[El-errata] New Ksplice updates for UEKR2 2.6.39 on OL5 and OL6 (ELSA-2019-4689)

[Errata Announcements for Oracle Linux]

Synopsis: ELSA-2019-4689 can now be patched using Ksplice
CVEs: CVE-2019-11477 CVE-2019-11478 CVE-2019-11479

Users with Oracle Linux Premier Support can now use Ksplice to patch
against the latest Oracle Linux Security Advisory, ELSA-2019-4689.
More information about this errata can be found at
https://linux.oracle.com/errata/ELSA-2019-4689.html

INSTALLING THE UPDATES

We recommend that all users of Ksplice Uptrack running UEKR2 2.6.39 on
OL5 and OL6 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-2019-11477, CVE-2019-11478, CVE-2019-11479: Remote Denial-of-service in TCP stack.

A number of errors 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
either panic the system or exhaust resources.

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

Orabug: 29884308, 29890843, 29886601

SUPPORT

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