Synopsis:	Low: libvirt security and bug fix update
Issue date:	2010-08-10
CVE Names:	CVE-2010-2239 CVE-2010-2242

It was found that libvirt did not set the user-defined backing store 
format when creating a new image, possibly resulting in applications 
having to probe the backing store to discover the format. A privileged 
guest user could use this flaw to read arbitrary files on the host. 
(CVE-2010-2239)

It was found that libvirt created insecure iptables rules on the host 
when a guest system was configured for IP masquerading, allowing the 
guest to use privileged ports on the host when accessing network 
resources. A privileged guest user could use this flaw to access network 
resources that would otherwise not be accessible to the guest. 
(CVE-2010-2242)

This update also fixes the following bugs:

* a Linux software bridge assumes the MAC address of the enslaved 
interface with the numerically lowest MAC address. When the bridge 
changes its MAC address, for a period of time it does not relay packets 
across network segments, resulting in a temporary network "blackout". 
The bridge should thus avoid changing its MAC address in order not to 
disrupt network communications.

The Linux kernel assigns network TAP devices a random MAC address.
Occasionally, this random MAC address is lower than that of the physical
interface which is enslaved (for example, eth0 or eth1), which causes 
the bridge to change its MAC address, thereby disrupting network 
communications for a period of time.

With this update, libvirt now sets an explicit MAC address for all TAP
devices created using the configured MAC address from the XML, but with 
the high bit set to 0xFE. The result is that TAP device MAC addresses 
are now numerically greater than those for physical interfaces, and 
bridges should no longer attempt to switch their MAC address to that of 
the TAP device, thus avoiding potential spurious network disruptions. 
(BZ#617243)

* a memory leak in the libvirt driver for the Xen hypervisor has been 
fixed with this update. (BZ#619711)

* the xm and virsh management user interfaces for virtual guests can be
called on the command line to list the number of active guests. However,
under certain circumstances, running the "virsh list" command resulted 
in virsh not listing all of the virtual guests that were active (that 
is, running) at the time. This update incorporates a fix that matches 
the logic used for determining active guests with that of "xm list", 
such that both commands should now list the same number of active 
virtual guests under all circumstances. (BZ#618200)

After installing the updated packages, the system must be rebooted for 
the update to take effect.

SL 5.x

     SRPMS:
libvirt-0.6.3-33.el5_5.3.src.rpm
     i386:
libvirt-0.6.3-33.el5_5.3.i386.rpm
libvirt-devel-0.6.3-33.el5_5.3.i386.rpm
libvirt-python-0.6.3-33.el5_5.3.i386.rpm
     x86_64:
libvirt-0.6.3-33.el5_5.3.i386.rpm
libvirt-0.6.3-33.el5_5.3.x86_64.rpm
libvirt-devel-0.6.3-33.el5_5.3.i386.rpm
libvirt-devel-0.6.3-33.el5_5.3.x86_64.rpm
libvirt-python-0.6.3-33.el5_5.3.x86_64.rpm

-Connie Sieh
-Troy Dawson