CVE-2023-46839 pci: phantom functions assigned to incorrect contexts

2024-03-2010:35:52

XEN

github.com

pci

phantom functions

iommu

device assignment

guest domain

AI Score

7.1

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

partial

JSON

PCI devices can make use of a functionality called phantom functions,
that when enabled allows the device to generate requests using the IDs
of functions that are otherwise unpopulated. This allows a device to
extend the number of outstanding requests.

Such phantom functions need an IOMMU context setup, but failure to
setup the context is not fatal when the device is assigned. Not
failing device assignment when such failure happens can lead to the
primary device being assigned to a guest, while some of the phantom
functions are assigned to a different domain.

CNA Affected

[
  {
    "vendor": "Xen",
    "product": "Xen",
    "versions": [
      {
        "status": "unknown",
        "version": "consult Xen advisory XSA-449"
      }
    ],
    "defaultStatus": "unknown"
  }
]