Bug 1969497 (CVE-2020-36387)

Summary:	CVE-2020-36387 kernel: use-after-free related to io_async_task_func() reference holding in fs/io_uring.c
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:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, bdettelb, bhu, bmasney, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarodwilson, jeremy, jforbes, jglisse, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, nmurray, ptalbert, qzhao, rvrbovsk, steved, tomckay, walters, wcosta, 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. A use-after-free can occur to io_async_task_func and ctx reference holding. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-06-08 14:29:38 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:	1969498
Bug Blocks:	1969499

Description Guilherme de Almeida Suckevicz 2021-06-08 14:14:27 UTC

An issue was discovered in the Linux kernel before 5.8.2. fs/io_uring.c has a use-after-free related to io_async_task_func and ctx reference holding.

Reference:
https://sites.google.com/view/syzscope/kasan-use-after-free-read-in-io_async_task_func

Upstream patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6d816e088c359866f9867057e04f244c608c42fe

Comment 1 Guilherme de Almeida Suckevicz 2021-06-08 14:15:13 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1969498]

Comment 2 Justin M. Forbes 2021-06-08 19:04:11 UTC

This was fixed for Fedora with the 5.7.16 stable kernel updates.