CUWebAuth is Cornell's single sign on system. I wrote a module to use this to authenticate Drupal users.

• The module is called culauth and is located in sites/all/modules/custom where installed. 

• The module is based on Adam Smith's work in the cul_common module. It uses cul_common's api for accessing LDAP data.
• To trigger the CUWebAuth authentication, culauth jumps to a .php file in a protected directory using drupal_goto. The directory is protected by a ,htaccess file containing this:

  AuthName CORNELL AuthType All require permit library