CVE-2017-5753
CVE-2017-5715

This adds a generic memory barrier before LD_IMM_DW and
LDX_MEM_B/H/W/DW eBPF instructions during eBPF program
execution in order to prevent speculative execution on out
of bound BFP_MAP array indexes. This way an arbitary kernel
memory is not exposed through side channel attacks.

For more details, please see this Google Project Zero report: tbd
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
(cherry picked from commit 69cfcc33d4ec282f14e47f1705bf45117e557b69)
Signed-off-by: Andy Whitcroft <apw@canonical.com>