Sometime ago, I did a challenging project for a client as a freelancer, and he uses my work as core of the software he sells. Basically my work is the main feature of that software, and he just ship it as part of his Software and make profit from it. I've been still working with that client on follow up projects.
Now another client approached me and he wants to buys the same work I did for the another client. I guess he is probably a competitor of the first client.
Regarding contract with first client, we have none. We never discussed about ownership of code, and all payment/work is done in good faith so far.
If it matters, both these client are remote and from a different continent than me.
So my questions are:
A) Do I legally own the work or client? Can I legally sell it to somebody else too?
B) What about moral reasons? Is it moral to sell it to their competitors.
C) Any advice in general on how I should approach this situation.