> Some people at MITRE have been working on similar policy analysis tools.

Yes, MITRE is developing tools for policy analysis.

We intend on developing functions to do the following first:

1. List the process transitions for type "T"
2. List the file transitions for type "T"
3. List the type enforcement entries for type "T"
4. List all roles for type "T"
5. List all roles to which role "R" can transition
6. List all roles that can transition to role "R"
7. List all types with permission "P" in class "C" to type "T"
8. List all types with attribute "A".
9. List contexts with attribute "A".
10. Which policy rule is blocking a particular permission "P" between two contexts "C1" and "C2"?
11. Trace how a process in context C1 gains access (as a set of one or more permissions) to an object with context C2.
12. Which file does rule "R" come from? (And where in that file is it?)
13. List all equivalent types in the policy. Already done in checkpolicy.c, but may need refinement.
14. Show the difference(s) between type "T1" and "T2" in the policy.
15. Identify types that are within some "delta" of each other in the policy. Useful for identifying possibly redundant types.
16. List all process types reachable from type "T" and show the path to them.
17. List all object types to which data of type "T" can flow and show the path to them.
18. Graph (or describe) all paths by which data might flow from type "T1" to type "T2"

For testing purposes, we implemented some of these functions (1-6, 7 under construction) as small, individual programs borrowing code from checkpolicy sources. Eventually we would like to combine these programs into one tool that provides policy analysis capabilities. Because we see the above list as growing and want it to be as flexible as possible to be able to handle tailored requests from the policy administrator, we plan on implementing an interactive query language front-end to this tool, as Steve suggested.

Steve also suggested incorporating these functions into checkpolicy. With the interactive query front-end, this would become the policy analysis tool. However, our take on checkpolicy is that it is intended to compile policies and to assist in debugging specific to security identifiers. We are thinking it might be cleaner to keep policy analysis tools separate from a policy compiling/debugging tool. Though perhaps we have the wrong take on checkpolicy. More thoughts on this?

The problem with building a separate tool is that both tools will share some of the same code. Does it makes sense to pull out commonly-used code in checkpolicy, specifically the code that reads in the binary and text versions of the policy into data structures, and put this code into some sort of library? It seems this code may be useful to future applications, and it would be easier to maintain and more accessible if it was in a library.

Jon Crowley
MITRE Corporation

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