Bug 450262

Summary: usermod/useradd may inadvertently give access to group root
Product: Red Hat Enterprise Linux 5 Reporter: Ralph Angenendt <ralph>
Component: shadow-utilsAssignee: Peter Vrabec <pvrabec>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: low    
Version: 5.2CC: bressers, mmalik, riek, sgrubb
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2008-09-03 09:03:32 UTC Type: ---
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fix candidate none

Description Ralph Angenendt 2008-06-06 09:27:58 UTC 
Description of problem:

With a simple typo when using useradd or usermod, you can give users access to
the root group. 

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

4.0.17-13.el5

How reproducible:

usermod -G group1,group2, username

gives that user access to group root

Steps to Reproduce:

[root@shutdown ~]# useradd -G content, foobar
[root@shutdown ~]# groups foobar
foobar : foobar root content
[root@shutdown ~]# usermod -G content foobar
[root@shutdown ~]# groups foobar
foobar : foobar content
[root@shutdown ~]# usermod -G content,backup, foobar
[root@shutdown ~]# groups foobar
foobar : foobar root content backup

  
Actual results:

user is member of the group root

Expected results:

Throw an error of some sort

Additional info:

This bug has been found in CentOS, see http://bugs.centos.org/view.php?id=2876
Comment 1 Peter Vrabec 2008-06-17 12:01:07 UTC 
Created attachment 309604 [details]
fix candidate
Comment 3 Ralph Angenendt 2008-06-17 12:41:03 UTC 
This fixes it for me.
Comment 4 Josh Bressers 2008-06-24 18:20:42 UTC 
This was just brought to my attention by sgrubb.  I'm inclined to say this isn't
a security issue as it's the result of user error.  I will agree that the
behavior is undesirable, but not serious enough to be classified as a security flaw.
Comment 5 Ralph Angenendt 2008-06-24 23:02:28 UTC 
Nobody said it's a security issue, but it's an ugly bug none the less. The patch
in comment 2 fixes the issue for me, as you cannot add empty groups anymore.
Comment 9 errata-xmlrpc 2008-09-03 09:03:32 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHBA-2008-0866.html