Security Advisory Important: qemu-kvm-rhev security and bug fix update

Advisory: RHSA-2012:1233-1
Type: Security Advisory
Severity: Important
Issued on: 2012-09-05
Last updated on: 2012-09-05
Affected Products: Red Hat Enterprise Virtualization 3
CVEs ( CVE-2012-3515


Updated qemu-kvm-rhev packages that fix one security issue and two bugs 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.

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. The qemu-kvm-rhev packages form 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)

When using qemu-kvm-rhev on a Red Hat Enterprise Linux 6 host not managed
by Red Hat Enterprise Virtualization:

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

- 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

When using qemu-kvm-rhev on a Red Hat Enterprise Virtualization managed Red
Hat Enterprise Linux 6 host:

* This flaw did not affect the default use of a Red Hat Enterprise
Virtualization host: it is not possible to add a device that uses a virtual
console back-end via Red Hat Enterprise Virtualization Manager.

To specify a virtual console back-end for a device and therefore be
vulnerable to this issue, the device would have to be created another way,
for example, by using a VDSM hook.

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

This update also fixes the following bugs:

* Previously, the KVM modules were not loaded by the postinstall scriptlet
of RPM scripts. This bug caused various issues and required the system to
be rebooted to resolve them. With this update, the modules are loaded
properly by the scriptlet and no unnecessary reboots are now required.

* Previously, when a guest was started up with two serial devices, qemu-kvm
returned an error message and terminated the boot because IRQ 4 for the ISA
bus was being used by both devices. This update fixes the qemu-kvm code,
which allows IRQ 4 to be used by more than one device on the ISA bus, and
the boot now succeeds in the described scenario. (BZ#840054)

All users of qemu-kvm-rhev are advised to upgrade to these updated
packages, which fix these issues. 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.


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

Updated packages

Red Hat Enterprise Virtualization 3

File outdated by:  RHSA-2017:1205
    MD5: 89b89d116c4ee2211c646ba2b73ea783
SHA-256: 182917a0cf8a0f215fde4ea2adafabe0250c4f6ca88d3cb5fe7b32892d3a1f3a
File outdated by:  RHSA-2017:1205
    MD5: 9a0a84e447cfd7b60c598cbbad547cff
SHA-256: 63354f59606179417a83c7674220bd589ac90b5e271e8482ff9421f430e6ae10
File outdated by:  RHSA-2017:1205
    MD5: db2f7fb866209e8c9d14c7d72cb11e5e
SHA-256: e9169279510640389a10b7f4799552dc9d0476ec6ea639616d227d7b174e08a7
File outdated by:  RHSA-2017:1205
    MD5: 825630168bf7bfcc6f6a86e4e9cff3e3
SHA-256: 22938669c7abbb4b6db1eda75eb454df7c7671b13be00769482a058c9fc0dc1b
File outdated by:  RHSA-2017:1205
    MD5: 21156e903fd671670ea028b8e89bfd7a
SHA-256: 59dd9fa07d919d20977f914b9ca194887e7238ab4cdbfef61eeaecd13675c510
(The unlinked packages above are only available from the Red Hat Network)

Bugs fixed (see bugzilla for more information)

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


These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from:

The Red Hat security contact is More contact details at