[Ksplice][Virtuozzo 4.7 Updates] New updates available via Ksplice (2.6.32-042stab116.1)

[Oracle Ksplice]

Synopsis: 2.6.32-042stab116.1 can now be patched using Ksplice
CVEs: CVE-2015-2925 CVE-2015-5157 CVE-2015-5307 CVE-2015-8104 CVE-2015-8767 CVE-2016-3156

Systems running Virtuozzo 4.7 or the OpenVZ RHEL 6 kernel can now use
Ksplice to patch against the latest Parallels Virtuozzo Containers 4.7
kernel security update, 2.6.32-042stab116.1.

INSTALLING THE UPDATES

We recommend that all users of Ksplice Uptrack on Virtuozzo 4.7 or
OpenVZ on RHEL 6 install these updates.

On systems that have "autoinstall = yes" in /etc/uptrack/uptrack.conf,
these updates will be installed automatically and you do not need to
take any action.

Alternatively, you can install these updates by running:

# /usr/sbin/uptrack-upgrade -y


DESCRIPTION

* CVE-2015-5307: KVM host denial-of-service in alignment check.

A guest could cause a denial-of-service on a KVM host by triggering an
infinite stream of alignment check exceptions and causing the processor
microcode to enter an infinite loop.  A privileged user in a guest could
use this flaw to crash the host.


* CVE-2015-8104: KVM host denial-of-service in debug exception.

A guest could cause a denial-of-service on a KVM host by triggering a
debug exception to fire during an existing debug exception.  This could
cause the host to get trapped in an infinite loop causing a
denial-of-service.  A privileged user in a guest could use this flaw to
crash the host.


* Improved fix for CVE-2015-2925: Privilege escalation in bind mounts inside namespaces.

Incorrect handling of renames inside container bind mounts could allow a
local user to escape a container and escalate privileges under specific
conditions.


* CVE-2015-5157: Disable modification of LDT by userspace processes.

The seldom-used modify_ldt syscall allowing processes to modify their local
descriptor table has several vulnerabilities allowing local unprivileged
users to elevate privileges.

This update disables by default the modify_ldt syscall and introduces a new
sysctl 'ksplice_modify_ldt' to allow administrators to re-enable it.
Re-enabling the syscall will make the machine vulnerable.

To re-enable modify_ldt, run the following command as root:

  sysctl ksplice_modify_ldt=1

To disable, run:

  sysctl ksplice_modify_ldt=0

This mitigates CVE-2015-3290, CVE-2015-3291 and CVE-2015-5157.


* CVE-2015-8767: Denial-of-service in SCTP heartbeat timeout.

Incorrect locking when accepting an SCTP connection during the 4-way
handshake could result in deadlock.  A local user could use this flaw to
block SCTP connections.


* CVE-2016-3156: Denial-of-service when removing a network interface.

Removal of a network interface with lots of IPv4 addresses may lead to the
kernel hanging for a long time, with all network operation blocked.  A
local, privileged user in a container could use this flaw to block network
access and cause a denial-of-service.

SUPPORT

Ksplice support is available at ksplice-support_ww at oracle.com.