CVE-2017-7518 Kernel: KVM: debug exception via syscall emulation

[P J P <ppandit () redhat com>]

   Hello,

Linux kernel built with the Kernel-based Virtual Machine(CONFIG_KVM) support 
is vulnerable to an incorrect debug exception(#DB) error. It could occur while 
emulating a syscall instruction.

A user/process inside guest could use this flaw to potentially escalate their 
privileges inside guest.

Note: Linux guests are not affected.

Upstream patch:
---------------
  -> https://www.spinics.net/lists/kvm/msg151817.html

Reference:
----------
  -> https://bugzilla.redhat.com/show_bug.cgi?id=1464473
  -> https://www.spinics.net/lists/kvm/msg151819.html
  -> https://xenbits.xen.org/xsa/advisory-204.html

'CVE-2017-7518' has been assigned to this issue by Red Hat Inc.

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F