Re: some capability queries

On 2015 Jan 7, at 19:55 , Jithu Joseph <[email protected]> wrote:

> We have been trying to understand this concept of capability based
> security for the past few months. It looks like we still have a few
> fundamental queries - so I though of reaching out to this group -to
> see if our understanding is correct and whether we are asking the
> right questions
> 
.....
> 3. From what I understood in KeyKOS (on which EROS is based), the
> component called reference monitor, is responsible for validating all
> the interaction between compartments . It is where the appropriate
> "sharing" rules and policies are defined, and thus where the
> discretionary and mandatory rules  are checked and enforced.

The sharing rules are defined in user mode programs whose job it is to make application specific policies and they do so by moving capabilities about.
I believe that security policies should be explicit in the design of the application.
The kernel includes the reference monitor and enforces capability discipline.

> 5. Can we express anything (policies) more / differently using
> capability systems than with other systems/ access control models ?

See this for just a few:
http://cap-lore.com/CapTheory/tddCap.html