Security update for xen

Open Source Vulnerabilities SUSE-SU-2017:2327-2

This update for xen fixes several issues. These security issues were fixed: - CVE-2017-12135: Unbounded recursion in grant table code allowed a malicious guest to crash the host or potentially escalate privileges/leak information (XSA-226, bsc#1051787). - CVE-2017-12137: Incorrectly-aligned updates to pagetables allowed for privilege escalation (XSA-227, bsc#1051788). - CVE-2017-12136: Race conditions with maptrack free list handling allows a malicious guest administrator to crash the host or escalate their privilege to that of the host (XSA-228, bsc#1051789). - CVE-2017-11434: The dhcp_decode function in slirp/bootp.c allowed local guest OS users to cause a denial of service (out-of-bounds read) via a crafted DHCP options string (bsc#1049578). - CVE-2017-10664: qemu-nbd did not ignore SIGPIPE, which allowed remote attackers to cause a denial of service (daemon crash) by disconnecting during a server-to-client reply attempt (bsc#1046637). - CVE-2017-12855: Premature clearing of GTF_writing / GTF_reading lead to potentially leaking sensitive information (XSA-230 bsc#1052686. These non-security issues were fixed: - bsc#1055695: XEN: 11SP4 and 12SP3 HVM guests can not be restored after the save using xl stack - bsc#1035231: Migration of HVM domU did not use superpages on destination dom0 - bsc#1002573: Optimized LVM functions in block-dmmd block-dmmd