/usr/src/linux-headers-4.4.0-57-generic/samples is in linux-headers-4.4.0-57-generic 4.4.0-57.78.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/src/linux-headers-4.4.0-57-generic/../linux-headers-4.4.0-57/samples