(original) (raw)

At 11:07 PM 7/23/2006 +0100, David Hopwood wrote:
>Phillip J. Eby wrote:

Brett's securing_python.txt don't refer to or cite Zope in any way, but
rather relies on broad and unsupported assertions about what can or can't
be done with Python.  I hope he isn't doing the same in his thesis, as this

is rather like writing about one's new theory of how to have a worldwide
ball-kicking contest without making any reference as to how one's theory
compares with the World Cup.

I'm not saying Zope is better or worse.  I'm simply saying that in a
business context, a failure to compare and contrast a proposed "build"

solution to show how it would be better than a well-established available
"buy" solution would be called something like "lack of due diligence".  I
think in the academic context it might be called something like "failure to

cite", but the general idea is the same, i.e., not doing your homework.  :)

In other words, if the solution being proposed is better than what Zope
does, the appropriate thing in business is to show the reasons why, and the

appropriate thing in science is to state a hypothesis regarding the
differences, and then perform an experiment to either prove or disprove it.

>In any case, Zope's sandboxing is not capability-based.

You're right: you haven't done a review of it.  :)  If you had, you'd know

that one proxy plus one namechecker equals one capability.  In other words,
you could take the restricted interpreter, the proxy mechanism, and the
namechecker and leave most of the rest alone, and you'd have your

capability system.  Then you could focus more time and attention on the
parts of the problem that Zope *doesn't* solve, instead of reinventing the
ones that it already does.

Now, if Brett believes that changing the Python language is a *better* way

to implement capabilities than using proxies to implement them, then
great.  His paper should explain why, and (presumably) include experimental
results to show that they're either better or worse than Zope's approach

based on some criteria.  The same information is relevant to Python-Dev as
to what is an appropriate approach to support sandboxing in CPython.  What
are the advantages of a built-in approach versus an add-on approach?  Are

there interpreter facilities that could be added to shore up any awkward
aspects of Zope's approach?  (Whatever those might be.)

For example, one part of Zope's approach uses a custom compiler and custom

builtins in order to redefine how attribute access works in certain
cases.  Could these customizations be replaced with options built into the
Python compiler and interpreter?  What improvements would that result in?

Simply handwaving all of these questions away, however, with broad
assertions of superiority and without even attempting to compare the new
work to Zope's existing work is really not acceptable for academia OR
Python development.

For the record: I have no personal interest in Zope's security system.  I
didn't develop it and haven't had the need to use it, myself.  I once
reviewed some of the code and offered some minor suggestions, mainly
regarding performance improvement.  My only axe to grind in this matter is
what I've already stated: I think it would be crazy (in the "monumental
waste of resources" sense) to consider putting \*any\* sandboxing system into
CPython without tapping the Zope team's experiences.  For example: having
implemented such a system, what compiler or interpreter changes would've
made the job easier?

Meanwhile, what Brett does or doesn't put in his thesis is between him and
his advisor, but what gets put into Python shouldn't be based on ignoring
the existing field experience and state of the art.