USN-3468-2: Linux kernel (HWE) vulnerabilities

31 October 2017

linux-hwe 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-hwe - Linux hardware enablement (HWE) kernel

Details

USN-3468-1 fixed vulnerabilities in the Linux kernel for Ubuntu 17.04. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 17.04 for Ubuntu 16.04 LTS.

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-4.10.0-38-generic - 4.10.0-38.42~16.04.1
linux-image-4.10.0-38-generic-lpae - 4.10.0-38.42~16.04.1
linux-image-4.10.0-38-lowlatency - 4.10.0-38.42~16.04.1
linux-image-generic-hwe-16.04 - 4.10.0.38.40
linux-image-generic-lpae-hwe-16.04 - 4.10.0.38.40
linux-image-lowlatency-hwe-16.04 - 4.10.0.38.40

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