[USN-2908-3] Linux kernel (Raspberry Pi 2) vulnerabilities

[Steve Beattie]

==========================================================================
Ubuntu Security Notice USN-2908-3
February 22, 2016

linux-raspi2 vulnerabilities
==========================================================================

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

- Ubuntu 15.10

Summary:

Several security issues were fixed in the kernel.

Software Description:
- linux-raspi2: Linux kernel for Raspberry Pi 2

Details:

halfdog discovered that OverlayFS, when mounting on top of a FUSE mount,
incorrectly propagated file attributes, including setuid. A local
unprivileged attacker could use this to gain privileges. (CVE-2016-1576)

halfdog discovered that OverlayFS in the Linux kernel incorrectly
propagated security sensitive extended attributes, such as POSIX ACLs. A
local unprivileged attacker could use this to gain privileges.
(CVE-2016-1575)

It was discovered that the Linux kernel did not properly enforce rlimits
for file descriptors sent over UNIX domain sockets. A local attacker could
use this to cause a denial of service. (CVE-2013-4312)

It was discovered that the Linux kernel's Filesystem in Userspace (FUSE)
implementation did not handle initial zero length segments properly. A
local attacker could use this to cause a denial of service (unkillable
task). (CVE-2015-8785)

Andy Lutomirski discovered a race condition in the Linux kernel's
translation lookaside buffer (TLB) handling of flush events. A local
attacker could use this to cause a denial of service or possibly leak
sensitive information. (CVE-2016-2069)

Update instructions:

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

Ubuntu 15.10:
  linux-image-4.2.0-1025-raspi2   4.2.0-1025.32

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:
  http://www.ubuntu.com/usn/usn-2908-3
  http://www.ubuntu.com/usn/usn-2908-1
  CVE-2013-4312, CVE-2015-8785, CVE-2016-1575, CVE-2016-1576,
  CVE-2016-2069

Package Information:
  https://launchpad.net/ubuntu/+source/linux-raspi2/4.2.0-1025.32

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