USN-3582-1: Linux kernel vulnerabilities

Ubuntu Security Notice USN-3582-1

22nd February, 2018

linux, linux-aws, linux-kvm, linux-raspi2, linux-snapdragon vulnerabilities

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

Ubuntu 16.04 LTS

Summary

Several security issues were fixed in the Linux kernel.

Software description

linux
– Linux kernel
linux-aws
– Linux kernel for Amazon Web Services (AWS) systems
linux-kvm
– Linux kernel for cloud environments
linux-raspi2
– Linux kernel for Raspberry Pi 2
linux-snapdragon
– Linux kernel for Snapdragon processors

Details

Mohamed Ghannam discovered that the IPv4 raw socket implementation in the
Linux kernel contained a race condition leading to uninitialized pointer
usage. A local attacker could use this to cause a denial of service or
possibly execute arbitrary code. (CVE-2017-17712)

Laurent Guerby discovered that the mbcache feature in the ext2 and ext4
filesystems in the Linux kernel improperly handled xattr block caching. A
local attacker could use this to cause a denial of service. (CVE-2015-8952)

Vitaly Mayatskikh discovered that the SCSI subsystem in the Linux kernel
did not properly track reference counts when merging buffers. A local
attacker could use this to cause a denial of service (memory exhaustion).
(CVE-2017-12190)

ChunYu Wang discovered that a use-after-free vulnerability existed in the
SCTP protocol implementation in the Linux kernel. A local attacker could
use this to cause a denial of service (system crash) or possibly execute
arbitrary code, (CVE-2017-15115)

Mohamed Ghannam discovered a use-after-free vulnerability in the DCCP
protocol implementation in the Linux kernel. A local attacker could use
this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2017-8824)

USN-3540-1 mitigated CVE-2017-5715 (Spectre Variant 2) for the
amd64 architecture in Ubuntu 16.04 LTS. This update provides the
compiler-based retpoline kernel mitigation for the amd64 and i386
architectures. Original advisory details:

Jann Horn discovered that microprocessors utilizing speculative execution
and branch prediction may allow unauthorized memory reads via sidechannel
attacks. This flaw is known as Spectre. A local attacker could use this to
expose sensitive information, including kernel memory. (CVE-2017-5715)

Update instructions

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

Ubuntu 16.04 LTS:: linux-image-powerpc-e500mc 4.4.0.116.122; linux-image-4.4.0-116-powerpc64-smp

4.4.0-116.140; linux-image-4.4.0-1052-aws

4.4.0-1052.61; linux-image-4.4.0-116-lowlatency

4.4.0-116.140; linux-image-4.4.0-1019-kvm

4.4.0-1019.24; linux-image-snapdragon 4.4.0.1087.79; linux-image-powerpc64-emb 4.4.0.116.122; linux-image-generic 4.4.0.116.122; linux-image-4.4.0-116-generic

4.4.0-116.140; linux-image-4.4.0-116-generic-lpae

4.4.0-116.140; linux-image-4.4.0-116-powerpc-e500mc

4.4.0-116.140; linux-image-4.4.0-1085-raspi2

4.4.0-1085.93; linux-image-aws 4.4.0.1052.54; linux-image-kvm 4.4.0.1019.18; linux-image-4.4.0-116-powerpc-smp

4.4.0-116.140; linux-image-raspi2 4.4.0.1085.85; linux-image-powerpc-smp 4.4.0.116.122; linux-image-4.4.0-116-powerpc64-emb

4.4.0-116.140; linux-image-generic-lpae 4.4.0.116.122; linux-image-powerpc64-smp 4.4.0.116.122; linux-image-4.4.0-1087-snapdragon

4.4.0-1087.92; linux-image-lowlatency 4.4.0.116.122

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.