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: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: 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   
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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:
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]