From: Ray Cromwell <rjc@clark.net>
Date: Mon, 9 Oct 95 23:16:10 PDT
To: perry@piermont.com
Subject: Re: java security concerns
In-Reply-To: <199510100547.BAA00623@jekyll.piermont.com>
Message-ID: <199510100615.CAA00389@clark.net>
MIME-Version: 1.0
Content-Type: text/plain


> 
> 
> Aleph One writes:
> > Iam sorry I dont fallow your logic. You find Postscript files
> > save because you can set up the interpreter to ignore Postscript commands
> > to write to files and execute programms (check the CIAC alerts), yet
> > you find Java applets insecure even when you can set up the same
> > restrictions and more under HotJava (and hopefully Netscape)?
> > That does not compute.
> 
> Yes it does.
> 
> To (perhaps over)simplify my point, the Java interpreter cannot be
> stripped of all i/o capabilities and still remain useful. I can
> physically remove all the "dangerous" calls from a Postscript
> interpreter and still have it be useful.

  There is a large class of Java apps that need no file i/o capability.
99% of all Java apps on the web right now don't save any persistent state 
information. I couldn't find any Java apps on the Java page that
used file i/o.  If by "stripped of i/o capabilities", you mean
that the Java interpreter is not permitted to ever call open/read/write,
not even to read in files it needs like config/preferences files or 
dynamically linked libraries, I'd say that's absurd. There's not many 
things that can be stripped of such capabilities, including postscript
interpreters, except for those which run the interpreter straight
out of rom. But it's still unclear whether those lack "i/o capabilities",
given that some postscript printers run operating systems and tcp/ip
stacks, and it is feasible for the interpreter to crash and execute
an i/o call. However, the Java interpreter can certainly be compiled
to not allow Java applets to ever do disk or network i/o. It doesn't
even take a recompile. Just delete the file i/o class.  

  It is certainly possible, to within a high degree of confidence,
to "box in" all i/o calls, especially if they are run in a separate
process. 

-Ray