Bug 1311564 (CVE-2016-2546)

Summary:	CVE-2016-2546 kernel: sound: GPF in snd_timer_user_params
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
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, esammons, fhrbata, gansalmon, iboverma, itamar, jforbes, jkacur, joelsmith, jonathan, jross, jwboyer, kernel-maint, kernel-mgr, kstutsma, lgoncalv, lwang, madhu.chinakonda, matt, mchehab, mcressma, mguzik, nmurray, pholasek, plougher, rt-maint, rvrbovsk, vdronov, 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:	2016-03-07 13:08:51 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:	1311573
Bug Blocks:	1311575

Description Andrej Nemec 2016-02-24 13:22:44 UTC

ALSA timer ioctls have an open race and this may lead to a use-after-free of timer instance object. A simplistic fix is to make each ioctl exclusive. We have already tread_sem for controlling the tread, and extend this as a global mutex to be applied to each ioctl.

Upstream patch:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=af368027a49a751d6ff4ee9e3f9961f35bb4fede

CVE-ID request and assignment:

http://seclists.org/oss-sec/2016/q1/133

http://seclists.org/oss-sec/2016/q1/410

Comment 1 Josh Boyer 2016-02-24 13:54:51 UTC

This was fixed in 4.3.5 with

commit 7066da22b1eb40e955f9dfe57022816fae53d3cf
Author: Takashi Iwai <tiwai>
Date:   Wed Jan 13 17:48:01 2016 +0100

    ALSA: timer: Fix race among timer ioctls
    
    commit af368027a49a751d6ff4ee9e3f9961f35bb4fede upstream.

and in 4.4.1 with:

commit d87622a1662af5782c94b88a613c09de0bde5288
Author: Takashi Iwai <tiwai>
Date:   Wed Jan 13 17:48:01 2016 +0100

    ALSA: timer: Fix race among timer ioctls
    
    commit af368027a49a751d6ff4ee9e3f9961f35bb4fede upstream.

All Fedora branches are on those or newer.  This issue is fixed in Fedora.

Comment 3 Vladis Dronov 2016-03-07 13:08:51 UTC

Statement:

This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 5, 6, 7 and MRG-2. This has been rated as having Moderate 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/.