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Bug 532030 (CVE-2014-9065) - <app-emulation/xen-{4.2.5-r3,4.3.3-r3,4.4.1-r4}: p2m lock starvation (CVE-2014-{9065,9066})
Summary: <app-emulation/xen-{4.2.5-r3,4.3.3-r3,4.4.1-r4}: p2m lock starvation (CVE-201...
Status: RESOLVED FIXED
Alias: CVE-2014-9065
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal minor (vote)
Assignee: Gentoo Security
URL: http://www.openwall.com/lists/oss-sec...
Whiteboard: B3 [glsa]
Keywords:
Depends on:
Blocks:
 
Reported: 2014-12-09 08:39 UTC by Agostino Sarubbo
Modified: 2015-04-11 20:37 UTC (History)
1 user (show)

See Also:
Package list:
Runtime testing required: ---


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Description Agostino Sarubbo gentoo-dev 2014-12-09 08:39:17 UTC
From ${URL} :

     Xen Security Advisory CVE-2014-9065,CVE-2014-9066 / XSA-114
                              version 3

                       p2m lock starvation

UPDATES IN VERSION 3
====================

Public release.

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

The current read/write lock implementation is read-biased, which allows
a consistent stream of readers to starve writers indefinitely.  There
are certain rwlocks where guests are capable of applying arbitrary read
pressure.

IMPACT
======

A malicious guest administrator can deny service to other tasks.  If
the NMI watchdog is active, a timeout might be triggered, resulting in
a host crash.

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

Xen 4.2 and later systems are vulnerable.

Xen 4.1 and earlier are not vulnerable in normal configurations.  4.1
and earlier are vulnerable only insofar as features are used which
have already been explicitly discounted for security support purposes
(TMEM, see XSA-15; XSM-based radical disaggregation, see XSA-77).

Only x86 systems offer avenues for attacking this vulnerability.
ARM systems do not and are therefore not vulnerable.

MITIGATION
==========

There is no mitigation available for this issue.

CREDITS
=======

This issue was discovered by Andrew Cooper of Citrix.

RESOLUTION
==========

Applying the appropriate attached patch resolves this issue in
practice for most systems.  (CVE-2014-9065 refers to these fixed
cases.)

In some deployments, large guests (more than around 30-40 VCPUs) may
still be able to trigger intermittent problems; a complete fix to this
issue requires substantial structural changes and is planned for Xen
4.6.  (CVE-2014-9066 refers to these yet-to-be-fixed cases.)



@maintainer(s): after the bump, in case we need to stabilize the package, please let us know if it is ready for the stabilization or not.
Comment 1 Yixun Lan gentoo-dev 2014-12-19 06:54:27 UTC
fixed in xen-4.2.5-r3, xen-4.3.3-r3, xen-4.4.1-r4


Arches, please test and mark stable:
=app-emulation/xen-4.2.5-r3
Target keywords Both : "amd64 x86"

=app-emulation/xen-4.3.3-r3
Target keywords Only: "amd64"
Comment 2 Agostino Sarubbo gentoo-dev 2014-12-21 11:37:49 UTC
amd64 stable
Comment 3 Agostino Sarubbo gentoo-dev 2014-12-21 11:42:35 UTC
x86 stable.

Maintainer(s), please cleanup.
Security, please vote.
Comment 4 GLSAMaker/CVETool Bot gentoo-dev 2015-01-04 21:42:35 UTC
CVE-2014-9066 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9066):
  Xen 4.4.x and earlier, when using a large number of VCPUs, does not properly
  handle read and write locks, which allows local x86 guest users to cause a
  denial of service (write denial or NMI watchdog timeout and host crash) via
  a large number of read request, a different vulnerability than
  CVE-2014-9065.

CVE-2014-9065 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9065):
  common/spinlock.c in Xen 4.4.x and earlier does not properly handle read and
  write locks, which allows local x86 guest users to cause a denial of service
  (write denial or NMI watchdog timeout and host crash) via a large number of
  read requests, a different vulnerability to CVE-2014-9066.
Comment 5 Yixun Lan gentoo-dev 2015-01-21 02:50:38 UTC
(In reply to GLSAMaker/CVETool Bot from comment #4)
> CVE-2014-9066 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9066):
>   Xen 4.4.x and earlier, when using a large number of VCPUs, does not
> 
> CVE-2014-9065 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2014-9065):
>   common/spinlock.c in Xen 4.4.x and earlier does not properly handle read

this two bugs already fixed at versions
=app-emulation/xen-4.2.5-r3
=app-emulation/xen-4.3.3-r3

which already goes stable.
Comment 6 Yury German Gentoo Infrastructure gentoo-dev 2015-04-04 21:42:25 UTC
Maintainer(s), Thank you for you for cleanup.

Added to an existing GLSA Request.
Comment 7 GLSAMaker/CVETool Bot gentoo-dev 2015-04-11 20:37:58 UTC
This issue was resolved and addressed in
 GLSA 201504-04 at https://security.gentoo.org/glsa/201504-04
by GLSA coordinator Yury German (BlueKnight).