Security update for xen (important)

xen was updated to version 4.7.1 to fix 17 security issues.

These security issues were fixed:

• CVE-2016-9637: ioport array overflow allowing a malicious guest
  administrator can escalate their privilege to that of the host
  (bsc#1011652).
• CVE-2016-9386: x86 null segments were not always treated as unusable
  allowing an unprivileged guest user program to elevate its privilege to
  that of the guest operating system. Exploit of this vulnerability is
  easy on Intel and more complicated on AMD (bsc#1009100).
• CVE-2016-9382: x86 task switch to VM86 mode was mis-handled, allowing a
  unprivileged guest process to escalate its privilege to that of the
  guest operating system on AMD hardware. On Intel hardware a malicious
  unprivileged guest process can crash the guest (bsc#1009103).
• CVE-2016-9385: x86 segment base write emulation lacked canonical address
  checks, allowing a malicious guest administrator to crash the host
  (bsc#1009104).
• CVE-2016-9384: Guest 32-bit ELF symbol table load leaking host data to
  unprivileged guest users (bsc#1009105).
• CVE-2016-9383: The x86 64-bit bit test instruction emulation was broken,
  allowing a guest to modify arbitrary memory leading to arbitray code
  execution (bsc#1009107).
• CVE-2016-9377: x86 software interrupt injection was mis-handled,
  allowing an unprivileged guest user to crash the guest (bsc#1009108).
• CVE-2016-9378: x86 software interrupt injection was mis-handled,
  allowing an unprivileged guest user to crash the guest (bsc#1009108)
• CVE-2016-9381: Improper processing of shared rings allowing guest
  administrators take over the qemu process, elevating their privilege to
  that of the qemu process (bsc#1009109).
• CVE-2016-9379: Delimiter injection vulnerabilities in pygrub allowed
  guest administrators to obtain the contents of sensitive host files or
  delete the files (bsc#1009111).
• CVE-2016-9380: Delimiter injection vulnerabilities in pygrub allowed
  guest administrators to obtain the contents of sensitive host files or
  delete the files (bsc#1009111).
• CVE-2016-7777: Xen did not properly honor CR0.TS and CR0.EM, which
  allowed local x86 HVM guest OS users to read or modify FPU, MMX, or XMM
  register state information belonging to arbitrary tasks on the guest by
  modifying an instruction while the hypervisor is preparing to emulate it
  (bsc#1000106).
• CVE-2016-8910: The rtl8139_cplus_transmit function in hw/net/rtl8139.c
  allowed local guest OS administrators to cause a denial of service
  (infinite loop and CPU consumption) by leveraging failure to limit the
  ring descriptor count (bsc#1007157).
• CVE-2016-8667: The rc4030_write function in hw/dma/rc4030.c in allowed
  local guest OS administrators to cause a denial of service
  (divide-by-zero error and QEMU process crash) via a large interval timer
  reload value (bsc#1005004).
• CVE-2016-8669: The serial_update_parameters function in hw/char/serial.c
  allowed local guest OS administrators to cause a denial of service
  (divide-by-zero error and QEMU process crash) via vectors involving a
  value of divider greater than baud base (bsc#1005005).
• CVE-2016-7908: The mcf_fec_do_tx function in hw/net/mcf_fec.c did not
  properly limit the buffer descriptor count when transmitting packets,
  which allowed local guest OS administrators to cause a denial of service
  (infinite loop and QEMU process crash) via vectors involving a buffer
  descriptor with a length of 0 and crafted values in bd.flags
  (bsc#1003030).
• CVE-2016-7909: The pcnet_rdra_addr function in hw/net/pcnet.c allowed
  local guest OS administrators to cause a denial of service (infinite
  loop and QEMU process crash) by setting the (1) receive or (2) transmit
  descriptor ring length to 0 (bsc#1003032).

These non-security issues were fixed:

• bsc#1004981: Xen RPM didn’t contain debug hypervisor for EFI systems
• bsc#1007941: Xen tools limited the number of vcpus to 256