Bug 1647573 (CVE-2018-19961, CVE-2018-19962)

Summary:	CVE-2018-19961 CVE-2018-19962 xen: insufficient TLB flushing / improper large page mappings with AMD IOMMUs
Product:	[Other] Security Response	Reporter:	Laura Pardo <lpardo>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	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 16:23:08 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Bug Depends On:	1651665
Bug Blocks:	1647577

Description Laura Pardo 2018-11-07 19:59:54 UTC

A flaw was found in xen. In order to be certain that no undue access to memory is possible anymore after IOMMU mappings of this memory have been removed, Translation Lookaside Buffers (TLBs) need to be flushed after most changes to such mappings. Xen bypassed certain IOMMU flushes on AMD
x86 hardware. Furthermore logic exists Xen to re-combine small page mappings into larger ones. Such re-combination could have occured in cases when it was not really safe/correct to do so.

Comment 1 Andrej Nemec 2018-11-20 14:11:40 UTC

References:

https://seclists.org/oss-sec/2018/q4/154

Comment 2 Andrej Nemec 2018-11-20 14:11:52 UTC

Acknowledgments:

Name: the Xen project

Comment 3 Andrej Nemec 2018-11-20 14:13:07 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1651665]