libphremoteuser

This extension to Phabricator performs authentication via a web server's REMOTE_USER variable. It should be able to work with a variety of major servers such as Apache and Nginx, but I have only tested it with Apache.

It can be used with Basic authentication, but is most useful when the server is configured for single-sign-on, for example, using kerberos.

Installation

To install this library, simply clone this repository alongside your phabricator installation:

cd /path/to/install
git clone https://github.com/make-all/libphremoteuser.git

Then, simply add the path to this library to your phabricator configuration:

cd /path/to/install/phabricator
./bin/config set load-libraries '["libphremoteuser/src/"]'

When you next log into Phabricator as an Administrator, go to Auth > Add Authentication Provider.
In the list, you should now see an entry called Web Server. Enabling this provider should add a new button to your login screen.

In order to actually log in, your web server needs to populate the $REMOTE_USER variable when the login button is pressed. You can do this by forcing the login URI that Phabricator uses to be restricted, by adding a directive like the following to your web server configuration (this is Apache2):

<Location "/auth/login/RemoteUser:self/">
  AuthType Kerberos
  AuthName "Phabricator at My Server"
  KrbAuthRealms DOMAIN.EXAMPLE.COM
  KrbServiceName HTTP
  Krb5Keytab /etc/apache2/kerberos.keytab
  KrbMethodNegotiate On
  KrbMethodK5Passwd On
  KrbLocalUserMapping On
  Require valid-user
</Location>

<Location "/auth/login/RemoteUser:self/">
  AuthType GSSAPI
  AuthName "Phabricator at My Server"
  GssapiCredStore keytab:/etc/apache2/kerberos.keytab
  GssapiCredStore ccache:MEMORY:user_ccache
  GssapiAllowedMech krb5
  GssapiUseSessions On
  GssapiNegotiateOnce On
  Session On
  SessionCookieName gssapi_session path=/gssapi-test;httponly;secure;
  Require valid-user
</Location>

When a user registers using this auth provider, it will attempt to discover the user's full name and email from LDAP. LDAP parameters are stored in INI file. You must edit this file named ldap_params.ini before use.

Security

I make no guarantees about this library being totally secure. It's not obviously insecure.
However, please make sure to at least REDIRECT THE LOGIN URI TO SSL, OTHERWISE YOU ARE POTENTIALLY SENDING PLAIN TEXT PASSWORDS.

If you care about security consider:

• Hosting Phabricator entirely on https/SSL
• Restricting access to the whole Phabricator installation directory, also using SSL.