========================================================================= Ubuntu Security Notice USN-4748-1 February 25, 2021 linux, linux-aws, linux-kvm, linux-lts-xenial, linux-raspi2, linux-snapdragon vulnerabilities ========================================================================= A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 16.04 LTS - Ubuntu 14.04 ESM 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-kvm: Linux kernel for cloud environments - linux-raspi2: Linux kernel for Raspberry Pi (V8) systems - linux-snapdragon: Linux kernel for Qualcomm Snapdragon processors - linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty Details: It was discovered that the jfs file system implementation in the Linux kernel contained an out-of-bounds read vulnerability. A local attacker could use this to possibly cause a denial of service (system crash). (CVE-2020-27815) It was discovered that the memory management subsystem in the Linux kernel did not properly handle copy-on-write operations in some situations. A local attacker could possibly use this to gain unintended write access to read-only memory pages. (CVE-2020-29374) Michael Kurth and Pawel Wieczorkiewicz discovered that the Xen event processing backend in the Linux kernel did not properly limit the number of events queued. An attacker in a guest VM could use this to cause a denial of service in the host OS. (CVE-2020-29568) Jann Horn discovered that the tty subsystem of the Linux kernel did not use consistent locking in some situations, leading to a read-after-free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly expose sensitive information (kernel memory). (CVE-2020-29660) Jann Horn discovered a race condition in the tty subsystem of the Linux kernel in the locking for the TIOCSPGRP ioctl(), leading to a use-after- free vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2020-29661) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 16.04 LTS: linux-image-4.4.0-1088-kvm 4.4.0-1088.97 linux-image-4.4.0-1122-aws 4.4.0-1122.136 linux-image-4.4.0-1146-raspi2 4.4.0-1146.156 linux-image-4.4.0-1150-snapdragon 4.4.0-1150.160 linux-image-4.4.0-203-generic 4.4.0-203.235 linux-image-4.4.0-203-generic-lpae 4.4.0-203.235 linux-image-4.4.0-203-lowlatency 4.4.0-203.235 linux-image-4.4.0-203-powerpc-e500mc 4.4.0-203.235 linux-image-4.4.0-203-powerpc-smp 4.4.0-203.235 linux-image-4.4.0-203-powerpc64-emb 4.4.0-203.235 linux-image-4.4.0-203-powerpc64-smp 4.4.0-203.235 linux-image-aws 4.4.0.1122.127 linux-image-generic 4.4.0.203.209 linux-image-generic-lpae 4.4.0.203.209 linux-image-kvm 4.4.0.1088.86 linux-image-lowlatency 4.4.0.203.209 linux-image-powerpc-e500mc 4.4.0.203.209 linux-image-powerpc-smp 4.4.0.203.209 linux-image-powerpc64-emb 4.4.0.203.209 linux-image-powerpc64-smp 4.4.0.203.209 linux-image-raspi2 4.4.0.1146.146 linux-image-snapdragon 4.4.0.1150.142 linux-image-virtual 4.4.0.203.209 Ubuntu 14.04 ESM: linux-image-4.4.0-1086-aws 4.4.0-1086.90 linux-image-4.4.0-203-generic 4.4.0-203.235~14.04.1 linux-image-4.4.0-203-generic-lpae 4.4.0-203.235~14.04.1 linux-image-4.4.0-203-lowlatency 4.4.0-203.235~14.04.1 linux-image-4.4.0-203-powerpc-e500mc 4.4.0-203.235~14.04.1 linux-image-4.4.0-203-powerpc-smp 4.4.0-203.235~14.04.1 linux-image-4.4.0-203-powerpc64-emb 4.4.0-203.235~14.04.1 linux-image-4.4.0-203-powerpc64-smp 4.4.0-203.235~14.04.1 linux-image-aws 4.4.0.1086.83 linux-image-generic-lpae-lts-xenial 4.4.0.203.177 linux-image-generic-lts-xenial 4.4.0.203.177 linux-image-lowlatency-lts-xenial 4.4.0.203.177 linux-image-powerpc-e500mc-lts-xenial 4.4.0.203.177 linux-image-powerpc-smp-lts-xenial 4.4.0.203.177 linux-image-powerpc64-emb-lts-xenial 4.4.0.203.177 linux-image-powerpc64-smp-lts-xenial 4.4.0.203.177 linux-image-virtual-lts-xenial 4.4.0.203.177 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://usn.ubuntu.com/4748-1 CVE-2020-27815, CVE-2020-29374, CVE-2020-29568, CVE-2020-29660, CVE-2020-29661 Package Information: https://launchpad.net/ubuntu/+source/linux/4.4.0-203.235 https://launchpad.net/ubuntu/+source/linux-aws/4.4.0-1122.136 https://launchpad.net/ubuntu/+source/linux-kvm/4.4.0-1088.97 https://launchpad.net/ubuntu/+source/linux-raspi2/4.4.0-1146.156 https://launchpad.net/ubuntu/+source/linux-snapdragon/4.4.0-1150.160