Bug 1012633 (CVE-2013-4377)

Summary:	CVE-2013-4377 qemu: hot-unplugging virtio devices in guest can crash host qemu process
Product:	[Other] Security Response	Reporter:	Vincent Danen <vdanen>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	amit.shah, areis, berrange, cfergeau, dwmw2, ehabkost, itamar, jrusnack, knoel, mtosatti, pbonzini, pfrields, rbalakri, rjones, scottt.tw, virt-maint, virt-maint
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2015-07-29 13:39:04 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:	983344, 1012641
Bug Blocks:

Description Vincent Danen 2013-09-26 18:26:50 UTC

A dangling pointer access flaw was found in the way qemu handled hot-unplugging virtio devices.  This flaw was introduced by virtio refactoring and exists in the virtio-pci implementation.  When the virtio-blk-pci device is deleted, the virtio-blk-device is removed first (removal is done in post-order).  Later, the virtio-blk-device is accessed again, but proxy->vdev->vq is no longer valid (a dangling pointer) and kvm_set_ioeventfd_pio fails.

A privileged guest user could use this flaw to crash the qemu process on the host system, causing a denial of service to it and any other running virtual machines.

Patches are available at http://thread.gmane.org/gmane.comp.emulators.qemu/234440


Acknowledgements:

This issue was discovered by Sibiao Luo of Red Hat.

Comment 1 Vincent Danen 2013-09-26 18:40:58 UTC

CVE request:

http://www.openwall.com/lists/oss-security/2013/09/26/4

Comment 2 Vincent Danen 2013-09-26 18:45:14 UTC

Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 1012641]

Comment 3 Vincent Danen 2013-09-26 22:17:46 UTC

This flaw was introduced in qemu version 1.4.0.

Comment 4 Vincent Danen 2013-09-26 22:18:57 UTC

This was assigned CVE-2013-4377:

http://www.openwall.com/lists/oss-security/2013/09/26/5

Comment 5 Vincent Danen 2013-09-26 22:20:03 UTC

Statement:

Not vulnerable.  This issue did not affect the version of qemu-kvm as shipped in Red Hat Enterprise Linux 5 and 6.

Comment 6 Fedora Update System 2013-10-15 06:37:10 UTC

qemu-1.6.0-10.fc20 has been pushed to the Fedora 20 stable repository.  If problems still persist, please make note of it in this bug report.