Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [day] [month] [year] [list]
Message-Id: <E1b9vTq-0001gg-6a@xenbits.xenproject.org>
Date: Mon, 06 Jun 2016 14:26:14 +0000
From: Xen.org security team <security@....org>
To: xen-announce@...ts.xen.org, xen-devel@...ts.xen.org,
 xen-users@...ts.xen.org, oss-security@...ts.openwall.com
CC: Xen.org security team <security@....org>
Subject: Xen Security Advisory 181 (CVE-2016-5242) - arm: Host crash
 caused by VMID exhaustion

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

            Xen Security Advisory CVE-2016-5242 / XSA-181
                              version 2

               arm: Host crash caused by VMID exhaustion

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

CVE assigned.

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

VMIDs are a finite hardware resource, and allocated as part of domain
creation.  If no free VMIDs are available when trying to create a new domain,
a bug in the error path causes a NULL pointer to be used, resulting in a Data
Abort and host crash.

IMPACT
======

Attempting to create too many concurrent domains causes a host crash rather
than a graceful error.  A malicious device driver domain can hold references
to domains, preventing its VMID being released.

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

Xen versions 4.4 and later are affected.  Older Xen versions are unaffected.

x86 systems are not affected.

Only arm systems with less-privileged device driver domains can expose this
vulnerability.

MITIGATION
==========

There is no mitigation.  Not using driver domains reclassifies the problem,
but does not fix it.

NOTE REGARDING LACK OF EMBARGO
==============================

The crash was discussed publicly on xen-devel, before it was appreciated
that there was a security problem.

CREDITS
=======

This issue was discovered by Aaron Cornelius of DornerWorks.

RESOLUTION
==========

Applying the appropriate attached patch resolves this issue.

xsa181.patch           xen-unstable, Xen 4.6.x, 4.5.x
xsa181-4.4.patch       Xen 4.4.x

$ sha256sum xsa181*
6756fcf44446675e5277f6d6c0e8a0aaa51a7909ad9a55af89a09367fded8733  xsa181.patch
97a90c7cb42466647622cb2ed98de531b7ba2e174a1bc639a32a6f1b626d503f  xsa181-4.4.patch
$
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iQEbBAEBAgAGBQJXUYxcAAoJEIP+FMlX6CvZgAAH+OiNDLSkAHUl3isXjFzK+Mf9
NGuIyXc2j5K8uTwz5KvZkhiWLVCeOY7Jo1Wix3Fa1wFtJ2rMlgQf7/hOt0tk0NjU
w97Re+xSi69iruPEdwb4k31ohnlfLSqriqL4JWh6EDrhftdnvEk/yXmriyu1RhKy
MLk1P24Ora/gvSj31px3vBkbu8KLImhIOkOcRmJ7FQb8gWsmMDluuVu7lhUAL7im
KCe6u99sDQo18wxubYID4XxFqJExBUd6L3cnpdN4UITgylSaIqJq/RBwd8jRrxW8
MxT9/IcNf0rmB1Sh1IARBFF7P7hj76ho3sIpMeE0cMPWBe2NWMItX9ula61vQA==
=kBFB
-----END PGP SIGNATURE-----

Download attachment "xsa181.patch" of type "application/octet-stream" (1243 bytes)

Download attachment "xsa181-4.4.patch" of type "application/octet-stream" (1285 bytes)

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.