Scientific Linux Security Update : libvirt on SL7.x x86_64

This script is Copyright (C) 2015 Tenable Network Security, Inc.

Synopsis :

The remote Scientific Linux host is missing one or more security

Description :

It was found that QEMU's qemuDomainMigratePerform() and
qemuDomainMigrateFinish2() functions did not correctly perform a
domain unlock on a failed ACL check. A remote attacker able to
establish a connection to libvirtd could use this flaw to lock a
domain of a more privileged user, causing a denial of service.

It was discovered that the virDomainSnapshotGetXMLDesc() and
virDomainSaveImageGetXMLDesc() functions did not sufficiently limit
the usage of the VIR_DOMAIN_XML_SECURE flag when fine-grained ACLs
were enabled. A remote attacker able to establish a connection to
libvirtd could use this flaw to obtain certain sensitive information
from the domain XML file. (CVE-2015-0236)

Bug fixes :

- The libvirtd daemon previously attempted to search for
SELinux contexts even when SELinux was disabled on the
host. Consequently, libvirtd logged 'Unable to lookup
SELinux process context' error messages every time a
client connected to libvirtd and SELinux was disabled.
libvirtd now verifies whether SELinux is enabled before
searching for SELinux contexts, and no longer logs the
error messages on a host with SELinux disabled.

- The libvirt utility passed incomplete PCI addresses to
QEMU. Consequently, assigning a PCI device that had a
PCI address with a non- zero domain to a guest failed.
Now, libvirt properly passes PCI domain to QEMU when
assigning PCI devices, which prevents the described

- Because the virDomainSetMaxMemory API did not allow
changing the current memory in the LXC driver, the
'virsh setmaxmem' command failed when attempting to set
the maximum memory to be lower than the current memory.
Now, 'virsh setmaxmem' sets the current memory to the
intended value of the maximum memory, which avoids the
mentioned problem.

- Attempting to start a non-existent domain caused network
filters to stay locked for read-only access. Because of
this, subsequent attempts to gain read-write access to
network filters triggered a deadlock. Network filters
are now properly unlocked in the described scenario, and
the deadlock no longer occurs.

- If a guest configuration had an active nwfilter using
the DHCP snooping feature and an attempt was made to
terminate libvirtd before the associated nwfilter rule
snooped the guest IP address from DHCP packets, libvirtd
became unresponsive. This problem has been fixed by
setting a longer wait time for snooping the guest IP

Enhancements :

- A new 'migrate_host' option is now available in
/etc/libvirt/qemu.conf, which allows users to set a
custom IP address to be used for incoming migrations.

- With this update, libvirt is able to create a compressed
memory-only crash dump of a QEMU domain. This type of
crash dump is directly readable by the GNU Debugger and
requires significantly less hard disk space than the
standard crash dump.

- Support for reporting the NUMA node distance of the host
has been added to libvirt. This enhances the current
libvirt capabilities for reporting NUMA topology of the
host, and allows for easier optimization of new domains.

- The XML file of guest and host capabilities generated by
the 'virsh capabilities' command has been enhanced to
list the following information, where relevant: the
interface speed and link status of the host, the PCI
Express (PCIe) details, the host's hardware support for
I/O virtualization, and a report on the huge memory

These packages also include a number of other bug fixes and

See also :

Solution :

Update the affected packages.

Risk factor :

Low / CVSS Base Score : 3.5

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 82257 ()

Bugtraq ID:

CVE ID: CVE-2014-8136

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