Bug 1012633 (CVE-2013-4377) - CVE-2013-4377 qemu: hot-unplugging virtio devices in guest can crash host qemu process
Summary: CVE-2013-4377 qemu: hot-unplugging virtio devices in guest can crash host qem...
Alias: CVE-2013-4377
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 983344 1012641
TreeView+ depends on / blocked
Reported: 2013-09-26 18:26 UTC by Vincent Danen
Modified: 2023-05-12 00:33 UTC (History)
17 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-07-29 13:39:04 UTC

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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vq is no longer valid (a dangling pointer) and kvm_set_ioeventfd_pio fails.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


This issue was discovered by Sibiao Luo of Red Hat.

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


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:


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

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.

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