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Advisory

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            Xen Security Advisory CVE-2015-0268 / XSA-117
                              version 2

           arm: vgic-v2: GICD_SGIR is not properly emulated

UPDATES IN VERSION 2
====================

CVE assigned.

Mention CVE and XSA numbers in patch commit message.

Public release.

ISSUE DESCRIPTION
=================

When decoding a guest write to a specific register in the virtual
interrupt controller Xen would treat an invalid value as a critical
error and crash the host.

IMPACT
======

By writing an invalid value to the GICD.SGIR register a guest can
crash the host, resulting in a Denial of Service attack.

VULNERABLE SYSTEMS
==================

Xen 4.5 and later systems running on ARM hardware with version 2 of
the generic interrupt controller are vulnerable.

Systems running on ARM hardware with version 3 of the generic
interrupt controller are not vulnerable.

x86 systems are not affected.

MITIGATION
==========

None.

CREDITS
=======

This issue was discovered by Julien Grall.

RESOLUTION
==========

Applying the appropriate attached patch resolves this issue.

xsa117.patch        Xen 4.5.x, xen-unstable

$ sha256sum xsa117*.patch
5d7c1ec3bd604ed49999a56fefeebda1206f424b1b48c0e44899f13bc1e55cd0  xsa117.patch
$
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