Bug 212168

Summary:	CVE-2006-5214 Xsession problems (CVE-2006-5215)
Product:	[Fedora] Fedora	Reporter:	Mark J. Cox <mjc>
Component:	gdm	Assignee:	Ray Strode [halfline] <rstrode>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	5	Keywords:	Security
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:	reported=20061010,source=cve,impact=low,public=20060212
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2006-10-25 14:31:29 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:

Description Mark J. Cox 2006-10-25 14:11:37 UTC

+++ This bug was initially created as a clone of Bug #212167 +++

Two issues in XFree86/xorg Xsession were reported and fixed upstream.  Both
relate to the handling of the xsession file.  

CVE-2006-5214: A local attacker could open for reading a users
~/.xsession-errors file if they are able to win a race during it's creation and
have sufficient privileges (+x) to the victims home directory already.

CVE-2006-5215: A local attacker could perform a temporary file attack on the
xsession error file created in /tmp and cause it to overwrite particular files
of the victim.  However this file is only created if the ability to create
~/.xsession-errors in the victims home directory fails, (something the attacker
has no control over).  The upstream Xsession code was different (and worse) than
our xinitrc code, but we should use mkstemp.

We've rated these issues as low severity and they can be deferred until a future
update for some other reason.

This affects Xsession as shipped in gdm package in FC5

Comment 1 Ray Strode [halfline] 2006-10-25 14:31:29 UTC

So we don't ship a separate Xsession file for GDM, we just use the system one in
/etc/X11/xinit/Xsession

From the fc5 gdm spec file:

# remove the gdm Xsession as we're using the xdm one
rm -f $RPM_BUILD_ROOT%{_sysconfdir}/gdm/Xsession
(cd $RPM_BUILD_ROOT%{_sysconfdir}/gdm; ln -sf ../X11/xinit/Xsession .)


Also, the xinit Xsession file has this guard around the icky code:

if [ -z "$GDMSESSION" ]; then
  ... icky xsession-errors code here ...
fi

because gdm creates the xsession-errors file itself, so i'm going to close this
NOTABUG.