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Ubuntu Security Notice USN-5647-1
September 28, 2022

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

- Ubuntu 20.04 LTS

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 framebuffer driver on the Linux kernel did not
verify size limits when changing font or screen size, leading to an out-of-
bounds write. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2021-33655)

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)

Norbert Slusarek discovered that a race condition existed in the perf
subsystem in the Linux kernel, resulting in a use-after-free vulnerability.
A privileged local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2022-1729)

It was discovered that the device-mapper verity (dm-verity) driver in the
Linux kernel did not properly verify targets being loaded into the device-
mapper table. A privileged attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2022-2503)

Domingo Dirutigliano and Nicola Guerrera discovered that the netfilter
subsystem in the Linux kernel did not properly handle rules that truncated
packets below the packet header size. When such rules are in place, a
remote attacker could possibly use this to cause a denial of service
(system crash). (CVE-2022-36946)

Update instructions:

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

Ubuntu 20.04 LTS:
   linux-image-5.4.0-1089-gcp      5.4.0-1089.97
   linux-image-gcp-lts-20.04       5.4.0.1089.94

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-5647-1
   CVE-2021-33655, CVE-2022-1012, CVE-2022-1729, CVE-2022-2503,
   CVE-2022-32296, CVE-2022-36946

Package Information:
   https://launchpad.net/ubuntu/+source/linux-gcp/5.4.0-1089.97