Bug 1877920 (CVE-2020-25220)

Summary:	CVE-2020-25220 kernel: use-after-free because skcd->no_refcnt was not considered during the backport of CVE-2020-14356
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, airlied, bhu, blc, bmasney, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mcressma, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rt-maint, rvrbovsk, steved, williams
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 Linux kernel. The cgroups feature is affected by a use-after-free memory flaw that was not considered during the backport for CVE-2020-14356. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-11-02 08:21:17 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:	1877922
Bug Blocks:	1877923

Description Guilherme de Almeida Suckevicz 2020-09-10 18:52:04 UTC

The Linux kernel 4.9.x before 4.9.233, 4.14.x before 4.14.194, and 4.19.x before 4.19.140 has a use-after-free because skcd->no_refcnt was not considered during a backport of a CVE-2020-14356 patch. This is related to the cgroups feature.

Reference:
https://bugzilla.redhat.com/show_bug.cgi?id=1868453

Upstream commit:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=82fd2138a5ffd7e0d4320cdb669e115ee976a26e

Comment 1 Guilherme de Almeida Suckevicz 2020-09-10 18:53:18 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1877922]

Comment 2 Justin M. Forbes 2020-09-14 12:55:41 UTC

Fedora does not support the 4.x LTS releases.

Comment 4 Product Security DevOps Team 2020-11-02 08:21:17 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-2020-25220