Bug 1905676 (CVE-2020-29571)

Summary:	CVE-2020-29571 xen: FIFO event channels control structure ordering
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 22:20:15 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:	1908089
Bug Blocks:	1903644

Description Guilherme de Almeida Suckevicz 2020-12-08 19:44:55 UTC

A bounds check common to most operation time functions specific to FIFO
event channels depends on the CPU observing consistent state.  While the
producer side uses appropriately ordered writes, the consumer side isn't
protected against re-ordered reads, and may hence end up de-referencing
a NULL pointer.

Comment 1 Guilherme de Almeida Suckevicz 2020-12-15 20:02:09 UTC

External References:

https://www.openwall.com/lists/oss-security/2020/12/15/16

Comment 2 Guilherme de Almeida Suckevicz 2020-12-15 20:02:22 UTC

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1908089]

Comment 3 Product Security DevOps Team 2020-12-15 22:20:15 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.