Bug 985540 (CVE-2013-4143)

Summary: CVE-2013-4143 xlockmore: NULL pointer dereference leads to crash and bypass of screen lock
Product: [Other] Security Response Reporter: Vincent Danen <vdanen>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: adrian, jlieskov
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=moderate,public=20130714,reported=20130716,source=oss-security,cvss2=4.6/AV:L/AC:L/Au:N/C:P/I:P/A:P,fedora-18/xlockmore=notaffected,fedora-19/xlockmore=affected,epel-6/xlockmore=notaffected,cwe=CWE-476[auto]
Fixed In Version: xlockmore 5.43 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2013-08-02 15:57:14 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 985542    
Bug Blocks:    

Description Vincent Danen 2013-07-17 13:34:55 EDT
It was reported [1],[2] that xlockmore 5.43 fixes a NULL pointer dereference in situations where the crypt() call fails (the release notes indicate this is possible with glibc starting with version 2.17 due to crypt() failures returning EINVAL with a NULL return in certain situations).  This could cause xlock to crash, which would allow for local users to obtain access to a locked desktop they would normally require a password to access.

A patch [3] is available.

This affects Fedora 19 as it provides glibc 2.17.  Earlier versions are not affected.

[1] http://www.tux.org/~bagleyd/xlock/xlockmore.README
[2] http://www.openwall.com/lists/oss-security/2013/07/16/8
[3] http://sourceforge.net/projects/miscellaneouspa/files/glibc217/xlockmore-5.42-glibc217-crypt.diff
Comment 1 Vincent Danen 2013-07-17 13:36:51 EDT
Created xlockmore tracking bugs for this issue:

Affects: fedora-19 [bug 985542]
Comment 2 Jan Lieskovsky 2013-07-18 09:39:06 EDT
The CVE identifier of CVE-2013-4143 has been assigned to this issue:
Comment 3 Fedora Update System 2013-07-30 13:49:45 EDT
xlockmore-5.43-1.fc19 has been pushed to the Fedora 19 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 4 Fedora Update System 2013-08-05 19:29:59 EDT
xlockmore-5.43-1.el6 has been pushed to the Fedora EPEL 6 stable repository.  If problems still persist, please make note of it in this bug report.