Bug 1623013 – CVE-2018-15855 libxkbcommon: NULL pointer dereference when handling xkb_geometry

Bugzilla will be upgraded to version 5.0 on a still to be determined date in the near future. The original upgrade date has been delayed.

Bug 1623013 - (CVE-2018-15855) CVE-2018-15855 libxkbcommon: NULL pointer dereference when handling xkb_geometry

Summary:	CVE-2018-15855 libxkbcommon: NULL pointer dereference when handling xkb_geometry

Status:	NEW

Aliases:	CVE-2018-15855

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	low Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=low,public=20180311,reported=2...
Keywords:	Security

Depends On:	1623038 1643073
Blocks:	1623044
	Show dependency tree / graph

Reported:	2018-08-28 07:50 EDT by Andrej Nemec
Modified:	2018-10-25 10:09 EDT (History)
CC List:	3 users (show)

See Also:
Fixed In Version:	libxkbcommon 0.8.1
Doc Type:	If docs needed, set a value
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Andrej Nemec 2018-08-28 07:50:56 EDT

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 10:09:22 EDT

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.

Note You need to log in before you can comment on or make changes to this bug.