Client Certificate Authorization Plugin for traefik

This plugin authorizes requests based on the SAN DNS names of a TLS client certificate. If the client does not present a certificate or does present a certificate which according to configuration is not allowed to continue, 403 Forbidden is returned.

CAUTION: This plugin does not validate the certificate it receives. Please use the traefik mTLS configuration to also validate the certificate against a CA that you specify.

Configuration

Static configuration

experimental:
  plugins:
    certauthz:
      moduleName: "github.com/famedly/traefik-certauthz"
      version: "v0.1.0"

Dynamic configuration

http:
  middlewares:
    my-certauthz:
      plugin:
        certauthz:
          domains:
            - "example.org"
            - "*.example.net"

  routers:
    my-router:
      middlewares:
        - "my-certauthz"
      tls:
        # Traefik mtls configuration is required for certificate validation
        # https://doc.traefik.io/traefik/https/tls/#client-authentication-mtls
        options: my-mtls
      entrypoints: […]
      rule: …
      service: …

tls:
  options:
    my-mtls:
      clientAuth:
        caFiles:
          - /etc/ssl/certs/ca-certificates.crt
        clientAuthType: RequireAndVerifyClientCert

Regex

Instead of providing a list of domains you can also specify a regex to match against. This is not recommended.

http:
  middlewares:
    my-certauthz:
      plugin:
        certauthz:
          regex: "^example\.org$"

If you forget to use ^ and $ an attacker would be able to pass with a certificate with SAN DNS:example.org.badactor.com. The . character should also be escaped.