USN-4427-1: Linux kernel vulnerabilities

Publication date

27 July 2020

Overview

Several security issues were fixed in the Linux kernel.


Packages

Details

It was discovered that the Kvaser CAN/USB driver in the Linux kernel did
not properly initialize memory in certain situations. A local attacker
could possibly use this to expose sensitive information (kernel memory).
(CVE-2019-19947)

Chuhong Yuan discovered that go7007 USB audio device driver in the Linux
kernel did not properly deallocate memory in some failure conditions. A
physically proximate attacker could use this to cause a denial of service
(memory exhaustion). (CVE-2019-20810)

Jason A. Donenfeld discovered that the ACPI implementation in the Linux
kernel did not properly restrict loading SSDT code from an EFI variable. A
privileged attacker could use this to bypass Secure Boot lockdown
restrictions and execute arbitrary code in the kernel. (CVE-2019-20908)

It was discovered that the elf handling...

It was discovered that the Kvaser CAN/USB driver in the Linux kernel did
not properly initialize memory in certain situations. A local attacker
could possibly use this to expose sensitive information (kernel memory).
(CVE-2019-19947)

Chuhong Yuan discovered that go7007 USB audio device driver in the Linux
kernel did not properly deallocate memory in some failure conditions. A
physically proximate attacker could use this to cause a denial of service
(memory exhaustion). (CVE-2019-20810)

Jason A. Donenfeld discovered that the ACPI implementation in the Linux
kernel did not properly restrict loading SSDT code from an EFI variable. A
privileged attacker could use this to bypass Secure Boot lockdown
restrictions and execute arbitrary code in the kernel. (CVE-2019-20908)

It was discovered that the elf handling code in the Linux kernel did not
initialize memory before using it in certain situations. A local attacker
could use this to possibly expose sensitive information (kernel memory).
(CVE-2020-10732)

It was discovered that the Linux kernel did not correctly apply Speculative
Store Bypass Disable (SSBD) mitigations in certain situations. A local
attacker could possibly use this to expose sensitive information.
(CVE-2020-10766)

It was discovered that the Linux kernel did not correctly apply Indirect
Branch Predictor Barrier (IBPB) mitigations in certain situations. A local
attacker could possibly use this to expose sensitive information.
(CVE-2020-10767)

It was discovered that the Linux kernel could incorrectly enable Indirect
Branch Speculation after it has been disabled for a process via a prctl()
call. A local attacker could possibly use this to expose sensitive
information. (CVE-2020-10768)

Mauricio Faria de Oliveira discovered that the aufs implementation in the
Linux kernel improperly managed inode reference counts in the
vfsub_dentry_open() method. A local attacker could use this vulnerability
to cause a denial of service. (CVE-2020-11935)

It was discovered that the Virtual Terminal keyboard driver in the Linux
kernel contained an integer overflow. A local attacker could possibly use
this to have an unspecified impact. (CVE-2020-13974)

It was discovered that the efi subsystem in the Linux kernel did not handle
memory allocation failures during early boot in some situations. A local
attacker could possibly use this to cause a denial of service (system
crash). (CVE-2019-12380)


Update instructions

After a standard system update you need to reboot your computer to make all the necessary changes.

Learn more about how to get the fixes.

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.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
16.04 xenial linux-image-4.4.0-1077-kvm –  4.4.0-1077.84
linux-image-4.4.0-1111-aws –  4.4.0-1111.123
linux-image-4.4.0-1136-raspi2 –  4.4.0-1136.145
linux-image-4.4.0-1140-snapdragon –  4.4.0-1140.148
linux-image-4.4.0-186-generic –  4.4.0-186.216
linux-image-4.4.0-186-generic-lpae –  4.4.0-186.216
linux-image-4.4.0-186-lowlatency –  4.4.0-186.216
linux-image-4.4.0-186-powerpc-e500mc –  4.4.0-186.216
linux-image-4.4.0-186-powerpc-smp –  4.4.0-186.216
linux-image-4.4.0-186-powerpc64-emb –  4.4.0-186.216
linux-image-4.4.0-186-powerpc64-smp –  4.4.0-186.216
linux-image-aws –  4.4.0.1111.116
linux-image-generic –  4.4.0.186.192
linux-image-generic-lpae –  4.4.0.186.192
linux-image-kvm –  4.4.0.1077.75
linux-image-lowlatency –  4.4.0.186.192
linux-image-powerpc-e500mc –  4.4.0.186.192
linux-image-powerpc-smp –  4.4.0.186.192
linux-image-powerpc64-emb –  4.4.0.186.192
linux-image-powerpc64-smp –  4.4.0.186.192
linux-image-raspi2 –  4.4.0.1136.136
linux-image-snapdragon –  4.4.0.1140.132
linux-image-virtual –  4.4.0.186.192
14.04 trusty linux-image-4.4.0-1075-aws –  4.4.0-1075.79
linux-image-4.4.0-186-generic –  4.4.0-186.216~14.04.1
linux-image-4.4.0-186-generic-lpae –  4.4.0-186.216~14.04.1
linux-image-4.4.0-186-lowlatency –  4.4.0-186.216~14.04.1
linux-image-4.4.0-186-powerpc-e500mc –  4.4.0-186.216~14.04.1
linux-image-4.4.0-186-powerpc-smp –  4.4.0-186.216~14.04.1
linux-image-4.4.0-186-powerpc64-emb –  4.4.0-186.216~14.04.1
linux-image-4.4.0-186-powerpc64-smp –  4.4.0-186.216~14.04.1
linux-image-aws –  4.4.0.1075.72
linux-image-generic-lpae-lts-xenial –  4.4.0.186.163
linux-image-generic-lts-xenial –  4.4.0.186.163
linux-image-lowlatency-lts-xenial –  4.4.0.186.163
linux-image-powerpc-e500mc-lts-xenial –  4.4.0.186.163
linux-image-powerpc-smp-lts-xenial –  4.4.0.186.163
linux-image-powerpc64-emb-lts-xenial –  4.4.0.186.163
linux-image-powerpc64-smp-lts-xenial –  4.4.0.186.163
linux-image-virtual-lts-xenial –  4.4.0.186.163

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