Instead of delegating control over private data to single large corporations, in friend-to-friend (F2F) systems users take control over their data into their own hands and they communicate only with users whom they know. In this paper we propose a push-pull-clone model for trust-based collaborative editing with contract deployed over F2F network. People specify contracts when they share data to their friends. A log auditing protocol is used to detect user's misbehavior if they do not respect contracts after they received data. Users maintain locally trust values on other users and these values are adjusted according to auditing results. We evaluate proposed model by using PeerSim simulator and experiment results show the feasibility of our model.