Bug 2016169 (CVE-2020-13974)

Summary:	CVE-2020-13974 kernel: integer overflow in k_ascii() in drivers/tty/vt/keyboard.c
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, adscvr, airlied, alciregi, bhu, blc, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarod, jarodwilson, jburrell, jeremy, jforbes, jglisse, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mlangsdo, nmurray, ptalbert, qzhao, rvrbovsk, steved, vkumar, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.8-rc1	Doc Type:	If docs needed, set a value
Doc Text:	A flaw integer overflow in the Linux kernel's virtual terminal keyboard driver was found in the way the user sends some specific keyboard code multiple times. A local user could use this flaw to crash the system or possibly escalate their privileges on the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-05-11 11:45:27 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:	2016170, 2017044, 2017045, 2017047
Bug Blocks:	2016171

Description Guilherme de Almeida Suckevicz 2021-10-20 20:13:17 UTC

An issue was discovered in the Linux kernel 4.4 through 5.7.1. drivers/tty/vt/keyboard.c has an integer overflow if k_ascii is called several times in a row. NOTE: Members in the community argue that the integer overflow does not lead to a security issue in this case.

Reference:
https://lkml.org/lkml/2020/3/22/482

Upstream patches:
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=dad0bf9ce93fa40b667eccd3306783f4db4b932b
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b86dab054059b970111b5516ae548efaae5b3aae

Comment 1 Guilherme de Almeida Suckevicz 2021-10-20 20:13:56 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2016170]

Comment 6 Justin M. Forbes 2021-10-25 18:39:39 UTC

This was fixed for Fedora with the 5.6.18 stable kernel updates.

Comment 9 errata-xmlrpc 2022-05-10 14:40:01 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1975 https://access.redhat.com/errata/RHSA-2022:1975

Comment 10 errata-xmlrpc 2022-05-10 14:45:51 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:1988 https://access.redhat.com/errata/RHSA-2022:1988

Comment 11 Product Security DevOps Team 2022-05-11 11:45:24 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-2020-13974