=========================================================================
Ubuntu Security Notice USN-4887-1
March 23, 2021

linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp,
linux-gcp-5.4, linux-gke-5.3, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4,
linux-hwe, linux-hwe-5.4, linux-hwe-5.8, linux-kvm, linux-oem-5.10,
linux-oem-5.6, linux-oracle, linux-oracle-5.4, linux-raspi,
linux-raspi-5.4, linux-raspi2-5.3 vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- 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-kvm: Linux kernel for cloud environments
- linux-oracle: Linux kernel for Oracle Cloud systems
- linux-raspi: Linux kernel for Raspberry Pi (V8) systems
- linux-gkeop: Linux kernel for Google Container Engine (GKE) systems
- linux-hwe-5.8: Linux hardware enablement (HWE) kernel
- linux-oem-5.10: Linux kernel for OEM systems
- linux-oem-5.6: Linux kernel for OEM 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-5.3: Linux kernel for Google Container Engine (GKE) 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: Linux hardware enablement (HWE) kernel
- linux-hwe-5.4: Linux hardware enablement (HWE) kernel
- linux-oracle-5.4: Linux kernel for Oracle Cloud systems
- linux-raspi-5.4: Linux kernel for Raspberry Pi (V8) systems
- linux-raspi2-5.3: Linux kernel for Raspberry Pi (V8) systems

Details:

De4dCr0w of 360 Alpha Lab discovered that the BPF verifier in the Linux
kernel did not properly handle mod32 destination register truncation when
the source register was known to be 0. A local attacker could use this to
expose sensitive information (kernel memory) or possibly execute arbitrary
code. (CVE-2021-3444)

Adam Nichols discovered that heap overflows existed in the iSCSI subsystem
in the Linux kernel. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2021-27365)

Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not
properly compute a speculative execution limit on pointer arithmetic in
some situations. A local attacker could use this to expose sensitive
information (kernel memory). (CVE-2020-27171)

Piotr Krysiuk discovered that the BPF subsystem in the Linux kernel did not
properly apply speculative execution limits on some pointer types. A local
attacker could use this to expose sensitive information (kernel memory).
(CVE-2020-27170)

Adam Nichols discovered that the iSCSI subsystem in the Linux kernel did
not properly restrict access to iSCSI transport handles. A local attacker
could use this to cause a denial of service or expose sensitive information
(kernel pointer addresses). (CVE-2021-27363)

Adam Nichols discovered that an out-of-bounds read existed in the iSCSI
subsystem in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or expose sensitive information (kernel
memory). (CVE-2021-27364)

Update instructions:

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

Ubuntu 20.10:
  linux-image-5.8.0-1019-raspi    5.8.0-1019.22
  linux-image-5.8.0-1019-raspi-nolpae  5.8.0-1019.22
  linux-image-5.8.0-1022-kvm      5.8.0-1022.24
  linux-image-5.8.0-1024-oracle   5.8.0-1024.25
  linux-image-5.8.0-1026-azure    5.8.0-1026.28
  linux-image-5.8.0-1026-gcp      5.8.0-1026.27
  linux-image-5.8.0-1027-aws      5.8.0-1027.29
  linux-image-5.8.0-48-generic    5.8.0-48.54
  linux-image-5.8.0-48-generic-64k  5.8.0-48.54
  linux-image-5.8.0-48-generic-lpae  5.8.0-48.54
  linux-image-5.8.0-48-lowlatency  5.8.0-48.54
  linux-image-aws                 5.8.0.1027.29
  linux-image-azure               5.8.0.1026.26
  linux-image-gcp                 5.8.0.1026.26
  linux-image-generic             5.8.0.48.53
  linux-image-generic-64k         5.8.0.48.53
  linux-image-generic-lpae        5.8.0.48.53
  linux-image-gke                 5.8.0.1026.26
  linux-image-kvm                 5.8.0.1022.24
  linux-image-lowlatency          5.8.0.48.53
  linux-image-oem-20.04           5.8.0.48.53
  linux-image-oracle              5.8.0.1024.23
  linux-image-raspi               5.8.0.1019.22
  linux-image-raspi-nolpae        5.8.0.1019.22
  linux-image-virtual             5.8.0.48.53

Ubuntu 20.04 LTS:
  linux-image-5.10.0-1019-oem     5.10.0-1019.20
  linux-image-5.4.0-1012-gkeop    5.4.0-1012.13
  linux-image-5.4.0-1032-raspi    5.4.0-1032.35
  linux-image-5.4.0-1036-kvm      5.4.0-1036.37
  linux-image-5.4.0-1040-gcp      5.4.0-1040.43
  linux-image-5.4.0-1041-aws      5.4.0-1041.43
  linux-image-5.4.0-1041-oracle   5.4.0-1041.44
  linux-image-5.4.0-1043-azure    5.4.0-1043.45
  linux-image-5.4.0-70-generic    5.4.0-70.78
  linux-image-5.4.0-70-generic-lpae  5.4.0-70.78
  linux-image-5.4.0-70-lowlatency  5.4.0-70.78
  linux-image-5.6.0-1052-oem      5.6.0-1052.56
  linux-image-5.8.0-48-generic    5.8.0-48.54~20.04.1
  linux-image-5.8.0-48-generic-64k  5.8.0-48.54~20.04.1
  linux-image-5.8.0-48-generic-lpae  5.8.0-48.54~20.04.1
  linux-image-5.8.0-48-lowlatency  5.8.0-48.54~20.04.1
  linux-image-aws                 5.4.0.1041.42
  linux-image-azure               5.4.0.1043.41
  linux-image-gcp                 5.4.0.1040.49
  linux-image-generic             5.4.0.70.73
  linux-image-generic-64k-hwe-20.04  5.8.0.48.54~20.04.32
  linux-image-generic-hwe-20.04   5.8.0.48.54~20.04.32
  linux-image-generic-lpae        5.4.0.70.73
  linux-image-generic-lpae-hwe-20.04  5.8.0.48.54~20.04.32
  linux-image-gkeop               5.4.0.1012.15
  linux-image-gkeop-5.4           5.4.0.1012.15
  linux-image-kvm                 5.4.0.1036.34
  linux-image-lowlatency          5.4.0.70.73
  linux-image-lowlatency-hwe-20.04  5.8.0.48.54~20.04.32
  linux-image-oem                 5.4.0.70.73
  linux-image-oem-20.04           5.6.0.1052.48
  linux-image-oem-20.04b          5.10.0.1019.20
  linux-image-oem-osp1            5.4.0.70.73
  linux-image-oracle              5.4.0.1041.38
  linux-image-raspi               5.4.0.1032.67
  linux-image-raspi2              5.4.0.1032.67
  linux-image-virtual             5.4.0.70.73
  linux-image-virtual-hwe-20.04   5.8.0.48.54~20.04.32

Ubuntu 18.04 LTS:
  linux-image-5.3.0-1038-raspi2   5.3.0-1038.40
  linux-image-5.3.0-1041-gke      5.3.0-1041.44
  linux-image-5.3.0-72-generic    5.3.0-72.68
  linux-image-5.3.0-72-lowlatency  5.3.0-72.68
  linux-image-5.4.0-1012-gkeop    5.4.0-1012.13~18.04.1
  linux-image-5.4.0-1032-raspi    5.4.0-1032.35~18.04.1
  linux-image-5.4.0-1039-gke      5.4.0-1039.41~18.04.1
  linux-image-5.4.0-1040-gcp      5.4.0-1040.43~18.04.1
  linux-image-5.4.0-1041-aws      5.4.0-1041.43~18.04.1
  linux-image-5.4.0-1041-oracle   5.4.0-1041.44~18.04.1
  linux-image-5.4.0-1043-azure    5.4.0-1043.45~18.04.1
  linux-image-5.4.0-70-generic    5.4.0-70.78~18.04.1
  linux-image-5.4.0-70-generic-lpae  5.4.0-70.78~18.04.1
  linux-image-5.4.0-70-lowlatency  5.4.0-70.78~18.04.1
  linux-image-aws                 5.4.0.1041.24
  linux-image-azure               5.4.0.1043.23
  linux-image-gcp                 5.4.0.1040.27
  linux-image-generic-hwe-18.04   5.4.0.70.78~18.04.63
  linux-image-generic-lpae-hwe-18.04  5.4.0.70.78~18.04.63
  linux-image-gke-5.3             5.3.0.1041.24
  linux-image-gke-5.4             5.4.0.1039.41~18.04.6
  linux-image-gkeop-5.3           5.3.0.72.129
  linux-image-gkeop-5.4           5.4.0.1012.13~18.04.13
  linux-image-lowlatency-hwe-18.04  5.4.0.70.78~18.04.63
  linux-image-oem                 5.4.0.70.78~18.04.63
  linux-image-oem-osp1            5.4.0.70.78~18.04.63
  linux-image-oracle              5.4.0.1041.44~18.04.23
  linux-image-raspi-hwe-18.04     5.4.0.1032.34
  linux-image-raspi2-hwe-18.04    5.3.0.1038.27
  linux-image-snapdragon-hwe-18.04  5.4.0.70.78~18.04.63
  linux-image-virtual-hwe-18.04   5.4.0.70.78~18.04.63

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-4887-1
  CVE-2020-27170, CVE-2020-27171, CVE-2021-27363, CVE-2021-27364,
  CVE-2021-27365, CVE-2021-3444

Package Information:
  https://launchpad.net/ubuntu/+source/linux/5.8.0-48.54
  https://launchpad.net/ubuntu/+source/linux-aws/5.8.0-1027.29
  https://launchpad.net/ubuntu/+source/linux-azure/5.8.0-1026.28
  https://launchpad.net/ubuntu/+source/linux-gcp/5.8.0-1026.27
  https://launchpad.net/ubuntu/+source/linux-kvm/5.8.0-1022.24
  https://launchpad.net/ubuntu/+source/linux-oracle/5.8.0-1024.25
  https://launchpad.net/ubuntu/+source/linux-raspi/5.8.0-1019.22
  https://launchpad.net/ubuntu/+source/linux/5.4.0-70.78
  https://launchpad.net/ubuntu/+source/linux-aws/5.4.0-1041.43
  https://launchpad.net/ubuntu/+source/linux-azure/5.4.0-1043.45
  https://launchpad.net/ubuntu/+source/linux-gcp/5.4.0-1040.43
  https://launchpad.net/ubuntu/+source/linux-gkeop/5.4.0-1012.13
  https://launchpad.net/ubuntu/+source/linux-hwe-5.8/5.8.0-48.54~20.04.1
  https://launchpad.net/ubuntu/+source/linux-kvm/5.4.0-1036.37
  https://launchpad.net/ubuntu/+source/linux-oem-5.10/5.10.0-1019.20
  https://launchpad.net/ubuntu/+source/linux-oem-5.6/5.6.0-1052.56
  https://launchpad.net/ubuntu/+source/linux-oracle/5.4.0-1041.44
  https://launchpad.net/ubuntu/+source/linux-raspi/5.4.0-1032.35
  https://launchpad.net/ubuntu/+source/linux-aws-5.4/5.4.0-1041.43~18.04.1
  https://launchpad.net/ubuntu/+source/linux-azure-5.4/5.4.0-1043.45~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gcp-5.4/5.4.0-1040.43~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gke-5.3/5.3.0-1041.44
  https://launchpad.net/ubuntu/+source/linux-gke-5.4/5.4.0-1039.41~18.04.1
  https://launchpad.net/ubuntu/+source/linux-gkeop-5.4/5.4.0-1012.13~18.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/5.3.0-72.68
  https://launchpad.net/ubuntu/+source/linux-hwe-5.4/5.4.0-70.78~18.04.1
  https://launchpad.net/ubuntu/+source/linux-oracle-5.4/5.4.0-1041.44~18.04.1
  https://launchpad.net/ubuntu/+source/linux-raspi-5.4/5.4.0-1032.35~18.04.1
  https://launchpad.net/ubuntu/+source/linux-raspi2-5.3/5.3.0-1038.40