Bug 1518155 (CVE-2017-16994)

Summary:	CVE-2017-16994 kernel: mm/pagewalk.c:walk_hugetlb_range function mishandles holes in hugetlb ranges causing information leak
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	airlied, ajax, aquini, bhu, blc, bskeggs, dhoward, ewk, fhrbata, hdegoede, hkrzesin, hwkernel-mgr, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jkacur, john.j5live, jonathan, josef, jross, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, plougher, rt-maint, rvrbovsk, steved, vdronov, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	upstream kernel v4.15-rc1	Doc Type:	Bug Fix
Doc Text:	The walk_hugetlb_range() function in 'mm/pagewalk.c' file in the Linux kernel from v4.0-rc1 through v4.15-rc1 mishandles holes in hugetlb ranges. This allows local users to obtain sensitive information from uninitialized kernel memory via crafted use of the mincore() system call.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 03:32:07 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:	1518156, 1520394, 1520395
Bug Blocks:	1518161

Description Adam Mariš 2017-11-28 10:43:52 UTC

The walk_hugetlb_range() function in 'mm/pagewalk.c' file in the Linux kernel from v4.0-rc1 through v4.15-rc1 mishandles holes in hugetlb ranges, which allows local users to obtain sensitive information from uninitialized kernel memory via crafted use of the mincore() system call.

References:

https://bugs.chromium.org/p/project-zero/issues/detail?id=1431

https://www.exploit-db.com/exploits/43178/

A flaw was introduced by:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1e25a271c8ac1c9faebf4eb3fa609189e4e7b1b6

An upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=373c4557d2aa362702c4c2d41288fb1e54990b7c

Comment 1 Adam Mariš 2017-11-28 10:45:14 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1518156]

Comment 4 Vladis Dronov 2017-12-04 12:08:30 UTC

Statement:

This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and Red Hat Enterprise MRG 2, as a code with the flaw is not present in the products listed.

This issue affects the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 7 for ARM and Red Hat Enterprise Linux 7 for Power LE in the "kernel-alt" packages.

Comment 5 Vladis Dronov 2017-12-04 12:10:01 UTC

What is Red Hat Enterprise Linux 7 for ARM,
        Red Hat Enterprise Linux 7 for Power LE,
        and the "kernel-alt" package:

The "kernel-alt" package as shipped with Red Hat Enterprise Linux 7 for ARM and Red Hat Enterprise Linux 7 for Power LE is an updated kernel intended to support new architectures not available at the time of Red Hat Enterprise Linux 7 original shipping. The new kernel version provided by the "kernel-alt" packages is based on upstream Linux kernel version 4.11. The offering is distributed with other updated packages, but most of the userspace is the standard Red Hat Enterprise Linux 7 Server RPM files.

For more information please refer to:

https://access.redhat.com/articles/3158541
https://access.redhat.com/articles/3158511

Comment 7 errata-xmlrpc 2018-03-13 15:36:23 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:0502 https://access.redhat.com/errata/RHSA-2018:0502