Bug 1992745 (CVE-2021-38203)

Summary:	CVE-2021-38203 kernel: btrfs: deadlock via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, bdettelb, bhu, blc, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarod, jarodwilson, jeremy, jforbes, jglisse, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mlangsdo, nmurray, ptalbert, qzhao, rvrbovsk, steved, tomckay, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.14 rc2	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the btrfs filesystem in the Linux kernel that allows attackers to cause a denial of service via processes that trigger allocation of new system chunks when there is a shortage of free space in the system space_info. The highest threat from this vulnerability is to system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-08-26 21:34:55 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:	1992746
Bug Blocks:	1992747

Description Guilherme de Almeida Suckevicz 2021-08-11 17:13:44 UTC

btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.

Reference and upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1cb3db1cf383a3c7dbda1aa0ce748b0958759947

Comment 1 Guilherme de Almeida Suckevicz 2021-08-11 17:14:11 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1992746]

Comment 2 Justin M. Forbes 2021-08-12 13:21:23 UTC

This was fixed for Fedora with the 5.13.4 stable kernel updates.

Comment 6 juneau 2021-08-26 16:45:19 UTC

Setting hosted services 'notaffected' per kernel analysis.

Comment 7 Product Security DevOps Team 2021-08-26 21:34:55 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-38203