Bug 611927

Summary:	freetype: write to non-mapped memory in base/ftojbs.c:1563
Product:	[Other] Security Response	Reporter:	Vincent Danen <vdanen>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED INSUFFICIENT_DATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	behdad, bressers, fonts-bugs, kevin, mkasik, osoukup
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:	2010-07-07 17:45:18 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 Vincent Danen 2010-07-06 21:08:03 UTC

Robert Swiecki reported a possibly exploitable write to non-mapped memory in the way freetype handles certain font [1].

The original report has two sample font files that caused the tested version to crash with a SIGSEGV (sigsegv16.pfb) and SIGABRT (sigabrt24.ttf).  When reproducing, observed behaviour was:

RHEL3 (freetype 2.1.4): pass on both files
RHEL4 (freetype 2.1.9): crashes (segfault) on both files
RHEL5 (freetype 2.2.1): crashes (segfault) on sigsegv16.pfb only
Fedora (freetype 2.3.11): crashes (segfault) on sigsegv16.pfb only

The upstream bug report claims this may be potentially exploitable for more than just a crash.  A patch was posted to correct the issue [2].  This needs to be looked at to determine whether or not this can be exploited to execute arbitrary code.

[1] http://savannah.nongnu.org/bugs/index.php?30248
[2] http://savannah.nongnu.org/bugs/download.php?file_id=20815

Comment 1 Vincent Danen 2010-07-06 21:36:47 UTC

There is actually 21 crashes reported upstream:

http://savannah.nongnu.org/bugs/index.php?go_report=Apply&group=freetype&func=browse&set=custom&msort=0&report_id=100&advsrch=0&status_id=0&resolution_id=0&assigned_to=0&bug_group_id=0&history_search=0&history_field=0&history_event=modified&history_date_dayfd=2&history_date_monthfd=7&history_date_yearfd=2010&chunksz=50&spamscore=5&boxoptionwanted=1#options

Roughly half of these are NULL pointer derefs or stack exhaustion.  This bug, and bug 30083, were noted as being higher risk.

Comment 4 Josh Bressers 2010-07-07 17:45:18 UTC

I'm going to close this bug and file individual bugs for each freetype flaw found (there are several)