Bug 1314253

Summary:	kernel: Partial SMAP bypass on 64-bit Linux kernels
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	aquini, arm-mgr, bhu, carnil, dhoward, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kstutsma, lgoncalv, madhu.chinakonda, matt, mchehab, mcressma, nmurray, plougher, ppandit, rt-maint, rvrbovsk, slawomir, williams
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:	2019-06-08 02:49:15 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:	1314255, 1316055, 1316056, 1316057
Bug Blocks:	1314257

Description Adam Mariš 2016-03-03 09:52:45 UTC

Linux kernel built with the Supervisor Mode Access Prevention(CONFIG_X86_SMAP)
and the IA32 Emulation(CONFIG_IA32_EMULATION) support is vulnerable to a partial SMAP protection bypass issue. It occurs because the 'AC' processor flag, which controls kernel mode access to user-space memory pages is not cleared when invoking IA32 system calls on 64-bit machines.

A process/user could potentially use this issue to various malicious ends.

Note: user would still need a vulnerability which can be leveraged to exploit the missing SMAP protection.

Upstream patch:
---------------
  -> https://git.kernel.org/linus/3d44d51bd339766f0178f0cf2e8d048b4a4872aa

Reference:
----------
  -> http://seclists.org/oss-sec/2016/q1/446

Comment 1 Adam Mariš 2016-03-03 09:53:41 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1314255]

Comment 2 Prasad Pandit 2016-03-09 10:21:35 UTC

Statement:

This issue does not affect the versions of Linux kernel as shipped with
Red Hat Enterprise Linux 5 and Red Hat Enterprise Linux 6.

This issue affects the version of the kernel package as shipped with Red Hat Enterprise Linux 7 and Red Hat Enterprise MRG 2.

This has been rated as having Low security impact and is not currently
planned to be addressed in future updates. For additional information, refer
to the Red Hat Enterprise Linux Life Cycle:
https://access.redhat.com/support/policy/updates/errata/.

Comment 7 Fedora Update System 2016-03-11 13:26:19 UTC

kernel-4.4.4-301.fc23 has been pushed to the Fedora 23 stable repository. If problems still persist, please make note of it in this bug report.

Comment 8 Fedora Update System 2016-03-12 00:51:14 UTC

kernel-4.4.4-200.fc22 has been pushed to the Fedora 22 stable repository. If problems still persist, please make note of it in this bug report.