Configure Central Authentication Service (CAS)

Authentication

Many campuses use some kind of single sign on, such as JASIG's Central Authentication Service, or CAS. This guide describes how to integrate Opencast into such a system.

Step 1: Enable Opencast CAS feature

First, you need to edit the file etc/org.apache.karaf.features.cfg and add the opencast-security-cas to the featuresBoot variable.

featuresBoot = ..., opencast-security-cas

Step 2: Security Configuration

Edit the security configuration file at etc/security/mh_default_org.xml. In a multi-tenant set-up, you will have one configuration file for each tenant at etc/security/<organization_id>.xml.

You need to comment or uncomment some sections in this file. All necessary changes are marked with a CAS Auth: tag. You can use the find function of your editor to find the parts of the file you need to modify.

Add the necessary configuration values to the CAS section of the new security file. The comments should be self-explanatory.

You must modify several settings in the sample to point to your CAS server:

<bean id="casEntryPoint" class="org.springframework.security.cas.web.CasAuthenticationEntryPoint">
  <property name="loginUrl" value="https://auth-test.berkeley.edu/cas/login"/>
  <property name="serviceProperties" ref="serviceProperties"/>
</bean>

<bean id="casAuthenticationProvider" class="org.springframework.security.cas.authentication.CasAuthenticationProvider">
  <property name="userDetailsService" ref="userDetailsService"/>
  <property name="serviceProperties" ref="serviceProperties" />
  <property name="ticketValidator">
    <bean class="org.jasig.cas.client.validation.Cas20ServiceTicketValidator">
      <constructor-arg index="0" value="https://auth-test.berkeley.edu/cas" />
    </bean>
  </property>
  <property name="key" value="cas"/>
</bean>

You will also need to set the public URL for your Opencast server:

<bean id="serviceProperties" class="org.springframework.security.cas.ServiceProperties">
  <property name="service" value="http://localhost:8080/j_spring_cas_security_check"/>
  <property name="sendRenew" value="false"/>
</bean>

Authorization

Now the system knows all the information necessary to authenticate users against CAS, but also need some authorization information, to tell which services the user is allowed to use and which resources is allowed to see and/or modify.

You will need to configure a UserProvider to look up users as identified by CAS.

Further Information

Original documentation from University of Saskatchewan: University of Saskatchewan CAS and LDAP integration