USN-3903-2: Linux kernel (HWE) vulnerabilities

6 March 2019

Several security issues were fixed in the Linux kernel.

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Releases

Packages

  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-hwe - Linux hardware enablement (HWE) kernel

Details

USN-3903-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.10.
This update provides the corresponding updates for the Linux Hardware
Enablement (HWE) kernel from Ubuntu 18.10 for Ubuntu 18.04 LTS.

Jason Wang discovered that the vhost net driver in the Linux kernel
contained an out of bounds write vulnerability. An attacker in a guest
virtual machine could use this to cause a denial of service (host system
crash) or possibly execute arbitrary code in the host kernel.
(CVE-2018-16880)

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)

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)

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Update instructions

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

Ubuntu 18.04

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

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