Renting an apartment and permesso di soggiorno

I have a question to which it seems like it is impossible to find and answer. I am starting my master program this September and looking for an apartment I will be living for at least a year. It seems like I found the one I like the most but now landlord requires permesso di soggiorno which I don't own yet. I will apply for it as soon as I come to Italy as a student. The landlord however claims that it is illegal to sign a contract to a person who doesn't have permesso. But then what are all the students who are not staying in the student accommodation supposed to do? I need to have a place a live in from September but I cannot get it because I dont have permesso, but I only can apply for permesso when I come in September. What is that vicious circle and how can this be resolved?

It is not true, you only need Codice Fiscale and passport number.