Description of problem:
If the namespace.conf file includes in the list of user accounts to
not polyinstantiate an account that doesn't exist, pam_namespace.so
will fail and no users can log in.

Version-Release number of selected component (if applicable):
It was seen in pam-0.99.6.2-3.14.el5 but I believe the problem
still exists in the latest code.

How reproducible:
always

Steps to Reproduce:
1.configure a system with pam_namespace.so configured as for an LSPP system.
This means pam_namespace in the /etc/pam.d/login file and the lines in
/etc/security/namespace.conf uncommented.
2.edit /etc/security/namespace.conf to add a login name for an account that
doesn't exist.
3.Try to log in 
  
Actual results:
pam_namespace.so crashes and no users can log in.
If debug is enabled for pam_namespace.so the last line in 
/var/log/secure will be that its parsing the config file.

Expected results:
Users should be able to log in.

Additional info:

This is an untested patch.  I don't know if there are other
instances of the same problem.

--- pam_namespace.c     2007-03-29 15:02:06.000000000 -0400
+++ pam_namespace.c.ljk 2007-03-29 15:08:59.000000000 -0400
@@ -302,6 +302,8 @@ static int process_line(char *line, cons
                 *tptr = '\0';

             pwd = getpwnam(ustr);
+            if (!pwd)
+               continue;
             *uidptr = pwd->pw_uid;
             if (i < count - 1) {
                 ustr = tptr + 1;