[LSN-0079-1] 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
-   Ubuntu 16.04 ESM
-   Ubuntu 14.04 ESM

Summary

Several security issues were fixed in the kernel.

Software Description

-   linux - Linux kernel
-   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
-   linux-oem - Linux kernel for OEM systems

Details

It was discovered that the eBPF implementation in the Linux kernel did
not properly track bounds information for 32 bit registers when
performing div and mod operations. A local attacker could use this to
possibly execute arbitrary code. (CVE-2021-3600)

It was discovered that the virtual file system implementation in the
Linux kernel contained an unsigned to signed integer conversion error.
A local attacker could use this to cause a denial of service (system
crash) or execute arbitrary code. (CVE-2021-33909)

Update instructions

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

Ubuntu 20.04 LTS
    gcp - 79.1
    generic - 79.1
    gke - 79.1
    gkeop - 79.1
    lowlatency - 79.1

Ubuntu 18.04 LTS
    generic - 79.1
    gke - 79.1
    gkeop - 79.1
    lowlatency - 79.1
    oem - 79.1

Ubuntu 16.04 ESM
    generic - 79.1
    lowlatency - 79.1

Ubuntu 14.04 ESM
    generic - 79.1
    lowlatency - 79.1

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 - 4.15.0-1054
    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 ESM
    linux-aws - 4.4.0-1098
    linux-azure - 4.15.0-1063
    linux-azure - 4.15.0-1078
    linux-hwe - 4.15.0-69
    linux - 4.4.0-168

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

References

-   CVE-2021-3600
-   CVE-2021-33909