Bug 1399722 (CVE-2016-7911)

Summary:	CVE-2016-7911 kernel: Use after free in sys_ioprio_get()
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	agordeev, aquini, arm-mgr, bhu, dhoward, dominik.mierzejewski, esammons, fhrbata, gansalmon, iboverma, ichavero, itamar, jforbes, jkacur, jkastner, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, labbott, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, vdronov, williams, wmealing
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A use-after-free vulnerability in sys_ioprio_get() was found due to get_task_ioprio() accessing the task->io_context without holding the task lock and could potentially race with exit_io_context(), leading to a use-after-free.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-02-09 13:23:23 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:	1418185
Bug Blocks:	1395238

Description Adam Mariš 2016-11-29 15:40:46 UTC

A use after free vulnerability in sys_ioprio_get() was found due to get_task_ioprio() accessing the task->io_context without holding the task lock and could potentially race with exit_io_context(), leading to a use-after-free.

At this time this use-after free is believed to be limited to a kernel panic via NULL pointer dreference of p->io_context->ioprio and does not lead to memory corruption or privilege escalation.  The page that is used after free may be controlled by an attacker and lead to further information leaks.


Upstream patch:
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=8ba8682107ee2ca3347354e018865d8e1967c5f4

Initial public release:
http://source.android.com/security/bulletin/2016-11-01.html

Comment 1 Wade Mealing 2016-12-02 07:31:22 UTC

Statement:

This issue affects the versions of the Linux kernel as shipped with
Red Hat Enterprise Linux 6, 7 and Red Hat Enterprise MRG 2. Future kernel
updates for Red Hat Enterprise Linux  6, 7 and Red Hat Enterprise MRG 2 are not planning to be updated to address this issue.   If this affects you please lodge a support request.

Red Hat Enterprise Linux 5 is now in Production 3 phase of the support and maintenance life cycle. This issue 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 4 Wade Mealing 2017-02-01 08:23:03 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1418185]