Bug 1311554 (CVE-2016-2543)

Summary:	CVE-2016-2543 kernel: sound: GPF in snd_seq_fifo_clear
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
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:	2016-03-04 12:48:34 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 13:00:21 UTC

A null dereference vulnerability was found in the Linux kernel. Function snd_seq_ioctl_remove_events() calls snd_seq_fifo_clear() unconditionally even if there is no FIFO assigned, and this leads to an Oops due to NULL dereference. The fix is just to add a proper NULL check.

Upstream patch:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=030e2c78d3a91dd0d27fef37e91950dde333eba1

External references:

https://lkml.org/lkml/2016/1/12/215

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 13:51:53 UTC

This was fixed in 4.3.5 with:

commit 6f54677f06bf3fd3c3f327d14ded94a0330d8d0c
Author: Takashi Iwai <tiwai>
Date:   Tue Jan 12 12:38:02 2016 +0100

    ALSA: seq: Fix missing NULL check at remove_events ioctl
    
    commit 030e2c78d3a91dd0d27fef37e91950dde333eba1 upstream.
    

and in 4.4.1 with:

commit 36d3fc15f50c22bbddfceb6c585f851130fb005f
Author: Takashi Iwai <tiwai>
Date:   Tue Jan 12 12:38:02 2016 +0100

    ALSA: seq: Fix missing NULL check at remove_events ioctl
    
    commit 030e2c78d3a91dd0d27fef37e91950dde333eba1 upstream.


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

Comment 4 Vladis Dronov 2016-03-04 12:48:34 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 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/.