[Ksplice][Ubuntu-18.04-Updates] New Ksplice updates for Ubuntu 18.04 Bionic (USN-3740-1)

[Oracle Ksplice]

Synopsis: USN-3740-1 can now be patched using Ksplice
CVEs: CVE-2018-3620 CVE-2018-3646 CVE-2018-5391

Systems running Ubuntu 18.04 Bionic can now use Ksplice to patch
against the latest Ubuntu Security Notice, USN-3740-1.

INSTALLING THE UPDATES

We recommend that all users of Ksplice Uptrack running Ubuntu 18.04
Bionic 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

* KPTI enablement for Ksplice.




* Ksplice enablement for khugepaged.




* CVE-2018-3620, CVE-2018-3646: Information leak in Intel CPUs under terminal fault.

A flaw in terminal fault handling on Intel CPUs could result in
information leaks across privilege boundaries including between
processes on a system or between virtual machines.

Mitigations for these CVEs include disabling SMT (HyperThreading) on
affected Intel CPUs, extra L1 data cache flushing when running virtual
machines when EPT is supported.  Both of these mitigations have workload
dependent performance implications can can be tuned by the
administrator.  This update will immediately enable L1 data cache
flushes on Intel CPUs if KVM is in use.  Where untrusted guests are in
use it is recommended to disable SMT.

SMT disable:

/sys/devices/system/cpu/smt/control: write "on" to enable SMT, "off" to
disable SMT.  Default: on.

L1D flushing:

/sys/module/kvm_intel/parameters/vmentry_l1d_flush, write:
  - "never": disable L1D flushing, leaving CVE-2018-3620 unmitigated but
  no noticeable performance impact
  - "cond": flush only in high risk transfers, mitigates CVE-2018-3620
  with the minimum number of flushes
  - "always": flush on every VM entry, fully mitigates CVE-2018-3620
  with the most overhead.
Default: "always"


* CVE-2018-5391: Remote denial-of-service in IP fragment handling.

A malicious remote user can use a flaw in IP fragment handling to starve
IP processing on the system causing loss of connectivity.

SUPPORT

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