USN-3901-1: Linux kernel vulnerabilities

5 March 2019

linux, linux-aws, linux-gcp, linux-kvm, linux-oem, linux-oracle, linux-raspi2 vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • 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-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-oem - Linux kernel for OEM processors
  • linux-oracle - Linux kernel for Oracle Cloud systems
  • linux-raspi2 - Linux kernel for Raspberry Pi 2

Details

Jann Horn discovered that the userfaultd implementation in the Linux kernel did not properly restrict access to certain ioctls. A local attacker could use this possibly to modify files. (CVE-2018-18397)

It was discovered that the crypto subsystem of the Linux kernel leaked uninitialized memory to user space in some situations. A local attacker could use this to expose sensitive information (kernel memory). (CVE-2018-19854)

Jann Horn discovered a race condition in the fork() system call in the Linux kernel. A local attacker could use this to gain access to services that cache authorizations. (CVE-2019-6133)

Update instructions

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

Ubuntu 18.04 LTS
linux-image-4.15.0-1009-oracle - 4.15.0-1009.11
linux-image-4.15.0-1028-gcp - 4.15.0-1028.29
linux-image-4.15.0-1030-kvm - 4.15.0-1030.30
linux-image-4.15.0-1032-raspi2 - 4.15.0-1032.34
linux-image-4.15.0-1033-aws - 4.15.0-1033.35
linux-image-4.15.0-1034-oem - 4.15.0-1034.39
linux-image-4.15.0-46-generic - 4.15.0-46.49
linux-image-4.15.0-46-generic-lpae - 4.15.0-46.49
linux-image-4.15.0-46-lowlatency - 4.15.0-46.49
linux-image-4.15.0-46-snapdragon - 4.15.0-46.49
linux-image-aws - 4.15.0.1033.32
linux-image-gcp - 4.15.0.1028.30
linux-image-generic - 4.15.0.46.48
linux-image-generic-lpae - 4.15.0.46.48
linux-image-gke - 4.15.0.1028.30
linux-image-kvm - 4.15.0.1030.30
linux-image-lowlatency - 4.15.0.46.48
linux-image-oem - 4.15.0.1034.39
linux-image-oracle - 4.15.0.1009.12
linux-image-raspi2 - 4.15.0.1032.30
linux-image-snapdragon - 4.15.0.46.48

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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