Security update for xen

Open Source Vulnerabilities SUSE-SU-2017:1715-1

This update for xen fixes the following security issues: - blkif responses leaked backend stack data, which allowed unprivileged guest to obtain sensitive information from the host or other guests (XSA-216, bsc#1042863) - Page transfer might have allowed PV guest to elevate privilege (XSA-217, bsc#1042882) - Races in the grant table unmap code allowed for informations leaks and potentially privilege escalation (XSA-218, bsc#1042893) - Insufficient reference counts during shadow emulation allowed a malicious pair of guest to elevate their privileges to the privileges that XEN runs under (XSA-219, bsc#1042915) - Stale P2M mappings due to insufficient error checking allowed malicious guest to leak information or elevate privileges (XSA-222, bsc#1042931) - Grant table operations mishandled reference counts allowing malicious guests to escape (XSA-224, bsc#1042938) - CVE-2017-9330: USB OHCI Emulation in qemu allowed local guest OS users to cause a denial of service (infinite loop) by leveraging an incorrect return value (bsc#1042160) - CVE-2017-8309: Memory leak in the audio/audio.c allowed remote attackers to cause a denial of service (memory consumption) by repeatedly starting and stopping audio capture (bsc#1037243) - CVE-2017-8905: Xen a failsafe callback, which might have allowed PV guest OS users to execute arbitrary code on the host OS (XSA-215, bsc#1034845).