RHSA-2009:1472 - Security Advisory

Topic

Updated xen packages that fix a security issue and multiple bugs are now
available for Red Hat Enterprise Linux 5.

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

Description

Xen is an open source virtualization framework. Virtualization allows users
to run guest operating systems in virtual machines on top of a host
operating system.

The pyGrub boot loader did not honor the "password" option in the grub.conf
file for para-virtualized guests. Users with access to a guest's console
could use this flaw to bypass intended access restrictions and boot the
guest with arbitrary kernel boot options, allowing them to get root
privileges in the guest's operating system. With this update, pyGrub
correctly honors the "password" option in grub.conf for para-virtualized
guests. (CVE-2009-3525)

This update also fixes the following bugs:

• rebooting para-virtualized guests sometimes caused those guests to crash

due to a race condition in the xend node control daemon. This update fixes
this race condition so that rebooting guests no longer potentially causes
them to crash and fail to reboot. (BZ#525141)

• due to a race condition in the xend daemon, a guest could disappear from

the list of running guests following a reboot, even though the guest
rebooted successfully and was running. This update fixes this race
condition so that guests always reappear in the guest list following a
reboot. (BZ#525143)

• attempting to use PCI pass-through to para-virtualized guests on certain

kernels failed with a "Function not implemented" error message. As a
result, users requiring PCI pass-through on para-virtualized guests were
not able to update the xen packages without also updating the kernel and
thus requiring a reboot. These updated packages enable PCI pass-through for
para-virtualized guests so that users do not need to upgrade the kernel in
order to take advantage of PCI pass-through functionality. (BZ#525149)

All Xen users should upgrade to these updated packages, which contain
backported patches to correct these issues. After installing the updated
packages, the xend service must be restarted for this update to take
effect.

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
http://kbase.redhat.com/faq/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.4 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.4 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 525141 - [REG][Xen][5.4] PV domains may crash after reboot
• BZ - 525142 - Add grub.conf password protection support to pygrub
• BZ - 525143 - Domain goes missing from xm list when rebooted
• BZ - 525149 - PCI-Paththrough with PCI-Card does not work anymore with RHEL5.4
• BZ - 525740 - CVE-2009-3525 Xen: PyGrub missing support for password configuration command

CVEs

• CVE-2009-3525

References

• http://www.redhat.com/security/updates/classification/#moderate