/usr/lib/x86_64-linux-gnu/libibmad.so.5 is in libibmad5 1.3.12-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libibmad.so.5.5.0
/usr/lib/x86_64-linux-gnu/libibmad.so.5.5.0