Bug 1910346 (CVE-2020-35503)

Summary:	CVE-2020-35503 QEMU: NULL pointer dereference issue in megasas-gen2 host bus adapter
Product:	[Other] Security Response	Reporter:	Mauro Matteo Cascella <mcascell>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	berrange, cfergeau, dbecker, itamar, jen, jferlan, jforbes, jjoyce, jmaloy, jschluet, knoel, lhh, lpeer, m.a.young, mburns, mkenneth, mrezanin, mst, ondrejj, pbonzini, philmd, ribarry, rjones, robinlee.sysu, sclewis, slinaber, virt-maint, virt-maint
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A NULL pointer dereference flaw was found in the megasas-gen2 SCSI host bus adapter emulation of QEMU. This issue occurs in the megasas_command_cancelled() callback function while dropping a SCSI request. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-12-23 18:27:36 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:	1910366, 1910367
Bug Blocks:	1907553

Description Mauro Matteo Cascella 2020-12-23 14:32:23 UTC

A NULL pointer dereference issue was found in the megasas-gen2 SCSI host bus adapter emulation of QEMU. It could occur in the megasas_command_cancelled() callback function in hw/scsi/megasas.c while dropping a SCSI request. A privileged guest user may exploit this issue to crash the QEMU process on the host, resulting in a denial of service condition.

Comment 1 Mauro Matteo Cascella 2020-12-23 14:32:29 UTC

Acknowledgments:

Name: Cheolwoo Myung

Comment 2 Mauro Matteo Cascella 2020-12-23 15:42:40 UTC

Statement:

This issue does not affect Red Hat Enterprise Linux, Red Hat OpenStack Platform and RHEL Advanced Virtualization, as the `qemu-kvm` package does not include support for the megasas-gen2 host bus adapter emulation.

Comment 3 Mauro Matteo Cascella 2020-12-23 15:43:06 UTC

Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 1910366]


Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1910367]