Linux kernel vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

– Ubuntu 18.04 LTS
– Ubuntu 20.04 LTS
– Ubuntu 16.04 LTS
– Ubuntu 14.04 ESM

Summary

Several security issues were fixed in the kernel.

Software Description

– linux – Linux kernel
– linux-aws – Linux kernel for Amazon Web Services (AWS) systems
– linux-azure – Linux kernel for Microsoft Azure Cloud systems
– linux-gcp – Linux kernel for Google Cloud Platform (GCP) systems
– linux-oem – Linux kernel for OEM systems

Details

It was discovered that the F2FS file system implementation in the Linux
kernel did not properly perform bounds checking on xattrs in some
situations. A local attacker could possibly use this to expose sensitive
information (kernel memory). (CVE-2020-0067)

It was discovered that the Serial CAN interface driver in the Linux
kernel did not properly initialize data. A local attacker could use this
to expose sensitive information (kernel memory). (CVE-2020-11494)

Mauricio Faria de Oliveira discovered that the aufs implementation in
the Linux kernel improperly managed inode reference counts in the
vfsub_dentry_open() method. A local attacker could use this
vulnerability to cause a denial of service. (CVE-2020-11935)

Piotr Krysiuk discovered that race conditions existed in the file system
implementation in the Linux kernel. A local attacker could use this to
cause a denial of service (system crash). (CVE-2020-12114)

Or Cohen discovered that the AF_PACKET implementation in the Linux
kernel did not properly perform bounds checking in some situations. A
local attacker could use this to cause a denial of service (system
crash) or possibly execute arbitrary code. (CVE-2020-14386)

Hador Manor discovered that the DCCP protocol implementation in the
Linux kernel improperly handled socket reuse, leading to a
use-after-free vulnerability. A local attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2020-16119)

Giuseppe Scrivano discovered that the overlay file system in the Linux
kernel did not properly perform permission checks in some situations. A
local attacker could possibly use this to bypass intended restrictions
and gain read access to restricted files. (CVE-2020-16120)

Update instructions

The problem can be corrected by updating your kernel livepatch to the
following versions:

Ubuntu 18.04 LTS
aws – 72.1
generic – 72.1
lowlatency – 72.1
oem – 72.1

Ubuntu 20.04 LTS
aws – 72.1
aws – 72.2
azure – 72.1
azure – 72.2
gcp – 72.1
gcp – 72.2
generic – 72.1
generic – 72.2
lowlatency – 72.1
lowlatency – 72.2

Ubuntu 16.04 LTS
aws – 72.1
generic – 72.1
lowlatency – 72.1

Ubuntu 14.04 ESM
generic – 72.1
lowlatency – 72.1

Support Information

Kernels older than the levels listed below do not receive livepatch
updates. If you are running a kernel version earlier than the one listed
below, please upgrade your kernel as soon as possible.

Ubuntu 18.04 LTS
linux-aws – 4.15.0-1054
linux-azure – 5.0.0-1025
linux-gcp – 5.0.0-1025
linux-oem – 4.15.0-1063
linux-oracle – 5.0.0-1000
linux – 4.15.0-69

Ubuntu 20.04 LTS
linux-aws – 5.4.0-1009
linux-azure – 5.4.0-1010
linux-gcp – 5.4.0-1009
linux-oem – 5.4.0-26
linux – 5.4.0-26

Ubuntu 16.04 LTS
linux-aws – 4.4.0-1098
linux-azure – 4.15.0-1063
linux-hwe – 4.15.0-69
linux – 4.4.0-168

Ubuntu 14.04 ESM
linux-lts-xenial – 4.4.0-168

References

– CVE-2020-0067
– CVE-2020-11494
– CVE-2020-11935
– CVE-2020-12114
– CVE-2020-14386
– CVE-2020-16119
– CVE-2020-16120

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