libcacard, qemu security update

CentOS Errata and Security Advisory CESA-2015:0349

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux
on AMD64 and Intel 64 systems. The qemu-kvm packages provide the user-space
component for running virtual machines using KVM.

It was found that the Cirrus blit region checks were insufficient. A privileged
guest user could use this flaw to write outside of VRAM-allocated buffer
boundaries in the host’s QEMU process address space with attacker-provided data.
(CVE-2014-8106)

An uninitialized data structure use flaw was found in the way the
set_pixel_format() function sanitized the value of bits_per_pixel. An attacker
able to access a guest’s VNC console could use this flaw to crash the guest.
(CVE-2014-7815)

It was found that certain values that were read when loading RAM during
migration were not validated. A user able to alter the savevm data (either on
the disk or over the wire during migration) could use either of these flaws to
corrupt QEMU process memory on the (destination) host, which could potentially
result in arbitrary code execution on the host with the privileges of the QEMU
process. (CVE-2014-7840)

A NULL pointer dereference flaw was found in the way QEMU handled UDP packets
with a source port and address of 0 when QEMU’s user networking was in use. A
local guest user could use this flaw to crash the guest. (CVE-2014-3640)

Red Hat would like to thank James Spadaro of Cisco for reporting CVE-2014-7815,
and Xavier Mehrenberger and Stephane Duverger of Airbus for reporting
CVE-2014-3640. The CVE-2014-8106 issue was found by Paolo Bonzini of Red Hat,
and the CVE-2014-7840 issue was discovered by Michael S. Tsirkin of Red Hat.

Bug fixes:

• The KVM utility executed demanding routing update system calls every time it
  performed an MSI vector mask/unmask operation. Consequently, guests running
  legacy systems such as Red Hat Enterprise Linux 5 could, under certain
  circumstances, experience significant slowdown. Now, the routing system calls
  during mask/unmask operations are skipped, and the performance of legacy guests
  is now more consistent. (BZ#1098976)

• Due to a bug in the Internet Small Computer System Interface (iSCSI) driver, a
  qemu-kvm process terminated unexpectedly with a segmentation fault when the
  “write same” command was executed in guest mode under the iSCSI protocol. This
  update fixes the bug, and the “write same” command now functions in guest mode
  under iSCSI as intended. (BZ#1083413)

• The QEMU command interface did not properly handle resizing of cache memory
  during guest migration, causing QEMU to terminate unexpectedly with a
  segmentation fault. This update fixes the related code, and QEMU no longer
  crashes in the described situation. (BZ#1066338)

Enhancements:

• The maximum number of supported virtual CPUs (vCPUs) in a KVM guest has been
  increased to 240. This increases the number of virtual processing units that the
  user can assign to the guest, and therefore improves its performance potential.
  (BZ#1134408)

• Support for the 5th Generation Intel Core processors has been added to the
  QEMU hypervisor, the KVM kernel code, and the libvirt API. This allows KVM
  guests to use the following instructions and features: ADCX, ADOX, RDSFEED,
  PREFETCHW, and supervisor mode access prevention (SMAP). (BZ#1116117)

• The “dump-guest-memory” command now supports crash dump compression. This
  makes it possible for users who cannot use the “virsh dump” command to require
  less hard disk space for guest crash dumps. In addition, saving a compressed
  guest crash dump frequently takes less time than saving a non-compressed one.
  (BZ#1157798)

• This update introduces support for flight recorder tracing, which uses
  SystemTap to automatically capture qemu-kvm data while the guest machine is
  running. For detailed instructions on how to configure and use flight recorder
  tracing, see the Virtualization Deployment and Administration Guide, linked to
  in the References section below. (BZ#1088112)

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-cr-announce/2015-March/028043.html

Affected packages:
libcacard
libcacard-devel
libcacard-tools
qemu-img
qemu-kvm
qemu-kvm-common
qemu-kvm-tools

Upstream details at:
https://access.redhat.com/errata/RHSA-2015:0349