Bug 1997524 (CVE-2021-28698)

Summary:	CVE-2021-28698 xen: malicious kernels lead to DoS
Product:	[Other] Security Response	Reporter:	Dhananjay Arunesh <darunesh>
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
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:	2021-08-26 15:35:37 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:	1997526
Bug Blocks:	1997570

Description Dhananjay Arunesh 2021-08-25 12:47:59 UTC

In order to properly monitor resource use, Xen maintains information on
the grant mappings a domain may create to map grants offered by other
domains.  In the process of carrying out certain actions, Xen would
iterate over all such entries, including ones which aren't in use
anymore and some which may have been created but never used.  If the
number of entries for a given domain is large enough, this iterating of
the entire table may tie up a CPU for too long, starving other domains
or causing issues in the hypervisor itself.

Comment 1 Dhananjay Arunesh 2021-08-25 12:50:25 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1997526]

Comment 2 Product Security DevOps Team 2021-08-26 15:35:37 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.