/issues/87
+    required: false
+
   overrideScopes:
     type: boolean
     description: |

README.md

@@ -128,6 +128,7 @@ The middleware supports the following configuration options:
 | `enablePKCE` | Enables PKCE (Proof Key for Code Exchange) for authorization code flow | `false` | `true`, `false` |
 | `refreshGracePeriodSeconds` | Seconds before token expiry to attempt proactive refresh | `60` | `120` |
 | `cookieDomain` | Explicit domain for session cookies (important for multi-subdomain setups) | auto-detected | `.example.com`, `app.example.com` |
+| `cookiePrefix` | Custom prefix for session cookie names (for isolating multiple middleware instances) | `_oidc_raczylo_` | `_oidc_userauth_`, `_oidc_admin_` |
 | `audience` | Custom audience for access token validation (for Auth0 custom APIs, etc.) | `clientID` | `https://my-api.example.com` |
 | `strictAudienceValidation` | Reject sessions with access token audience mismatch (prevents token confusion attacks) | `false` | `true` |
 | `allowOpaqueTokens` | Enable opaque (non-JWT) access token support via RFC 7662 introspection | `false` | `true` |
@@ -885,6 +886,54 @@ spec:
 
 **Important**: The `cookieDomain` parameter is crucial when running behind a reverse proxy or when your application serves multiple subdomains. Without it, cookies may be created with inconsistent domains, leading to authentication issues like "CSRF token missing in session" errors.
 
+### With Multiple Middleware Instances (Session Isolation)
+
+When running multiple middleware instances with different authorization requirements (e.g., one for general users and one for admins), you must use different `cookiePrefix` values to prevent session sharing between instances:
+
+```yaml
+# Middleware for general user authentication
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: oidc-userauth
+  namespace: traefik
+spec:
+  plugin:
+    traefikoidc:
+      providerURL: https://auth.example.com
+      clientID: your-client-id
+      clientSecret: your-client-secret
+      sessionEncryptionKey: user-key-at-least-32-bytes-long
+      callbackURL: /oauth2/callback
+      cookiePrefix: "_oidc_userauth_"  # Unique prefix for this instance
+---
+# Middleware for admin authentication with stricter requirements
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: oidc-adminauth
+  namespace: traefik
+spec:
+  plugin:
+    traefikoidc:
+      providerURL: https://auth.example.com
+      clientID: your-client-id
+      clientSecret: your-client-secret
+      sessionEncryptionKey: admin-key-at-least-32-bytes-long  # Different encryption key
+      callbackURL: /oauth2/admin/callback  # Different callback URL
+      cookiePrefix: "_oidc_adminauth_"  # Different prefix for isolation
+      allowedUsers:  # Restricted to specific admin users
+        - [email protected]
+        - [email protected]
+```
+
+**Security Note**: When running multiple instances, ensure you use:
+1. **Different `cookiePrefix`** values to prevent cookie name collisions
+2. **Different `sessionEncryptionKey`** values for complete session isolation
+3. **Different `callbackURL`** paths to avoid routing conflicts
+
+This configuration prevents authorization bypass issues where a user authenticated via the general middleware could access admin-protected routes. See [issue #87](https://github.com/lukaszraczylo/traefikoidc/issues/87) for more details.
+
 ### With Custom Logging and Rate Limiting
 
 ```yaml