src/chapters/cas-auth.xml

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<chapter xml:id="cas-auth" xmlns="http://docbook.org/ns/docbook" version="5.0" xml:lang="en"
    xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xlink="http://www.w3.org/1999/xlink">
    <title>CAS Authentication</title>
    <indexterm>
        <primary>CAS Authentication</primary>
    </indexterm>
    <para>CAS is an open-source Single Sign On (SSO) provider that allows multiple applications
        and services to authenticate against it and brokers those authentication requests to a
        back-end authentication provider.  This module allows Guacamole to redirect to CAS for
        authentication and user services.  This module must be layered on top of other authentication
        extensions that provide connection information, as it only provides user authentication.
        </para>
    <section xml:id="cas-downloading">
        <title>Downloading the CAS authentication extension</title>
        <para>The CAS authentication extension is available separately from the main
                <filename>guacamole.war</filename>. The link for this and all other
            officially-supported and compatible extensions for a particular version of Guacamole are
            provided on the release notes for that version. You can find the release notes for
            current versions of Guacamole here: <link
                xlink:href="http://guacamole.apache.org/releases/"
                >http://guacamole.apache.org/releases/</link>.</para>
        <para>The CAS authentication extension is packaged as a <filename>.tar.gz</filename>
            file containing only the extension itself,
                <filename>guacamole-auth-cas-1.2.0.jar</filename>, which must
            ultimately be placed in <filename>GUACAMOLE_HOME/extensions</filename>.</para>
    </section>
    <section xml:id="installing-cas-auth">
        <title>Installing CAS authentication</title>
        <para>Guacamole extensions are self-contained <filename>.jar</filename> files which are
            located within the <filename>GUACAMOLE_HOME/extensions</filename> directory.
                <emphasis>If you are unsure where <varname>GUACAMOLE_HOME</varname> is located on
                your system, please consult <xref linkend="configuring-guacamole"/> before
                proceeding.</emphasis></para>
        <para>To install the CAS authentication extension, you must:</para>
        <procedure>
            <step>
                <para>Create the <filename>GUACAMOLE_HOME/extensions</filename> directory, if it
                    does not already exist.</para>
            </step>
            <step>
                <para>Copy <filename>guacamole-auth-cas-1.2.0.jar</filename> within
                        <filename>GUACAMOLE_HOME/extensions</filename>.</para>
            </step>
            <step>
                <para>Configure Guacamole to use CAS authentication, as described
                    below.</para>
            </step>
        </procedure>
        <section xml:id="guac-cas-config">
            <title>Configuring Guacamole for CAS Authentication</title>
            <indexterm>
                <primary>configuring CAS authentication</primary>
            </indexterm>
            <indexterm>
                <primary>CAS authentication</primary>
                <secondary>configuration</secondary>
            </indexterm>
            <para>The CAS authentication extension provides two configuration properties, both
                of which are required.</para>
            <variablelist>
                <varlistentry>
                    <term><property>cas-authorization-endpoint</property></term>
                    <listitem>
                        <para>The URL of the CAS authentication server.  This should be the full
                            path to the base of the CAS installation.</para>
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term><property>cas-redirect-uri</property></term>
                    <listitem>
                        <para>The URI to redirect back to upon successful authentication.  Normally
                            this will be the full URL of your Guacamole installation.</para>
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term><property>cas-clearpass-key</property></term>
                    <listitem>
                        <para>If using CAS ClearPass to pass the SSO password to Guacamole, this
                            parameter specifies the private key file to use to decrypt the
                            password.  See the section on ClearPass below.</para>
                    </listitem>
                </varlistentry>
            </variablelist>
        </section>
        <section xml:id="completing-cas-install">
            <title>Completing the installation</title>
            <para>Guacamole will only reread <filename>guacamole.properties</filename> and load
                newly-installed extensions during startup, so your servlet container will need to be
                restarted before CAS authentication can be used. <emphasis>Doing this will
                    disconnect all active users, so be sure that it is safe to do so prior to
                    attempting installation.</emphasis> When ready, restart your servlet container
                and give the new authentication a try.</para>
        </section>
        <section xml:id="cas-clearpass">
            <title>Using CAS ClearPass</title>
            <para>CAS has a function called ClearPass that can be used to cache the password
                used for SSO authentication and make that available to services at a later
                time.  Configuring the CAS server for ClearPass is beyond the scope of this
                article - more information can be found on the Apereo CAS wiki at the
                following URL: <link xlink:href="https://apereo.github.io/cas">
                https://apereo.github.io/cas</link>.</para>
            <para>Once you have CAS configured for credential caching, you need to configure
                the service with a keypair for passing the credential securely.  The public 
                key gets installed on the CAS server, while the private key gets configured
                with the <property>cas-clearpass-key</property> property.  The private key
                file needs to be in RSA PKCS8 format.</para>
        </section>
    </section>
</chapter>