USN-2843-2: Linux kernel (Wily HWE) vulnerabilities

Ubuntu Security Notice USN-2843-2

17th December, 2015

linux-lts-wily 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-wily - Linux hardware enablement kernel from Wily

Details

Jan Beulich discovered that the KVM svm hypervisor implementation in the
Linux kernel did not properly catch Debug exceptions on AMD processors. An
attacker in a guest virtual machine could use this to cause a denial of
service (system crash) in the host OS. (CVE-2015-8104)

郭永刚 discovered that the ppp implementation in the Linux kernel did
not ensure that certain slot numbers are valid. A local attacker with the
privilege to call ioctl() on /dev/ppp could cause a denial of service
(system crash). (CVE-2015-7799)

Dmitry Vyukov discovered that the Linux kernel's keyring handler attempted
to garbage collect incompletely instantiated keys. A local unprivileged
attacker could use this to cause a denial of service (system crash).
(CVE-2015-7872)

It was discovered that the virtual video osd test driver in the Linux
kernel did not properly initialize data structures. A local attacker could
use this to obtain sensitive information from the kernel. (CVE-2015-7884)

It was discovered that the driver for Digi Neo and ClassicBoard devices did
not properly initialize data structures. A local attacker could use this to
obtain sensitive information from the kernel. (CVE-2015-7885)

Update instructions

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

Ubuntu 14.04 LTS:
linux-image-4.2.0-21-powerpc64-emb 4.2.0-21.25~14.04.1
linux-image-4.2.0-21-powerpc-smp 4.2.0-21.25~14.04.1
linux-image-4.2.0-21-lowlatency 4.2.0-21.25~14.04.1
linux-image-4.2.0-21-generic-lpae 4.2.0-21.25~14.04.1
linux-image-4.2.0-21-generic 4.2.0-21.25~14.04.1
linux-image-4.2.0-21-powerpc-e500mc 4.2.0-21.25~14.04.1
linux-image-4.2.0-21-powerpc64-smp 4.2.0-21.25~14.04.1

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. If
you use linux-restricted-modules, you have to update that package as
well to get modules which work with the new kernel version. Unless you
manually uninstalled the standard kernel metapackages (e.g. linux-generic,
linux-server, linux-powerpc), a standard system upgrade will automatically
perform this as well.

References

CVE-2015-7799, CVE-2015-7872, CVE-2015-7884, CVE-2015-7885, CVE-2015-8104