USN-3507-2: Linux kernel (GCP) vulnerabilities

8 December 2017

linux-gcp vulnerabilities

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

  • Ubuntu 16.04 LTS

Summary

Several security issues were fixed in the Linux kernel.

Software Description

  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems

Details

Mohamed Ghannam discovered that a use-after-free vulnerability existed in the Netlink subsystem (XFRM) in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-16939)

It was discovered that the Linux kernel did not properly handle copy-on- write of transparent huge pages. A local attacker could use this to cause a denial of service (application crashes) or possibly gain administrative privileges. (CVE-2017-1000405)

Fan Wu, Haoran Qiu, and Shixiong Zhao discovered that the associative array implementation in the Linux kernel sometimes did not properly handle adding a new entry. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-12193)

Eric Biggers discovered that the key management subsystem in the Linux kernel did not properly restrict adding a key that already exists but is uninstantiated. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-15299)

It was discovered that a null pointer dereference error existed in the PowerPC KVM implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-15306)

Eric Biggers discovered a race condition in the key management subsystem of the Linux kernel around keys in a negative state. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-15951)

Update instructions

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

Ubuntu 16.04 LTS
linux-image-4.13.0-1002-gcp - 4.13.0-1002.5
linux-image-gcp - 4.13.0.1002.4
linux-image-gke - 4.13.0.1002.4

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.

References