kmod, kvm security update

CentOS Errata and Security Advisory CESA-2013:0727

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module built for
the standard Red Hat Enterprise Linux kernel.

A flaw was found in the way KVM handled guest time updates when the buffer
the guest registered by writing to the MSR_KVM_SYSTEM_TIME machine state
register (MSR) crossed a page boundary. A privileged guest user could use
this flaw to crash the host or, potentially, escalate their privileges,
allowing them to execute arbitrary code at the host kernel level.
(CVE-2013-1796)

A potential use-after-free flaw was found in the way KVM handled guest time
updates when the GPA (guest physical address) the guest registered by
writing to the MSR_KVM_SYSTEM_TIME machine state register (MSR) fell into a
movable or removable memory region of the hosting user-space process (by
default, QEMU-KVM) on the host. If that memory region is deregistered from
KVM using KVM_SET_USER_MEMORY_REGION and the allocated virtual memory
reused, a privileged guest user could potentially use this flaw to
escalate their privileges on the host. (CVE-2013-1797)

A flaw was found in the way KVM emulated IOAPIC (I/O Advanced Programmable
Interrupt Controller). A missing validation check in the
ioapic_read_indirect() function could allow a privileged guest user to
crash the host, or read a substantial portion of host kernel memory.
(CVE-2013-1798)

Red Hat would like to thank Andrew Honig of Google for reporting all of
these issues.

All users of kvm are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. Note that the procedure
in the Solution section must be performed before this update will take
effect.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2013-April/081845.html

Affected packages:
kmod-kvm
kmod-kvm-debug
kvm
kvm-qemu-img
kvm-tools

Upstream details at:
https://access.redhat.com/errata/RHSA-2013:0727