[LSN-0077-1] Linux kernel vulnerability

[benjamin.romer at canonical.com]

Linux kernel vulnerabilities

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

-   Ubuntu 20.04 LTS
-   Ubuntu 18.04 LTS

Summary

Several security issues were fixed in the kernel.

Software Description

-   linux - Linux kernel
-   linux-aws - Linux kernel for Amazon Web Services (AWS) systems
-   linux-azure - Linux kernel for Microsoft Azure Cloud systems
-   linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
-   linux-gke - Linux kernel for Google Container Engine (GKE) systems
-   linux-gkeop - Linux kernel for Google Container Engine (GKE)
systems

Details

Vincent Dehors discovered that the shiftfs file system in the Ubuntu
Linux kernel did not properly handle faults in copy_from_user() when
passing through ioctls to an underlying file system. A local attacker
could use this to cause a denial of service (memory exhaustion) or
execute arbitrary code. (CVE-2021-3492)

Update instructions

The problem can be corrected by updating your kernel livepatch to the
following versions:

Ubuntu 20.04 LTS
    aws - 77.1
    azure - 77.1
    gcp - 77.1
    generic - 77.1
    gke - 77.1
    gkeop - 77.1
    lowlatency - 77.1

Ubuntu 18.04 LTS
    generic - 77.1
    gke - 77.1
    gkeop - 77.1
    lowlatency - 77.1

Support Information

Kernels older than the levels listed below do not receive livepatch
updates. If you are running a kernel version earlier than the one
listed
below, please upgrade your kernel as soon as possible.

Ubuntu 20.04 LTS
    linux-aws - 5.4.0-1009
    linux-azure - 5.4.0-1010
    linux-gcp - 5.4.0-1009
    linux-gke - 5.4.0-1033
    linux-gkeop - 5.4.0-1009
    linux-oem - 5.4.0-26
    linux - 5.4.0-26

Ubuntu 18.04 LTS
    linux-aws-fips - 4.15.0-2030
    linux-aws - 4.15.0-1054
    linux-azure-fips - 4.15.0-2012
    linux-fips - 4.15.0-1045
    linux-gke-4.15 - 4.15.0-1076
    linux-gke-5.4 - 5.4.0-1009
    linux-gkeop-5.4 - 5.4.0-1007
    linux-hwe-5.4 - 5.4.0-26
    linux-oem - 4.15.0-1063
    linux - 4.15.0-69

Ubuntu 16.04 LTS
    linux-aws - 4.4.0-1098
    linux-azure - 4.15.0-1063
    linux-azure - 4.15.0-1078
    linux-fips - 4.4.0-1049
    linux-hwe - 4.15.0-69
    linux - 4.4.0-168

Ubuntu 14.04 ESM
    linux-lts-xenial - 4.4.0-168

References

-   CVE-2021-3492