6.6 - USN-3443-1

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

- Ubuntu 17.04

Summary:

Several security issues were fixed in the Linux kernel.

Software Description: - linux: Linux kernel - linux-raspi2: Linux kernel for Raspberry Pi 2

Details:

It was discovered that on the PowerPC architecture, the kernel did not properly sanitize the signal stack when handling sigreturn(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2017-1000255)

Andrey Konovalov discovered that a divide-by-zero error existed in the TCP stack implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-14106)

Update instructions:

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

Ubuntu 17.04:
linux-image-4.10.0-1019-raspi2 4.10.0-1019.22
linux-image-4.10.0-37-generic 4.10.0-37.41
linux-image-4.10.0-37-generic-lpae 4.10.0-37.41
linux-image-4.10.0-37-lowlatency 4.10.0-37.41
linux-image-generic 4.10.0.37.37
linux-image-generic-lpae 4.10.0.37.37
linux-image-lowlatency 4.10.0.37.37
linux-image-powerpc-e500mc 4.10.0.37.37
linux-image-powerpc-smp 4.10.0.37.37
linux-image-powerpc64-emb 4.10.0.37.37
linux-image-powerpc64-smp 4.10.0.37.37
linux-image-raspi2 4.10.0.1019.20
linux-image-virtual 4.10.0.37.37

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-3443-1
CVE-2017-1000255, CVE-2017-14106

Package Information:
https://launchpad.net/ubuntu/+source/linux/4.10.0-37.41
https://launchpad.net/ubuntu/+source/linux-raspi2/4.10.0-1019.22