=========================================================================
Ubuntu Security Notice USN-3695-2
July 02, 2018

linux-hwe, linux-azure vulnerabilities
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in the Linux kernel.

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

Details:

USN-3695-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu
16.04 LTS.

Wen Xu discovered that the ext4 file system implementation in the Linux
kernel did not properly initialize the crc32c checksum driver. A local
attacker could use this to cause a denial of service (system crash).
(CVE-2018-1094)

It was discovered that the cdrom driver in the Linux kernel contained an
incorrect bounds check. A local attacker could use this to expose sensitive
information (kernel memory). (CVE-2018-10940)

Wen Xu discovered that the ext4 file system implementation in the Linux
kernel did not properly validate xattr sizes. A local attacker could use
this to cause a denial of service (system crash). (CVE-2018-1095)

Jann Horn discovered that the 32 bit adjtimex() syscall implementation for
64 bit Linux kernels did not properly initialize memory returned to user
space in some situations. A local attacker could use this to expose
sensitive information (kernel memory). (CVE-2018-11508)

It was discovered that an information leak vulnerability existed in the
floppy driver in the Linux kernel. A local attacker could use this to
expose sensitive information (kernel memory). (CVE-2018-7755)

Update instructions:

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

Ubuntu 16.04 LTS:
  linux-image-4.15.0-1014-azure   4.15.0-1014.14~16.04.1
  linux-image-4.15.0-24-generic   4.15.0-24.26~16.04.1
  linux-image-4.15.0-24-generic-lpae  4.15.0-24.26~16.04.1
  linux-image-4.15.0-24-lowlatency  4.15.0-24.26~16.04.1
  linux-image-azure               4.15.0.1014.21
  linux-image-generic-hwe-16.04   4.15.0.24.46
  linux-image-generic-lpae-hwe-16.04  4.15.0.24.46
  linux-image-lowlatency-hwe-16.04  4.15.0.24.46

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/usn/usn-3695-2
  https://usn.ubuntu.com/usn/usn-3695-1
  CVE-2018-1094, CVE-2018-10940, CVE-2018-1095, CVE-2018-11508,
  CVE-2018-7755

Package Information:
  https://launchpad.net/ubuntu/+source/linux-azure/4.15.0-1014.14~16.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/4.15.0-24.26~16.04.1