consulting agreement issue?

Currently I am holding a H1B visa and working in the university with the funds from a company. Recently the company required me to sign the consulting agreement with them directly for the total sake of the company without any benifits for me, it is a very severe agreement related to all the things I may involve. Since I signed the agreement related to my work with the univeristy already (I am a postdoc of the univeristy with H1B visa), I want to know if it is legal for me to sign any kinds of agreements with the company?

Any one has the similar experience? Please let me know.
Thanks a lot.