Bug 1941781 (CVE-2021-28972)

Summary:	CVE-2021-28972 kernel: Buffer overflow in hotplug/rpadlpar_sysfs.c
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, blc, bmasney, brdeoliv, bskeggs, chwhite, crwood, dhoward, dvlasenk, fhrbata, fpacheco, hdegoede, hkrzesin, 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:	A flaw in the Linux kernels implementation of the RPA PCI Hotplug driver for power-pc. A user with permissions to write to the sysfs settings for this driver can trigger a buffer overflow when writing a new device name to the driver from userspace, overwriting data in the kernel's stack.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-11-08 01:43:15 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:	1943622, 1941782, 1943435, 1943436, 1943437, 1943438
Bug Blocks:	1941783

Description Pedro Sampaio 2021-03-22 18:58:30 UTC

A flaw in the Linux kernels implementation of the RPA PCI Hotplug driver.  A user with permissions to write to the sysfs settings for this driver can trigger a buffer overflow when writing a new device name to the driver from userspace, overwriting data in the kernel's stack.

At this time this driver is only used by Power-PC based systems and does not affect x86-64, ARM, s390 architectures.

Upstream patch:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc7a0bb058b85ea03db87169c60c7cfdd5d34678

Comment 1 Pedro Sampaio 2021-03-22 18:59:08 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1941782]

Comment 2 Wade Mealing 2021-03-26 02:57:21 UTC

This only affects the powerpc architecture, so its not affecting or built for x86 or ARM.

Comment 4 Wade Mealing 2021-03-26 03:35:36 UTC

This flaw is rated as moderate, the sysfs file requires root or CAP_SYS_ADMIN priledges to be able to abuse this flaw.

Comment 6 Wade Mealing 2021-03-26 03:56:39 UTC

Mitigation:

Mitigation for this issue is either not available or the currently available options does not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.