UPSTREAM: bpf: Explicitly memset some bpf info structures declared on the stack

Trying to initialize a structure with "= {};" will not always clean out
all padding locations in a structure. So be explicit and call memset to
initialize everything for a number of bpf information structures that
are then copied from userspace, sometimes from smaller memory locations
than the size of the structure.

Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200320162258.GA794295@kroah.com


(cherry picked from commit 269efb7fc478563a7e7b22590d8076823f4ac82a)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I52a2cab20aa310085ec104bd811ac4f2b83657b6