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Description of problem:

The routine uses an incorrect comparison in 
BUILD/Linux-PAM-0.75/modules/pam_localuser/pam_localuser.c:114
If the user "abcXYZ" is authorized it wrongly assumes that a user "abc" is
authorized too.  i.e. if we had a user "ro" it would be as authorized as "root" is.

Version-Release number of selected component (if applicable):
pam-0.75-48, the one in rawhide has the same bug

How reproducible:
Always

Steps to Reproduce:
1. create an account for a nice user "anna".  

2. create an account for a bad user "ann".

3. Add a restriction to /etc/pam.d/sshd
   account required /lib/security/pam_localuser.so file=/etc/nice_users debug

4. Authorize her using:
   echo anna: > /etc/nice_users


    

Actual Results:  
Now both anna and ann can use the machine.

Expected Results:  The user "anna" should be authorized but "ann" should not,
unless she is added to /etc/nice_users

Additional info:

I made a patch: http://www.camk.edu.pl/~chris/pam-0.75-localuser-strcmp.patch.gz
It applies to pam-0.75-48