USN-2947-3: Linux kernel (Raspberry Pi 2) vulnerabilities

Ubuntu Security Notice USN-2947-3

6th April, 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

Ralf Spenneberg discovered that the usbvision driver in the Linux kernel
did not properly sanity check the interfaces and endpoints reported by the
device. An attacker with physical access could cause a denial of service
(system crash). (CVE-2015-7833)

Venkatesh Pottem discovered a use-after-free vulnerability in the Linux
kernel's CXGB3 driver. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2015-8812)

Xiaofei Rex Guo discovered a timing side channel vulnerability in the Linux
Extended Verification Module (EVM). An attacker could use this to affect
system integrity. (CVE-2016-2085)

It was discovered that the extended Berkeley Packet Filter (eBPF)
implementation in the Linux kernel did not correctly compute branch offsets
for backward jumps after ctx expansion. A local attacker could use this to
cause a denial of service (system crash) or possibly execute arbitrary
code. (CVE-2016-2383)

David Herrmann discovered that the Linux kernel incorrectly accounted file
descriptors to the original opener for in-flight file descriptors sent over
a unix domain socket. A local attacker could use this to cause a denial of
service (resource exhaustion). (CVE-2016-2550)

It was discovered that the Linux kernel did not enforce limits on the
amount of data allocated to buffer pipes. A local attacker could use this
to cause a denial of service (resource exhaustion). (CVE-2016-2847)

Update instructions

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

Ubuntu 15.10:

linux-image-4.2.0-1028-raspi2 4.2.0-1028.36

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-2015-7833, CVE-2015-8812, CVE-2016-2085, CVE-2016-2383, CVE-2016-2550, CVE-2016-2847