[El-errata] New Ksplice updates for UEKR6 5.4.17 on OL7 and OL8 (ELSA-2021-9621)

[Errata Announcements for Oracle Linux]

Synopsis: ELSA-2021-9621 can now be patched using Ksplice
CVEs: CVE-2021-34556 CVE-2021-35477 CVE-2021-3753 CVE-2021-41864 CVE-2021-42252

Users with Oracle Linux Premier Support can now use Ksplice to patch
against the latest Oracle Linux Security Advisory, ELSA-2021-9621.
More information about this errata can be found at
https://linux.oracle.com/errata/ELSA-2021-9621.html

INSTALLING THE UPDATES

We recommend that all users of Ksplice Uptrack running UEKR6 5.4.17 on
OL7 and OL8 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-2021-3753: information disclosure in virtual terminal device.

A race condition flaw in its ioctl handling of the virtual terminal
device implementation could lead to out-of-bounds reads. A local user
could use this flaw for information disclosure.


* Note: Oracle has determined that CVE-2021-42252 is not applicable.

Oracle has determined that CVE-2021-42252 is not applicable to
the running kernel. Applying the patch has no resulting changes
in the generated object files.


* Note: Oracle will not provide a zero-downtime update for CVE-2021-34556, CVE-2021-35477.

An unprivileged BPF program can obtain sensitive information from kernel memory
via a Speculative Store Bypass side-channel attack by leveraging certain flaws
in the BPF implementation if unprivileged BPF is enabled.

Oracle has determined that patching CVE-2021-34556 and CVE-2021-35477 on
a running system would not be safe. These vulnerabilities have a medium
CVSS score of 5.5. In addition, disabling unprivileged BPF can be used
as a runtime mitigation.

Oracle recommends disabling unprivileged BPF or rebooting into the newest
kernel to mitigate these vulnerabilities.


* CVE-2021-41864: Code execution in BPF due to out-of-bounds writes.

An integer overflow flaw Berkeley Packet Filter when preallocating
objects for stack maps could result in out-of-bounds writes.
A privileged local user could use this to cause a denial of service or
possibly execute arbitrary code.

Orabug: 33431722


* Denial-of-service in NFSv4 client code losing connection.

Multiple logic errors in the Netfilter Connection Tracking sub-system
could lead NFSv4 client connections to drop and cause hangs on
the client side.

Orabug: 33524419


* Denial-of-service in AMD SVM support with Hyper-V role and Credential Guard enabled.

Logic error in AMD SVM support could result in a system crash at VM
boot when booting a VM with Hyper-V role and Credential Guard enabled
on AMD Zen2 or Zen3 machine.

Orabug: 33590307

SUPPORT

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