Home page logo
/

oss-sec logo oss-sec mailing list archives

Xen Security Advisory 73 - Lock order reversal between page allocation and grant table locks
From: Xen.org security team <security () xen org>
Date: Fri, 01 Nov 2013 15:07:14 +0000

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

                    Xen Security Advisory XSA-73

    Lock order reversal between page allocation and grant table locks

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

While the response to this issue was being prepared by the security
team, the bug was independently discovered by a third party who
publicly disclosed it without realising the security impact.

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

The locks page_alloc_lock and grant_table.lock are not always taken in
the same order.  This opens the possibility of deadlock.

IMPACT
======

A malicious guest administrator can deny service to the entire host.

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

Xen versions going back to at least Xen 3.2 are vulnerable.

To exploit the vulnerability, the attacker must have control of more
than one vcpu, either by controlling a malicious multi-vcpu guest, or
by controlling more than one guest.

MITIGATION
==========

There is no practical mitigation for this issue.

CREDITS
=======

This issue was discovered by Coverity Scan and diagnosed by Andrew
Cooper.

RESOLUTION
==========

Applying the appropriate attached patch resolves this issue.

xsa73-4.3-unstable.patch    Xen 4.3.x, xen-unstable
xsa73-4.2.patch             Xen 4.2.x
xsa73-4.1.patch             Xen 4.1.x

$ sha256sum xsa73*.patch
b828ff085f2dc1f2042bda1dc8a6c52b56ad1c1e3639c3efe32e5706e4ef424f  xsa73-4.1.patch
10b809c39582a7f29150f0635b78bc2ce40df0bded963b78f42db3e21775da8c  xsa73-4.2.patch
48411cd6b15e4e4fa3c4335298179a4b1094c5e1ae8dc7582bbfb9439d97037b  xsa73-4.3-unstable.patch
$
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iQEcBAEBAgAGBQJSc8OAAAoJEIP+FMlX6CvZNoMH/Al1MD/FJXpJ6BnLZH3zV505
wKc1x38OGpM61X2PrMLCqaqZfRTDuUWFkAx4wOdp1OXx6Do8nwtyzXYInNYKHjse
xS5JhBM0GPY+pABVYJ4IDcskKHDCLew/L4RcPK3oDiS9sZACSrVRXGVLnNUupLit
KmCbN1sZkFwUZSCpF+TBH7QbSkk9h2ytTGDaiZKgmrsmL7TMEOP4ikqxjBDC6gM7
Ty6NzaGJUpIx3nIEjFTnggE8UYN0NkQVDjZlhsDJPbcEWCuHXMYNaXrqFjSY68ac
4uDmwmR6exk38AGQhRir2FkwoXg2Gyim4pxWx7SYge/Ssc2Mft1aMNOdz7uCr3c=
=6AqT
-----END PGP SIGNATURE-----

Attachment: xsa73-4.1.patch
Description:

Attachment: xsa73-4.2.patch
Description:

Attachment: xsa73-4.3-unstable.patch
Description:


  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]
AlienVault