USN-3054-1: Linux kernel (Xenial HWE) vulnerabilities

Ubuntu Security Notice USN-3054-1

10th August, 2016

linux-lts-xenial vulnerabilities

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

  • Ubuntu 14.04 LTS

Summary

Several security issues were fixed in the kernel.

Software description

  • linux-lts-xenial - Linux hardware enablement kernel from Xenial for Trusty

Details

Ben Hawkes discovered an integer overflow in the Linux netfilter
implementation. On systems running 32 bit kernels, a local unprivileged
attacker could use this to cause a denial of service (system crash) or
possibly execute arbitrary code with administrative privileges.
(CVE-2016-3135)

It was discovered that the keyring implementation in the Linux kernel did
not ensure a data structure was initialized before referencing it after an
error condition occurred. A local attacker could use this to cause a denial
of service (system crash). (CVE-2016-4470)

Sasha Levin discovered that a use-after-free existed in the percpu
allocator in the Linux kernel. A local attacker could use this to cause a
denial of service (system crash) or possibly execute arbitrary code with
administrative privileges. (CVE-2016-4794)

Kangjie Lu discovered an information leak in the netlink implementation of
the Linux kernel. A local attacker could use this to obtain sensitive
information from kernel memory. (CVE-2016-5243)

Update instructions

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

Ubuntu 14.04 LTS:
linux-image-4.4.0-34-generic-lpae 4.4.0-34.53~14.04.1
linux-image-4.4.0-34-powerpc-e500mc 4.4.0-34.53~14.04.1
linux-image-4.4.0-34-powerpc64-smp 4.4.0-34.53~14.04.1
linux-image-4.4.0-34-generic 4.4.0-34.53~14.04.1
linux-image-4.4.0-34-powerpc64-emb 4.4.0-34.53~14.04.1
linux-image-4.4.0-34-powerpc-smp 4.4.0-34.53~14.04.1
linux-image-4.4.0-34-lowlatency 4.4.0-34.53~14.04.1

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

CVE-2016-3135, CVE-2016-4470, CVE-2016-4794, CVE-2016-5243