Bug 950703 - (CVE-2015-7969) VUL-1: CVE-2015-7969: xen: leak of main per-domain vcpu pointer array (DoS) (XSA-149)
(CVE-2015-7969)
VUL-1: CVE-2015-7969: xen: leak of main per-domain vcpu pointer array (DoS) (...
Status: RESOLVED FIXED
Classification: Novell Products
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents
unspecified
Other Other
: P4 - Low : Minor
: ---
Assigned To: Security Team bot
Security Team bot
CVSSv2:NVD:CVE-2015-7969:4.9:(AV:L/AC...
:
Depends on:
Blocks:
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Reported: 2015-10-16 08:08 UTC by Andreas Stieger
Modified: 2021-01-21 18:25 UTC (History)
3 users (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---


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Comment 2 Swamp Workflow Management 2015-10-16 22:00:15 UTC
bugbot adjusting priority
Comment 3 Andreas Stieger 2015-10-26 12:40:11 UTC
Note that CVE-2015-7969 covers both XSA-149 (bsc#950703) and XSA-151 (bsc#950705).
Comment 4 Andreas Stieger 2015-10-29 12:34:33 UTC
Public at http://xenbits.xen.org/xsa/advisory-149.html

            Xen Security Advisory CVE-2015-7969 / XSA-149
                              version 3

              leak of main per-domain vcpu pointer array

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

Public release.

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

A domain's primary array of vcpu pointers can be allocated by a
toolstack exactly once in the lifetime of a domain via the
XEN_DOMCTL_max_vcpus hypercall.

This array is leaked on domain teardown.  This memory leak could --
over time -- exhaust the host's memory.

IMPACT
======

A domain given partial management control via XEN_DOMCTL_max_vcpus can
mount a denial of service attack affecting the whole system.

The ability to also restart or create suitable domains is also
required to fully exploit the issue.  Without this the leak is limited
to a small multiple of the maximum number of vcpus for the domain.

The maximum leak is 64kbytes per domain (re)boot (less on ARM).

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

This issue is only relevant to systems which intend to increase
security through the use of advanced disaggregated management
techniques.

This does not include systems using libxl, libvirt, or OpenStack
(unless substantially modified or supplemented, as compared to
versions supplied by the respective upstreams).

Versions of Xen from 4.0 onwards are vulnerable.

All architectures are affected.

MITIGATION
==========

The leak is small.  Preventing the creation of large numbers of new
domains, and limiting the number of times an existing domain can be
rebooted, can reduce the impact of this vulnerability.

Switching from disaggregated to a non-disaggregated operation does NOT
mitigate the XEN_DOMCTL_max_vcpus vulnerability.  Rather, it simply
recategorises the vulnerability to hostile management code, regarding
it "as designed"; thus it merely reclassifies these issues as "not a
bug".  Users and vendors of disaggregated systems should not change
their configuration.

NOTE REGARDING CVE
==================

Note that CVE-2015-7969 covers both this issue and XSA-151.

CREDITS
=======

This issue was discovered by Ian Campbell of Citrix.

RESOLUTION
==========

Applying the attached patch resolves this issue.
(To resolve CVE-2015-7969, the patch from XSA-151 is required too.)

xsa149.patch        xen-unstable, Xen 4.6.x, Xen 4.5.x, Xen 4.4.x, Xen 4.3.x

$ sha256sum xsa149*.patch
e01628400b81c4bb7bafba348f2ecb1fe80f16e3162cee5013e0be1d7311738b  xsa149.patch
$

DEPLOYMENT DURING EMBARGO
=========================

Deployment of the PATCH (or others which are substantially similar) is
permitted during the embargo, even on public-facing systems with
untrusted guest users and administrators.


However deployment of the (RE)BOOT LIMIT MITIGATION is NOT permitted
(except where all the affected systems and VMs are administered and
used only by organisations which are members of the Xen Project
Security Issues Predisclosure List).  Specifically, deployment on
public cloud systems is NOT permitted.

This is because applying domain creation and reboot limits in
connection with a security issue would be a user-visible change which
could lead to the rediscovery of the vulnerability.

Deployment of the mitigation is permitted only AFTER the embargo ends.


Also: Distribution of updated software is prohibited (except to other
members of the predisclosure list).

Predisclosure list members who wish to deploy significantly different
patches and/or mitigations, please contact the Xen Project Security
Team.


(Note: this during-embargo deployment notice is retained in
post-embargo publicly released Xen Project advisories, even though it
is then no longer applicable.  This is to enable the community to have
oversight of the Xen Project Security Team's decisionmaking.)

For more information about permissible uses of embargoed information,
consult the Xen Project community's agreed Security Policy:
  http://www.xenproject.org/security-policy.html
Comment 5 Swamp Workflow Management 2015-10-30 16:16:35 UTC
SUSE-SU-2015:1853-1: An update that solves 8 vulnerabilities and has 6 fixes is now available.

Category: security (important)
Bug References: 877642,907514,910258,918984,923967,932267,941074,944463,944697,947165,950367,950703,950705,950706
CVE References: CVE-2014-0222,CVE-2015-4037,CVE-2015-5239,CVE-2015-6815,CVE-2015-7311,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971
Sources used:
SUSE Linux Enterprise Software Development Kit 11-SP3 (src):    xen-4.2.5_14-18.2
SUSE Linux Enterprise Server 11-SP3 (src):    xen-4.2.5_14-18.2
SUSE Linux Enterprise Desktop 11-SP3 (src):    xen-4.2.5_14-18.2
SUSE Linux Enterprise Debuginfo 11-SP3 (src):    xen-4.2.5_14-18.2
Comment 6 Swamp Workflow Management 2015-11-03 10:36:30 UTC
SUSE-SU-2015:1894-1: An update that solves 8 vulnerabilities and has 9 fixes is now available.

Category: security (important)
Bug References: 877642,901488,907514,910258,918984,923967,932267,944463,944697,945167,947165,949138,949549,950367,950703,950705,950706
CVE References: CVE-2014-0222,CVE-2015-4037,CVE-2015-5239,CVE-2015-6815,CVE-2015-7311,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971
Sources used:
SUSE Linux Enterprise Software Development Kit 11-SP4 (src):    xen-4.4.3_02-26.2
SUSE Linux Enterprise Server 11-SP4 (src):    xen-4.4.3_02-26.2
SUSE Linux Enterprise Desktop 11-SP4 (src):    xen-4.4.3_02-26.2
SUSE Linux Enterprise Debuginfo 11-SP4 (src):    xen-4.4.3_02-26.2
Comment 7 Swamp Workflow Management 2015-11-04 16:16:09 UTC
SUSE-SU-2015:1908-1: An update that solves 8 vulnerabilities and has 8 fixes is now available.

Category: security (important)
Bug References: 877642,901488,907514,910258,918984,923967,932267,944463,944697,945167,947165,949138,950367,950703,950705,950706
CVE References: CVE-2014-0222,CVE-2015-4037,CVE-2015-5239,CVE-2015-6815,CVE-2015-7311,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971
Sources used:
SUSE Linux Enterprise Software Development Kit 12 (src):    xen-4.4.3_02-22.12.1
SUSE Linux Enterprise Server 12 (src):    xen-4.4.3_02-22.12.1
SUSE Linux Enterprise Desktop 12 (src):    xen-4.4.3_02-22.12.1
Comment 8 Swamp Workflow Management 2015-11-10 17:11:18 UTC
SUSE-SU-2015:1952-1: An update that solves 7 vulnerabilities and has one errata is now available.

Category: security (important)
Bug References: 877642,932267,944463,944697,950367,950703,950705,950706
CVE References: CVE-2014-0222,CVE-2015-4037,CVE-2015-5239,CVE-2015-6815,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971
Sources used:
SUSE Linux Enterprise Server 11-SP2-LTSS (src):    xen-4.1.6_08-20.1
SUSE Linux Enterprise Debuginfo 11-SP2 (src):    xen-4.1.6_08-20.1
Comment 9 Swamp Workflow Management 2015-11-12 11:12:29 UTC
openSUSE-SU-2015:1964-1: An update that solves 12 vulnerabilities and has two fixes is now available.

Category: security (important)
Bug References: 877642,932267,938344,939709,939712,941074,944463,944697,947165,950367,950703,950705,950706,951845
CVE References: CVE-2014-0222,CVE-2015-4037,CVE-2015-5154,CVE-2015-5165,CVE-2015-5166,CVE-2015-5239,CVE-2015-6815,CVE-2015-7311,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971,CVE-2015-7972
Sources used:
openSUSE 13.1 (src):    xen-4.3.4_06-50.1
Comment 10 Swamp Workflow Management 2015-11-12 11:13:53 UTC
openSUSE-SU-2015:1965-1: An update that solves 6 vulnerabilities and has one errata is now available.

Category: security (moderate)
Bug References: 877642,932267,950367,950703,950705,950706,951845
CVE References: CVE-2014-0222,CVE-2015-4037,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971,CVE-2015-7972
Sources used:
openSUSE Leap 42.1 (src):    xen-4.5.1_12-3.1
Comment 11 Swamp Workflow Management 2015-11-17 10:15:31 UTC
openSUSE-SU-2015:2003-1: An update that solves 13 vulnerabilities and has 9 fixes is now available.

Category: security (important)
Bug References: 877642,901488,907514,910258,918984,923967,925466,932267,935634,938344,939709,939712,944463,944697,945167,947165,949138,950367,950703,950705,950706,951845
CVE References: CVE-2014-0222,CVE-2015-3259,CVE-2015-4037,CVE-2015-5154,CVE-2015-5165,CVE-2015-5166,CVE-2015-5239,CVE-2015-6815,CVE-2015-7311,CVE-2015-7835,CVE-2015-7969,CVE-2015-7971,CVE-2015-7972
Sources used:
openSUSE 13.2 (src):    xen-4.4.3_02-30.1
Comment 12 Marcus Meissner 2015-12-03 09:53:19 UTC
This is already fixed.

It showed up in current updates as a new CVE was assigned and added to .changes
Comment 13 Swamp Workflow Management 2015-12-18 21:13:07 UTC
SUSE-SU-2015:2306-1: An update that fixes 10 vulnerabilities is now available.

Category: security (moderate)
Bug References: 950703,950704,950705,950706,951845,953527,954405,956408,956411,956832
CVE References: CVE-2015-5307,CVE-2015-7504,CVE-2015-7969,CVE-2015-7970,CVE-2015-7971,CVE-2015-7972,CVE-2015-8104,CVE-2015-8339,CVE-2015-8340,CVE-2015-8345
Sources used:
SUSE Linux Enterprise Server 11-SP2-LTSS (src):    xen-4.1.6_08-23.1
SUSE Linux Enterprise Debuginfo 11-SP2 (src):    xen-4.1.6_08-23.1
Comment 14 Swamp Workflow Management 2015-12-19 15:13:32 UTC
SUSE-SU-2015:2326-1: An update that solves 12 vulnerabilities and has one errata is now available.

Category: security (moderate)
Bug References: 947165,950703,950704,950705,950706,951845,954018,954405,956408,956409,956411,956592,956832
CVE References: CVE-2015-5307,CVE-2015-7311,CVE-2015-7504,CVE-2015-7969,CVE-2015-7970,CVE-2015-7971,CVE-2015-7972,CVE-2015-8104,CVE-2015-8339,CVE-2015-8340,CVE-2015-8341,CVE-2015-8345
Sources used:
SUSE Linux Enterprise Software Development Kit 11-SP3 (src):    xen-4.2.5_18-21.1
SUSE Linux Enterprise Server 11-SP3 (src):    xen-4.2.5_18-21.1
SUSE Linux Enterprise Desktop 11-SP3 (src):    xen-4.2.5_18-21.1
SUSE Linux Enterprise Debuginfo 11-SP3 (src):    xen-4.2.5_18-21.1
Comment 15 Swamp Workflow Management 2015-12-19 15:16:39 UTC
SUSE-SU-2015:2328-1: An update that fixes 13 vulnerabilities is now available.

Category: security (moderate)
Bug References: 947165,950703,950704,950705,950706,951845,954018,954405,956408,956409,956411,956592,956832
CVE References: CVE-2015-5307,CVE-2015-7311,CVE-2015-7504,CVE-2015-7835,CVE-2015-7969,CVE-2015-7970,CVE-2015-7971,CVE-2015-7972,CVE-2015-8104,CVE-2015-8339,CVE-2015-8340,CVE-2015-8341,CVE-2015-8345
Sources used:
SUSE Linux Enterprise Software Development Kit 12 (src):    xen-4.4.3_06-22.15.1
SUSE Linux Enterprise Server 12 (src):    xen-4.4.3_06-22.15.1
SUSE Linux Enterprise Desktop 12 (src):    xen-4.4.3_06-22.15.1
Comment 16 Swamp Workflow Management 2015-12-22 12:11:51 UTC
SUSE-SU-2015:2338-1: An update that solves 13 vulnerabilities and has one errata is now available.

Category: security (moderate)
Bug References: 947165,950703,950704,950705,950706,951845,954018,954405,955399,956408,956409,956411,956592,956832
CVE References: CVE-2015-5307,CVE-2015-7311,CVE-2015-7504,CVE-2015-7835,CVE-2015-7969,CVE-2015-7970,CVE-2015-7971,CVE-2015-7972,CVE-2015-8104,CVE-2015-8339,CVE-2015-8340,CVE-2015-8341,CVE-2015-8345
Sources used:
SUSE Linux Enterprise Software Development Kit 11-SP4 (src):    xen-4.4.3_06-29.1
SUSE Linux Enterprise Server 11-SP4 (src):    xen-4.4.3_06-29.1
SUSE Linux Enterprise Desktop 11-SP4 (src):    xen-4.4.3_06-29.1
SUSE Linux Enterprise Debuginfo 11-SP4 (src):    xen-4.4.3_06-29.1