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Red Hat: Security update for KVM

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. A flaw was found in the way QEMU handled VT100 terminal escape sequences when emulating certain character devices. A guest user with privileges to write to a character device that is emulated on the host using a virtual console back-end could use this flaw to crash the qemu-kvm process on the host or, possibly, escalate their privileges on the host.

Updated packages are available from ftp.redhat.com.

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=====================================================================
                  Red Hat Security Advisory

Synopsis:          Important: qemu-kvm security update
Advisory ID:       RHSA-2012:1234-01
Product:           Red Hat Enterprise Linux
Advisory URL:      https://rhn.redhat.com/errata/RHSA-2012-1234.html
Issue date:        2012-09-05
CVE Names:         CVE-2012-3515 
=====================================================================

1. Summary:

Updated qemu-kvm packages that fix one security issue are now available for
Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having
important security impact. A Common Vulnerability Scoring System (CVSS)
base score, which gives a detailed severity rating, is available from the
CVE link in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Desktop (v. 6) - x86_64
Red Hat Enterprise Linux HPC Node (v. 6) - x86_64
Red Hat Enterprise Linux Server (v. 6) - x86_64
Red Hat Enterprise Linux Workstation (v. 6) - x86_64

3. Description:

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.

A flaw was found in the way QEMU handled VT100 terminal escape sequences
when emulating certain character devices. A guest user with privileges to
write to a character device that is emulated on the host using a virtual
console back-end could use this flaw to crash the qemu-kvm process on the
host or, possibly, escalate their privileges on the host. (CVE-2012-3515)

This flaw did not affect the default use of KVM. Affected configurations
were:

* When guests were started from the command line ("/usr/libexec/qemu-kvm")
without the "-nodefaults" option, and also without specifying a
serial or parallel device, or a virtio-console device, that specifically
does not use a virtual console (vc) back-end. (Note that Red Hat does not
support invoking "qemu-kvm" from the command line without "-nodefaults" on
Red Hat Enterprise Linux 6.)

* Guests that were managed via libvirt, such as when using Virtual Machine
Manager (virt-manager), but that have a serial or parallel device, or a
virtio-console device, that uses a virtual console back-end. By default,
guests managed via libvirt will not use a virtual console back-end
for such devices.

Red Hat would like to thank the Xen project for reporting this issue.

All users of qemu-kvm should upgrade to these updated packages, which
resolve this issue. 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.

4. Solution:

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/knowledge/articles/11258

5. Bugs fixed (http://bugzilla.redhat.com/):

851252 - CVE-2012-3515 qemu: VT100 emulation vulnerability

6. Package List:

Red Hat Enterprise Linux Desktop (v. 6):

Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/6Client/en/os/SRPMS/qemu-kvm-0.12.1.2-2.295.el6_3.2.src.rpm

x86_64:
qemu-guest-agent-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-img-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-debuginfo-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-tools-0.12.1.2-2.295.el6_3.2.x86_64.rpm

Red Hat Enterprise Linux HPC Node (v. 6):

Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/6ComputeNode/en/os/SRPMS/qemu-kvm-0.12.1.2-2.295.el6_3.2.src.rpm

x86_64:
qemu-guest-agent-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-img-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-debuginfo-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-tools-0.12.1.2-2.295.el6_3.2.x86_64.rpm

Red Hat Enterprise Linux Server (v. 6):

Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/6Server/en/os/SRPMS/qemu-kvm-0.12.1.2-2.295.el6_3.2.src.rpm

x86_64:
qemu-guest-agent-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-img-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-debuginfo-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-tools-0.12.1.2-2.295.el6_3.2.x86_64.rpm

Red Hat Enterprise Linux Workstation (v. 6):

Source:
ftp://ftp.redhat.com/pub/redhat/linux/enterprise/6Workstation/en/os/SRPMS/qemu-kvm-0.12.1.2-2.295.el6_3.2.src.rpm

x86_64:
qemu-guest-agent-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-img-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-debuginfo-0.12.1.2-2.295.el6_3.2.x86_64.rpm
qemu-kvm-tools-0.12.1.2-2.295.el6_3.2.x86_64.rpm

These packages are GPG signed by Red Hat for security.  Our key and
details on how to verify the signature are available from
https://access.redhat.com/security/team/key/#package

7. References:

https://www.redhat.com/security/data/cve/CVE-2012-3515.html
https://access.redhat.com/security/updates/classification/#important

8. Contact:

The Red Hat security contact is <secalert@redhat.com>.  More contact
details at https://access.redhat.com/security/team/contact/

Copyright 2012 Red Hat, Inc.
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