Ubuntu 20.04 LTS: USN-4916-2 Critical: Kernel Memory Leak Fix

ubuntu

April 21, 2021

USN-4916-1 introduced a regression in the Linux kernel.

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 ...

Read the Full Advisory

Topics Covered

security advisory denial of service critical critical fix memory leak system update ubuntu linux kernel regression issue kernel regression

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.