7.2 - USN-3507-2

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

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:
https://www.ubuntu.com/usn/usn-3507-2
https://www.ubuntu.com/usn/usn-3507-1
CVE-2017-1000405, CVE-2017-12193, CVE-2017-15299, CVE-2017-15306,
CVE-2017-15951, CVE-2017-16939

Package Information:
https://launchpad.net/ubuntu/+source/linux-gcp/4.13.0-1002.5