Bug 1749175 (CVE-2019-15767)

Summary:	CVE-2019-15767 gnuchess: stack-based overflow in cmd_load in frontend/cmd.cc via crafted EPD file
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	caillon+fedoraproject, gwync, karsten, mcepl
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-09-11 18:45:35 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:	1749177, 1749178
Bug Blocks:	1749176

Description Dhananjay Arunesh 2019-09-05 05:39:32 UTC

A vulnerability was found in GNU Chess 6.2.5, there is a stack-based buffer overflow in the cmd_load
function in frontend/cmd.cc via a crafted chess position in an EPD file.

Reference:
https://lists.gnu.org/archive/html/bug-gnu-chess/2019-08/msg00004.html
https://lists.gnu.org/archive/html/bug-gnu-chess/2019-08/msg00005.html

Comment 1 Dhananjay Arunesh 2019-09-05 05:40:38 UTC

Created gnuchess tracking bugs for this issue:

Affects: epel-7 [bug 1749178]
Affects: fedora-all [bug 1749177]

Comment 2 Riccardo Schirone 2019-09-11 12:19:07 UTC

gnuchess is only shipped in the optional repository.

Comment 3 Riccardo Schirone 2019-09-11 13:42:41 UTC

Statement:

This issue did not affect the versions of gnuchess as shipped with Red Hat Enterprise Linux 6 as the vulnerable code is not present in the older version shipped there.

Comment 4 Riccardo Schirone 2019-09-11 13:50:39 UTC

Function cmd_load() reads at most MAXSTR(128) bytes from the EPD file in the `epdline` array of size MAXSTR, then it creates the data to send to the engine: this is done by copying `epdline` in a new array `data` of size MAXSTR and prefixing it with the string "setboard". However in some cases it is possible that while copying `epdline` in `data` the bytes are written beyond the limits of the `data` array, causing a stack-based buffer overflow that could be used to gain code execution with the privileges of the gnuchess binary.

Comment 5 Riccardo Schirone 2019-09-11 14:27:25 UTC

Vulnerable code is present since version v5.9.90.

Comment 6 Product Security DevOps Team 2019-09-11 18:45:35 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-2019-15767