Vigil@nce - Xen: invalid access via the hypercall XENMEM_exchange
December 2012 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can pass malicious adress intervals to the hypercall
XENMEM_exchange(), in order to corrupt the Xen’s memory or make it
halt.
Impacted products: XenServer, Debian, Fedora, RHEL, SUSE Linux
Enterprise Desktop, SLES, Unix (platform)
Severity: 2/4
Creation date: 04/12/2012
DESCRIPTION OF THE VULNERABILITY
The hypercall XENMEM_exchange() takes 2 address intervals as
argument. These addresses should be part of the guest system space.
However, Xen does not check that these addresses are valid before
writing here, this allows the guest system to write to the memory
with the Xen privileges, and perhaps to cause an exception,
triggered by the processor and not managed by Xen.
An attacker can therefore pass malicious address interval to the
hypercall XENMEM_exchange(), in order to corrupt the Xen’s memory
or make it halt.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Xen-invalid-access-via-the-hypercall-XENMEM-exchange-12203