Bug 1298874 (CVE-2016-0740)

Summary:	CVE-2016-0740 python-pillow: Integer overflow resulting in buffer overflow when reading invalid tiff file
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	carnil, miminar, security-response-team, tsmetana
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:	2016-03-01 13:38:06 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:	1298648
Bug Blocks:	1298877

Description Adam Mariš 2016-01-15 10:42:58 UTC

It was reported that python-pillow 3.1.0 when linked against libtiff >= 4.0.0 may overflow a buffer when reading a specially crafted tiff file. libtiff >=4.0.0 changed the return type of TIFFScanlineSize from int32 to machine dependent int32|64. If the scanline is sized so that it overflows an int32, it may be interpreted as a negative number, which will then pass the size check in TiffDecode.c line 236. To do this, the logical scanline size has to be > 2gb. If the size of allocated buffer is 64k, any image data over 64k is written over the heap, causing a segfault. 

Original bug report (contains reproducer):

https://bugzilla.redhat.com/show_bug.cgi?id=1298648

Comment 1 Stefan Cornelius 2016-01-18 09:49:33 UTC

Introduced via the following commit:
https://github.com/python-pillow/Pillow/commit/e782fe721e0156de9636e78cd881d9f9e7e6ce50

Comment 2 Stefan Cornelius 2016-01-18 12:28:40 UTC

RHEL7 is affected. However, the sample reproducer image was compressed in a format that our python-pillow does not support. For testing purposes, I've backported https://github.com/python-pillow/Pillow/commit/a130c45990578a1bb0a6a000ed1b110e27324910 and can see the crash.

Although I failed to do so, it may be possible to create an image that would trigger this image using a different, supported compression algorithm.

Comment 3 Stefan Cornelius 2016-01-18 13:01:26 UTC

python-imaging on RHEL5 and 6 is not linked to and does not support libtiff > 4.0.0. Since this issue requires the libtiff 4.0.0 64bit changes and they don't ship the vulnerable image processing code, they are not vulnerable.

Comment 4 Stefan Cornelius 2016-02-03 20:07:08 UTC

Acknowledgements:

Red Hat would like to thank the Pillow project for reporting this issue. Upstream acknowledges FourOne as the original reporter.