A Linux kernel security update has been released for Ubuntu Linux 18.04 LTS and 20.04 LTS.

USN-5045-1: Linux kernel vulnerabilities

=========================================================================
Ubuntu Security Notice USN-5045-1
August 18, 2021

linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp,
linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4,
linux-hwe-5.4, linux-kvm, linux-oracle, linux-oracle-5.4, linux-raspi
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 Linux 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
- linux-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-raspi: Linux kernel for Raspberry Pi (V8) systems
- linux-aws-5.4: Linux kernel for Amazon Web Services (AWS) systems
- linux-azure-5.4: Linux kernel for Microsoft Azure cloud systems
- linux-gcp-5.4: Linux kernel for Google Cloud Platform (GCP) systems
- linux-gke-5.4: Linux kernel for Google Container Engine (GKE) systems
- linux-gkeop-5.4: Linux kernel for Google Container Engine (GKE) systems
- linux-hwe-5.4: Linux hardware enablement (HWE) kernel
- linux-oracle-5.4: Linux kernel for Oracle Cloud systems

Details:

Norbert Slusarek discovered that the CAN broadcast manger (bcm) protocol
implementation in the Linux kernel did not properly initialize memory in
some situations. A local attacker could use this to expose sensitive
information (kernel memory). (CVE-2021-34693)

It was discovered that the bluetooth subsystem in the Linux kernel did not
properly handle HCI device initialization failure, leading to a double-free
vulnerability. An attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2021-3564)

It was discovered that the bluetooth subsystem in the Linux kernel did not
properly handle HCI device detach events, leading to a use-after-free
vulnerability. An attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2021-3573)

It was discovered that the NFC implementation in the Linux kernel did not
properly handle failed connect events leading to a NULL pointer
dereference. A local attacker could use this to cause a denial of service.
(CVE-2021-3587)

Update instructions:

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

Ubuntu 20.04 LTS:
linux-image-5.4.0-1022-gkeop 5.4.0-1022.23
linux-image-5.4.0-1042-raspi 5.4.0-1042.46
linux-image-5.4.0-1045-kvm 5.4.0-1045.47
linux-image-5.4.0-1051-gcp 5.4.0-1051.55
linux-image-5.4.0-1051-gke 5.4.0-1051.54
linux-image-5.4.0-1053-oracle 5.4.0-1053.57
linux-image-5.4.0-1055-aws 5.4.0-1055.58
linux-image-5.4.0-1056-azure 5.4.0-1056.58
linux-image-5.4.0-81-generic 5.4.0-81.91
linux-image-5.4.0-81-generic-lpae 5.4.0-81.91
linux-image-5.4.0-81-lowlatency 5.4.0-81.91
linux-image-aws-lts-20.04 5.4.0.1055.58
linux-image-azure-lts-20.04 5.4.0.1056.54
linux-image-gcp-lts-20.04 5.4.0.1051.61
linux-image-generic 5.4.0.81.85
linux-image-generic-lpae 5.4.0.81.85
linux-image-gke 5.4.0.1051.61
linux-image-gke-5.4 5.4.0.1051.61
linux-image-gkeop 5.4.0.1022.25
linux-image-gkeop-5.4 5.4.0.1022.25
linux-image-kvm 5.4.0.1045.44
linux-image-lowlatency 5.4.0.81.85
linux-image-oem 5.4.0.81.85
linux-image-oem-osp1 5.4.0.81.85
linux-image-oracle-lts-20.04 5.4.0.1053.53
linux-image-raspi 5.4.0.1042.77
linux-image-raspi2 5.4.0.1042.77
linux-image-virtual 5.4.0.81.85

Ubuntu 18.04 LTS:
linux-image-5.4.0-1022-gkeop 5.4.0-1022.23~18.04.1
linux-image-5.4.0-1051-gcp 5.4.0-1051.55~18.04.1
linux-image-5.4.0-1051-gke 5.4.0-1051.54~18.04.1
linux-image-5.4.0-1053-oracle 5.4.0-1053.57~18.04.1
linux-image-5.4.0-1055-aws 5.4.0-1055.58~18.04.1
linux-image-5.4.0-1056-azure 5.4.0-1056.58~18.04.1
linux-image-5.4.0-81-generic 5.4.0-81.91~18.04.1
linux-image-5.4.0-81-generic-lpae 5.4.0-81.91~18.04.1
linux-image-5.4.0-81-lowlatency 5.4.0-81.91~18.04.1
linux-image-aws 5.4.0.1055.38
linux-image-azure 5.4.0.1056.36
linux-image-gcp 5.4.0.1051.37
linux-image-generic-hwe-18.04 5.4.0.81.91~18.04.73
linux-image-generic-lpae-hwe-18.04 5.4.0.81.91~18.04.73
linux-image-gke-5.4 5.4.0.1051.54~18.04.16
linux-image-gkeop-5.4 5.4.0.1022.23~18.04.23
linux-image-lowlatency-hwe-18.04 5.4.0.81.91~18.04.73
linux-image-oem 5.4.0.81.91~18.04.73
linux-image-oem-osp1 5.4.0.81.91~18.04.73
linux-image-oracle 5.4.0.1053.57~18.04.33
linux-image-snapdragon-hwe-18.04 5.4.0.81.91~18.04.73
linux-image-virtual-hwe-18.04 5.4.0.81.91~18.04.73

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-5045-1
CVE-2021-34693, CVE-2021-3564, CVE-2021-3573, CVE-2021-3587

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.4.0-81.91
  https://launchpad.net/ubuntu/+source/linux-aws/5.4.0-1055.58
  https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1056.58
  https://launchpad.net/ubuntu/+source/linux-gcp/5.4.0-1051.55
  https://launchpad.net/ubuntu/+source/linux-gke/5.4.0-1051.54
  https://launchpad.net/ubuntu/+source/linux-gkeop/5.4.0-1022.23
  https://launchpad.net/ubuntu/+source/linux-kvm/5.4.0-1045.47
  https://launchpad.net/ubuntu/+source/linux-oracle/5.4.0-1053.57
  https://launchpad.net/ubuntu/+source/linux-raspi/5.4.0-1042.46
  https://launchpad.net/ubuntu/+source/linux-aws-5.4/5.4.0-1055.58~18.04.1
  https://launchpad.net/ubuntu/+source/linux-azure-5.4/5.4.0-1056.58~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gcp-5.4/5.4.0-1051.55~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gke-5.4/5.4.0-1051.54~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gkeop-5.4/5.4.0-1022.23~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe-5.4/5.4.0-81.91~18.04.1
  https://launchpad.net/ubuntu/+source/linux-oracle-5.4/5.4.0-1053.57~18.04.1

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