qemu-kvm (SL6)

Synopsis: Important: qemu-kvm security and bug fix update
Advisory ID: SLSA-2017:0309-1
Issue Date: 2017-02-23
CVE Numbers: CVE-2016-2857

Security Fix(es):

* Quick emulator (Qemu) built with the Cirrus CLGD 54xx VGA emulator
support is vulnerable to an out-of-bounds access issue. It could occur
while copying VGA data via bitblt copy in backward mode. A privileged user
inside a guest could use this flaw to crash the Qemu process resulting in
DoS or potentially execute arbitrary code on the host with privileges of
Qemu process on the host. (CVE-2017-2615)

* An out-of-bounds read-access flaw was found in the QEMU emulator built
with IP checksum routines. The flaw could occur when computing a TCP/UDP
packet’s checksum, because a QEMU function used the packet’s payload
length without checking against the data buffer’s size. A user inside a
guest could use this flaw to crash the QEMU process (denial of service).

This update also fixes the following bug:

* Previously, rebooting a guest virtual machine more than 128 times in a
short period of time caused the guest to shut down instead of rebooting,
because the virtqueue was not cleaned properly. This update ensures that
the virtqueue is cleaned more reliably, which prevents the described
problem from occurring.

After installing this update, shut down all running virtual machines. Once
all virtual machines have shut down, start them again for this update to
take effect.


– Scientific Linux Development Team