USN-3468-3: Linux kernel (GCP) vulnerabilities

31 October 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

It was discovered that the KVM subsystem in the Linux kernel did not properly bound guest IRQs. A local attacker in a guest VM could use this to cause a denial of service (host system crash). (CVE-2017-1000252)

It was discovered that the Flash-Friendly File System (f2fs) implementation in the Linux kernel did not properly validate superblock metadata. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-10663)

Anthony Perard discovered that the Xen virtual block driver did not properly initialize some data structures before passing them to user space. A local attacker in a guest VM could use this to expose sensitive information from the host OS or other guest VMs. (CVE-2017-10911)

It was discovered that a use-after-free vulnerability existed in the POSIX message queue 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-2017-11176)

Dave Chinner discovered that the XFS filesystem did not enforce that the realtime inode flag was settable only on filesystems on a realtime device. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-14340)

Update instructions

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

Ubuntu 16.04 LTS
linux-image-4.10.0-1008-gcp - 4.10.0-1008.8
linux-image-gcp - 4.10.0.1008.10

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