Vigil@nce - Xen: denial of service via PHYSDEVOP
February 2014 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker who is located in a PV guest system can use two
PHYSDEVOP hypercalls of Xen, in order to trigger a denial of
service, and possibly to elevate his privileges.
Impacted products: Fedora, Unix (platform)
Severity: 2/4
Creation date: 24/01/2014
DESCRIPTION OF THE VULNERABILITY
The Xen Dom0 domain uses the hypercall PHYSDEVOP_prepare_msix to
announce that MMIO resources of a MSI-X device will not change.
The hypercall PHYSDEVOP_release_msix announces that resources may
change.
However, Xen does not check if the domain is privileged before
accepting to perform both operations.
An attacker who is located in a PV guest system can therefore use
two PHYSDEVOP hypercalls of Xen, in order to trigger a denial of
service, and possibly to elevate his privileges.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Xen-denial-of-service-via-PHYSDEVOP-14134