Scientific Linux: Important qemu-kvm Update for Buffer Overflow Issues

Date: Wed, 6 Jul 2011 14:14:16 -0500
Reply-To: Troy Dawson 
Sender: Security Errata for Scientific Linux
 
From: Troy Dawson 
Subject: Security ERRATA Important: qemu-kvm on SL6.x x86_64
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Synopsis:	Important: qemu-kvm security and bug fix update
Issue date:	2011-07-05
CVE Names:	CVE-2011-2212 CVE-2011-2512

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

It was found that the virtio subsystem in qemu-kvm did not properly
validate virtqueue in and out requests from the guest. A privileged
guest user could use this flaw to trigger a buffer overflow, allowing
them to crash the guest (denial of service) or, possibly, escalate their
privileges on the host. (CVE-2011-2212)

It was found that the virtio_queue_notify() function in qemu-kvm did not
perform sufficient input validation on the value later used as an index
into the array of virtqueues. An unprivileged guest user could use this
flaw to crash the guest (denial of service) or, possibly, escalate their
privileges on the host. (CVE-2011-2512)

This update also fixes the following bug:

* A bug was found in the way vhost (in qemu-kvm) set up mappings with
the host kernel's vhost module. This could result in the host kernel's
vhost module not having a complete view of a guest system's memory, if
that guest had more than 4 GB of memory. Consequently, hot plugging a
vhost-net network device and restarting the guest may have resulted in
that device no longer working. (BZ#701771)

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.

SL 6.x

 SRPMS:
qemu-kvm-0.12.1.2-2.160.el6_1.2.src.rpm
 x86_64:
qemu-img-0.12.1.2-2.160.el6_1.2.x86_64.rpm
qemu-kvm-0.12.1.2-2.160.el6_1.2.x86_64.rpm
qemu-kvm-tools-0.12.1.2-2.160.el6_1.2.x86_64.rpm

- Scientific Linux Development Team