Bug 1841136 (CVE-2019-20808)

Summary:	CVE-2019-20808 QEMU: out-of-bounds read in ati_cursor_define() function in hw/display/ati.c leads to DoS
Product:	[Other] Security Response	Reporter:	Mauro Matteo Cascella <mcascell>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	ailan, amit, berrange, cfergeau, dbecker, drjones, dwmw2, imammedo, itamar, jen, jferlan, jforbes, jjoyce, jmaloy, jschluet, kbasil, knoel, lhh, lkundrak, lpeer, m.a.young, mburns, mkenneth, mrezanin, mst, pbonzini, ribarry, rjones, robinlee.sysu, sclewis, slinaber, virt-maint, virt-maint, vkuznets, xen-maint
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	qemu 4.2.0	Doc Type:	If docs needed, set a value
Doc Text:	An out-of-bounds read flaw was found in the ATI VGA implementation of the QEMU emulator. This flaw occurs in the ati_cursor_define() routine while handling MMIO write operations through ati_mm_write() callback. A malicious guest could abuse this flaw to crash the QEMU process, resulting in a denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-05-28 17:20:49 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:	1841160, 1910694
Bug Blocks:	1752920

Description Mauro Matteo Cascella 2020-05-28 13:05:06 UTC

An out-of-bounds read flaw was found in function ati_cursor_define() in hw/display/ati.c, leading to possible denial of service under certain conditions.

Upstream fix:
https://git.qemu.org/?p=qemu.git;a=commit;h=aab0e2a661b2b6bf7915c0aefe807fb60d6d9d13

Comment 2 Mauro Matteo Cascella 2020-05-28 13:21:16 UTC

Statement:

This flaw did not affect the following versions of QEMU as they did not include support for ATI VGA emulation:
* `qemu-kvm-ma` as shipped with Red Hat Enterprise Linux 7.
* `qemu-kvm-rhev` as shipped with Red Hat Virtualization and Red Hat OpenStack.
* `qemu-kvm` as shipped with Red Hat Enterprise Linux 6, 7 and 8.
* `virt:8.2/qemu-kvm` as shipped with RHEL Advanced Virtualization.

ATI VGA emulation feature was introduced in QEMU upstream version 4.0.0.

Comment 3 Mauro Matteo Cascella 2020-05-28 14:00:57 UTC

Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 1841160]

Comment 4 Product Security DevOps Team 2020-05-28 17:20:49 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-2019-20808