Bug 1012633 - (CVE-2013-4377) CVE-2013-4377 qemu: hot-unplugging virtio devices in guest can crash host qemu process
CVE-2013-4377 qemu: hot-unplugging virtio devices in guest can crash host qem...
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Red Hat Product Security
: Security
Depends On: 983344 1012641
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Reported: 2013-09-26 14:26 EDT by Vincent Danen
Modified: 2015-10-15 14:01 EDT (History)
17 users (show)

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Doc Type: Bug Fix
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Last Closed: 2015-07-29 09:39:04 EDT
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Description Vincent Danen 2013-09-26 14:26:50 EDT
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vq is no longer valid (a dangling pointer) and kvm_set_ioeventfd_pio fails.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 14:40:58 EDT
CVE request:

Comment 2 Vincent Danen 2013-09-26 14:45:14 EDT
Created qemu tracking bugs for this issue:

Affects: fedora-all [bug 1012641]
Comment 3 Vincent Danen 2013-09-26 18:17:46 EDT
This flaw was introduced in qemu version 1.4.0.
Comment 4 Vincent Danen 2013-09-26 18:18:57 EDT
This was assigned CVE-2013-4377:

Comment 5 Vincent Danen 2013-09-26 18:20:03 EDT

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 02:37:10 EDT
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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