Bug 2063236 (CVE-2021-39713)

Summary:	CVE-2021-39713 kernel: race condition in the network scheduling subsystem could lead to an use-after-free
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:	Li Shuang <shuali>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, allarkin, bdettelb, bhu, chwhite, crwood, dcaratti, dvlasenk, hdegoede, hkrzesin, jarod, jarodwilson, jburrell, jeremy, jfaracco, jforbes, jglisse, jlelli, joe.lawrence, jonathan, josef, jpoimboe, jshortt, jstancek, jthierry, jwboyer, jwyatt, kcarcia, kernel-maint, kernel-mgr, kpatch-maint-bot, lgoncalv, linville, lzampier, masami256, mchehab, michal.skrivanek, mperina, nmurray, nobody, ptalbert, qzhao, rhandlin, rkeshri, rvrbovsk, scweaver, shuali, steved, vkumar, walters, williams, ycote, zulinx86
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.1 rc1	Doc Type:	If docs needed, set a value
Doc Text:	A use-after-free flaw was found in the Linux kernel’s network scheduling subsystem due to a race condition. This flaw allows a local user to cause a denial of service (memory corruption or crash) or privilege escalation.	Story Points:	---
Clone Of:		Environment:
Last Closed:		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:	2063237, 2063841, 2063842, 2063843, 2063844, 2063845, 2063846, 2063847, 2063848, 2063849, 2063850, 2063851, 2063852, 2064650
Bug Blocks:	2063238

Description Guilherme de Almeida Suckevicz 2022-03-11 14:55:38 UTC

The syzbot tool found a race condition in the network scheduling subsystem which could lead to a use-after-free. A local user could exploit this for denial of service (memory corruption or crash) or possibly for privilege escalation.

References and upstream patches:
https://source.android.com/security/bulletin/pixel/2022-03-01
https://android.googlesource.com/kernel/common/+/e368fdb61d8e7
https://android.googlesource.com/kernel/common/+/9d7e82cec35c0
https://android.googlesource.com/kernel/common/+/3a7d0d07a3867
https://android.googlesource.com/kernel/common/+/86bd446b5cebd
https://android.googlesource.com/kernel/common/+/6f99528e97977

Comment 1 Guilherme de Almeida Suckevicz 2022-03-11 14:57:12 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2063237]

Comment 2 Justin M. Forbes 2022-03-11 17:05:01 UTC

These fixes went upstream in 4.20 and addressed in Fedora with the 4.20.x kernel rebases.