ISSUE DESCRIPTION ================= Virtual interrupt injection could be triggered by a guest when sending an SGI (e.g IPI) to any vCPU or by configuring timers. When the virtual interrupt is masked, a missing check in the injection path may result in reading invalid hardware register or crashing the host. IMPACT ====== A guest may cause a hypervisor crash, resulting in a Denial of Service (DoS). VULNERABLE SYSTEMS ================== All Xen versions which support ARM are affected. x86 systems are not affected. Mitigation: On systems where the guest kernel is controlled by the host rather than guest administrator, running only kernels which do not disable SGI and PPI (i.e IRQ < 32) will prevent untrusted guest users from exploiting this issue. However untrusted guest administrators can still trigger it unless further steps are taken to prevent them from loading code into the kernel (e.g by disabling loadable modules etc) or from using other mechanisms which allow them to run code at kernel privilege. External References: http://xenbits.xen.org/xsa/advisory-223.html Acknowledgements: Name: the Xen project Upstream: Julien Grall (ARM)
Created xen tracking bugs for this issue: Affects: fedora-all [bug 1463247]