/usr/lib/x86_64-linux-gnu/libffi.so.6 is in libffi6 3.2.1-8.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libffi.so.6.0.4
/usr/lib/x86_64-linux-gnu/libffi.so.6.0.4