USN-4426-1: Linux kernel vulnerabilities

Releases

• Ubuntu 18.04 ESM
• Ubuntu 16.04 ESM

Packages

• linux - Linux kernel
• linux-aws - Linux kernel for Amazon Web Services (AWS) systems
• linux-aws-hwe - Linux kernel for Amazon Web Services (AWS-HWE) systems
• linux-azure - Linux kernel for Microsoft Azure Cloud systems
• linux-azure-4.15 - Linux kernel for Microsoft Azure Cloud systems
• linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
• linux-gcp-4.15 - Linux kernel for Google Cloud Platform (GCP) systems
• linux-gke-4.15 - Linux kernel for Google Container Engine (GKE) systems
• linux-hwe - Linux hardware enablement (HWE) kernel
• linux-kvm - Linux kernel for cloud environments
• linux-oem - Linux kernel for OEM systems
• linux-oracle - Linux kernel for Oracle Cloud systems
• linux-raspi2 - Linux kernel for Raspberry Pi (V7) systems
• linux-snapdragon - Linux kernel for Qualcomm Snapdragon processors

Details

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)

Fan Yang discovered that the mremap implementation in the Linux kernel did
not properly handle DAX Huge Pages. A local attacker with access to DAX
storage could use this to gain administrative privileges. (CVE-2020-10757)

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)

Jason A. Donenfeld discovered that the ACPI implementation in the Linux
kernel did not properly restrict loading ACPI tables via configfs. A
privileged attacker could use this to bypass Secure Boot lockdown
restrictions and execute arbitrary code in the kernel. (CVE-2020-15780)

Update instructions

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

Ubuntu 18.04

• linux-image-4.15.0-1050-oracle - 4.15.0-1050.54
• linux-image-4.15.0-1066-gke - 4.15.0-1066.69
• linux-image-4.15.0-1067-raspi2 - 4.15.0-1067.71
• linux-image-4.15.0-1071-kvm - 4.15.0-1071.72
• linux-image-4.15.0-1079-aws - 4.15.0-1079.83
• linux-image-4.15.0-1080-gcp - 4.15.0-1080.90
• linux-image-4.15.0-1092-azure - 4.15.0-1092.102
• linux-image-4.15.0-1093-oem - 4.15.0-1093.103
• linux-image-4.15.0-112-generic - 4.15.0-112.113
• linux-image-4.15.0-112-generic-lpae - 4.15.0-112.113
• linux-image-4.15.0-112-lowlatency - 4.15.0-112.113
• linux-image-aws-lts-18.04 - 4.15.0.1079.81
• linux-image-azure-lts-18.04 - 4.15.0.1092.63
• linux-image-gcp-lts-18.04 - 4.15.0.1080.96
• linux-image-generic - 4.15.0.112.100
• linux-image-generic-lpae - 4.15.0.112.100
• linux-image-gke - 4.15.0.1066.68
• linux-image-gke-4.15 - 4.15.0.1066.68
• linux-image-kvm - 4.15.0.1071.67
• linux-image-lowlatency - 4.15.0.112.100
• linux-image-oem - 4.15.0.1093.96
• linux-image-oracle-lts-18.04 - 4.15.0.1050.59
• linux-image-raspi2 - 4.15.0.1067.65
• linux-image-virtual - 4.15.0.112.100

Ubuntu 16.04

• linux-image-4.15.0-1050-oracle - 4.15.0-1050.54~16.04.1
• linux-image-4.15.0-1079-aws - 4.15.0-1079.83~16.04.1
• linux-image-4.15.0-1080-gcp - 4.15.0-1080.90~16.04.1
• linux-image-4.15.0-1092-azure - 4.15.0-1092.102~16.04.1
• linux-image-4.15.0-112-generic - 4.15.0-112.113~16.04.1
• linux-image-4.15.0-112-generic-lpae - 4.15.0-112.113~16.04.1
• linux-image-4.15.0-112-lowlatency - 4.15.0-112.113~16.04.1
• linux-image-aws-hwe - 4.15.0.1079.76
• linux-image-azure - 4.15.0.1092.87
• linux-image-gcp - 4.15.0.1080.82
• linux-image-generic-hwe-16.04 - 4.15.0.112.114
• linux-image-generic-lpae-hwe-16.04 - 4.15.0.112.114
• linux-image-gke - 4.15.0.1080.82
• linux-image-lowlatency-hwe-16.04 - 4.15.0.112.114
• linux-image-oem - 4.15.0.112.114
• linux-image-oracle - 4.15.0.1050.41
• linux-image-virtual-hwe-16.04 - 4.15.0.112.114

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

• CVE-2019-20908
• CVE-2020-10757
• CVE-2020-11935
• CVE-2020-15780

Related notices

• USN-4427-1: linux-image-kvm, linux-image-powerpc-e500mc-lts-vivid, linux-image-virtual-lts-vivid, linux-image-powerpc64-smp, linux-image-4.4.0-186-generic-lpae, linux, linux-image-4.4.0-186-lowlatency, linux-image-generic-lpae-lts-vivid, linux-image-powerpc-e500mc-lts-utopic, linux-image-powerpc-smp-lts-wily, linux-image-powerpc64-emb-lts-utopic, linux-image-virtual-lts-utopic, linux-image-4.4.0-186-generic, linux-image-powerpc64-smp-lts-xenial, linux-image-powerpc64-smp-lts-wily, linux-image-powerpc-e500mc-lts-wily, linux-image-powerpc64-emb-lts-xenial, linux-raspi2, linux-image-4.4.0-186-powerpc-smp, linux-image-4.4.0-186-powerpc64-emb, linux-image-lowlatency-lts-xenial, linux-image-powerpc-smp-lts-vivid, linux-image-lowlatency-lts-wily, linux-image-powerpc-e500mc, linux-snapdragon, linux-image-lowlatency, linux-image-snapdragon, linux-image-powerpc-smp, linux-lts-xenial, linux-image-generic-lpae, linux-image-powerpc64-smp-lts-vivid, linux-image-generic-lts-vivid, linux-image-generic-lpae-lts-utopic, linux-image-virtual-lts-xenial, linux-image-4.4.0-186-powerpc-e500mc, linux-image-powerpc-e500mc-lts-xenial, linux-image-4.4.0-1111-aws, linux-image-4.4.0-1136-raspi2, linux-image-generic-lts-utopic, linux-image-generic-lpae-lts-wily, linux-image-4.4.0-186-powerpc64-smp, linux-image-lowlatency-lts-utopic, linux-image-generic, linux-image-lowlatency-lts-vivid, linux-image-powerpc64-emb-lts-wily, linux-image-raspi2, linux-image-powerpc-smp-lts-utopic, linux-image-virtual, linux-image-aws, linux-image-powerpc-smp-lts-xenial, linux-kvm, linux-aws, linux-image-generic-lts-wily, linux-image-powerpc64-emb-lts-vivid, linux-image-4.4.0-1077-kvm, linux-image-4.4.0-1075-aws, linux-image-powerpc64-smp-lts-utopic, linux-image-powerpc64-emb, linux-image-generic-lpae-lts-xenial, linux-image-generic-lts-xenial, linux-image-4.4.0-1140-snapdragon, linux-image-virtual-lts-wily
• USN-4439-1: linux-image-oem-osp1, linux-image-5.0.0-1065-oem-osp1, linux-oem-osp1, linux-image-gke-5.0, linux-gke-5.0, linux-image-5.0.0-1045-gke
• USN-4440-1: linux-image-5.3.0-1030-oracle, linux-image-5.3.0-1032-gcp, linux-image-5.3.0-1030-raspi2, linux-image-gkeop-5.3, linux-gke-5.3, linux-image-5.3.0-1034-azure, linux-image-5.3.0-64-generic, linux-image-raspi2-hwe-18.04, linux-raspi2-5.3, linux-image-5.3.0-64-generic-lpae, linux-gcp-5.3, linux-oracle-5.3, linux-image-azure, linux-image-5.3.0-1032-aws, linux-image-gke-5.3, linux-image-oracle, linux-image-gcp, linux-image-5.3.0-64-lowlatency, linux-aws-5.3, linux-image-5.3.0-1032-gke, linux-image-aws, linux-hwe, linux-azure-5.3
• USN-4483-1: linux-image-kvm, linux-image-snapdragon-hwe-18.04, linux, linux-image-generic-lpae-hwe-20.04, linux-image-lowlatency-hwe-18.04-edge, linux-oracle-5.4, linux-image-generic-hwe-20.04, linux-azure-5.4, linux-image-virtual-hwe-20.04, linux-image-5.4.0-1022-aws, linux-image-lowlatency-hwe-18.04, linux-image-oracle-edge, linux-image-5.4.0-45-generic-lpae, linux-image-gcp-edge, linux-image-generic-hwe-18.04, linux-image-raspi, linux-hwe-5.4, linux-gcp-5.4, linux-raspi, linux-image-raspi2-hwe-18.04, linux-image-azure-edge, linux-image-virtual-hwe-18.04-edge, linux-image-5.4.0-45-lowlatency, linux-azure, linux-image-generic-hwe-18.04-edge, linux-image-lowlatency, linux-image-5.4.0-1022-oracle, linux-image-virtual-hwe-18.04, linux-image-generic-lpae, linux-image-generic-lpae-hwe-18.04-edge, linux-aws-5.4, linux-image-oem-osp1, linux-image-azure, linux-raspi-5.4, linux-image-aws-edge, linux-gcp, linux-image-5.4.0-1022-gcp, linux-image-snapdragon-hwe-18.04-edge, linux-image-5.4.0-1023-azure, linux-image-generic, linux-image-raspi-hwe-18.04-edge, linux-image-oem, linux-image-5.4.0-1016-raspi, linux-image-oracle, linux-image-raspi2, linux-image-gcp, linux-image-raspi-hwe-18.04, linux-image-raspi2-hwe-18.04-edge, linux-image-gkeop-5.4, linux-image-generic-lpae-hwe-18.04, linux-image-gke-5.4, linux-image-virtual, linux-image-5.4.0-45-generic, linux-image-aws, linux-kvm, linux-image-lowlatency-hwe-20.04, linux-aws, linux-image-gke, linux-oracle
• LSN-0069-1: generic-4.4, aws, lowlatency-5.4, generic-4.15, lowlatency-4.4, lowlatency-4.15, oem, gcp, azure, generic-5.4
• USN-4425-1: linux-image-kvm, linux-image-snapdragon-hwe-18.04, linux, linux-image-generic-lpae-hwe-20.04, linux-image-lowlatency-hwe-18.04-edge, linux-image-5.4.0-1015-raspi, linux-azure-5.4, linux-image-5.4.0-1021-gcp, linux-image-generic-hwe-20.04, linux-image-virtual-hwe-20.04, linux-image-lowlatency-hwe-18.04, linux-image-generic-hwe-18.04, linux-image-raspi, linux-hwe-5.4, linux-raspi, linux-image-raspi2-hwe-18.04, linux-image-azure-edge, linux-image-virtual-hwe-18.04-edge, linux-azure, linux-image-generic-hwe-18.04-edge, linux-image-lowlatency, linux-image-virtual-hwe-18.04, linux-image-generic-lpae, linux-image-generic-lpae-hwe-18.04-edge, linux-image-5.4.0-42-generic-lpae, linux-image-oem-osp1, linux-image-azure, linux-image-5.4.0-1022-azure, linux-raspi-5.4, linux-image-5.4.0-1021-oracle, linux-image-5.4.0-1020-aws, linux-image-5.4.0-30-generic, linux-image-5.4.0-42-generic, linux-gcp, linux-image-snapdragon-hwe-18.04-edge, linux-image-generic, linux-image-raspi-hwe-18.04-edge, linux-image-oem, linux-riscv, linux-image-raspi2, linux-image-oracle, linux-image-gcp, linux-image-raspi-hwe-18.04, linux-image-raspi2-hwe-18.04-edge, linux-image-gkeop-5.4, linux-image-generic-lpae-hwe-18.04, linux-image-virtual, linux-image-5.4.0-42-lowlatency, linux-image-aws, linux-kvm, linux-image-lowlatency-hwe-20.04, linux-aws, linux-image-gke, linux-oracle
• LSN-0070-1: generic-4.4, aws, lowlatency-5.4, generic-4.15, lowlatency-4.4, lowlatency-4.15, oem, gcp, azure, generic-5.4
• LSN-0072-1: generic-4.4, aws, lowlatency-5.4, generic-4.15, lowlatency-4.4, lowlatency-4.15, oem, gcp, azure, generic-5.4