Bug 1893287 (CVE-2020-25668)

Summary:	CVE-2020-25668 kernel: race condition in fg_console can lead to use-after-free in con_font_op
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, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, 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, walters, williams, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.10-rc3	Doc Type:	If docs needed, set a value
Doc Text:	A use-after-free flaw was found in the Linux kernel’s TTY driver functionality in the way the user triggers the con_font_op function. This flaw allows a local user to crash or escalate their privileges on the system or expose sensitive information (kernel memory).	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-11-18 11:28:33 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:	1893288
Bug Blocks:	1891756, 1939821

Description Guilherme de Almeida Suckevicz 2020-10-30 16:27:48 UTC

A flaw was found in Linux Kernel because access to the global variable fg_console is not properly synchronized leading to a use after free in con_font_op.

Reference:
https://www.openwall.com/lists/oss-security/2020/10/30/1

Comment 1 Guilherme de Almeida Suckevicz 2020-10-30 16:30:51 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1893288]

Comment 2 Alex 2020-11-15 19:44:57 UTC

The patch:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=90bfdeef83f1d6c696039b6a917190dcbbad3220

Comment 3 Product Security DevOps Team 2020-11-18 11:28:33 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-2020-25668