Towards Remote Attestation of Security Policies

In the environment which supports access control, the behaviors of an application not only depend on the logic of its code, also depend on the security policy enforced in the system. So, while verifying the trustworthy of a remote application, related security policy should be verified besides the application itself. However, the security policies to restrict different applications are commonly mixed as an aggregation, and the alteration of any statement will influence the final binary file of policy, which makes the integrity measurement in mutability, so it´s difficult to verify the integrity of security policies by existing methods which search the measurement in a standard measurement library. For this reason, this paper presents a method for remote attestation of security policy, we firstly divide the security policy into smaller low-coupling modules, and then verify the properties of security policy based on the set of all modules´ measurement in the process of remote attestation, thus we can effectively reduce the size of standard measurement library, and this makes remote attestation of security policy more easily in the complex distributed environment. In addition, to validate the feasibility of our method, we design and implement some key parts of remote attestation with the policy of SELinux, then analyze the procedure of building trust chain in it.