7.2 - USN-3405-1

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: 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:

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)

Huang Weller discovered that the ext4 filesystem implementation in the Linux kernel mishandled a needs-flushing-before-commit list. A local attacker could use this to expose sensitive information. (CVE-2017-7495)

It was discovered that a buffer overflow existed in the Broadcom FullMAC WLAN driver in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-7541)

It was discovered that the Linux kernel did not honor the UEFI secure boot mode when performing a kexec operation. A local attacker could use this to bypass secure boot restrictions. (CVE-2015-7837)

Update instructions:

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

Ubuntu 16.04 LTS:
linux-image-4.4.0-1028-gke 4.4.0-1028.28
linux-image-4.4.0-1032-aws 4.4.0-1032.41
linux-image-4.4.0-1071-raspi2 4.4.0-1071.79
linux-image-4.4.0-1073-snapdragon 4.4.0-1073.78
linux-image-4.4.0-93-generic 4.4.0-93.116
linux-image-4.4.0-93-generic-lpae 4.4.0-93.116
linux-image-4.4.0-93-lowlatency 4.4.0-93.116
linux-image-4.4.0-93-powerpc-e500mc 4.4.0-93.116
linux-image-4.4.0-93-powerpc-smp 4.4.0-93.116
linux-image-4.4.0-93-powerpc64-emb 4.4.0-93.116
linux-image-4.4.0-93-powerpc64-smp 4.4.0-93.116
linux-image-aws 4.4.0.1032.34
linux-image-generic 4.4.0.93.98
linux-image-generic-lpae 4.4.0.93.98
linux-image-gke 4.4.0.1028.29
linux-image-lowlatency 4.4.0.93.98
linux-image-powerpc-smp 4.4.0.93.98
linux-image-powerpc64-emb 4.4.0.93.98
linux-image-powerpc64-smp 4.4.0.93.98
linux-image-raspi2 4.4.0.1071.71
linux-image-snapdragon 4.4.0.1073.65

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-3405-1
CVE-2015-7837, CVE-2017-11176, CVE-2017-7495, CVE-2017-7541

Package Information:
https://launchpad.net/ubuntu/+source/linux/4.4.0-93.116
https://launchpad.net/ubuntu/+source/linux-aws/4.4.0-1032.41
https://launchpad.net/ubuntu/+source/linux-gke/4.4.0-1028.28
https://launchpad.net/ubuntu/+source/linux-raspi2/4.4.0-1071.79
https://launchpad.net/ubuntu/+source/linux-snapdragon/4.4.0-1073.78