USN-3931-2: Linux kernel (HWE) vulnerabilities

2 April 2019

Several security issues were fixed in the Linux kernel.

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Releases

Packages

  • linux-aws-hwe - Linux kernel for Amazon Web Services (AWS-HWE) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-hwe - Linux hardware enablement (HWE) kernel
  • linux-oracle - Linux kernel for Oracle Cloud systems

Details

USN-3931-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu
16.04 LTS and for the Linux Azure kernel for Ubuntu 14.04 LTS.

M. Vefa Bicakci and Andy Lutomirski discovered that the kernel did not
properly set up all arguments to an error handler callback used when
running as a paravirtualized guest. An unprivileged attacker in a
paravirtualized guest VM could use this to cause a denial of service (guest
VM crash). (CVE-2018-14678)

It was discovered that the KVM implementation in the Linux kernel on ARM
64bit processors did not properly handle some ioctls. An attacker with the
privilege to create KVM-based virtual machines could use this to cause a
denial of service (host system crash) or execute arbitrary code in the
host. (CVE-2018-18021)

Mathias Payer and Hui Peng discovered a use-after-free vulnerability in the
Advanced Linux Sound Architecture (ALSA) subsystem. A physically proximate
attacker could use this to cause a denial of service (system crash).
(CVE-2018-19824)

Shlomi Oberman, Yuli Shapiro, and Ran Menscher discovered an information
leak in the Bluetooth implementation of the Linux kernel. An attacker
within Bluetooth range could use this to expose sensitive information
(kernel memory). (CVE-2019-3459, CVE-2019-3460)

Jann Horn discovered that the KVM implementation in the Linux kernel
contained a use-after-free vulnerability. An attacker in a guest VM with
access to /dev/kvm could use this to cause a denial of service (guest VM
crash). (CVE-2019-6974)

Jim Mattson and Felix Wilhelm discovered a use-after-free vulnerability in
the KVM subsystem of the Linux kernel, when using nested virtual machines.
A local attacker in a guest VM could use this to cause a denial of service
(system crash) or possibly execute arbitrary code in the host system.
(CVE-2019-7221)

Felix Wilhelm discovered that an information leak vulnerability existed in
the KVM subsystem of the Linux kernel, when nested virtualization is used.
A local attacker could use this to expose sensitive information (host
system memory to a guest VM). (CVE-2019-7222)

Jann Horn discovered that the eBPF implementation in the Linux kernel was
insufficiently hardened against Spectre V1 attacks. A local attacker could
use this to expose sensitive information. (CVE-2019-7308)

It was discovered that a use-after-free vulnerability existed in the user-
space API for crypto (af_alg) 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-2019-8912)

It was discovered that the Linux kernel did not properly deallocate memory
when handling certain errors while reading files. A local attacker could
use this to cause a denial of service (excessive memory consumption).
(CVE-2019-8980)

Jann Horn discovered that the mmap implementation in the Linux kernel did
not properly check for the mmap minimum address in some situations. A local
attacker could use this to assist exploiting a kernel NULL pointer
dereference vulnerability. (CVE-2019-9213)

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Update instructions

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

Ubuntu 16.04
Ubuntu 14.04

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

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