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Ubuntu Security Notice USN-5695-1
October 21, 2022

linux-gcp vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems

Details:

It was discovered that the SUNRPC RDMA protocol implementation in the Linux
kernel did not properly calculate the header size of a RPC message payload.
A local attacker could use this to expose sensitive information (kernel
memory). (CVE-2022-0812)

Moshe Kol, Amit Klein and Yossi Gilad discovered that the IP implementation
in the Linux kernel did not provide sufficient randomization when
calculating port offsets. An attacker could possibly use this to expose
sensitive information. (CVE-2022-1012, CVE-2022-32296)

Duoming Zhou discovered that race conditions existed in the timer handling
implementation of the Linux kernel's Rose X.25 protocol layer, resulting in
use-after-free vulnerabilities. A local attacker could use this to cause a
denial of service (system crash). (CVE-2022-2318)

Roger Pau Monné discovered that the Xen virtual block driver in the Linux
kernel did not properly initialize memory pages to be used for shared
communication with the backend. A local attacker could use this to expose
sensitive information (guest kernel memory). (CVE-2022-26365)

Roger Pau Monné discovered that the Xen paravirtualization frontend in the
Linux kernel did not properly initialize memory pages to be used for shared
communication with the backend. A local attacker could use this to expose
sensitive information (guest kernel memory). (CVE-2022-33740)

It was discovered that the Xen paravirtualization frontend in the Linux
kernel incorrectly shared unrelated data when communicating with certain
backends. A local attacker could use this to cause a denial of service
(guest crash) or expose sensitive information (guest kernel memory).
(CVE-2022-33741, CVE-2022-33742)

Oleksandr Tyshchenko discovered that the Xen paravirtualization platform in
the Linux kernel on ARM platforms contained a race condition in certain
situations. An attacker in a guest VM could use this to cause a denial of
service in the host OS. (CVE-2022-33744)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 ESM:
   linux-image-4.15.0-1137-gcp     4.15.0-1137.153~16.04.1
   linux-image-gcp                 4.15.0.1137.131
   linux-image-gke                 4.15.0.1137.131

After a standard system update you need to reboot your computer to make
all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have
been given a new version number, which requires you to recompile and
reinstall all third party kernel modules you might have installed.
Unless you manually uninstalled the standard kernel metapackages
(e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual,
linux-powerpc), a standard system upgrade will automatically perform
this as well.

References:
   https://ubuntu.com/security/notices/USN-5695-1
   CVE-2022-0812, CVE-2022-1012, CVE-2022-2318, CVE-2022-26365,
   CVE-2022-32296, CVE-2022-33740, CVE-2022-33741, CVE-2022-33742,
   CVE-2022-33744