1. Ubuntu Security Notices
  2. USN-3234-1

USN-3234-1: Linux kernel vulnerabilities

Publication date

15 March 2017

Overview

Several security issues were fixed in the kernel.

Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-gke - Linux kernel for Google Container Engine (GKE) systems
  • linux-raspi2 - Linux kernel for Raspberry Pi 2
  • linux-snapdragon - Linux kernel for Snapdragon Processors

Details

Ralf Spenneberg discovered that the ext4 implementation in the Linux kernel
did not properly validate meta block groups. An attacker with physical
access could use this to specially craft an ext4 image that causes a denial
of service (system crash). (CVE-2016-10208)

It was discovered that the Linux kernel did not clear the setgid bit during
a setxattr call on a tmpfs filesystem. A local attacker could use this to
gain elevated group privileges. (CVE-2017-5551)

Ralf Spenneberg discovered that the ext4 implementation in the Linux kernel
did not properly validate meta block groups. An attacker with physical
access could use this to specially craft an ext4 image that causes a denial
of service (system crash). (CVE-2016-10208)

It was discovered that the Linux kernel did not clear the setgid bit during
a setxattr call on a tmpfs filesystem. A local attacker could use this to
gain elevated group privileges. (CVE-2017-5551)

Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

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

Ubuntu Release Package Version
16.04 xenial linux-image-4.4.0-1006-gke –  4.4.0-1006.6
linux-image-4.4.0-1009-aws –  4.4.0-1009.18
linux-image-4.4.0-1048-raspi2 –  4.4.0-1048.55
linux-image-4.4.0-1051-snapdragon –  4.4.0-1051.55
linux-image-4.4.0-67-generic –  4.4.0-67.88
linux-image-4.4.0-67-generic-lpae –  4.4.0-67.88
linux-image-4.4.0-67-lowlatency –  4.4.0-67.88
linux-image-4.4.0-67-powerpc-e500mc –  4.4.0-67.88
linux-image-4.4.0-67-powerpc-smp –  4.4.0-67.88
linux-image-4.4.0-67-powerpc64-emb –  4.4.0-67.88
linux-image-4.4.0-67-powerpc64-smp –  4.4.0-67.88

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References

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