Re: Specification for Trusted PLs?

On Fri, May 21, 2010 at 12:22 PM, David Fetter <david@fetter.org> wrote:
> On Fri, May 21, 2010 at 11:57:33AM -0400, Magnus Hagander wrote:
>> On Fri, May 21, 2010 at 11:55 AM, Josh Berkus <josh@agliodbs.com> wrote:
>> > So, here's a working definition:
>> >
>> > 1) cannot directly read or write files on the server.
>> > 2) cannot bind network ports
>>
>> To make that more covering, don't yu really need something like
>> "cannot communicate with outside processes"?
>
> These need to be testable conditions, and new tests need to get added
> any time we find that we've missed something.  Making this concept
> fuzzier is exactly the wrong direction to go.

Well, the best way to define what a trusted language can do is to
define a *whitelist* of what it can do, not a blacklist of what it
can't do. That's the only way to get a complete definition. It's then
up to the implementation step to figure out how to represent that in
the form of tests.

-- Magnus HaganderMe: http://www.hagander.net/Work: http://www.redpill-linpro.com/