[Ksplice][Ubuntu-19.04-Updates] New Ksplice updates for Ubuntu 19.04 Disco (USN-4041-1)

[Oracle Ksplice]

Synopsis: USN-4041-1 can now be patched using Ksplice
CVEs: CVE-2019-11478 CVE-2019-11479

Systems running Ubuntu 19.04 Disco can now use Ksplice to patch
against the latest Ubuntu Security Notice, USN-4041-1.

INSTALLING THE UPDATES

We recommend that all users of Ksplice Uptrack running Ubuntu 19.04
Disco 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-2019-11479: Remote Denial-of-service in TCP stack.

An error in the TCP stack could result in a remotely triggerable
denial-of-service on links with a small Maximum Segment Size (MSS).
A remote user could use a maliciously crafted TCP stream to exhaust
resources.

A new sysctl, ksplice_net_ipv4.tcp_min_snd_mss can be used to adjust
the minimum Maximum Segment Size and defaults to 48 bytes.


* Improved fix to CVE-2019-11478: Remote Denial-of-service in TCP stack.

The previous fix for CVE-2019-11478 might overzealously check sockets
with abnormally low SO_SNDBUF sockopt settings, resulting in performance
degradation.

SUPPORT

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