Immediately after announcing the availability of new kernel updates for all supported Ubuntu OSes, Canonical published another Ubuntu security notice to inform users about the release of another patch for the Linux kernel packages of Ubuntu 15.10 for Raspberry Pi 2.
The announcement comes only two days after Canonical published details about the first-ever Linux kernel update for the Ubuntu 15.10 (Wily Werewolf) operating system for the Raspberry Pi 2 single-board computer (SBC), and it promises to fix a ptrace issue with Linux kernel’s user namespaces.
“Jann Horn discovered a ptrace issue with user namespaces in the Linux kernel. The namespace owner could potentially exploit this flaw by ptracing a root owned process entering the user namespace to elevate its privileges and potentially gain access outside of the namespace,” reads today’s Ubuntu Security Notice USN-2852-1.
Therefore, we’re urging all users of the Ubuntu 15.10 port for Raspberry Pi 2 to update the kernel packages in their installations to linux-image-4.2.0-1017-raspi2 4.2.0-1017.24. The new version is now live in Ubuntu 15.10’s default software repositories, so all you have to do is run the “sudo apt-get update && sudo apt-get dist-upgrade” command.
Make sure that you run the command in a terminal emulator and that you reboot your Raspberry Pi 2 device after the new kernel version was downloaded and installed. Also, be aware of the fact that you will need to rebuild any third-party kernel modules you might have installed.