Bug 1871727 (CVE-2016-2854)

Summary:	CVE-2016-2854 kernel: aufs module does not properly maintain POSIX ACL xattr data
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	acaringi, airlied, bhu, blc, bmasney, brdeoliv, bskeggs, dhoward, dvlasenk, esammons, fhrbata, hdegoede, hkrzesin, iboverma, ichavero, itamar, jarodwilson, jeremy, jforbes, jglisse, jlelli, john.j5live, jonathan, josef, jross, jshortt, jstancek, jwboyer, kcarcia, kernel-maint, kernel-mgr, labbott, lgoncalv, linville, masami256, matt, mchehab, mcressma, mjg59, mlangsdo, nmurray, ptalbert, qzhao, rt-maint, rvrbovsk, steved, williams
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 was found in the Linux kernel. The aufs module does not properly maintain POSIX ACL xattr data, which allows local users to gain privileges by leveraging a group-writable setgid directory. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-08-28 15:24:43 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:	1871728
Bug Blocks:	1871730

Description Dhananjay Arunesh 2020-08-24 07:06:08 UTC

The aufs module for the Linux kernel does not properly maintain POSIX ACL xattr data, which allows local users to gain privileges by leveraging a group-writable setgid directory.

References:
http://www.halfdog.net/Security/2016/AufsPrivilegeEscalationInUserNamespaces/
http://www.openwall.com/lists/oss-security/2016/02/24/9

Comment 1 Dhananjay Arunesh 2020-08-24 07:07:09 UTC

Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 1871728]

Comment 2 Justin M. Forbes 2020-08-24 12:57:00 UTC

Aufs was never a part of the linux kernel. Overlayfs was the preferred solution that was brought in upstream.