January 4th, 2007 - CGI/PHP Server Upgraded to RHEL

1. Kerberos Username Change - The cgi server is running a newer version of the kerberos authentication module for apache (mod_auth_kerb) and this version handles usernames differently. If you are using something like the following in your .htaccess:

   require valid-user

   then no change is necessary. However, if you are limiting access to a specific user or set of users like this:

   require user janedoe joedoe

   then this will no longer work on the cgi server. Usernames are now specified as USER@REALM where USER is the username and REALM is the kerberos realm (which is IU.EDU for us). So, the above line would have to be changed to:

   require user janedoe@IU.EDU joedoe@IU.EDU

   If you want to use a single .htaccess file that is compatible between the new kerberos module on cgi.cs.indiana.edu and the old module on www.cs.indiana.edu then you can simply include both forms with something like:

   require user janedoe janedoe@IU.EDU joedoe joedoe@IU.EDU

2. REMOTE_USER Change - Corresponding to the change in the kerberos module, the REMOTE_USER environment variable that is passed to cgi/php scripts is similarly changed. So, if you are using REMOTE_USER in your scripts you will have to strip off the @IU.EDU to get just the username.

3. Missing Perl Modules and Other Software - It is likely that people are using software or perl modules that were installed on the old cgi server but have not yet been installed on the new one. We have worked to identify missing software by monitoring the error logs but there are almost certainly things missing that we haven't caught. Please let us know if you discover missing software and we will work to get it installed.

4. WWWBoard Username Change - If you are using kerberos authentication with a WWWBoard Message Board then you will notice two changes as a result of the mod_auth_kerb change noted above:
   • Admin Access - Access to the administrator interface may be broken. You will need to modify the .htaccess file in the wwwadmin directory for your instance of the wwwboard software and add @IU.EDU to any usernames listed there.

   • Usernames - The usernames listed in postings will change for new postings from username to username@IU.EDU. If you want to change this, you will have to edit the wwwboard.cgi script which can be found in the wwwboard directory of your instance of the wwwboard software. Here is a diff showing the change that is needed. You will need to add the one line that is prefixed with a + in this diff output:

     
     *** wwwboard.cgi.orig   2003-01-07 10:42:02.000000000 -0500
     --- wwwboard.cgi        2007-01-05 11:55:10.000000000 -0500
     ***************
     *** 241,246 ****
     --- 241,247 ----
     
          if ($use_remote_user == 1) {
            $name = "$ENV{'REMOTE_USER'}";
     +      $name =~ s/\@.*//;
          }
          elsif ($FORM{'name'}) {
             $name = "$FORM{'name'}";
     
     

     Any new wwwboards that are created will have these changes in effect so it is only existing wwwboards that are affected.

For more information about running CGI and PHP scripts on the CS CGI server, please see the associated FAQs for CGI and PHP.

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