Bug 1528602 – CVE-2018-5244 xen: memory leak with MSR emulation (XSA-253)

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Bug 1528602 - (CVE-2018-5244, xsa253) CVE-2018-5244 xen: memory leak with MSR emulation (XSA-253)

Summary:	CVE-2018-5244 xen: memory leak with MSR emulation (XSA-253)

Status:	NEW

Aliases:	CVE-2018-5244, xsa253

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
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Assigned To:	Red Hat Product Security
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URL:
Whiteboard:	impact=moderate,public=20180104,repor...
Keywords:	Security

Depends On:	1531110
Blocks:
	Show dependency tree / graph

Reported:	2017-12-22 05:57 EST by Andrej Nemec
Modified:	2018-01-08 06:01 EST (History)
CC List:	13 users (show)

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Description Andrej Nemec 2017-12-22 05:57:47 EST

ISSUE DESCRIPTION
=================

In Xen 4.10, new infrastructure was introduced as part of an overhaul to
how MSR emulation happens for guests.  Unfortunately, one tracking
structure isn't freed when a vcpu is destroyed.

IMPACT
======

A memory allocation of 8 bytes is leaked each time a vcpu is destroyed.

A malicious guest may, by frequently rebooting over extended periods of
time, run the system out of memory, resulting in a Denial of Service
(DoS).

VULNERABLE SYSTEMS
==================

Xen versions 4.10 and later are affected.  Xen 4.9 and earlier are not
affected.

Only x86 systems are affected.  ARM systems are not.

All guest kinds can exploit this vulnerability.

MITIGATION
==========

Limiting the frequency with which a guest is able to reboot, will
limit the memory leak.

Rebooting each host (after migrating its guests) periodically will
reclaim the leaked space.

Comment 2 Andrej Nemec 2018-01-04 10:32:40 EST

Public via:

http://seclists.org/oss-sec/2018/q1/4

Comment 3 Andrej Nemec 2018-01-04 10:33:09 EST

Created xen tracking bugs for this issue:

Affects: fedora-all [bug 1531110]

Comment 4 Adam Mariš 2018-01-08 06:01:11 EST

Acknowledgments:

Name: the Xen project
Upstream: Andrew Cooper (Citrix)

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