Bug 1647588 (CVE-2018-19965)

Summary:	CVE-2018-19965 xen: x86: DoS from attempting to use INVPCID with a non-canonical addresses
Product:	[Other] Security Response	Reporter:	Laura Pardo <lpardo>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	ailan, anemec, dhoward, drjones, dvlasenk, fhrbata, imammedo, jen, jforbes, jstancek, knoel, m.a.young, mrezanin, nmurray, pbonzini, plougher, rkrcmar, 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:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-11-08 16:19:12 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:	1651970
Bug Blocks:	1647590

Description Laura Pardo 2018-11-07 20:32:12 UTC

A flaw was found in xen. The INVPCID instruction raises #GP[0] if an attempt is made to invalidate a non-canonical address. Older flushing mechanisms such as INVLPG tolerate this without error, and perform no action. There is one guest accessible path in Xen where a non-canonical address was passed into the TLB flushing code. This previously had no ill effect, but became vulnerable with the introduction of PCID to reduce the performance hit from the Meltdown mitigations.

Comment 1 Andrej Nemec 2018-11-21 10:34:01 UTC

References:

https://seclists.org/oss-sec/2018/q4/155

Comment 2 Andrej Nemec 2018-11-21 10:34:14 UTC

Acknowledgments:

Name: the Xen project

Comment 3 Andrej Nemec 2018-11-21 10:34:58 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1651970]