Bug 1623013 (CVE-2018-15855)

Summary:	CVE-2018-15855 libxkbcommon: NULL pointer dereference when handling xkb_geometry
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	me, peter.hutterer, xgl-maint
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libxkbcommon 0.8.1	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-08-06 19:19:26 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:	1623038, 1643073
Bug Blocks:	1623044

Description Andrej Nemec 2018-08-28 11:50:56 UTC

Unchecked NULL pointer usage in xkbcommon before 0.8.1 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file, because the XkbFile for an xkb_geometry section was mishandled.

Upstream patch:

https://github.com/xkbcommon/libxkbcommon/commit/917636b1d0d70205a13f89062b95e3a0fc31d4ff

References:

https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html

Comment 4 Riccardo Schirone 2018-10-25 14:09:22 UTC

The parser implemented in parser.y returns NULL when a xkb_geometry FileType is parsed, but some parts of the code, like parser.y:parse(), do not handle NULL values, causing the application to crash.

Comment 5 errata-xmlrpc 2019-08-06 12:11:13 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2019:2079 https://access.redhat.com/errata/RHSA-2019:2079

Comment 6 Product Security DevOps Team 2019-08-06 19:19:26 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2018-15855