Bug 1843771 (CVE-2020-13800)

Summary:	CVE-2020-13800 QEMU: ati-vga: infinite recursion in ati_mm_read/write calls may lead to DoS
Product:	[Other] Security Response	Reporter:	Prasad Pandit <ppandit>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	amit, berrange, cfergeau, dbecker, dwmw2, itamar, jen, jferlan, jforbes, jjoyce, jmaloy, jschluet, kbasil, knoel, lhh, lpeer, m.a.young, mburns, mkenneth, mrezanin, mst, pbonzini, ribarry, rjones, robinlee.sysu, sclewis, slinaber, virt-maint, virt-maint
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	QEMU 5.0.1	Doc Type:	If docs needed, set a value
Doc Text:	An infinite recursion flaw was found in the ati-vga emulator of the QEMU. The issue occurs in ati_mm_read/write routines while accessing VGA registers, for certain values of the 'mm_index' variable. This flaw allows a guest user or process to crash the QEMU process, resulting in a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-06-04 11:20:31 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:	1843772, 1910689
Bug Blocks:	1772801

Description Prasad Pandit 2020-06-04 05:45:28 UTC

An infinite recursion issue was found in the ati-vga emulator of the QEMU. It could occur in ati_mm_read/write routines while accessing VGA registers, for certain values of the 'mm_index' variable. A guest user/process may use this flaw to crash the QEMU process resulting in DoS scenario.

Upstream patch:
---------------
  -> https://lists.gnu.org/archive/html/qemu-devel/2020-06/msg00944.html

Comment 1 Prasad Pandit 2020-06-04 05:45:35 UTC

Acknowledgments:

Name: Ren Ding (SSLab Georgia Tech), Hanqing Zhao (SSLab Georgia Tech), Yi Ren

Comment 2 Prasad Pandit 2020-06-04 05:46:01 UTC

Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 1843772]

Comment 4 Prasad Pandit 2020-06-04 06:29:35 UTC

External References:

https://www.openwall.com/lists/oss-security/2020/06/04/2

Comment 5 Product Security DevOps Team 2020-06-04 11:20:31 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-2020-13800