Bug 995785 - (CVE-2016-7092) VUL-0: CVE-2016-7092: xen: x86: Disallow L3 recursive pagetable for 32-bit PV guests (XSA-185)
(CVE-2016-7092)
VUL-0: CVE-2016-7092: xen: x86: Disallow L3 recursive pagetable for 32-bit PV...
Status: RESOLVED FIXED
Classification: Novell Products
Product: SUSE Security Incidents
Classification: Novell Products
Component: Incidents
unspecified
Other Other
: P3 - Medium : Major
: ---
Assigned To: Security Team bot
Security Team bot
maint:planned:update CVSSv2:NVD:CVE-2...
:
Depends on:
Blocks:
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Reported: 2016-08-26 13:45 UTC by Johannes Segitz
Modified: 2021-01-21 18:29 UTC (History)
2 users (show)

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


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Comment 2 Swamp Workflow Management 2016-08-26 22:00:42 UTC
bugbot adjusting priority
Comment 3 Johannes Segitz 2016-09-08 14:24:55 UTC
            Xen Security Advisory CVE-2016-7092 / XSA-185
                              version 3

        x86: Disallow L3 recursive pagetable for 32-bit PV guests

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

Public release.

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

On real hardware, a 32-bit PAE guest must leave the USER and RW bit
clear in L3 pagetable entries, but the pagetable walk behaves as if
they were set.  (The L3 entries are cached in processor registers, and
don't actually form part of the pagewalk.)

When running a 32-bit PV guest on a 64-bit Xen, Xen must always OR in
the USER and RW bits for L3 updates for the guest to observe
architectural behaviour.  This is unsafe in combination with recursive
pagetables.

As there is no way to construct an L3 recursive pagetable in native
32-bit PAE mode, disallow this option in 32-bit PV guests.

IMPACT
======

A malicious 32-bit PV guest administrator can escalate their privilege
to that of the host.

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

All versions of Xen are vulnerable.

Only 64-bit builds of the hypervisor are vulnerable.  For Xen 4.3 and
earlier, 32-bit builds of the hypervisor are not vulnerable.

The vulnerability is only exposed to 32-bit PV guests on x86 hardware.

The vulnerability is not exposed to 64-bit PV guests, x86 HVM guests,
or ARM guests.

MITIGATION
==========

Running only 64-bit PV or HVM guests will avoid this vulnerability.

CREDITS
=======

This issue was found in parallel by multiple discoverers, who each
disclosed it to the Xen Project Security Team.

The first report to us was made by Jérémie Boutoille of Quarkslab.
The second report, one working day later, by Shangcong Luan of Alibaba
Cloud.

RESOLUTION
==========

Applying the attached patch resolves this issue.

xsa185.patch           xen-unstable - Xen 4.4

$ sha256sum xsa185*
3328a1953ecdf4de35462ea8396b0927171d718e95f73a87a7f651427bd8f8b4  xsa185.patch
Comment 4 Swamp Workflow Management 2016-09-29 16:20:18 UTC
An update workflow for this issue was started.
This issue was rated as important.
Please submit fixed packages until 2016-10-06.
When done, reassign the bug to security-team@suse.de.
https://swamp.suse.de/webswamp/wf/63075
Comment 5 Charles Arnold 2016-10-03 17:24:01 UTC
Submitted for,

SLE10-SP3
SLE10-SP4
SLE-11-SP1
SLE-11-SP2
SLE-11-SP3
SLE-11-SP4
SLE-12
SLE-12-SP1
Comment 6 Swamp Workflow Management 2016-10-07 12:11:58 UTC
SUSE-SU-2016:2473-1: An update that solves 10 vulnerabilities and has 11 fixes is now available.

Category: security (important)
Bug References: 953518,955104,959330,959552,970135,971949,988675,988676,990500,990970,991934,992224,993665,994421,994625,994761,994772,994775,995785,995789,995792
CVE References: CVE-2016-6258,CVE-2016-6259,CVE-2016-6833,CVE-2016-6834,CVE-2016-6835,CVE-2016-6836,CVE-2016-6888,CVE-2016-7092,CVE-2016-7093,CVE-2016-7094
Sources used:
SUSE Linux Enterprise Software Development Kit 12-SP1 (src):    xen-4.5.3_10-20.1
SUSE Linux Enterprise Server 12-SP1 (src):    xen-4.5.3_10-20.1
SUSE Linux Enterprise Desktop 12-SP1 (src):    xen-4.5.3_10-20.1
Comment 7 Swamp Workflow Management 2016-10-11 17:19:22 UTC
openSUSE-SU-2016:2494-1: An update that solves 46 vulnerabilities and has 17 fixes is now available.

Category: security (important)
Bug References: 900418,949889,953339,953362,953518,954872,955104,958848,959330,959552,961100,961600,963161,964427,970135,971949,973188,973631,974038,975130,975138,975907,976058,976111,978164,978295,978413,979620,979670,980716,980724,981264,981276,982024,982025,982026,982224,982225,982286,982695,982960,983973,983984,984981,985503,986586,988675,988676,990500,990843,990923,990970,991934,992224,993665,994421,994625,994761,994772,994775,995785,995789,995792
CVE References: CVE-2014-3615,CVE-2014-3672,CVE-2015-7512,CVE-2015-8504,CVE-2015-8558,CVE-2015-8568,CVE-2015-8613,CVE-2015-8743,CVE-2016-1714,CVE-2016-1981,CVE-2016-3158,CVE-2016-3159,CVE-2016-3710,CVE-2016-3712,CVE-2016-3960,CVE-2016-4001,CVE-2016-4002,CVE-2016-4020,CVE-2016-4037,CVE-2016-4439,CVE-2016-4441,CVE-2016-4453,CVE-2016-4454,CVE-2016-4480,CVE-2016-4952,CVE-2016-4962,CVE-2016-4963,CVE-2016-5105,CVE-2016-5106,CVE-2016-5107,CVE-2016-5126,CVE-2016-5238,CVE-2016-5337,CVE-2016-5338,CVE-2016-5403,CVE-2016-6258,CVE-2016-6259,CVE-2016-6351,CVE-2016-6833,CVE-2016-6834,CVE-2016-6835,CVE-2016-6836,CVE-2016-6888,CVE-2016-7092,CVE-2016-7093,CVE-2016-7094
Sources used:
openSUSE Leap 42.1 (src):    xen-4.5.3_10-15.2
Comment 8 Swamp Workflow Management 2016-10-11 17:29:56 UTC
openSUSE-SU-2016:2497-1: An update that solves 38 vulnerabilities and has 20 fixes is now available.

Category: security (important)
Bug References: 953339,953362,953518,954872,955399,958848,961100,961600,963161,964427,970135,971949,973188,973631,974038,975130,975138,975907,976058,976111,978164,978295,978413,979035,979620,979670,980716,980724,981264,981276,982024,982025,982026,982224,982225,982286,982695,982960,983973,983984,984981,985503,986586,988675,990843,990923,990970,991934,992224,994421,994625,994761,994772,994775,995785,995789,995792,997731
CVE References: CVE-2014-3615,CVE-2014-3672,CVE-2016-3158,CVE-2016-3159,CVE-2016-3710,CVE-2016-3712,CVE-2016-3960,CVE-2016-4001,CVE-2016-4002,CVE-2016-4020,CVE-2016-4037,CVE-2016-4439,CVE-2016-4441,CVE-2016-4453,CVE-2016-4454,CVE-2016-4480,CVE-2016-4952,CVE-2016-4962,CVE-2016-4963,CVE-2016-5105,CVE-2016-5106,CVE-2016-5107,CVE-2016-5126,CVE-2016-5238,CVE-2016-5337,CVE-2016-5338,CVE-2016-5403,CVE-2016-6258,CVE-2016-6351,CVE-2016-6833,CVE-2016-6834,CVE-2016-6835,CVE-2016-6836,CVE-2016-6888,CVE-2016-7092,CVE-2016-7093,CVE-2016-7094,CVE-2016-7154
Sources used:
openSUSE 13.2 (src):    xen-4.4.4_05-49.1
Comment 9 Swamp Workflow Management 2016-10-12 13:13:58 UTC
SUSE-SU-2016:2507-1: An update that solves 10 vulnerabilities and has 8 fixes is now available.

Category: security (important)
Bug References: 966467,970135,971949,988675,990970,991934,992224,993507,994136,994421,994625,994761,994772,994775,995785,995789,995792,997731
CVE References: CVE-2016-6258,CVE-2016-6833,CVE-2016-6834,CVE-2016-6835,CVE-2016-6836,CVE-2016-6888,CVE-2016-7092,CVE-2016-7093,CVE-2016-7094,CVE-2016-7154
Sources used:
SUSE Linux Enterprise Software Development Kit 11-SP4 (src):    xen-4.4.4_08-40.2
SUSE Linux Enterprise Server 11-SP4 (src):    xen-4.4.4_08-40.2
SUSE Linux Enterprise Debuginfo 11-SP4 (src):    xen-4.4.4_08-40.2
Comment 10 Swamp Workflow Management 2016-10-13 18:10:46 UTC
SUSE-SU-2016:2528-1: An update that fixes 16 vulnerabilities is now available.

Category: security (important)
Bug References: 973188,974038,975130,975138,978164,978295,980716,980724,981264,982960,983984,988675,995785,995792
CVE References: CVE-2014-3615,CVE-2014-3672,CVE-2016-3158,CVE-2016-3159,CVE-2016-3710,CVE-2016-3960,CVE-2016-4001,CVE-2016-4002,CVE-2016-4439,CVE-2016-4441,CVE-2016-4480,CVE-2016-5238,CVE-2016-5338,CVE-2016-6258,CVE-2016-7092,CVE-2016-7094
Sources used:
SUSE Linux Enterprise Server 11-SP2-LTSS (src):    xen-4.1.6_08-29.1
Comment 11 Swamp Workflow Management 2016-10-13 19:19:10 UTC
SUSE-SU-2016:2533-1: An update that solves 38 vulnerabilities and has 20 fixes is now available.

Category: security (important)
Bug References: 953339,953362,953518,954872,955399,957986,958848,961600,963161,964427,970135,971949,973188,973631,974038,975130,975138,975907,976058,976111,978164,978295,978413,979035,979620,979670,980716,980724,981264,981276,982024,982025,982026,982224,982225,982286,982695,982960,983973,983984,984981,985503,986586,988675,990843,990923,990970,991934,992224,994421,994625,994761,994772,994775,995785,995789,995792,997731
CVE References: CVE-2014-3615,CVE-2014-3672,CVE-2016-3158,CVE-2016-3159,CVE-2016-3710,CVE-2016-3712,CVE-2016-3960,CVE-2016-4001,CVE-2016-4002,CVE-2016-4020,CVE-2016-4037,CVE-2016-4439,CVE-2016-4441,CVE-2016-4453,CVE-2016-4454,CVE-2016-4480,CVE-2016-4952,CVE-2016-4962,CVE-2016-4963,CVE-2016-5105,CVE-2016-5106,CVE-2016-5107,CVE-2016-5126,CVE-2016-5238,CVE-2016-5337,CVE-2016-5338,CVE-2016-5403,CVE-2016-6258,CVE-2016-6351,CVE-2016-6833,CVE-2016-6834,CVE-2016-6835,CVE-2016-6836,CVE-2016-6888,CVE-2016-7092,CVE-2016-7093,CVE-2016-7094,CVE-2016-7154
Sources used:
SUSE Linux Enterprise Server for SAP 12 (src):    xen-4.4.4_04-22.22.2
SUSE Linux Enterprise Server 12-LTSS (src):    xen-4.4.4_04-22.22.2
Comment 12 Swamp Workflow Management 2016-11-04 14:16:07 UTC
SUSE-SU-2016:2725-1: An update that solves 21 vulnerabilities and has four fixes is now available.

Category: security (important)
Bug References: 954872,961600,963161,973188,973631,974038,975130,975138,976470,978164,978295,978413,980716,980724,981264,982224,982225,982960,983984,985503,988675,990843,990923,995785,995792
CVE References: CVE-2014-3615,CVE-2014-3672,CVE-2016-3158,CVE-2016-3159,CVE-2016-3710,CVE-2016-3712,CVE-2016-3960,CVE-2016-4001,CVE-2016-4002,CVE-2016-4439,CVE-2016-4441,CVE-2016-4453,CVE-2016-4454,CVE-2016-4480,CVE-2016-5238,CVE-2016-5338,CVE-2016-5403,CVE-2016-6258,CVE-2016-6351,CVE-2016-7092,CVE-2016-7094
Sources used:
SUSE OpenStack Cloud 5 (src):    xen-4.2.5_21-27.1
SUSE Manager Proxy 2.1 (src):    xen-4.2.5_21-27.1
SUSE Manager 2.1 (src):    xen-4.2.5_21-27.1
SUSE Linux Enterprise Server 11-SP3-LTSS (src):    xen-4.2.5_21-27.1
SUSE Linux Enterprise Point of Sale 11-SP3 (src):    xen-4.2.5_21-27.1
Comment 13 Marcus Meissner 2016-12-22 11:58:27 UTC
released