UC Berkeley CAS 7.x


UC Berkeley CAS is a Drupal "feature" (a collection of modules and configuration) which adds UC Berkeley CalNet (CAS) authentication to a Drupal site. Once UC Berkeley CAS is enabled logging into your site via CalNet will be possible by visiting http://EXAMPLE.berkeley.edu/cas.

UC Berkeley CAS was developed to provide CAS authentication to sites using the Open Berkeley Drupal distribution. Since this feature was developed to work on any Drupal site, Web Platform Solutions was granted permission to make it publically available to the UC Berkeley Drupal community.


No Warranty: This software is provided "as is." UC Berkeley IST does not provide support for this code when it is used outside of the Open Berkeley product. Anyone using this code does so at their own risk and would do well to monitor releases to the Drupal modules, phpCAS and other 3rd-party libraries themselves. (That said, see this information about upgrading parts of this feature.)

UC Berkeley CAS applies a default configuration to the modules it installs. This configuration assumes that everyone, including the site administrators, will login to the site using CalNet. See Standard Configuration.

Security Considerations

By default ucberkeley_cas is configured so that anyone logging into your site must use UCB CalNet authentication. If you visit http://EXAMPLE.berkeley.edu/user/login (the standard Drupal login URL) after installing UC Berkeley CAS, you will encounter a CAS login form instead of the familiar Drupal login form. The reason for this is that Drupal's standard authentication is insecure -- unless used in conjunction with the https protocol. (Drupal standard authentication is vulnerable to (1) username/password interception (especially if a wireless network is in use) and (2) session hijacking.) A second reason for requiring CalNet authentication is to prevent the complexity that results from allowing multiple authentication channels (i.e. CalNet and Drupal standard authentication.)


CalNet/CAS authentication is not immune to attack on a site using the http protocol. A CAS ticket could theoretically be hijacked, however exploiting an stolen CAS ticket is significantly more difficult than exploiting Drupal's standard authentication token. The most secure configuration for your site would be to use https in addition to UC Berkeley CAS.

Additionally, UC Berkeley CAS does not provide a login link on any of your pages. You may provide this yourself if you choose. A common practice is to simply instruct site builders to visit the path /cas when they want to login. When a login link appears on site pages, it will be discovered by nefarious bots attempting brute force login attacks. It also invites users to attempt to login when they really don't need to authenticate.

Quick Start

  1. See Requirements
  2. Install and enable the most recent release of ucberkeley_cas. (More info: Installing)
  3. Using an incognito window (or a second browser) in which you are not logged to the site as User 1, visit the login url http://example.com/cas and login with your CalNet id.
  4. In your main window, where you are logged in as User 1, edit the new user that got created in the last step and assign it the "administrator" role (or whichever role is appropriate). (More info: Setup a CalNet-authenticated administrator)
  5. Visit the path /admin/config/people/ucberkeley_cas on your site for recommendations on further configuration.
  6. Subscribe to ucberkeley-cas-drupal-users@lists.berkeley.edu for information on releases and security advisories.


You need the following modules installed:

UC Berkeley CAS will install these modules:

Specific versions of the above modules are specified in ucberkeley_cas-7.x.make. If your site is using unsupported versions of these modules, you'll be notified of the problem when you attemp to enable UC Berkeley CAS.

CAS Registration

In order to use CalNet (CAS) authentication, your website must be registered with CalNet. Register your site here. Make sure your registration is approved before you install UC Berkeley CAS on a production site.

Localhost Sites Do Not Require Registration

Developers working local webserver should use one of these domains:

  • http://localhost
  • http://local

These urls will work with the CAS server auth-test.berkeley.edu and don't require CAS registration. Other common development URLs (e.g. http://*.dev, and Acquia Dev Desktop's http://example.dd) will not work the the auth-test CAS server.


  1. Make sure your site meets the requirements above.
  2. Download the tarball included with the latest release of UC Berkeley CAS, (e.g. ucberkeley_cas-7.x-x.x.tar.gz) to the host serving your Drupal site.
  3. Unarchive the module in sites/all/modules
  4. Enable the module at admin/modules. (During this step you may notice the message "CAS has been enabled. Please configure it." You can disregard this. We have already applied the UC Berkeley configuration for you.)
  5. Make sure your CAS registration has been processed.
  6. Test your site:

If your site runs at http://EXAMPLE.berkeley.edu, go to http://EXAMPLE.berkeley.edu/cas. You should see the CAS login page. When you authenticate successfully you should be returned to your Drupal site and you should see "Logged in as [your name]."

Go to http://EXAMPLE.berkeley.edu/user. You should see the email address and full name that was retrieved from LDAP for your account.

Setup a CalNet-authenticated Administrator

User 1 is the "superuser" on a Drupal site. (This account is often named "admin.") If you are installing UC Berkeley CAS, you are probably logged in as User 1. Once UC Berkeley CAS is enabled on your site, the best practice is to stop logging in as this user and to login using your CalNet credentials instead. Here's how to set that up:

  1. Log into your site as User 1 and enable the UC Berkeley CAS module.
  2. Using an incognito window, visit your CAS url which will be something like http://EXAMPLE.berkeley.edu/cas. When you successfully authenticate using CAS a new Drupal user will be created that is associated with your CalNet credentials.
  3. Back in your main window where you are still logged in as User 1, visit your people page. The url for this page is something like http://EXAMPLE.berkeley.edu/admin/people. You should see a new user with a username matching your first and last names. Click the "edit" link to the right of this user and assign it the administrator role.
  4. Now in your first browser you can logout of the User 1 account and visit the CAS url (above) to log back in via CalNet. At this point you should be able to do anything that User 1 could do.
  5. Make sure that you have set a hard-to-guess password for User 1.

Should something go wrong with CAS or the CAS module on your site, you can still login as User 1 using the administrator back door. (Please do not use the backdoor unless it is really necessary.)

It's a good idea to change the password on your User 1 account to a long random string. This will make it less likely that your site would be compromised by a brute force password attack. If you forget the password for User 1 it can be reset. When you need to login as User 1 you can use the administrator back door which includes a link to reset your password.

The Administrator "Back Door"

Above, we mentioned that the path /user/login will not provide the traditional Drupal login form.

If for some reason you can't login as your CalNet-authenticated administrator, you can still login as User 1 at http://example.com/user/admin_login.


This is not a secure form and it suffers from the Drupal standard authentication vulnerabilities described above. Do not distribute this URL to your users and do not make a practice of logging in via this URL.

What if auth.berkeley.edu goes down?

This would affect all campus services depending on CAS. The responsibility for fixing the problem would be on the CalNet team.

The CalNet team uses healthchecks and automatic DNS failover to point auth.berkeley.edu to an offsite cluster when a problem is detected.


Upgrading to a new version of ucberkeley_cas (versions > 1.x)

Follow this procedure to upgrade ucberkeley_cas:

Upgrade the module on your development site first and test it. Before you upgrade the module on your live site, make a backup of your live site's database just in case there is a problem.

  1. Delete the ucberkeley_cas folder from your modules directory.
  2. Replace it with the new version of the module downloaded which you downloaded and unarchived
  3. Run update.php on your drupal site.

The new version should now be working. Test it on your development site to make sure that logging in and out of the site is working.


Do not uninstall the cas module found in ucberkeley_cas folder. (By "uninstall" we mean "run the Drupal uninstall process at /admin/modules/uninstall.) Doing this can cause problems with your existing CAS users.

Upgrading from legacy ucb_cas 1.x to ucberkeley_cas 2.x

The module UC Berkeley CAS (ucberkeley_cas) is a replacement for the older UCB CAS (ucb_cas) module. UCB CAS must be removed from your system before UC Berkeley CAS can be installed.

Here's what to do:

  1. Disable UCB CAS by un-checking its entry at /admin/modules and clicking submit (or by using drush).
  2. Do not tell Drupal to "uninstall" UCB CAS. Also do not "uninstall" the CAS module. By this we mean do not use the "Uninstall" tab which is available at the /admin/modules path when you are logged into your site as an administrator.
  3. Using your file manager simply remove the ucb_cas folder from your site (look under /sites/all/modules or /profiles).
  4. Check that you have added and enabled the other modules required by UC Berkeley CAS to your site. See the Requirements section.
  5. Enable UC Berkeley CAS. (At this point you may see a message about ucb_envconf. See the instructions below.)
  6. Run update.php

If you are using ucb_envconf 1.x, upgrade to ucberkeley_envconf 2.x

For background on UC Berkeley Environments Configurations see the UC Berkeley Environments Configuration section.

The module UC Berkeley CAS (ucberkeley_cas) can optionally be used with the UC Berkeley Environment Configurations module. If you have upgraded from an old (1.x) version of UC Berkeley CAS, you may also have an old version of UC Berkeley Environments Configurations installed. If this is the case, the UC Berkeley CAS installer will detect the problem and warn you. Here's what to do if that happens:

  1. Disable UC Berkeley Environment Configurations by un-checking its entry at /admin/modules and clicking submit.
  2. Download the latest version of UC Berkeley Environment Configurations.
  3. Using your file manager simply remove the ucb_envconf folder from your site (look under /sites/all/modules or /profiles). (The 1.0 version was called ucb_envconf. The 2.0 version is called ucberkeley_envconf.)
  4. Unpack the new version of UC Berkeley Environment Configurations and copy it into /sites/all/modules (or your preferred module directory.)
  5. Enable ucberkeley_envconf. (Running update.php is not necessary.)

At this point your site will be using the latest version of UC Berkeley Environment Configurations.

My site already uses CAS, but I want to switch to ucberkeley_cas

  1. Remove the directories for cas, cas_attributes and ldap from site/all/modules (or wherever they reside).
  2. Unpack ucberkeley_cas into sites/all/modules or your desired module directory.
  3. At admin/modules enable the UC Berkeley CAS module. UC Berkeley CAS will tell you if there is anything wrong.
  4. Run update.php.

UC Berkeley CAS will attempt to configure the ldap server for ldap.berkeley.edu at /admin/config/people/ldap/servers. If this duplicates servers that you previously configured, disable your old entries.

If you are using UC Berkeley CAS with UC Berkeley Environments Configurations, it's important that your LDAP server uses the same "sid" (see the ldap_servers table in the database) that is specified in ucberkeley_cas.features.defaultconfig.inc.


To remove UC Berkeley CAS from your site see the modules listed in the Requirements section above.

  1. Disable these modules at admin/modules.
  2. Uninstall these modules at admin/modules/uninstall. Uninstalling will disable any CAS-authenticated users on your site.

Avoid Uninstalling the CAS Module

If you have accounts on your site that were created while the UC Berkeley CAS module was enabled, avoid uninstalling the cas module found in the ucberekely_cas folder. If you uninstall the cas module you will find that your existing CalNet-authenticated accounts can no longer login. They will be greeted with a PHP error like

Integrity constraint violation: 1062 Duplicate entry 'Brian Wood'...

The reason for this error is that the uninstallation removed the cas_users database table and the data it contained. This is not an issue with ucberkeley_cas, but with the cas module itself.

In order to preserve your CalNet-authenticated accounts follow this uninstall/reinstall procedure:

  1. Using phpMyAdmin (or the mysql command line client), export the contents of your ucberkeley_cas table to a file. In phpMyAdmin click on the cas_user table then click on the Export link at the bottom of the page. Choose "Dump all rows" at the next screen and submit the form. This will download a file called cas_user.sql which will contain data like:
  INSERT INTO `cas_user` (`aid`, `uid`, `cas_name`) VALUES
  (1, 15, '212373'),
  (3, 19, '212372');
  1. Uncheck the UC Berkeley CAS module on the Modules administration page and submit the form.

  2. Click the Uninstall tab at the top of the page and uninstall UCB CAS.

  3. Reinstall the UC Berkeley CAS module by checking its box on the Modules administration page and submitting the form.

  4. In phpMyAdmin select your database and choose the SQL tab. Replace the contents of the sql query text area with the insert statements from step 1. Submit the form.

Now your existing CalNet-authenticated accounts should be able to login via CAS.

Alternate procedure

You could also simply delete all of your existing CalNet users and then recreate them by having the users log in again after you reinstall the ucberkeley_cas module. If you do this, the recreated users will no longer be the owners of any content that they created. The sql solution above will preserve the users association to their content.

Standard Configuration

The ucberkeley_cas module has made some configuration decisions for you. These decisions can be overridden by you. See the Configuration Details section below.

The Authenticated User role

With the ucberkeley_cas standard configuration, when a user logs in via CalNet for the first time Drupal will create an account for them and assign them to the "authenticated user" role. We suggest that you avoid assigning the "authenticated user" role any privileges beyond those assigned to the "anonymous user" role. The best way to manage privileges for your CalNet users is to create a role like "editor" which is allowed to create content. You should then review each new person in the "authenticated user" role and decide whether or not to assign them your "editor" role. (Drupal's Rules module can be used to send you automatic emails each time a new user account is created on your site.)

Combining Drupal Standard Authentication with CAS

"Mixed mode authentication" describes then scenario where a site is configured to allow some users to authenticate using CalNet and others to authenticate using Drupal standard authentication. The ucberkeley_cas standard configuration is not geared towards this scenario. Instead all users are directed to CalNet for authentication.

Mixed mode authentication presents user experience challenges. The user must be presented with two different login mechanisms and must choose between them every time they login to the site. It becomes easy for a user to create two different accounts, one that authenticates via CalNet and one that uses Drupal standard authentication. Typically this is undesirable.

If you choose to alter the UC Berkeley CAS settings on your site to allow mixed mode authentication, please remember that you should be running your UCB site using https if you are using Drupal standard authentication.

Use Case Recommendations Page

After installation see /admin/config/people/ucberkely_cas for recommendations on fine tuning your CAS configuration according to common UCB Drupal site use cases.

User accounts for testing

These test accounts can be useful for testing your website.

Reporting Bugs

If you think you've found a bug with UC Berkeley CAS please report it to ist-drupal@lists.berkeley.edu. Make sure your bug report includes:

  1. The exact steps we should take to recreate the problem.
  2. The version of ucberkeley_cas that you are using.
  3. The version of Drupal that you are using.