Re: Avoiding memory access vulnerabilities

From	anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups	comp.lang.forth
Subject	Re: Avoiding memory access vulnerabilities
Date	2016-02-28 14:21 +0000
Organization	Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID	<2016Feb28.152154@mips.complang.tuwien.ac.at> (permalink)
References	<2016Feb26.143842@mips.complang.tuwien.ac.at> <naskf0$tts$1@dont-email.me> <2016Feb27.180447@mips.complang.tuwien.ac.at> <nasljb$8ms$1@dont-email.me>

Show all headers | View raw

Ron Aaron <rambamist@gmail.com> writes:
>
>
>On 27/02/2016 19:04, Anton Ertl wrote:
>> Ron Aaron <rambamist@gmail.com> writes:
>>> The user is never* given direct access to memory
>> 
>> That is actually more or less the idea I explored in my posting,
>> except that I allow the programmer to perform classic Forth memory
>> accesses in INSECURE code, and there is no effort to prevent the
>> programmer from intentionally subverting the SECURE regime.
>
>So in that case, what exactly is meant by 'SECURE'?

It is an indication from the programmer to the system that this part
of the code does not use memory access words with arbitrary addresses.

What this means is that, if the INSECURE part (plus foreign functions)
of the code does not contain any way to subvert the SECURE regime, the
program is safe from stuff like buffer overflows.  That means that you
only need to inspect the INSECURE part (plus any foreign functions)
carefully for these kinds of problems, not the whole program.

>One other item which doesn't apply I think to ANS: in 8th, strings are
>UTF-8, and we enforce validity to prevent certain kinds of attacks based
>on invalid UTF-8.  In our case, an invalid string (e.g. caused by the
>user converting a buffer into a string) will throw an exception.  That's
>somewhat related to the FFI issue as well.

UTF-8 is also relevant for Forth (in particular Forth-2012), and
validity checking is something that we should have standard support
for, but are still missing; if that is not done, there may be a
vulnerability, but not a memory access vulnerability, so that's
outside the scope of the present discussion.

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2015: http://www.rigwit.co.uk/EuroForth2015/

Thread

Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-26 13:38 +0000
  Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-02-26 16:05 +0000
  Re: Avoiding memory access vulnerabilities Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-02-26 17:18 -0500
    Re: Avoiding memory access vulnerabilities Raimond Dragomir <raimond.dragomir@gmail.com> - 2016-02-26 22:53 -0800
    Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 07:15 +0000
      Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-02-27 04:54 -0600
      Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-02-27 14:27 +0000
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 15:31 +0000
          Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-01 16:30 +0000
            Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-02 10:04 +0000
              Re: Avoiding memory access vulnerabilities Doug Hoffman <glidedog@gmail.com> - 2016-03-02 08:41 -0500
              Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-02 23:22 +0000
                Re: Avoiding memory access vulnerabilities humptydumpty <ouatubi@gmail.com> - 2016-03-02 22:57 -0800
                Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-03 13:50 +0000
                Re: Avoiding memory access vulnerabilities Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-04 21:01 +0000
                Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-06 10:55 +0000
      Re: Avoiding memory access vulnerabilities Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-02-27 11:31 -0500
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 17:14 +0000
  Re: Avoiding memory access vulnerabilities Ron Aaron <rambamist@gmail.com> - 2016-02-27 18:59 +0200
    Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-27 17:04 +0000
      Re: Avoiding memory access vulnerabilities Ron Aaron <rambamist@gmail.com> - 2016-02-27 19:18 +0200
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-02-28 14:21 +0000
  Re: Avoiding memory access vulnerabilities "Elizabeth D. Rather" <erather@forth.com> - 2016-03-02 21:18 -1000
    Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-03 10:23 +0000
      Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-03 14:22 +0000
    Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-03 04:53 -0600
      Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-03 13:15 +0000
        Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-04 04:34 -0600
          Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-04 04:56 -0600
            Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-04 12:07 +0000
              Re: Avoiding memory access vulnerabilities Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-03-04 09:48 -0600
              Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-04 17:11 +0000
          Re: Avoiding memory access vulnerabilities Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-04 11:55 +0000
    Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-03 11:33 +0000
      Re: Avoiding memory access vulnerabilities Rod Pemberton <NoHaveNotOne@bcczxcfre.cmm> - 2016-03-04 20:55 -0500
    Re: Avoiding memory access vulnerabilities Mark Wills <markwills1970@gmail.com> - 2016-03-05 02:55 -0800
      Re: Avoiding memory access vulnerabilities "Elizabeth D. Rather" <erather@forth.com> - 2016-03-10 22:39 -0800
        Re: Avoiding memory access vulnerabilities anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-12 12:44 +0000

csiph-web