Bug 1006298 - (CVE-2013-4329) CVE-2013-4329 xen: libxl partially sets up HVM passthrough even with disabled iommu
CVE-2013-4329 xen: libxl partially sets up HVM passthrough even with disabled...
Status: CLOSED NOTABUG
Product: Security Response
Classification: Other
Component: vulnerability (Show other bugs)
unspecified
All Linux
high Severity high
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Assigned To: Red Hat Product Security
impact=important,public=20130910,repo...
: Security
Depends On: 1006301
Blocks: 1006302
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Reported: 2013-09-10 08:06 EDT by Petr Matousek
Modified: 2013-09-10 13:24 EDT (History)
11 users (show)

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Doc Type: Bug Fix
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Last Closed: 2013-09-10 08:08:05 EDT
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RHEL 7.3 requirements from Atomic Host:


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Description Petr Matousek 2013-09-10 08:06:44 EDT
With HVM domains, libxl's setup of PCI passthrough devices does the IOMMU setup after giving (via the device model) the guest access to the hardware and advertising it to the guest.

If the IOMMU is disabled the overall setup fails, but after the device has been made available to the guest; subsequent DMA instructions from the guest to the device will cause wild DMA.

A HVM domain, given access to a device which bus mastering capable in the absence of a functioning IOMMU, can mount a privilege escalation or denial of service attack affecting the whole system.

References:

http://lists.xen.org/archives/html/xen-announce/2013-09/msg00001.html

Acknowledgements:

Red Hat would like to thank the Xen project for reporting this issue.
Comment 1 Petr Matousek 2013-09-10 08:08:05 EDT
Statement:

Not vulnerable.

This issue does not affect the versions of the xen package as shipped with Red Hat Enterprise Linux 5 as it does not provide support for the libxl toolstack.

This issue does not affect Red Hat Enterprise Linux 6 and Red Hat Enterprise MRG 2.
Comment 2 Petr Matousek 2013-09-10 08:09:14 EDT
Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1006301]
Comment 3 Petr Matousek 2013-09-10 13:24:06 EDT
Adding CVE as per:

  http://seclists.org/oss-sec/2013/q3/579

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