Modern military activities involve significant data sharing across security domains. We present the concepts and architecture of a Mission-oriented Multi-domain Multi-level security Graphics Server (M3GS) in the environment of GIG 2.0 and cloud computing. M3GS aims at providing information support for a dynamic team collaborating on a mission of warfighting, intelligence, anti-terrorism, or rescue and disaster relief; information providers input data (with various security labels in different security domains) into M3GS, and through M3GS, those data are displayed with proper widgets on the screens of information clients permitted to access; what data can flow to which screen is governed by security policies. While the Bell-LaPadula model is used to enforce traditional mandatory access control, a new challenge is that the data shared have different owners from different security domains, and are subject to their own security policies. We address this problem by using dynamic provenance-dependent attribute-based policies.