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Category:   Application (Generic)  >   KVM Vendors:
(Red Hat Issues Fix for Red Hat Enterprise Virtualization Hypervisor) KVM pit_ioport_read() Bug Lets Local Users Deny Service
SecurityTracker Alert ID:  1023638
SecurityTracker URL:
CVE Reference:   CVE-2010-0309   (Links to External Site)
Date:  Feb 19 2010
Impact:   Denial of service via local system
Fix Available:  Yes  Vendor Confirmed:  Yes  

Description:   A vulnerability was reported in KVM. A local user can cause denial of service conditions.

A local user can invoke a specially crafted call to cause the host system to crash.

The vulnerability resides in 'arch/x86/kvm/i8254.c'.

Impact:   A local user can cause denial of service conditions on the host system.
Solution:   Red Hat has issued a fix for Red Hat Enterprise Virtualization Hypervisor.

The Red Hat advisory is available at:

Vendor URL: (Links to External Site)
Cause:   Access control error
Underlying OS:  Linux (Red Hat Enterprise)
Underlying OS Comments:  RHEV Hypervisor 2.1

Message History:   This archive entry is a follow-up to the message listed below.
Feb 10 2010 KVM pit_ioport_read() Bug Lets Local Users Deny Service

 Source Message Contents

Subject:  [RHSA-2010:0095-01] Important: rhev-hypervisor security and bug fix update

Hash: SHA1

                   Red Hat Security Advisory

Synopsis:          Important: rhev-hypervisor security and bug fix update
Advisory ID:       RHSA-2010:0095-01
Product:           Red Hat Enterprise Virtualization
Advisory URL:
Issue date:        2010-02-09
CVE Names:         CVE-2007-4567 CVE-2009-4272 CVE-2009-4536 
                   CVE-2009-4537 CVE-2009-4538 CVE-2010-0298 
                   CVE-2010-0306 CVE-2010-0309 

1. Summary:

An updated rhev-hypervisor package that fixes security issues and several
bugs is now available.

This update has been rated as having important security impact by the Red
Hat Security Response Team.

2. Relevant releases/architectures:

RHEV Hypervisor 2.1 - noarch

3. Description:

The rhev-hypervisor package provides a Red Hat Enterprise Virtualization
(RHEV) Hypervisor ISO disk image. The RHEV Hypervisor is a dedicated
Kernel-based Virtual Machine (KVM) hypervisor. It includes everything
necessary to run and manage virtual machines: A subset of the Red Hat
Enterprise Linux operating environment and the Red Hat Enterprise
Virtualization Agent.

Note: RHEV Hypervisor is only available for the Intel 64 and AMD64
architectures with virtualization extensions.

A flaw was found in the IPv6 Extension Header (EH) handling
implementation in the Linux kernel. The skb->dst data structure was not
properly validated in the ipv6_hop_jumbo() function. This could possibly
lead to a remote denial of service. (CVE-2007-4567)

The Parallels Virtuozzo Containers team reported two flaws in the routing
implementation. If an attacker was able to cause a large enough number of
collisions in the routing hash table (via specially-crafted packets) for
the emergency route flush to trigger, a deadlock could occur. Secondly, if
the kernel routing cache was disabled, an uninitialized pointer would be
left behind after a route lookup, leading to a kernel panic.

A flaw was found in each of the following Intel PRO/1000 Linux drivers in
the Linux kernel: e1000 and e1000e. A remote attacker using packets larger
than the MTU could bypass the existing fragment check, resulting in
partial, invalid frames being passed to the network stack. These flaws
could also possibly be used to trigger a remote denial of service.
(CVE-2009-4536, CVE-2009-4538)

A flaw was found in the Realtek r8169 Ethernet driver in the Linux kernel.
Receiving overly-long frames with a certain revision of the network cards
supported by this driver could possibly result in a remote denial of
service. (CVE-2009-4537)

The x86 emulator implementation was missing a check for the Current
Privilege Level (CPL) and I/O Privilege Level (IOPL). A user in a guest
could leverage these flaws to cause a denial of service (guest crash) or
possibly escalate their privileges within that guest. (CVE-2010-0298,

A flaw was found in the Programmable Interval Timer (PIT) emulation. Access
to the internal data structure pit_state, which represents the data state
of the emulated PIT, was not properly validated in the pit_ioport_read()
function. A privileged guest user could use this flaw to crash the host.

This updated package provides updated components that include fixes for
security issues; however, these issues have no security impact for RHEV
Hypervisor. These fixes are for kernel issues CVE-2006-6304, CVE-2009-2910,
CVE-2009-3080, CVE-2009-3556, CVE-2009-3889, CVE-2009-3939, CVE-2009-4020,
CVE-2009-4021, CVE-2009-4138, and CVE-2009-4141; ntp issue CVE-2009-3563;
dbus issue CVE-2009-1189; dnsmasq issues CVE-2009-2957 and CVE-2009-2958;
gnutls issue CVE-2009-2730; krb5 issue CVE-2009-4212; bind issue 
CVE-2010-0097; gzip issue CVE-2010-0001; openssl issues CVE-2009-2409 and 
CVE-2009-4355; and gcc issue CVE-2009-3736.

This update also fixes the following bugs:

* on systems with a large number of disk devices, USB storage devices may
get enumerated after "/dev/sdz", for example, "/dev/sdcd". This was not
handled by the udev rules, resulting in a missing "/dev/live" symbolic
link, causing installations from USB media to fail. With this update, udev
rules correctly handle USB storage devices on systems with a large number
of disk devices, which resolves this issue. (BZ#555083)

As RHEV Hypervisor is based on KVM, the bug fixes from the KVM update
RHSA-2010:0088 have been included in this update:

Users of the Red Hat Enterprise Virtualization Hypervisor are advised to
upgrade to this updated package, which corrects these issues.

4. Solution:

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

This update is available via Red Hat Network.  Details on how to use
the Red Hat Network to apply this update are available at

5. Bugs fixed (

545411 - CVE-2009-4272 kernel: emergency route cache flushing leads to node deadlock
548641 - CVE-2007-4567 kernel: ipv6_hop_jumbo remote system crash
550907 - CVE-2009-4537 kernel: r8169 issue reported at 26c3
551214 - CVE-2009-4538 kernel: e1000e frame fragment issue
552126 - CVE-2009-4536 kernel: e1000 issue reported at 26c3
559091 - CVE-2010-0298 kvm: emulator privilege escalation
560654 - CVE-2010-0306 kvm: emulator privilege escalation IOPL/CPL level check
560887 - CVE-2010-0309 kvm: cat /dev/port in guest cause the host hang

6. Package List:

RHEV Hypervisor 2.1:



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

7. References:

8. Contact:

The Red Hat security contact is <>.  More contact
details at

Copyright 2010 Red Hat, Inc.
Version: GnuPG v1.4.4 (GNU/Linux)


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