Ubuntu Security Notice 2840-1 - 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). 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. Various other issues were also addressed.
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==========================================================================Ubuntu Security Notice USN-2840-1
December 17, 2015
linux vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 12.04 LTS
Summary:
Several security issues were fixed in the kernel.
Software Description:
- linux: Linux kernel
Details:
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)
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)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 12.04 LTS:
linux-image-3.2.0-96-generic 3.2.0-96.136
linux-image-3.2.0-96-generic-pae 3.2.0-96.136
linux-image-3.2.0-96-highbank 3.2.0-96.136
linux-image-3.2.0-96-omap 3.2.0-96.136
linux-image-3.2.0-96-powerpc-smp 3.2.0-96.136
linux-image-3.2.0-96-powerpc64-smp 3.2.0-96.136
linux-image-3.2.0-96-virtual 3.2.0-96.136
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:
http://www.ubuntu.com/usn/usn-2840-1
CVE-2015-7872, CVE-2015-8104
Package Information:
https://launchpad.net/ubuntu/+source/linux/3.2.0-96.136