/usr/lib/x86_64-linux-gnu/libgetfem.so is in libgetfem++-dev 4.2.1~beta1~svn4635~dfsg-3+b1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libgetfem.so.4.0.3
/usr/lib/x86_64-linux-gnu/libgetfem.so.4.0.3