From Bugzilla Helper:
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; 
Maxthon; .NET CLR 1.1.4322)

Description of problem:
Many pam/nss modules (IE: winbind, ldap, etc..) allow the user to 
enter a non-Unix username at the login prompt. IE: domain+user, 
user@domain, domain\\user, etc...   Since gdm passes exactly what was 
typed to sessreg, it will often fail, or worse, create non-sensical 
wtmp entries.

All such pam modules will map the non-standard name to a standard one 
and either find or generate a correct password entry structure.

A simple change to gdm to pass the username from the pwent rather 
than what the user typed in.   The pwent name should also be used for 
environment variables as well.

Version-Release number of selected component (if applicable):
gdm-2.4.1.6-5

How reproducible:
Always

Steps to Reproduce:
1. Configure windbind, log in using the Windows username including a 
space or some other non-unix friendly character.

    

Actual Results:  User is told their session exited immediately.  
Following error in /var/log/messages:

gdm_slave_session_start: Execution of PreSession script returned > 0. 
Aborting.


Expected Results:  User should be able to log in with their unix name 
put in wtmp.

Additional info:

Patch attached...