Bug 2108696 (CVE-2021-33656)

Summary:	CVE-2021-33656 kernel: when setting font with malicious data by ioctl PIO_FONT, kernel will write memory out of bounds
Product:	[Other] Security Response	Reporter:	Alex <allarkin>
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, bdettelb, bhu, brdeoliv, bskeggs, chwhite, crwood, ddepaula, dvlasenk, hdegoede, hkrzesin, hpa, jarod, jarodwilson, jburrell, jfaracco, jferlan, jforbes, jglisse, jlelli, joe.lawrence, jonathan, josef, jshortt, jstancek, jwboyer, jwyatt, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, lzampier, masami256, mcascell, mchehab, nmurray, ptalbert, qzhao, rvrbovsk, scweaver, sgrubb, steved, tyberry, vkumar, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	Kernel 5.12	Doc Type:	If docs needed, set a value
Doc Text:	An out-of-bounds write flaw was found in the Linux kernel’s console driver functionality in the way a user triggers the ioctl PIO_FONT with malicious data. This flaw allows a local user to crash or potentially escalate their privileges on the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2023-05-16 19:11:21 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:	2109148, 2109164, 2109165, 2109166, 2109167, 2224517, 2225155
Bug Blocks:	2108340

Description Alex 2022-07-19 17:46:29 UTC

A flaw in the Linux Kernel console driver found. When setting font with malicious data by ioctl PIO_FONT, kernel will write memory out of bounds. To trigger the vulnerability user need to have access to console driver like if text mode being used through a generic VGA standard display.

Reference:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch

Comment 2 Alex 2022-07-20 14:15:54 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2109148]

Comment 5 Justin M. Forbes 2022-07-22 18:35:24 UTC

This was fixed for Fedora with the 5.12 stable kernel rebases.

Comment 11 errata-xmlrpc 2023-05-16 08:04:41 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2023:2736 https://access.redhat.com/errata/RHSA-2023:2736

Comment 12 errata-xmlrpc 2023-05-16 08:33:33 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2023:2951 https://access.redhat.com/errata/RHSA-2023:2951

Comment 13 Product Security DevOps Team 2023-05-16 19:11:17 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-2021-33656

Comment 22 errata-xmlrpc 2023-08-29 08:43:55 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Extended Update Support

Via RHSA-2023:4789 https://access.redhat.com/errata/RHSA-2023:4789