Bug 1851470 (CVE-2020-15564)

Summary:	CVE-2020-15564 xen: missing alignment check in VCPUOP_register_vcpu_info leads to DoS (XSA-327)
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, ailan, bhu, bmasney, brdeoliv, dhoward, drjones, dvlasenk, fhrbata, hkrzesin, imammedo, jforbes, jshortt, jstancek, knoel, m.a.young, mrezanin, nmurray, pbonzini, ptalbert, robinlee.sysu, rvrbovsk, security-response-team, vkuznets, xen-maint
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 input validation flaw was found in Xen. A malicious guest administrator could abuse this flaw to cause a hypervisor crash by passing a misaligned address, resulting in a Denial of Service condition (DoS).	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-07-07 19:28:20 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:	1854458
Bug Blocks:	1851487

Description Dhananjay Arunesh 2020-06-26 16:19:10 UTC

The hypercall VCPUOP_register_vcpu_info is used by a guest to register a shared region with the hypervisor. The region will be mapped into Xen address space so it can be directly accessed. On Arm, the region is accessed with instructions which require a specific alignment. Unfortunately, there is no check that the address provided by the guest will be correctly aligned. As a result, a malicious guest could cause a hypervisor crash by passing a misaligned address.

Comment 1 Mauro Matteo Cascella 2020-07-01 14:52:39 UTC

Acknowledgments:

Name: the Xen project

Comment 2 Mauro Matteo Cascella 2020-07-06 13:45:09 UTC

Statement:

Only ARM systems are vulnerable, x86 systems are not affected by this flaw.

Comment 3 Mauro Matteo Cascella 2020-07-07 13:55:56 UTC

External References:

https://xenbits.xen.org/xsa/advisory-327.html

Comment 4 Mauro Matteo Cascella 2020-07-07 13:56:18 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1854458]

Comment 5 Product Security DevOps Team 2020-07-07 19:28:20 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-2020-15564

Comment 6 Product Security DevOps Team 2020-07-08 01:27:35 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-2020-15564

Comment 7 Product Security DevOps Team 2020-07-08 07:27:36 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-2020-15564