Cloudflare Zero Trust

Tested Versions #

• Authelia
  • v4.35.6

Before You Begin #

Common Notes #

1. The OpenID Connect 1.0 client_id parameter:
   1. This must be a unique value for every client.
   2. The value used in this guide is merely for demonstration purposes and you can theoretically use nearly any alphanumeric string.
2. The OpenID Connect 1.0 secret parameter:
   1. The value used in this guide is merely for demonstration purposes and you should absolutely not use this in production and should instead utilize the How Do I Generate Client Secrets FAQ.
   2. This string may be stored as plaintext in the Authelia configuration but this behaviour is deprecated and is not guaranteed to be supported in the future. See the Plaintext guide for more information.
3. The Configuration example for Authelia is only a portion of the required configuration and it should be used as a guide in conjunction with the standard OpenID Connect 1.0 Configuration guide.

Assumptions #

This example makes the following assumptions:

• Cloudflare Team Name: example-team
• Authelia Root URL: https://auth.example.com
• Client ID: cloudflare
• Client Secret: insecure_secret

Important Note: Cloudflare Zero Trust does not properly URL encode the secret per RFC6749 Appendix B at the time this article was last modified (noted at the bottom). This means you’ll either have to use only alphanumeric characters for the secret or URL encode the secret yourself.

Configuration #

Application #

Important Note: It is a requirement that the Authelia URL’s can be requested by Cloudflare’s servers. This usually means that the URL’s are accessible to foreign clients on the internet. There may be a way to configure this without accessibility to foreign clients on the internet on Cloudflare’s end but this is beyond the scope of this document.

To configure Cloudflare Zero Trust to utilize Authelia as an OpenID Connect 1.0 Provider:

1. Visit the Cloudflare Zero Trust Dashboard
2. Visit Settings
3. Visit Authentication
4. Under Login nethods select Add new
5. Select OpenID Connect
6. Set the following values:
   1. Name: Authelia
   2. App ID: cloudflare
   3. Client Secret: insecure_secret
   4. Auth URL: https://auth.example.com/api/oidc/authorization
   5. Token URL: https://auth.example.com/api/oidc/token
   6. Certificate URL: https://auth.example.com/jwks.json
   7. Enable Proof Key for Code Exchange (PKCE)
   8. Add the following OIDC Claims: preferred_username, mail
7. Click Save

Authelia #

The following YAML configuration is an example Authelia client configuration for use with Cloudflare which will operate with the above example:

identity_providers:
  oidc:
    ## The other portions of the mandatory OpenID Connect 1.0 configuration go here.
    ## See: https://www.authelia.com/c/oidc
    clients:
    - id: cloudflare
      description: Cloudflare ZeroTrust
      secret: '$pbkdf2-sha512$310000$c8p78n7pUMln0jzvd4aK4Q$JNRBzwAo0ek5qKn50cFzzvE9RXV88h1wJn5KGiHrD0YKtZaR/nCb2CJPOsKaPK0hjf.9yHxzQGZziziccp6Yng'  # The digest of 'insecure_secret'.
      public: false
      authorization_policy: two_factor
      redirect_uris:
        - https://example-team.cloudflareaccess.com/cdn-cgi/access/callback
      scopes:
        - openid
        - profile
        - email
      userinfo_signing_algorithm: none

See Also #

• Cloudflare Zero Trust Generic OIDC Documentation