From 00DIST:

Distribution Restrictions
=========================

Lsof may be used and distributed freely, subject to these limitations:

1. Neither the author nor Purdue University is responsible for
   any consequences of the use of this software.

2. The origin of this software must not be misrepresented, either
   by explicit claim or by omission.  Credit to the author and
   Purdue University must appear in documentation and sources.

3. Altered versions must be plainly marked as such, and must not
   be misrepresented as being the original software.

4. This notice may not be removed from or altered in the lsof source
   files.

Warranty
========

Lsof is provided as-is without any warranty of any kind, either
expressed or implied, including, but not limited to, the implied
warranties of merchantability and fitness for a particular purpose.
The entire risk as to the quality and performance of lsof is with
you.  Should lsof prove defective, you assume the cost of all
necessary servicing, repair, or correction.