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mod_auth_openidc
================

*mod_auth_openidc* is an authentication/authorization module for the Apache 2.x
HTTP server that functions as an **OpenID Connect Relying Party**, authenticating users against an
OpenID Connect Provider. It can also function as an **OAuth 2.0 Resource Server**, validating 
OAuth 2.0 bearer access tokens presented by OAuth 2.0 Clients.

Overview
--------

This module enables an Apache 2.x web server to operate as an [OpenID Connect](http://openid.net/specs/openid-connect-core-1_0.html)
*Relying Party* (RP) to an OpenID Connect *Provider* (OP). It authenticates users against an OpenID Connect Provider,
receives user identity information from the OP in a so called ID Token and passes on the identity information
(a.k.a. claims) in the ID Token to applications hosted and protected by the Apache web server.

It can also be configured as an OAuth 2.0 *Resource Server* (RS), consuming bearer access tokens and validating
them against an OAuth 2.0 Authorization Server, authorizing Clients based on the validation results.

The protected content and/or applications can be served by the Apache server itself or it can be served from elsewhere
when Apache is configured as a Reverse Proxy in front of the origin server(s).

By default the module sets the `REMOTE_USER` variable to the `id_token` `[sub]` claim, concatenated with the OP's Issuer
identifier (`[sub]@[iss]`). Other `id_token` claims are passed in HTTP headers and/or environment variables together with those
(optionally) obtained from the UserInfo endpoint.

It allows for authorization rules (based on standard Apache `Require` primitives) that can be matched against the set
of claims provided in the `id_token`/ `userinfo` claims.

*mod_auth_openidc* supports the following specifications:
- [OpenID Connect Core 1.0](http://openid.net/specs/openid-connect-core-1_0.html) *(Basic, Implicit, Hybrid and Refresh flows)*
- [OpenID Connect Discovery 1.0](http://openid.net/specs/openid-connect-discovery-1_0.html)
- [OpenID Connect Dynamic Client Registration 1.0](http://openid.net/specs/openid-connect-registration-1_0.html)
- [OAuth 2.0 Multiple Response Type Encoding Practices 1.0](http://openid.net/specs/oauth-v2-multiple-response-types-1_0.html)
- [OAuth 2.0 Form Post Response Mode 1.0](http://openid.net/specs/oauth-v2-form-post-response-mode-1_0.html)
- [RFC7 7636 - Proof Key for Code Exchange by OAuth Public Clients](https://tools.ietf.org/html/rfc7636)
- [OpenID Connect Session Management 1.0](http://openid.net/specs/openid-connect-session-1_0.html) *(implementers draft; see the [Wiki](https://github.com/zmartzone/mod_auth_openidc/wiki/OpenID-Connect-Session-Management) for information on how to configure it)*
- [OpenID Connect Front-Channel Logout 1.0](http://openid.net/specs/openid-connect-frontchannel-1_0.html) *(implementers draft)*
- [OpenID Connect Back-Channel Logout 1.0](https://openid.net/specs/openid-connect-backchannel-1_0.html) *(implementers draft)*
- [Encoding claims in the OAuth 2 state parameter using a JWT](https://tools.ietf.org/html/draft-bradley-oauth-jwt-encoded-state-08) *(draft spec)*
- [OpenID Connect Token Bound Authentication](https://openid.net/specs/openid-connect-token-bound-authentication-1_0.html) *(draft spec; when combined with [mod_token_binding](https://github.com/zmartzone/mod_token_binding))*
- [OAuth 2.0 Token Binding for Authorization Codes for Web Server Clients](https://tools.ietf.org/html/draft-ietf-oauth-token-binding-07#section-5.2) *(draft spec)*

Alternatively the module can operate as an OAuth 2.0 Resource Server to an OAuth 2.0 Authorization Server,
validating bearer Access Tokens by introspecting them or verifying them locally if they are JWTs.
In the OAuth 2.0 Resource Server mode *mod_auth_openidc* supports the following specifications:
- [RFC 6750 - The OAuth 2.0 Authorization Framework: Bearer Token Usage](https://tools.ietf.org/html/rfc6750)
- [RFC 7662 - OAuth 2.0 Token Introspection](https://tools.ietf.org/html/rfc7662) (or similar)
- [RFC 8414 - OAuth 2.0 Authorization Server Metadata](https://tools.ietf.org/html/rfc8414)
- [OAuth 2.0 Token Binding for Access Tokens](https://tools.ietf.org/html/draft-ietf-oauth-token-binding-07#section-3) *(draft spec)*
- [OAuth 2.0 Mutual TLS Client Certificate Bound Access Tokens](https://tools.ietf.org/html/draft-ietf-oauth-mtls-12#section-3) *(draft spec)*

The `REMOTE_USER` variable setting, passing claims in HTTP headers and authorization based on `Require` primitives
works in the same way as described for OpenID Connect above. See the [Wiki](https://github.com/zmartzone/mod_auth_openidc/wiki/OAuth-2.0-Resource-Server) for information on how to configure it.

For an exhaustive description of all configuration options, see the file `auth_openidc.conf`
in this directory. This file can also serve as an include file for `httpd.conf`.

Support
-------

#### Give back to mod_auth_openidc
Please consider giving back by sponsoring mod_auth_openidc development/maintenance/continuity and to express
your gratitude as a happy user or company.  
See: https://www.patreon.com/mod_auth_openidc  
Sponsored by: [Auth0](https://auth0.com) and [GLUU](https://www.gluu.org)

#### Community Support
For generic questions, see the Wiki pages with Frequently Asked Questions at:  
  [https://github.com/zmartzone/mod_auth_openidc/wiki](https://github.com/zmartzone/mod_auth_openidc/wiki)  
There is a Google Group/mailing list at:  
  [mod_auth_openidc@googlegroups.com](mailto:mod_auth_openidc@googlegroups.com)  
The corresponding forum/archive is at:  
  [https://groups.google.com/forum/#!forum/mod_auth_openidc](https://groups.google.com/forum/#!forum/mod_auth_openidc)  
Any questions/issues should go to the mailing list. The Github issues tracker should be used only for bugs reports and feature requests.

#### Commercial Services
For commercial Support contracts, Professional Services, Training and use-case specific support you can contact:  
  [sales@zmartzone.eu](mailto:sales@zmartzone.eu)  

How to Use It  
-------------

### OpenID Connect SSO with Google+ Sign-In

Sample configuration for using Google as your OpenID Connect Provider running on
`www.example.com` and `https://www.example.com/example/redirect_uri` registered
as the *redirect_uri* for the client through the Google API Console. You will also
have to enable the `Google+ API` under `APIs & auth` in the [Google API console](https://console.developers.google.com).

```apache
OIDCProviderMetadataURL https://accounts.google.com/.well-known/openid-configuration
OIDCClientID <your-client-id-administered-through-the-google-api-console>
OIDCClientSecret <your-client-secret-administered-through-the-google-api-console>

# OIDCRedirectURI is a vanity URL that must point to a path protected by this module but must NOT point to any content
OIDCRedirectURI https://www.example.com/example/redirect_uri
OIDCCryptoPassphrase <password>

<Location /example/>
   AuthType openid-connect
   Require valid-user
</Location>
```

Note if you want to securely restrict logins to a specific Google Apps domain you would not only
add the `hd=<your-domain>` setting to the `OIDCAuthRequestParams` primitive for skipping the Google Account
Chooser screen, but you must also ask for the `email` scope using `OIDCScope` and use a `Require claim`
authorization setting in the `Location` primitive similar to:

```apache
OIDCScope "openid email"
Require claim hd:<your-domain>
```

The above is an authorization example of an exact match of a provided claim against a string value.
For more authorization options see the [Wiki page on Authorization](https://github.com/zmartzone/mod_auth_openidc/wiki/Authorization).

### Quickstart with a generic OpenID Connect Provider

1. install and load `mod_auth_openidc.so` in your Apache server
1. configure your protected content/locations with `AuthType openid-connect`
1. set `OIDCRedirectURI` to a "vanity" URL within a location that is protected by mod_auth_openidc
1. register/generate a Client identifier and a secret with the OpenID Connect Provider and configure those in `OIDCClientID` and `OIDCClientSecret` respectively
1. and register the `OIDCRedirectURI` as the Redirect or Callback URI with your client at the Provider
1. configure `OIDCProviderMetadataURL` so it points to the Discovery metadata of your OpenID Connect Provider served on the `.well-known/openid-configuration` endpoint
1. configure a random password in `OIDCCryptoPassphrase` for session/state encryption purposes

```apache
LoadModule auth_openidc_module modules/mod_auth_openidc.so

OIDCProviderMetadataURL <issuer>/.well-known/openid-configuration
OIDCClientID <client_id>
OIDCClientSecret <client_secret>

# OIDCRedirectURI is a vanity URL that must point to a path protected by this module but must NOT point to any content
OIDCRedirectURI https://<hostname>/secure/redirect_uri
OIDCCryptoPassphrase <password>

<Location /secure>
   AuthType openid-connect
   Require valid-user
</Location>
```
For details on configuring multiple providers see the [Wiki](https://github.com/zmartzone/mod_auth_openidc/wiki/Multiple-Providers).

### Quickstart for Other Providers

See the [Wiki](https://github.com/zmartzone/mod_auth_openidc/wiki) for configuration docs for other OpenID Connect Providers:
- [GLUU Server](https://github.com/zmartzone/mod_auth_openidc/wiki/Gluu-Server)
- [Keycloak](https://github.com/zmartzone/mod_auth_openidc/wiki/Keycloak)
- [Azure AD](https://github.com/zmartzone/mod_auth_openidc/wiki/Azure-OAuth2.0-and-OpenID)
- [LemonLDAP::NG](https://github.com/zmartzone/mod_auth_openidc/wiki/LemonLDAP::NG)
- [GitLab](https://github.com/zmartzone/mod_auth_openidc/wiki/GitLab-OAuth2)
- [Globus](https://github.com/zmartzone/mod_auth_openidc/wiki/Globus)
and [more](https://github.com/zmartzone/mod_auth_openidc/wiki/Useful-Links)

### Quickstart with a generic OAuth 2.0 Resource Server

Using "local" validation of JWT bearer tokens:

1. install and load `mod_auth_openidc.so` in your Apache server
1. configure your protected APIs/locations with `AuthType oauth20` and `Require claim` directives to restrict access to specific clients/scopes/claims/resource-owners
1. configure local or remote bearer token validation following the [Wiki](https://github.com/zmartzone/mod_auth_openidc/wiki/OAuth-2.0-Resource-Server)

```apache
# local validation
OIDCOAuthVerifySharedKeys plain##<shared-secret-to-validate-symmetric-jwt-signatures>

<Location /api>
   AuthType oauth20
   Require claim sub:<resource_owner_identifier>
</Location>
```

Disclaimer
----------

*This software is open sourced by ZmartZone IAM. For commercial services
you can contact [ZmartZone IAM](https://www.zmartzone.eu) as described above in the [Support](#support) section.*