Bug 1035823 (CVE-2013-6885)

Summary:	CVE-2013-6885 hw: AMD CPU erratum may cause core hang
Product:	[Other] Security Response	Reporter:	Petr Matousek <pmatouse>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	agordeev, collura, dhoward, drjones, imammedo, jkurik, lwang, mrezanin, nobody, pbonzini, pholasek, plougher, rkrcmar, rvrbovsk, security-response-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2014-06-20 13:16:06 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1035834, 1035836
Bug Blocks:	1035806

Description Petr Matousek 2013-11-28 14:57:09 UTC

793 Specific Combination of Writes to Write Combined Memory
Types and Locked Instructions May Cause Core Hang

Under a highly specific and detailed set of internal timing
conditions, a locked instruction may trigger a timing sequence whereby
the write to a write combined memory type is not flushed, causing the
locked instruction to stall indefinitely.

Potential Effect on System
Processor core hang.

Suggested Workaround
BIOS should set MSRC001_1020[15] = 1b.

The vulnerability is applicable only to family 16h model 00h-0fh AMD
CPUs. Non-AMD CPUs are not vulnerable.

References:
http://support.amd.com/TechDocs/51810_16h_00h-0Fh_Rev_Guide.pdf
http://thread.gmane.org/gmane.comp.security.oss.general/11555

Acknowledgements:

Red Hat would like to thank the Xen project for reporting this issue. Upstream acknowledges Jan Beulich as the original reporter.

Comment 2 Petr Matousek 2013-11-28 14:58:48 UTC

Statement:

This hardware issue is affecting certain AMD processors. Please consult your hardware vendor for any potential firmware updates providing a workaround for this issue.

Comment 4 Petr Matousek 2013-12-02 17:44:04 UTC

Xen issued advisory:

  http://www.openwall.com/lists/oss-security/2013/12/02/1

Comment 5 Petr Matousek 2014-01-15 11:39:42 UTC

Linux kernel proposed workaround:

  http://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?id=3b56496865f9f7d9bcb2f93b44c63f274f08e3b6

Comment 6 Vincent Danen 2014-02-19 21:42:10 UTC

It was noted that the previous fix was not sufficient for 32bit systems and also requires the following patch:

http://xenbits.xenproject.org/xsa/xsa82-4.1-32bit.patch

or

http://xenbits.xenproject.org/xsa/xsa82-4.2-32bit.patch

The advisory has further details.


External References:

http://xenbits.xenproject.org/xsa/advisory-82.html

Comment 7 Andrew Jones 2014-02-20 11:42:14 UTC

This shouldn't affect our backport. No additional patch needed for rhel5.

Comment 8 errata-xmlrpc 2014-03-12 18:30:18 UTC

This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2014:0285 https://rhn.redhat.com/errata/RHSA-2014-0285.html