[USN-3582-1] Linux kernel vulnerabilities

Steve Beattie steve.beattie at canonical.com
Thu Feb 22 10:13:14 UTC 2018

Ubuntu Security Notice USN-3582-1
February 22, 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


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


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).

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 versions:

Ubuntu 16.04 LTS:
  linux-image-4.4.0-1019-kvm      4.4.0-1019.24
  linux-image-4.4.0-1052-aws      4.4.0-1052.61
  linux-image-4.4.0-1085-raspi2   4.4.0-1085.93
  linux-image-4.4.0-1087-snapdragon  4.4.0-1087.92
  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-lowlatency  4.4.0-116.140
  linux-image-4.4.0-116-powerpc-e500mc  4.4.0-116.140
  linux-image-4.4.0-116-powerpc-smp  4.4.0-116.140
  linux-image-4.4.0-116-powerpc64-emb  4.4.0-116.140
  linux-image-4.4.0-116-powerpc64-smp  4.4.0-116.140

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.

  CVE-2015-8952, CVE-2017-12190, CVE-2017-15115, CVE-2017-17712,
  CVE-2017-5715, CVE-2017-8824

Package Information:

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