Bug 1381865 (CVE-2016-7944)

Summary:	CVE-2016-7944 libXfixes: Insufficient validation of server responses results in Integer overflow
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	btissoir, kbost, sandmann, slawomir
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libXfixes 5.0.3	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 02:59:27 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:	1381866
Bug Blocks:	1381939

Description Andrej Nemec 2016-10-05 08:45:50 UTC

It was found that when receiving a response from the server protocol data is not validated sufficiently. The 32 bit field "rep.length" is not checked for validity, which allows an integer overflow on 32 bit systems.

A malicious server could send INT_MAX as length, which gets multiplied by the size of XRectangle. In that case the client won't read the whole data from server, getting out of sync.

Upstream patch:

https://cgit.freedesktop.org/xorg/lib/libXfixes/commit/?id=61c1039ee23a2d1de712843bed3480654d7ef42e

External References:

https://lists.x.org/archives/xorg-announce/2016-October/002720.html

CVE assignment:

http://seclists.org/oss-sec/2016/q4/17

Comment 1 Andrej Nemec 2016-10-05 08:46:10 UTC

Created libXfixes tracking bugs for this issue:

Affects: fedora-all [bug 1381866]