Re: WWW-safe Forth?

Newsgroups	comp.lang.forth
Date	2013-07-06 14:01 -0700
References	<kr76h9$dqd$1@odin.sdf-eu.org> <0897f137-9711-4eb8-b43b-41f99bc07f11@googlegroups.com> <7x1u7b8oig.fsf@ruckus.brouhaha.com>
Message-ID	<e2b002a6-8fa6-41b0-9e8d-d0a66305209f@googlegroups.com> (permalink)
Subject	Re: WWW-safe Forth?
From	Howerd <howerdo@yahoo.co.uk>

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On Saturday, July 6, 2013 9:41:27 PM UTC+2, Paul Rubin wrote:
> Howerd <how....@yahoo.co.uk> writes:
> 
> > I would say that it is very easy to create a safe Forth - you need to
> 
> > do four things : ...
> 
> > Am I missing something here? Because this sounds so much simpler 
> 
> 
> 
> You have to be extremely careful to make sure there are no leaks.
> 
> History has shown that people always underestimate how hard that is.
> 
> It's better to start with no capabilities at all, then carefully add
> 
> capabilities that are precisely constrained, than to start with
> 
> something wide open and then try to plug its holes.
> 
> 
> 
> Another thing not mentioned, you also have to control resource
> 
> consumption by the user scripts.  
> 
> 
> 
> I may have mentioned this but I think I'd consider a Retroforth
> 
> approach, where you have a virtual machine which you can then modify to
> 
> do resource checks after every simulated instruction, rather than a
> 
> traditional threaded Forth.

Hi Paul,

> It's better to start with no capabilities at all
The idea of a sealed vocabulary is that you specify only the words that you want in your safe list.

> than to start with
> something wide open and then try to plug its holes.
There is nothing "wide open" about a sealed vocabulary - it only contains words that you put there yourself.

> you also have to control resource
> consumption by the user scripts
If you have resources that can be consumed, clearly you must take care that these resources are not exhausted. Are you thinking of a heap here? If you need a heap you must create your own - don't just give access to malloc.

It has been common practise in Forth for a long time to provide a user interface through a sealed vocabulary. If you include functionality that can break the system in this vocabulary you will get what you deserve.

I still don't see why this is difficult...

Best regards,
Howerd

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Thread

WWW-safe Forth? papa@sdf.lNoOnSePsAtMar.org (David Meyer) - 2013-07-05 19:24 +0000
  Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-05 13:37 -0700
    Re: WWW-safe Forth? papa@sdf.lNoOnSePsAtMar.org (David Meyer) - 2013-07-05 21:17 +0000
      Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-05 15:22 -0700
        Re: WWW-safe Forth? papa@sdf.lNoOnSePsAtMar.org (David Meyer) - 2013-07-06 01:56 +0000
      Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-06 14:42 +0200
        Re: WWW-safe Forth? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-06 07:56 -0500
          Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-07 01:11 +0200
            Re: WWW-safe Forth? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-07 02:44 -0500
              Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-07 10:28 +0000
        Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-06 13:42 +0000
          Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-07 01:40 +0200
  Re: WWW-safe Forth? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-07-05 20:20 +0000
  Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-06 12:41 -0400
  Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-06 12:03 -0700
    Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-06 12:41 -0700
      Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-06 14:01 -0700
        Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-06 14:26 -0700
          Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-06 12:32 -1000
            Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-06 19:58 -0700
              Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-06 18:14 -1000
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-06 21:51 -0700
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-06 21:01 -1000
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 00:36 -0700
              Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-07 01:25 -0700
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 01:56 -0700
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-07 08:34 -1000
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-07 07:08 -0400
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-07 08:41 -1000
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 12:59 -0700
                Re: WWW-safe Forth? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-07-07 20:18 +0000
                Re: WWW-safe Forth? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-07-09 01:09 +0000
                Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-08 00:09 +0200
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 18:15 -0700
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-07 17:22 -1000
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-07 17:20 -1000
                Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-07 13:13 -0700
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 14:02 -0700
                Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-08 01:25 +0200
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 18:26 -0700
                Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-09 19:21 +0200
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-10 01:55 -0700
                Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-10 23:51 +0200
                Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-07 21:10 -0700
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 22:03 -0700
                Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-07 22:27 -0700
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-08 00:30 -0700
                Re: WWW-safe Forth? Hannu Vuolasaho <hannu.vuolasaho@nospam.tut.fi.invalid> - 2013-07-08 13:08 +0000
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-08 09:18 -0400
                Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-08 07:02 -0700
                Re: WWW-safe Forth? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-08 09:46 -0500
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-08 11:04 -0700
                Re: WWW-safe Forth? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-08 12:49 -0500
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-08 11:26 -0700
                Re: WWW-safe Forth? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-08 16:28 -0500
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-08 11:15 -1000
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-09 17:09 -0400
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-09 12:02 -1000
                Re: WWW-safe Forth? Hans Bezemer <the.beez.speaks@gmail.com> - 2013-07-10 23:52 +0200
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-12 03:04 -0400
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-12 03:31 -0400
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-11 23:03 -1000
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-14 18:15 -0400
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-14 13:50 -1000
                Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-15 14:12 +0000
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-15 10:22 -0700
                Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-15 17:07 +0000
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-17 01:12 -0700
                Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-17 09:43 +0000
                Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-17 15:04 +0200
                Re: WWW-safe Forth? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-07-17 13:50 +0000
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-15 07:57 -1000
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-15 22:45 -0400
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-15 18:21 -1000
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-15 07:52 -1000
                Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-16 16:15 +0000
                Re: WWW-safe Forth? "Elizabeth D. Rather" <erather@forth.com> - 2013-07-16 08:17 -1000
                Re: WWW-safe Forth? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-07-17 09:33 +0000
                Re: WWW-safe Forth? "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-07-15 22:40 -0400
                Re: WWW-safe Forth? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-07-10 03:26 -0500
              Re: WWW-safe Forth? Howerd <howerdo@yahoo.co.uk> - 2013-07-07 01:46 -0700
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 02:39 -0700
                Re: WWW-safe Forth? AKK <akk@nospam.org> - 2013-07-07 11:56 +0200
                Re: WWW-safe Forth? Paul Rubin <no.email@nospam.invalid> - 2013-07-07 03:20 -0700
      Re: WWW-safe Forth? Bernd Paysan <bernd.paysan@gmx.de> - 2013-07-07 01:21 +0200
  Re: WWW-safe Forth? Hans Bezemer <the.beez.speaks@gmail.com> - 2013-07-09 23:22 +0200

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