Security update for xen (important)

This update for xen fixes the following issues:

These security issues were fixed:

• CVE-2017-7228: Broken check in memory_exchange() permited PV guest
  breakout (bsc#1030442).
• XSA-206: Unprivileged guests issuing writes to xenstore were able to
  stall progress of the control domain or driver domain, possibly leading
  to a Denial of Service (DoS) of the entire host (bsc#1030144).
• CVE-2017-6505: The ohci_service_ed_list function in hw/usb/hcd-ohci.c
  allowed local guest OS users to cause a denial of service (infinite
  loop) via vectors involving the number of link endpoint list descriptors
  (bsc#1028235).
• CVE-2017-6414: Memory leak in the vcard_apdu_new function in card_7816.c
  in libcacard allowed local guest OS users to cause a denial of service
  (host memory consumption) via vectors related to allocating a new APDU
  object (bsc#1027570).
• CVE-2017-2633: The VNC display driver support was vulnerable to an
  out-of-bounds memory access issue. A user/process inside guest could use
  this flaw to cause DoS (bsc#1026636).
• CVE-2016-9603: A privileged user within the guest VM can cause a heap
  overflow in the device model process, potentially escalating their
  privileges to that of the device model process (bsc#1028655).

These non-security issues were fixed:

• bsc#1022555: Timeout in "execution of /etc/xen/scripts/block add"
• bsc#1029827: Forward port xenstored