Bug 1905632 (CVE-2020-29481)

Summary:	CVE-2020-29481 xen: Xenstore: new domains inheriting existing node permissions (XSA-322)
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	jforbes, m.a.young, robinlee.sysu, security-response-team
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-12-15 22:19:42 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:	1908095
Bug Blocks:	1903644

Description Guilherme de Almeida Suckevicz 2020-12-08 17:27:56 UTC

Access rights of Xenstore nodes are per domid.  Unfortunately, existing granted access rights are not removed when a domain is destroyed.  This means that a new domain created with the same domid will inherit the access rights to Xenstore nodes from the previous domain(s) with the same domid. All Xenstore entries of a guest below /local/domain/<domid> are deleted by Xen tools when a guest is destroyed.  Therefore only entries belonging to other guests, referring to the deleted guests, are potentially affected.

Comment 1 Guilherme de Almeida Suckevicz 2020-12-15 20:04:52 UTC

External References:

https://www.openwall.com/lists/oss-security/2020/12/15/3

Comment 2 Guilherme de Almeida Suckevicz 2020-12-15 20:05:41 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1908095]

Comment 3 Product Security DevOps Team 2020-12-15 22:19:42 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.