A Linux kernel security update has been released for Ubuntu Linux 19.10 and 18.04 LTS.

USN-4412-1: Linux kernel vulnerabilities

=========================================================================
Ubuntu Security Notice USN-4412-1
July 02, 2020

linux, linux-azure, linux-gcp, linux-gcp-5.3, linux-hwe, linux-kvm,
linux-oracle, linux-oracle-5.3 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.10
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:
- linux: Linux kernel
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-gcp-5.3: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel
- linux-oracle-5.3: Linux kernel for Oracle Cloud systems

Details:

Matthew Sheets discovered that the SELinux network label handling
implementation in the Linux kernel could be coerced into de-referencing a
NULL pointer. A remote attacker could use this to cause a denial of service
(system crash). (CVE-2020-10711)

It was discovered that the SCSI generic (sg) driver in the Linux kernel did
not properly handle certain error conditions correctly. A local privileged
attacker could use this to cause a denial of service (system crash).
(CVE-2020-12770)

It was discovered that the USB Gadget device driver in the Linux kernel did
not validate arguments passed from configfs in some situations. A local
attacker could possibly use this to cause a denial of service (system
crash) or possibly expose sensitive information. (CVE-2020-13143)

Dmitry Vyukov discovered that the SELinux netlink security hook in the
Linux kernel did not validate messages in some situations. A privileged
attacker could use this to bypass SELinux netlink restrictions.
(CVE-2020-10751)

It was discovered that the KVM implementation in the Linux kernel did not
properly deallocate memory on initialization for some processors. A local
attacker could possibly use this to cause a denial of service.
(CVE-2020-12768)

Update instructions:

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

Ubuntu 19.10:
linux-image-5.3.0-1024-kvm 5.3.0-1024.26
linux-image-5.3.0-1028-oracle 5.3.0-1028.30
linux-image-5.3.0-1030-gcp 5.3.0-1030.32
linux-image-5.3.0-1031-azure 5.3.0-1031.32
linux-image-5.3.0-62-generic 5.3.0-62.56
linux-image-5.3.0-62-generic-lpae 5.3.0-62.56
linux-image-5.3.0-62-lowlatency 5.3.0-62.56
linux-image-5.3.0-62-snapdragon 5.3.0-62.56
linux-image-azure 5.3.0.1031.49
linux-image-gcp 5.3.0.1030.40
linux-image-generic 5.3.0.62.52
linux-image-generic-lpae 5.3.0.62.52
linux-image-gke 5.3.0.1030.40
linux-image-kvm 5.3.0.1024.22
linux-image-lowlatency 5.3.0.62.52
linux-image-oracle 5.3.0.1028.43
linux-image-snapdragon 5.3.0.62.52
linux-image-virtual 5.3.0.62.52

Ubuntu 18.04 LTS:
linux-image-5.3.0-1028-oracle 5.3.0-1028.30~18.04.1
linux-image-5.3.0-1030-gcp 5.3.0-1030.32~18.04.1
linux-image-5.3.0-62-generic 5.3.0-62.56~18.04.1
linux-image-5.3.0-62-generic-lpae 5.3.0-62.56~18.04.1
linux-image-5.3.0-62-lowlatency 5.3.0-62.56~18.04.1
linux-image-gcp 5.3.0.1030.24
linux-image-generic-hwe-18.04 5.3.0.62.115
linux-image-generic-lpae-hwe-18.04 5.3.0.62.115
linux-image-gkeop-5.3 5.3.0.62.115
linux-image-lowlatency-hwe-18.04 5.3.0.62.115
linux-image-oracle 5.3.0.1028.25
linux-image-snapdragon-hwe-18.04 5.3.0.62.115
linux-image-virtual-hwe-18.04 5.3.0.62.115

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://usn.ubuntu.com/4412-1
CVE-2020-10711, CVE-2020-10751, CVE-2020-12768, CVE-2020-12770,
CVE-2020-13143

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.3.0-62.56
  https://launchpad.net/ubuntu/+source/linux-azure/5.3.0-1031.32
  https://launchpad.net/ubuntu/+source/linux-gcp/5.3.0-1030.32
  https://launchpad.net/ubuntu/+source/linux-kvm/5.3.0-1024.26
  https://launchpad.net/ubuntu/+source/linux-oracle/5.3.0-1028.30
  https://launchpad.net/ubuntu/+source/linux-gcp-5.3/5.3.0-1030.32~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/5.3.0-62.56~18.04.1
  https://launchpad.net/ubuntu/+source/linux-oracle-5.3/5.3.0-1028.30~18.04.1