USN-3444-2: Linux kernel (Xenial HWE) vulnerabilities

USN-3444-1 fixed vulnerabilities in the Linux kernel for Ubuntu 16.04 LTS. This update provides the corresponding updates for the Linux Hardware Enablement (HWE) kernel from Ubuntu 16.04 LTS for Ubuntu 14.04 LTS. Jan H. Schönherr discovered that the Xen subsystem did not properly handle block IO merges correctly in some situations. An attacker in a guest vm could use this to cause a denial of service (host crash) or possibly gain administrative privileges in the host. (CVE-2017-12134) Andrey Konovalov discovered that a divide-by-zero error existed in the TCP stack implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2017-14106) Otto Ebeling discovered that the memory manager in the Linux kernel did not properly check the effective UID in some situations. A local attacker could use this to expose sensitive information. (CVE-2017-14140)