Bug 1743539 (CVE-2019-15118)

Summary:	CVE-2019-15118 kernel: mishandling recursion in sound/usb/mixer.c leading to kernel stack exhaustion and crash
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bdettelb, bhu, blc, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mcressma, mjg59, mlangsdo, nmurray, rt-maint, rvrbovsk, steved, 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 flaw was found in the sound mixer handling of the Linux kernel. An attacker with physical access able to insert a specially crafted USB device can cause a recursive loop which continues to consume the reserved stack space leading to a system panic. The highest threat from this vulnerability is to system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-10-27 10:48:03 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:	1814084, 1814085, 1814086, 1814087
Bug Blocks:	1743542

Description Marian Rehak 2019-08-20 08:09:42 UTC

A flaw was found in the Linux kernels implementation of Mixer handling.  An attacker with physical access can insert a maliciously crafted USB device that can convince the kernels USB mixing hardware to enter a recursive loop which continues to consume the reserved stack space for the thread and panic the system.

Comment 1 Marian Rehak 2019-08-20 08:12:06 UTC

Upstream Patch:

https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/commit/?id=19bce474c45be69a284ecee660aa12d8f1e88f18

Comment 5 Wade Mealing 2020-03-16 05:28:29 UTC

Mitigation:


As the snd_usb_audio module will be auto-loaded when a usb device is hot plugged, the module can be prevented by loading with the following instructions:

# echo "install snd_usb_audio /bin/true" >> /etc/modprobe.d/disable-snd-usb-audio.conf 
 
The system will need to be restarted if the modules are loaded. In most circumstances, the sound kernel modules will be unable to be unloaded while any programs are active and the device are in use."

If the system requires this module to work correctly, this mitigation may not be suitable.

If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services.

Comment 6 Wade Mealing 2020-03-17 00:32:40 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1814084]

Comment 9 Justin M. Forbes 2020-03-17 13:46:43 UTC

This was fixes for Fedora with the 5.2.10 stable kernel updates.