Univention Corporate Server 4.3 erratum 562 (security)

This update addresses the following issues:
* Non-maskable interrupts triggerable by guests (xsa120) (CVE-2015-8553)
* Information Exposure through dmesg data from a "pages/cpu" printk call
  (CVE-2018-5995)
* Race condition in smp_task_timedout() and smp_task_done() in
  drivers/scsi/libsas/sas_expander.c leads to use-after-free (CVE-2018-20836)
* Use-after-free in __blk_drain_queue() function in block/blk-core.c
  (CVE-2018-20856)
* hw: Spectre SWAPGS gadget vulnerability (CVE-2019-1125)
* Denial of service vector through vfio DMA mappings (CVE-2019-3882)
* vhost_net: infinite loop while receiving packets leads to DoS
  (CVE-2019-3900)
* Null-pointer dereference in hci_uart_set_flow_control (CVE-2019-10207)
* net: weak IP ID generation leads to remote device tracking (CVE-2019-10638)
* net: using kernel space address bits to derive IP ID may potentially break
  KASLR (CVE-2019-10639)
* OOB writes in parse_hid_report_descriptor in drivers/input/tablet/gtco.c
  (CVE-2019-13631)
* Denial of service in arch/powerpc/kernel/signal_32.c and
  arch/powerpc/kernel/signal_64.c via sigreturn() system call
  (CVE-2019-13648)
* Integer overflow and OOB read in drivers/block/floppy.c (CVE-2019-14283)
* Denial of service in drivers/block/floppy.c by setup_format_params
  division-by-zero (CVE-2019-14284)