Bug 2034342 (CVE-2021-4157)

Summary:	CVE-2021-4157 kernel: Buffer overwrite in decode_nfs_fh function
Product:	[Other] Security Response	Reporter:	Pedro Sampaio <psampaio>
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, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, jarod, jarodwilson, jburrell, jeremy, jfaracco, jforbes, jglisse, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, lzampier, masami256, mchehab, nmurray, ptalbert, qzhao, rvrbovsk, scweaver, steved, vkumar, walters, williams
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel 5.13-rc1	Doc Type:	If docs needed, set a value
Doc Text:	An out of memory bounds write flaw (1 or 2 bytes of memory) in the Linux kernel NFS subsystem was found in the way users use mirroring (replication of files with NFS). A user, having access to the NFS mount, could potentially use this flaw to crash the system or escalate privileges on the system.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-05-11 04:45:37 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:	2017166, 2034343, 2035016, 2035017, 2035018
Bug Blocks:	2034344, 2034920

Description Pedro Sampaio 2021-12-20 18:21:50 UTC

A flaw was found in the Linux kernel. A incorrect size check in decode_nfs_fh() may lead to an overwrite of 2 bytes beyond destination.

References:

https://lore.kernel.org/lkml/20210517140244.822185482@linuxfoundation.org/

Comment 1 Pedro Sampaio 2021-12-20 18:22:23 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2034343]

Comment 2 Justin M. Forbes 2021-12-21 14:55:00 UTC

This was fixed for Fedora with the 5.12.5 stable kernel updates.

Comment 9 errata-xmlrpc 2022-05-10 14:40:37 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 14:46:35 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 04:45:33 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-2021-4157