arm: Host crash caused by VMID exhaustion

2016-06-0309:47:00

Xen Project

xenbits.xen.org

5.6 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

4.7 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:L/AC:M/Au:N/C:N/I:N/A:C

0.001 Low

EPSS

Percentile

23.9%

JSON

ISSUE DESCRIPTION

VMIDs are a finite hardware resource, and allocated as part of domain creation. If no free VMIDs are available when trying to create a new domain, a bug in the error path causes a NULL pointer to be used, resulting in a Data Abort and host crash.

IMPACT

Attempting to create too many concurrent domains causes a host crash rather than a graceful error. A malicious device driver domain can hold references to domains, preventing its VMID being released.

VULNERABLE SYSTEMS

Xen versions 4.4 and later are affected. Older Xen versions are unaffected.
x86 systems are not affected.
Only arm systems with less-privileged device driver domains can expose this vulnerability.