Bug 1919210 (CVE-2021-20196)

Summary: CVE-2021-20196 QEMU: block: fdc: null pointer dereference may lead to guest crash
Product: [Other] Security Response Reporter: Prasad Pandit <ppandit>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: ailan, berrange, cfergeau, dbecker, drjones, imammedo, itamar, jen, jferlan, jforbes, jjoyce, jmaloy, jschluet, knoel, lhh, lpeer, m.a.young, mburns, mkenneth, mrezanin, mst, ondrejj, pbonzini, qinwang, ribarry, rjones, robinlee.sysu, sclewis, security-response-team, slinaber, virt-maint, virt-maint, vkuznets, xen-maint
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. 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: 2022-02-02 10:01:43 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: 1919532, 1919533, 1921546, 1921547, 1921548, 1921549, 1929016, 1929017, 1929019, 1929020, 1944624, 2028980    
Bug Blocks: 1909094    

Description Prasad Pandit 2021-01-22 12:02:50 UTC
A NULL pointer dereference issue was found in the Floopy disk emulator of QEMU. It could occur while processing read/write ioport commands, if the selected Floopy drive is not initialised with a block device. A privileged guest user could use this flaw to crash the QEMU process on the host resulting in DoS scenario.

Upstream patch:
  -> https://lists.nongnu.org/archive/html/qemu-devel/2021-01/msg05986.html

Comment 1 Prasad Pandit 2021-01-22 12:02:55 UTC

Name: Gaoning Pan (Zhejiang University & Ant Security Light-Year Lab)

Comment 4 Prasad Pandit 2021-01-23 13:13:22 UTC
Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 1919532]

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1919533]

Comment 10 RaTasha Tillery-Smith 2021-02-22 18:54:28 UTC

This issue affects the version of the qemu-kvm package shipped with Red Hat Enterprise Linux 5, 6, 7 and 8. Future qemu-kvm package updates for Red Hat Enterprise Linux 7 and 8 may address this issue.

This has been rated as having Low security impact and is not currently planned to be addressed in future updates of Red Hat Enterprise Linux 5 & 6. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.

Comment 14 errata-xmlrpc 2022-01-31 15:17:28 UTC
This issue has been addressed in the following products:

  Advanced Virtualization for RHEL 8.4.0.EUS

Via RHSA-2022:0325 https://access.redhat.com/errata/RHSA-2022:0325

Comment 15 errata-xmlrpc 2022-02-02 08:47:52 UTC
This issue has been addressed in the following products:

  Advanced Virtualization for RHEL 8.5.0.Z

Via RHSA-2022:0397 https://access.redhat.com/errata/RHSA-2022:0397

Comment 16 Product Security DevOps Team 2022-02-02 10:01:40 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 17 errata-xmlrpc 2022-05-10 13:16:37 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1759 https://access.redhat.com/errata/RHSA-2022:1759