Bug 973695 (CVE-2013-2179)

Summary:	CVE-2013-2179 xorg-x11-xdm: NULL pointer dereference (DoS) when verifying user credentials in FIPS-140 mode or using glibc >= 2.17
Product:	[Other] Security Response	Reporter:	Jan Lieskovsky <jlieskov>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	lemenkov, pertusus, sandmann, xgl-maint
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-06-14 03:46:57 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	973698
Bug Blocks:	973700

Description Jan Lieskovsky 2013-06-12 13:58:21 UTC

A NULL pointer dereference, leading to denial of service flaw was found in the way X.Org X11 xdm, X.Org X Display Manager, performed user credentials verification, when the FIPS-140 mode was enabled on the underlying Linux system or the xdm was compiled against glibc library of version of 2.17 and above. A local attacker could provide a specially-crafted input that, when processed would lead to xdm executable crash.

References:
[1] http://www.openwall.com/lists/oss-security/2013/06/11/5

Relevant upstream patch:
[2] http://cgit.freedesktop.org/xorg/app/xdm/commit/?id=8d1eb5c74413e4c9a21f689fc106949b121c0117

Comment 1 Jan Lieskovsky 2013-06-12 14:02:20 UTC

Created xorg-x11-xdm tracking bugs for this issue

Affects: fedora-all [bug 973698]

Comment 2 Huzaifa S. Sidhpurwala 2013-06-14 03:45:23 UTC

This issue only affects those builds of xdm which use raw crypt() authentication, instead of a higher level system such as PAM or BSD Auth. The version of xdm binary as shipped in xorg-x11-xdm package, in Red Hat Enterprise Linux 5 and 6 is linked against PAM libraries and is therefore not affected by this flaw.

Comment 3 Huzaifa S. Sidhpurwala 2013-06-14 03:46:08 UTC

Statement:

Not Vulnerable. This issue does not affect the version of xorg-x11-xdm as shipped with Red Hat Enterprise Linux 5 and 6.

Comment 4 Huzaifa S. Sidhpurwala 2013-06-14 03:46:57 UTC

This issue does not affect the version of xorg-x11-xdm package as shipped with Fedora 17 and Fedora 18.