Ubuntu Security Notice 4426-1 - 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. 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. Various other issues were also addressed.
c08d99828ab0121536e6f7fbfa804274851e82d4f947dc4c837c3f5da9f63b08
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Ubuntu Security Notice USN-4426-1
July 21, 2020
linux, linux-aws, linux-aws-hwe, linux-gcp, linux-gcp-4.15,
linux-gke-4.15, linux-kvm, linux-oem, linux-oracle, linux-raspi2
vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 18.04 LTS
- Ubuntu 16.04 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-gcp-4.15: Linux kernel for Google Cloud Platform (GCP) systems
- linux-gke-4.15: Linux kernel for Google Container Engine (GKE) systems
- 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-aws-hwe: Linux kernel for Amazon Web Services (AWS-HWE) systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
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 LTS:
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-4.15.0-1093-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-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-powerpc-e500mc 4.15.0.112.100
linux-image-powerpc-smp 4.15.0.112.100
linux-image-powerpc64-emb 4.15.0.112.100
linux-image-powerpc64-smp 4.15.0.112.100
linux-image-raspi2 4.15.0.1067.65
linux-image-virtual 4.15.0.112.100
Ubuntu 16.04 LTS:
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-aws-hwe 4.15.0.1079.76
linux-image-gcp 4.15.0.1080.82
linux-image-gke 4.15.0.1080.82
linux-image-oracle 4.15.0.1050.41
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://usn.ubuntu.com/4426-1
CVE-2019-20908, CVE-2020-10757, CVE-2020-11935, CVE-2020-15780
Package Information:
https://launchpad.net/ubuntu/+source/linux/4.15.0-112.113
https://launchpad.net/ubuntu/+source/linux-aws/4.15.0-1079.83
https://launchpad.net/ubuntu/+source/linux-gcp-4.15/4.15.0-1080.90
https://launchpad.net/ubuntu/+source/linux-gke-4.15/4.15.0-1066.69
https://launchpad.net/ubuntu/+source/linux-kvm/4.15.0-1071.72
https://launchpad.net/ubuntu/+source/linux-oem/4.15.0-1093.103
https://launchpad.net/ubuntu/+source/linux-oracle/4.15.0-1050.54
https://launchpad.net/ubuntu/+source/linux-raspi2/4.15.0-1067.71
https://launchpad.net/ubuntu/+source/linux-aws-hwe/4.15.0-1079.83~16.04.1
https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1080.90~16.04.1
https://launchpad.net/ubuntu/+source/linux-oracle/4.15.0-1050.54~16.04.1