FreeBSD : xen-kernel -- x86: Missing SMAP whitelisting in 32-bit exception / event delivery (04cf89e3-5854-11e6-b334-002590263bf5)
Medium Nessus Plugin ID 92675
SynopsisThe remote FreeBSD host is missing a security-related update.
DescriptionThe Xen Project reports :
Supervisor Mode Access Prevention is a hardware feature designed to make an Operating System more robust, by raising a pagefault rather than accidentally following a pointer into userspace. However, legitimate accesses into userspace require whitelisting, and the exception delivery mechanism for 32bit PV guests wasn't whitelisted.
A malicious 32-bit PV guest kernel can trigger a safety check, crashing the hypervisor and causing a denial of service to other VMs on the host.
SolutionUpdate the affected package.