========================================================================== Ubuntu Security Notice USN-4916-2 April 21, 2021 linux, linux-aws, linux-gke-5.3, linux-hwe, linux-kvm, linux-lts-xenial, linux-oem-5.6, linux-raspi2-5.3, linux-snapdragon regression ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 20.04 LTS - Ubuntu 18.04 LTS - Ubuntu 16.04 LTS - Ubuntu 14.04 ESM Summary: USN-4916-1 introduced a regression in the Linux kernel. Software Description: - linux-oem-5.6: Linux kernel for OEM systems - linux-gke-5.3: Linux kernel for Google Container Engine (GKE) systems - linux-hwe: Linux hardware enablement (HWE) kernel - linux-raspi2-5.3: Linux kernel for Raspberry Pi (V8) systems - linux: Linux kernel - linux-aws: Linux kernel for Amazon Web Services (AWS) systems - linux-kvm: Linux kernel for cloud environments - linux-snapdragon: Linux kernel for Qualcomm Snapdragon processors - linux-lts-xenial: Linux hardware enablement kernel from Xenial for Trusty Details: USN-4916-1 fixed vulnerabilities in the Linux kernel. Unfortunately, the fix for CVE-2021-3493 introduced a memory leak in some situations. This update fixes the problem. We apologize for the inconvenience. Original advisory details: It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. (CVE-2021-3493) Piotr Krysiuk discovered that the BPF JIT compiler for x86 in the Linux kernel did not properly validate computation of branch displacements in some situations. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-29154) Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 20.04 LTS: linux-image-5.6.0-1055-oem 5.6.0-1055.59 linux-image-oem-20.04 5.6.0.1055.51 Ubuntu 18.04 LTS: linux-image-5.3.0-1040-raspi2 5.3.0-1040.42 linux-image-5.3.0-1043-gke 5.3.0-1043.46 linux-image-5.3.0-74-generic 5.3.0-74.70 linux-image-5.3.0-74-lowlatency 5.3.0-74.70 linux-image-gke-5.3 5.3.0.1043.26 linux-image-gkeop-5.3 5.3.0.74.131 linux-image-raspi2-hwe-18.04 5.3.0.1040.29 Ubuntu 16.04 LTS: linux-image-4.4.0-1093-kvm 4.4.0-1093.102 linux-image-4.4.0-1128-aws 4.4.0-1128.142 linux-image-4.4.0-1156-snapdragon 4.4.0-1156.166 linux-image-4.4.0-210-generic 4.4.0-210.242 linux-image-4.4.0-210-generic-lpae 4.4.0-210.242 linux-image-4.4.0-210-lowlatency 4.4.0-210.242 linux-image-4.4.0-210-powerpc-e500mc 4.4.0-210.242 linux-image-4.4.0-210-powerpc-smp 4.4.0-210.242 linux-image-4.4.0-210-powerpc64-emb 4.4.0-210.242 linux-image-4.4.0-210-powerpc64-smp 4.4.0-210.242 linux-image-aws 4.4.0.1128.133 linux-image-generic 4.4.0.210.216 linux-image-generic-lpae 4.4.0.210.216 linux-image-kvm 4.4.0.1093.91 linux-image-lowlatency 4.4.0.210.216 linux-image-powerpc-e500mc 4.4.0.210.216 linux-image-powerpc-smp 4.4.0.210.216 linux-image-powerpc64-emb 4.4.0.210.216 linux-image-powerpc64-smp 4.4.0.210.216 linux-image-snapdragon 4.4.0.1156.148 linux-image-virtual 4.4.0.210.216 Ubuntu 14.04 ESM: linux-image-4.4.0-1092-aws 4.4.0-1092.96 linux-image-4.4.0-210-generic 4.4.0-210.242~14.04.1 linux-image-4.4.0-210-generic-lpae 4.4.0-210.242~14.04.1 linux-image-4.4.0-210-lowlatency 4.4.0-210.242~14.04.1 linux-image-4.4.0-210-powerpc-e500mc 4.4.0-210.242~14.04.1 linux-image-4.4.0-210-powerpc-smp 4.4.0-210.242~14.04.1 linux-image-4.4.0-210-powerpc64-emb 4.4.0-210.242~14.04.1 linux-image-4.4.0-210-powerpc64-smp 4.4.0-210.242~14.04.1 linux-image-aws 4.4.0.1092.89 linux-image-generic-lpae-lts-xenial 4.4.0.210.183 linux-image-generic-lts-xenial 4.4.0.210.183 linux-image-lowlatency-lts-xenial 4.4.0.210.183 linux-image-powerpc-e500mc-lts-xenial 4.4.0.210.183 linux-image-powerpc-smp-lts-xenial 4.4.0.210.183 linux-image-powerpc64-emb-lts-xenial 4.4.0.210.183 linux-image-powerpc64-smp-lts-xenial 4.4.0.210.183 linux-image-virtual-lts-xenial 4.4.0.210.183 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://ubuntu.com/security/notices/USN-4916-2 https://ubuntu.com/security/notices/USN-4916-1 https://launchpad.net/bugs/1924611 Package Information: https://launchpad.net/ubuntu/+source/linux-oem-5.6/5.6.0-1055.59 https://launchpad.net/ubuntu/+source/linux-gke-5.3/5.3.0-1043.46 https://launchpad.net/ubuntu/+source/linux-hwe/5.3.0-74.70 https://launchpad.net/ubuntu/+source/linux-raspi2-5.3/5.3.0-1040.42 https://launchpad.net/ubuntu/+source/linux/4.4.0-210.242 https://launchpad.net/ubuntu/+source/linux-aws/4.4.0-1128.142 https://launchpad.net/ubuntu/+source/linux-kvm/4.4.0-1093.102 https://launchpad.net/ubuntu/+source/linux-snapdragon/4.4.0-1156.166