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             AUSCERT External Security Bulletin Redistribution

                               ESB-2019.4274
                  USN-4183: Linux kernel vulnerabilities
                             14 November 2019

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           linux kernel
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Root Compromise        -- Existing Account
                   Access Privileged Data -- Existing Account
                   Denial of Service      -- Existing Account
                   Unauthorised Access    -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-17666 CVE-2019-16746 CVE-2019-15793
                   CVE-2019-15792 CVE-2019-15791 CVE-2019-11135
                   CVE-2019-0155 CVE-2019-0154 CVE-2018-12207

Reference:         ASB-2019.0330
                   ASB-2019.0321
                   ASB-2019.0313
                   ESB-2019.4252
                   ESB-2019.4246

Original Bulletin: 
   https://usn.ubuntu.com/4183-1/
   https://usn.ubuntu.com/4183-2/

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

USN-4183-1: Linux kernel vulnerabilities
13 November 2019

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

  o Ubuntu 19.10

Summary

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-oracle - Linux kernel for Oracle Cloud systems
  o linux-raspi2 - Linux kernel for Raspberry Pi 2

Details

Stephan van Schaik, Alyssa Milburn, Sebastian A sterlund, Pietro Frigo, Kaveh
Razavi, Herbert Bos, Cristiano Giuffrida, Giorgi Maisuradze, Moritz Lipp,
Michael Schwarz, Daniel Gruss, and Jo Van Bulck discovered that Intel
processors using Transactional Synchronization Extensions (TSX) could expose
memory contents previously stored in microarchitectural buffers to a malicious
process that is executing on the same CPU core. A local attacker could use this
to expose sensitive information. (CVE-2019-11135)

It was discovered that the Intel i915 graphics chipsets allowed userspace to
modify page table entries via writes to MMIO from the Blitter Command Streamer
and expose kernel memory information. A local attacker could use this to expose
sensitive information or possibly elevate privileges. (CVE-2019-0155)

Deepak Gupta discovered that on certain Intel processors, the Linux kernel did
not properly perform invalidation on page table updates by virtual guest
operating systems. A local attacker in a guest VM could use this to cause a
denial of service (host system crash). (CVE-2018-12207)

It was discovered that the Intel i915 graphics chipsets could cause a system
hang when userspace performed a read from GT memory mapped input output (MMIO)
when the product is in certain low power states. A local attacker could use
this to cause a denial of service. (CVE-2019-0154)

Jann Horn discovered a reference count underflow in the shiftfs implementation
in the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2019-15791)

Jann Horn discovered a type confusion vulnerability in the shiftfs
implementation in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2019-15792)

Jann Horn discovered that the shiftfs implementation in the Linux kernel did
not use the correct file system uid/gid when the user namespace of a lower file
system is not in the init user namespace. A local attacker could use this to
possibly bypass DAC permissions or have some other unspecified impact.
(CVE-2019-15793)

It was discovered that a buffer overflow existed in the 802.11 Wi-Fi
configuration interface for the Linux kernel when handling beacon settings. A
local attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2019-16746)

Nico Waisman discovered that a buffer overflow existed in the Realtek Wi-Fi
driver for the Linux kernel when handling Notice of Absence frames. A
physically proximate attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2019-17666)

Update instructions

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

Ubuntu 19.10
    linux-image-5.3.0-1006-oracle - 5.3.0-1006.7
    linux-image-5.3.0-1007-aws - 5.3.0-1007.8
    linux-image-5.3.0-1007-azure - 5.3.0-1007.8
    linux-image-5.3.0-1007-kvm - 5.3.0-1007.8
    linux-image-5.3.0-1008-gcp - 5.3.0-1008.9
    linux-image-5.3.0-1012-raspi2 - 5.3.0-1012.14
    linux-image-5.3.0-22-generic - 5.3.0-22.24
    linux-image-5.3.0-22-generic-lpae - 5.3.0-22.24
    linux-image-5.3.0-22-lowlatency - 5.3.0-22.24
    linux-image-5.3.0-22-snapdragon - 5.3.0-22.24
    linux-image-aws - 5.3.0.1007.9
    linux-image-azure - 5.3.0.1007.25
    linux-image-gcp - 5.3.0.1008.9
    linux-image-generic - 5.3.0.22.26
    linux-image-generic-lpae - 5.3.0.22.26
    linux-image-gke - 5.3.0.1008.9
    linux-image-kvm - 5.3.0.1007.9
    linux-image-lowlatency - 5.3.0.22.26
    linux-image-oracle - 5.3.0.1006.7
    linux-image-raspi2 - 5.3.0.1012.9
    linux-image-snapdragon - 5.3.0.22.26
    linux-image-virtual - 5.3.0.22.26

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

Please note that mitigating the TSX (CVE-2019-11135) and i915 (CVE-2019-0154)
issues requires corresponding microcode and graphics firmware updates
respectively.

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

  o CVE-2018-12207
  o CVE-2019-0154
  o CVE-2019-0155
  o CVE-2019-11135
  o CVE-2019-15791
  o CVE-2019-15792
  o CVE-2019-15793
  o CVE-2019-16746
  o CVE-2019-17666
  o https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/TAA_MCEPSC_i915

=============================================================================

USN-4183-2: Linux kernel vulnerability
13 November 2019

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

  o Ubuntu 19.10

Summary

Several security issues were fixed in the Linux kernel.

Software Description

  o linux - Linux kernel

Details

USN-4183-1 fixed vulnerabilities in the Linux kernel. It was discovered that
the kernel fix for CVE-2019-0155 (i915 missing Blitter Command Streamer check)
was incomplete on 64-bit Intel x86 systems. This update addresses the issue.

We apologize for the inconvenience.

Original advisory details:

Stephan van Schaik, Alyssa Milburn, Sebastian A sterlund, Pietro Frigo, Kaveh
Razavi, Herbert Bos, Cristiano Giuffrida, Giorgi Maisuradze, Moritz Lipp,
Michael Schwarz, Daniel Gruss, and Jo Van Bulck discovered that Intel
processors using Transactional Synchronization Extensions (TSX) could expose
memory contents previously stored in microarchitectural buffers to a malicious
process that is executing on the same CPU core. A local attacker could use this
to expose sensitive information. (CVE-2019-11135)

It was discovered that the Intel i915 graphics chipsets allowed userspace to
modify page table entries via writes to MMIO from the Blitter Command Streamer
and expose kernel memory information. A local attacker could use this to expose
sensitive information or possibly elevate privileges. (CVE-2019-0155)

Deepak Gupta discovered that on certain Intel processors, the Linux kernel did
not properly perform invalidation on page table updates by virtual guest
operating systems. A local attacker in a guest VM could use this to cause a
denial of service (host system crash). (CVE-2018-12207)

It was discovered that the Intel i915 graphics chipsets could cause a system
hang when userspace performed a read from GT memory mapped input output (MMIO)
when the product is in certain low power states. A local attacker could use
this to cause a denial of service. (CVE-2019-0154)

Jann Horn discovered a reference count underflow in the shiftfs implementation
in the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2019-15791)

Jann Horn discovered a type confusion vulnerability in the shiftfs
implementation in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code.
(CVE-2019-15792)

Jann Horn discovered that the shiftfs implementation in the Linux kernel did
not use the correct file system uid/gid when the user namespace of a lower file
system is not in the init user namespace. A local attacker could use this to
possibly bypass DAC permissions or have some other unspecified impact.
(CVE-2019-15793)

It was discovered that a buffer overflow existed in the 802.11 Wi-Fi
configuration interface for the Linux kernel when handling beacon settings. A
local attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code. (CVE-2019-16746)

Nico Waisman discovered that a buffer overflow existed in the Realtek Wi-Fi
driver for the Linux kernel when handling Notice of Absence frames. A
physically proximate attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2019-17666)

Update instructions

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

Ubuntu 19.10
    linux-image-5.3.0-23-generic - 5.3.0-23.25
    linux-image-5.3.0-23-generic-lpae - 5.3.0-23.25
    linux-image-5.3.0-23-lowlatency - 5.3.0-23.25
    linux-image-5.3.0-23-snapdragon - 5.3.0-23.25
    linux-image-generic - 5.3.0.23.27
    linux-image-generic-lpae - 5.3.0.23.27
    linux-image-lowlatency - 5.3.0.23.27
    linux-image-snapdragon - 5.3.0.23.27
    linux-image-virtual - 5.3.0.23.27

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

Please note that mitigating the TSX (CVE-2019-11135) and i915 (CVE-2019-0154)
issues requires corresponding microcode and graphics firmware updates
respectively.

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

  o USN-4183-1
  o CVE-2019-0155
  o LP: 1852141

- --------------------------END INCLUDED TEXT--------------------

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