Vigil@nce - Xen: NULL pointer dereference via MMU Update
November 2014 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can force a NULL pointer to be dereferenced in MMU
Update of Xen, in order to trigger a denial of service.
Impacted products: Unix (platform)
Severity: 1/4
Creation date: 18/11/2014
DESCRIPTION OF THE VULNERABILITY
The Xen product can be configured with a PV domain with privileges
over HVM guest systems with HAP (Hardware Assisted Paging) or PVH
(PV Hybrid, which virtualize memory pages) systems, usually via
qemu-dm.
However, in this configuration, the do_mmu_update() function of
the xen/arch/x86/mm.c file does not check if a pointer is NULL,
before using it.
An attacker can therefore force a NULL pointer to be dereferenced
in MMU Update of Xen, in order to trigger a denial of service.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Xen-NULL-pointer-dereference-via-MMU-Update-15662