CVE-2021-28692 Information

Description

inappropriate x86 IOMMU timeout detection / handling IOMMUs process commands issued to them in parallel with the operation of the CPU(s) issuing such commands. In the current implementation in Xen asynchronous notification of the completion of such commands is not used. Instead the issuing CPU spin-waits for the completion of the most recently issued command(s). Some of these waiting loops try to apply a timeout to fail overly-slow commands. The course of action upon a perceived timeout actually being detected is inappropriate: - on Intel hardware guests which did not originally cause the timeout may be marked as crashed - on AMD hardware higher layer callers would not be notified of the issue making them continue as if the IOMMU operation succeeded.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Reference

https://xenbits.xenproject.org/xsa/advisory-373.txt https://security.gentoo.org/glsa/202107-30

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

HIGH

Base Severity

7.1