Bug 1981950 (CVE-2021-21781)

Summary:	CVE-2021-21781 kernel: arm: SIGPAGE information disclosure vulnerability
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, jeremy, jforbes, jlelli, jonathan, josef, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, lgoncalv, linville, masami256, mchehab, mlangsdo, nmurray, ptalbert, qzhao, rvrbovsk, steved, walters, williams, wmealing
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	An information disclosure flaw exists in the ARM SIGPAGE functionality of the Linux kernel. An attacker with a local account can read the contents of the sigpage, which contains previously initialized kernel memory contents. This flaw requires an attacker to read a process’s memory at a specific offset to trigger this vulnerability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-05-11 08:16:32 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:	1981951, 1983849, 1983850, 1983853
Bug Blocks:	1981953

Description Guilherme de Almeida Suckevicz 2021-07-13 19:01:09 UTC

An information disclosure vulnerability exists in the ARM SIGPAGE functionality of Linux Kernel.  A userland application can read the contents of the sigpage (A page in which signal handler information is stored), which can leak kernel memory contents. A local attacker can read a process’s memory at a specific offset to read this information leak.

Reference:
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1243

Comment 1 Guilherme de Almeida Suckevicz 2021-07-13 19:01:51 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1981951]

Comment 7 Justin M. Forbes 2021-07-26 16:35:28 UTC

This was fixed for Fedora with the 5.10.17 stable kernel updates.

Comment 9 errata-xmlrpc 2022-05-10 14:44:48 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 10 Product Security DevOps Team 2022-05-11 08:16:29 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-2021-21781