RT 4.4.1 Documentation

Authentication

RT Authentication

RT allows for several different ways to authenticate users including an internal user management system and a number of ways to integrate with existing authentication systems.

Internal Authentication

RT's native internal authentication system provides administration tools to manage usernames and passwords. If you plan to run your RT as a stand-alone system and don't need to use accounts associated with any other system, this may be all you need. The administration pages under Admin → Users provide new user creation as well as password setting and control of RT's privileged flag for existing users.

External Authentication

There are two primary types of external authentication: in one you type your username and password into RT's login form, and in the other your web server (such as Apache) handles authentication, often seamlessly, and tells RT the user logged in.

Starting with RT 4.4, both of these options are supported by RT out of the box, activated using different configuration options. The first is supported by the RT::Authen::ExternalAuth module. The second is activated using the configuration option $WebRemoteUserAuth along with some related options. These two types may be used independently or together, and both can fallback to RT's internal authentication.

If you are running a version of RT earlier than 4.4, you can install RT::Authen::ExternalAuth as an extension.

No matter what type of external authentication you use, RT still maintains user records in its database that correspond to your external source. This is necessary so RT can link tickets, groups, rights, dashboards, etc. to users.

All that is necessary for integration with external authentication systems is a shared username or email address. However, in RT you may want to leverage additional information from your external source. Synchronization of users, user data, and groups is provided by an extension named RT::LDAPImport. It uses an external LDAP source, such an OpenLDAP or Active Directory server, as the authoritative repository and keeps RT up to date accordingly. This can be used in tandem with any of the external authentication options as it does not provide any authentication itself.

Via your web server, aka $WebRemoteUserAuth, aka REMOTE_USER

This type of external authentication is built-in to RT and bypasses the RT login form. Instead, RT defers authentication to the web server which is expected to set a REMOTE_USER environment variable. Upon a request, RT checks the value of REMOTE_USER against its internal database and logs in the matched user.

It is often used to provide single sign-on (SSO) support via Apache modules such as mod_auth_kerb (to talk to Active Directory). $WebRemoteUserAuth is widely used by organizations with existing authentication standards for web services that leverge web server modules for central authentication services. The flexibility of RT's $WebRemoteUserAuth support means that it can be setup with almost any authentication system.

In order to keep user data in sync, this type of external auth is almost always used in combination with one or both of RT::Authen::ExternalAuth and RT::LDAPImport.

Apache Configuration

When configuring Apache to protect RT, remember that the RT mail gateway uses the web interface to upload the incoming email messages. You will thus need to provide an exception for the mail gateway endpoint.

An example of using LDAP authentication and HTTP Basic auth:

    <Location />
        Require valid-user
        AuthType Basic
        AuthName "RT access"
        AuthBasicProvider ldap
        AuthLDAPURL \
            "ldap://ldap.example.com/dc=example,dc=com"
    </Location>
    <Location /REST/1.0/NoAuth/mail-gateway>
        # For Apache 2.4
        <IfVersion >= 2.4>
            Require local
        </IfVersion>
        # For Apache 2.2
        <IfVersion < 2.4>
            Order deny,allow
            Deny from all
            Allow from localhost
            Satisfy any
        </IfVersion>
    </Location>

RT Configuration Options

All of the following options control the behavior of RT's built-in external authentication which relies on the web server. They are documented in detail under the "Authorization and user configuration" section of RT_Config and you can read the documentation by running perldoc /opt/rt4/etc/RT_Config.pm.

The list below is meant to make you aware of what's available. You should read the full documentation as described above.

$WebRemoteUserAuth

Enables or disables RT's expectation that the web server will provide authentication using the REMOTE_USER environment variable.

$WebRemoteUserContinuous

Check REMOTE_USER on every request rather than the initial request.

When this is off, users will remain logged into RT even after REMOTE_USER is no longer provided. This provides a separation of sessions, but it may not be desirable in all cases. For example, if a user logs out of the external authentication system their RT session will remain active unless $WebRemoteUserContinuous is on.

$WebFallbackToRTLogin

If true, allows internal logins as well as REMOTE_USER by providing a login form if external authentication fails. This is useful to provide local admin access (usually as root) or self service access for people without external user accounts.

$WebRemoteUserAutocreate

Enables or disables auto-creation of RT users when a new REMOTE_USER is encountered.

$UserAutocreateDefaultsOnLogin

Specifies the default properties of auto-created users.

$WebRemoteUserGecos

Tells RT to compare REMOTE_USER to the Gecos field of RT users instead of the Name field.

Via RT's login form, aka RT::Authen::ExternalAuth

RT::Authen::ExternalAuth provides authentication using RT's login form. It can be configured to talk to an LDAP source (such as Active Directory), an external database, or an SSO cookie.

The key difference between $WebRemoteUserAuth and RT::Authen::ExternalAuth is the use of the RT login form and what part of the system talks to your authentication source (your web server vs. RT itself).

As noted above, for versions of RT before 4.4, you can install RT::Authen::ExternalAuth as an extension.

Info mode and Authentication mode

There are two modes of operation in RT::Authen::ExternalAuth: info and auth. Usually you want to configure both so that successfully authenticated users also get their information pulled and updated from your external source.

Auth-only configurations are rare, and generally not as useful.

Info-only configurations are commonly setup in tandem with $WebRemoteUserAuth. This lets your web server handle authentication (usually for SSO) and RT::Authen::ExternalAuth ensures user data is updated every time someone logs in.

RT::Extension::LDAPImport

RT::LDAPImport provides no authentication, but is useful alongside authentication because it provides user data and group member synchronization from any LDAP source into RT. It provides a similar but more complete sync solution than RT::Authen::ExternalAuth (which only updates upon login and doesn't handle groups). It may be used with either of RT's external authentication sources, or on it's own.

Starting with RT 4.4, RT::LDAPImport is part of RT. For earlier versions of RT, you can install RT::Extension::LDAPImport as an extension.

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