RHEL 5 : kvm (RHSA-2010:0126)

This script is Copyright (C) 2013-2014 Tenable Network Security, Inc.


Synopsis :

The remote Red Hat host is missing one or more security updates.

Description :

Updated kvm packages that fix two security issues and two bugs are now
available for Red Hat Enterprise Linux 5.

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

KVM (Kernel-based Virtual Machine) is a full virtualization solution
for Linux on AMD64 and Intel 64 systems. KVM is a Linux kernel module
built for the standard Red Hat Enterprise Linux kernel.

A flaw was found in the way the x86 emulator loaded segment selectors
(used for memory segmentation and protection) into segment registers.
In some guest system configurations, an unprivileged guest user could
leverage this flaw to crash the guest or possibly escalate their
privileges within the guest. (CVE-2010-0419)

The x86 emulator implementation was missing a check for the Current
Privilege Level (CPL) while accessing debug registers. An unprivileged
user in a guest could leverage this flaw to crash the guest.
(CVE-2009-3722)

This update also fixes the following bugs :

With Red Hat Enterprise Virtualization, the
virtio_blk_dma_restart_bh() function was previously used to handle
write errors
however, a bug fix provided by the RHSA-2009:1659 update
meant that read errors would also have to be handled by this function.
The function was not updated for this, causing read errors to be
resubmitted as writes. This caused guest image corruption in some
cases.

Additionally, the return values of the bdrv_aio_write() and
bdrv_aio_read() functions were ignored. If an immediate failure
occurred in one of these functions, errors would be missed and the
guest could hang or read corrupted data. (BZ#562776)

All KVM users should upgrade to these updated packages, which contain
backported patches to resolve these issues. Note: The procedure in the
Solution section must be performed before this update will take
effect.

See also :

https://www.redhat.com/security/data/cve/CVE-2009-3722.html
https://www.redhat.com/security/data/cve/CVE-2010-0419.html
http://rhn.redhat.com/errata/RHSA-2010-0126.html

Solution :

Update the affected packages.

Risk factor :

High / CVSS Base Score : 7.1
(CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:C)
CVSS Temporal Score : 5.3
(CVSS2#E:U/RL:OF/RC:C)
Public Exploit Available : false

Family: Red Hat Local Security Checks

Nessus Plugin ID: 63920 ()

Bugtraq ID: 37221

CVE ID: CVE-2009-3722
CVE-2010-0419