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             AUSCERT External Security Bulletin Redistribution

                 USN-4342-1: Linux kernel vulnerabilities
                               29 April 2020


        AusCERT Security Bulletin Summary

Product:           kernel
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Denial of Service               -- Existing Account
                   Access Confidential Data        -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-11884 CVE-2020-10942 CVE-2020-9383
                   CVE-2020-8992 CVE-2020-8648 CVE-2019-19768

Reference:         ESB-2020.1257

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

USN-4342-1: Linux kernel vulnerabilities
28 April 2020

linux, linux-aws, linux-azure, linux-gcp, linux-gke-5.3, linux-hwe, linux-kvm, linux-raspi2, linux-raspi2-5.3 vulnerabilities
A security issue affects these releases of Ubuntu and its derivatives:

  o Ubuntu 19.10
  o Ubuntu 18.04 LTS


Several security issues were fixed in the Linux kernel.

Software Description

  o linux - Linux kernel
  o linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  o linux-azure - Linux kernel for Microsoft Azure Cloud systems
  o linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  o linux-kvm - Linux kernel for cloud environments
  o linux-raspi2 - Linux kernel for Raspberry Pi 2
  o linux-gke-5.3 - Linux kernel for Google Container Engine (GKE) systems
  o linux-hwe - Linux hardware enablement (HWE) kernel
  o linux-raspi2-5.3 - Linux kernel for Raspberry Pi 2


Al Viro discovered that the Linux kernel for s390x systems did not properly
perform page table upgrades for kernel sections that use secondary address
mode. A local attacker could use this to cause a denial of service (system
crash) or execute arbitrary code. (CVE-2020-11884)

It was discovered that the Intel Wi-Fi driver in the Linux kernel did not
properly check for errors in some situations. A local attacker could possibly
use this to cause a denial of service (system crash). (CVE-2019-16234)

Tristan Madani discovered that the block I/O tracing implementation in the
Linux kernel contained a race condition. A local attacker could use this to
cause a denial of service (system crash) or possibly expose sensitive
information. (CVE-2019-19768)

It was discovered that the vhost net driver in the Linux kernel contained a
stack buffer overflow. A local attacker with the ability to perform ioctl()
calls on /dev/vhost-net could use this to cause a denial of service (system
crash). (CVE-2020-10942)

It was discovered that the virtual terminal implementation in the Linux kernel
contained a race condition. A local attacker could possibly use this to cause a
denial of service (system crash) or expose sensitive information.

Shijie Luo discovered that the ext4 file system implementation in the Linux
kernel did not properly check for a too-large journal size. An attacker could
use this to construct a malicious ext4 image that, when mounted, could cause a
denial of service (soft lockup). (CVE-2020-8992)

Jordy Zomer discovered that the floppy driver in the Linux kernel did not
properly check for errors in some situations. A local attacker could possibly
use this to cause a denial of service (system crash) or possibly expose
sensitive information. (CVE-2020-9383)

Update instructions

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

Ubuntu 19.10
    linux-image-5.3.0-1016-kvm - 5.3.0-1016.17
    linux-image-5.3.0-1017-aws - 5.3.0-1017.18
    linux-image-5.3.0-1018-gcp - 5.3.0-1018.19
    linux-image-5.3.0-1020-azure - 5.3.0-1020.21
    linux-image-5.3.0-1023-raspi2 - 5.3.0-1023.25
    linux-image-5.3.0-51-generic - 5.3.0-51.44
    linux-image-5.3.0-51-generic-lpae - 5.3.0-51.44
    linux-image-5.3.0-51-lowlatency - 5.3.0-51.44
    linux-image-5.3.0-51-snapdragon - 5.3.0-51.44
    linux-image-aws -
    linux-image-azure -
    linux-image-gcp -
    linux-image-generic -
    linux-image-generic-lpae -
    linux-image-gke -
    linux-image-kvm -
    linux-image-lowlatency -
    linux-image-raspi2 -
    linux-image-snapdragon -
    linux-image-virtual -
Ubuntu 18.04 LTS
    linux-image-5.3.0-1018-gke - 5.3.0-1018.19~18.04.1
    linux-image-5.3.0-1023-raspi2 - 5.3.0-1023.25~18.04.1
    linux-image-5.3.0-51-generic - 5.3.0-51.44~18.04.2
    linux-image-5.3.0-51-generic-lpae - 5.3.0-51.44~18.04.2
    linux-image-5.3.0-51-lowlatency - 5.3.0-51.44~18.04.2
    linux-image-generic-hwe-18.04 -
    linux-image-generic-lpae-hwe-18.04 -
    linux-image-gke-5.3 -
    linux-image-lowlatency-hwe-18.04 -
    linux-image-raspi2-hwe-18.04 -
    linux-image-snapdragon-hwe-18.04 -
    linux-image-virtual-hwe-18.04 -

To update your system, please follow these instructions: https://
wiki.ubuntu.com/Security/Upgrades .

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.


  o CVE-2019-16234
  o CVE-2019-19768
  o CVE-2020-10942
  o CVE-2020-11884
  o CVE-2020-8648
  o CVE-2020-8992
  o CVE-2020-9383

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