[Ksplice][Ubuntu-20.04-Updates] New Ksplice updates for Ubuntu 20.04 Focal (USN-5071-1)

[Oracle Ksplice]

Synopsis: USN-5071-1 can now be patched using Ksplice
CVEs: CVE-2020-26541 CVE-2020-36311 CVE-2021-22543 CVE-2021-35039 CVE-2021-3612 CVE-2021-3653 CVE-2021-3656

Systems running Ubuntu 20.04 Focal can now use Ksplice to patch
against the latest Ubuntu Security Notice, USN-5071-1.

INSTALLING THE UPDATES

We recommend that all users of Ksplice Uptrack running Ubuntu 20.04
Focal 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-2021-22543: Privilege escalation in KVM due to RO page check bypass.

The reference counts of VM_IO|VM_PFNMAP pages can be manipulated to
cause a deliberate use-after-free. This can be manipulated to cause
writes to arbitrary memory pages, allowing a malicious user with the
ability to create virtual machines to escalate their privileges.


* CVE-2021-3656, CVE-2021-3653: Privilege escalation in the AMD SVM L2 guests handling.

Multiple security bypasses potentially allow L2 guests to read/write host
physical memory.  An untrusted L1 guest running on certain AMD CPUs could
use these flaws to run with full ring zero privileges.


* Note: Oracle will not be providing an update for CVE-2020-26541.

This CVE is only applicable at boot time, so by the time Ksplice live updates
are applied, the relevant code has already ran.


* Note: Oracle has determined that CVE-2021-35039 is not applicable.

The kernel is not affected by CVE-2021-35039 since the code under
consideration is not compiled.


* CVE-2020-36311: Denial-of-service in KVM due to a soft lockup.

A flaw in SEV VM destruction of Kernel-based Virtual Machine could lead
to a soft lockup during encrypted regions deregistration. A local user
could use this flaw to cause a denial-of-service.


* CVE-2021-3612: Privilege escalation in joystick subsystem due to out-of-bounds write access.

Improper data validation in ioctls of joystick devices subsystem could
lead to out-of-bounds memory write access. A local user could use this
flaw to cause a denial-of-service or escalate their privileges.

SUPPORT

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