USN-4068-1: Linux kernel vulnerabilities

23 July 2019

Several security issues were fixed in the Linux kernel.

Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) 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-raspi2 - Linux kernel for Raspberry Pi 2
  • linux-snapdragon - Linux kernel for Snapdragon processors

Details

Adam Zabrocki discovered that the Intel i915 kernel mode graphics driver in
the Linux kernel did not properly restrict mmap() ranges in some
situations. A local attacker could use this to cause a denial of service
(system crash) or possibly execute arbitrary code. (CVE-2019-11085)

It was discovered that a race condition leading to a use-after-free existed
in the Reliable Datagram Sockets (RDS) protocol implementation in the Linux
kernel. The RDS protocol is blacklisted by default in Ubuntu. If enabled, a
local attacker could use this to cause a denial of service (system crash)
or possibly execute arbitrary code. (CVE-2019-11815)

It was discovered that the ext4 file system implementation in the Linux
kernel did not properly zero out memory in some situations. A local
attacker could use this to expose sensitive information (kernel memory).
(CVE-2019-11833)

It was discovered that the Bluetooth Human Interface Device Protocol (HIDP)
implementation in the Linux kernel did not properly verify strings were
NULL terminated in certain situations. A local attacker could use this to
expose sensitive information (kernel memory). (CVE-2019-11884)

Update instructions

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

Ubuntu 18.04

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.