traefik-jwt-plugin

Traefik plugin for verifying JSON Web Tokens (JWT). Supports public keys, certificates or JWKS endpoints. Supports RSA, ECDSA and symmetric keys. Supports Open Policy Agent (OPA) for additional authorization checks.

Features:

• RS256, RS384, RS512, PS256, PS384, PS512, ES256, ES384, ES512, HS256, HS384, HS512
• Certificates or public keys can be configured in the dynamic config
• Supports JWK endpoints for fetching keys remotely
• Reject a request or Log warning when required field is missing from JWT payload
• Validate request with Open Policy Agent
• Adds the verified and decoded token to the OPA input

Installation

The plugin needs to be configured in the Traefik static configuration before it can be used.

Kubernetes

Tested with official Traefik chart version 26.0.0.

The following snippet should be added to values.yaml:

experimental:
  plugins:
    jwt:
      moduleName: github.com/traefik-plugins/traefik-jwt-plugin
      version: v0.7.1

Command line

traefik \
  --experimental.plugins.jwt.moduleName=github.com/traefik-plugins/traefik-jwt-plugin \
  --experimental.plugins.jwt.version=v0.7.1

Configuration

The plugin currently supports the following configuration settings: (all fields are optional)

Name	Description
OpaUrl	URL of OPA policy document requested for decision, e.g. http://opa:8181/v1/data/example.
OpaAllowField	Field in the JSON result which contains a boolean, indicating whether the request is allowed or not. Default allow.
OpaBody	Boolean indicating whether the request body should be added to the OPA input.
OpaDebugMode	Set the opa response in the http response body when the request isn't allowed otherwise the response body is forbidden
PayloadFields	The field-name in the JWT payload that are required (e.g. exp). Multiple field names may be specified (string array)
Required	Is Authorization header with JWT token required for every request.
Keys	Used to validate JWT signature. Multiple keys are supported. Allowed values include certificates, public keys, symmetric keys. In case the value is a valid URL, the plugin will fetch keys from the JWK endpoint.
ForceRefreshKeys	Force fetching keys from JWKS service when the key of current JWT token is not found. If set false, keys will only be refreshed every 15 minutes by default.
Alg	Used to verify which PKI algorithm is used in the JWT.
JwksHeaders	Map used to add headers to a JWKS request (e.g. credentials for a 3rd party JWKS service).
JwtHeaders	Map used to inject JWT payload fields as HTTP request headers.
OpaHeaders	Map used to inject OPA result fields as HTTP request headers. Populated if request is allowed by OPA. Only 1st level keys from OPA document are supported.
OpaResponseHeaders	Map used to inject OPA result fields as HTTP response headers. Populated if OPA response has OpaAllowField present, regardless of value. Only 1st level keys from OPA document are supported.
OpaHttpStatusField	Field in OPA JSON result, which contains int or string HTTP status code that will be returned in case of disallowed OPA response. Accepted range is >= 300 and < 600. Only 1st level keys from OPA document are supported.
JwtCookieKey	Name of the cookie to extract JWT if not found in Authorization header.
JwtQueryKey	Name of the query parameter to extract JWT if not found in Authorization header or in the specified cookie.

Example configuration

This example uses Kubernetes Custom Resource Descriptors (CRD) :

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: jwt
spec:
  plugin:
    jwt:
      OpaUrl: http://localhost:8181/v1/data/example
      OpaAllowField: allow
      OpaBody: true
      PayloadFields:
        - exp
      Required: true
      Keys:
        - https://samples.auth0.com/.well-known/jwks.json
        - |
          -----BEGIN PUBLIC KEY-----
          MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAnzyis1ZjfNB0bBgKFMSv
          vkTtwlvBsaJq7S5wA+kzeVOVpVWwkWdVha4s38XM/pa/yr47av7+z3VTmvDRyAHc
          aT92whREFpLv9cj5lTeJSibyr/Mrm/YtjCZVWgaOYIhwrXwKLqPr/11inWsAkfIy
          tvHWTxZYEcXLgAXFuUuaS3uF9gEiNQwzGTU1v0FqkqTBr4B8nW3HCN47XUu0t8Y0
          e+lf4s4OxQawWD79J9/5d3Ry0vbV3Am1FtGJiJvOwRsIfVChDpYStTcHTCMqtvWb
          V6L11BWkpzGXSW4Hv43qa+GSYOD2QU68Mb59oSk2OB+BtOLpJofmbGEGgvmwyCI9
          MwIDAQAB
        -----END PUBLIC KEY-----
      OpaHeaders:
        X-Allowed: allow
      JwtHeaders:
        X-Subject: sub
      OpaResponseHeaders:
        X-Allowed: allow
      OpaHttpStatusField: allow_status_code
      JwtCookieKey: jwt
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: test-server
  labels:
    app: test-server
  annotations:
    kubernetes.io/ingress.class: traefik
    traefik.ingress.kubernetes.io/router.middlewares: default-jwt@kubernetescrd

Open Policy Agent

The following section describes how to use this plugin with Open Policy Agent (OPA)

OPA input payload

The plugin will translate the HTTP request (including headers and parameters) and forwards the payload as JSON to OPA. For example, the following URL: http://localhost/api/path?param1=foo&param2=bar will result in the following payload (headers are reduced for readability):

{
    "headers": {
      "Accept-Encoding": [
        "gzip, deflate, br"
      ],
      "Authorization": [
        "Bearer XXX.XXX.XXX"
      ],
      "X-Forwarded-Host": [
        "localhost"
      ],
      "X-Forwarded-Port": [
        "80"
      ],
      "X-Forwarded-Proto": [
        "http"
      ],
      "X-Forwarded-Server": [
        "traefik-84c77c5547-sm2cb"
      ],
      "X-Real-Ip": [
        "172.18.0.1"
      ]
    },
    "host": "localhost",
    "method": "POST",
    "parameters": {
      "param1": [
        "foo"
      ],
      "param2": [
        "bar"
      ]
    },
    "body": {
      "foo": "bar"
    },
    "path": [
      "api",
      "path"
    ],
    "tokenHeader": {
        "alg": "RS512",
        "kid": "abc123"
    },
    "tokenPayload": {
        "exp": 1652263686,
        "sub": "johndoe@host.com"
    }
}

Example OPA policy in Rego

The policies you enforce can be as complex or simple as you prefer. For example, the policy could decode the JWT token and verify the token is valid and has not expired, and that the user has the required claims in the token.

The policy below shows an simplified example:

package example

import future.keywords.in
import future.keywords.if

default allow := false

allow if {
    input.method == "GET"
    input.path[0] == "public"
}

allow if {
    input.method == "GET"
    input.path[0] == "secure"
    input.path[1] in {"123", "456"}
}

In the above example, requesting /public/anything or /secure/123 or /secure/456 is allowed, however requesting /secure/xxx would be rejected and results in a 403 Forbidden.

License

This software is released under the Apache 2.0 License