Re: History of byte addressing

Message-ID	<4DF39E44.8070705@SPAM.comp-arch.net> (permalink)
Date	2011-06-11 09:56 -0700
From	"Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net>
Organization	comp-arch.net
Newsgroups	comp.arch
Subject	Re: History of byte addressing
References	(9 earlier) <isht8n$m84$1@dont-email.me> <Nd8Hp.394$tp.382@newsfe06.iad> <isj3ub$44n$1@dont-email.me> <4DEDBA2F.6010503@SPAM.comp-arch.net> <islfn2$h6g$1@dont-email.me>

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On 6/7/2011 8:22 AM, Stephen Fuld wrote:
> On 6/6/2011 10:42 PM, Andy "Krazy" Glew wrote:
>> On 6/6/2011 10:49 AM, Stephen Fuld wrote:
>
> snip
>
>>> Not having user access to write "assembler" level code is integral to
>>> the security and integrity model. You see, there is no hardware "user
>>> mode" versus "Supervisor" or "Privileged" mode. Thus allowing user
>>> access to the low level stuff would allow him to compromise the system
>>> as he could over write the OS, other user's code, etc.
>>
>> And I believe that the problems with validating Burroughs' security
>> model were what led Virgil Gligor to make it a requirement that all
>> secure machines for US government use had to have at least
>> kernel/user privilege levels.
>
> While you know far more about this than I do, and you may very well be
> right about what the government did, that seems too simplistic. A
> minimal kernel/user privilege just prevents user mode programs from
> executing certain instructions. That is, it does not assure memory
> protection. For example, IBM's CICS (its major transaction system for
> S/370 and successors) had for a long time (and may still have) the
> "feature" that both the CICS monitor and all user written transactions
> were in a single address space. Thus a user written transaction program
> with a subscript gone awry could over write another user program, or
> even the CICS monitor. So for reasonable security, you need more than
> just user/kernel mode protection.
>
>
>> The problem with Burroughs' model is that you have to prove the compiler
>> and/or assembler correct.
>
> I am not sure about this. Isn't it sufficient to prove that the compiler
> (remember, no assembler!) doesn't emit the privileged instructions, and
> that the language doesn't support "dangerous" idioms, like pointer
> arithmetic, checks array bounds, etc? This seems much simpler than
> proving the compiler correct. As mentioned elsewhere in this thread,
> Burroughs has different versions of the compiler, one for the OS and one
> for users to use. Presumably the user compiler doesn't emit the
> privileged op codes.

I assume that you have at least the ability to divide memory into 
kernel-accessible-only and user-accessible regions, along with control 
of specific instructions.

---

Now, let's progress to supposition:   Let's imagine that you have 
separate user and OS versions of the compiler and assembler - and that 
you have not simply ifdeffed them.  And let's imagine that the user 
tools do not emit "privileged" instructions (however, remember that 
there is no privilege enforced at the hardware level). And that an 
"OS"library is linked to the "user" code.

At the very least you have  to make sure that the user tools do not have 
any bugs in indirect branches or other control flow.  Oh, yes, and 
buffer overflows. And...

I do not know exactly what bugs in the Burroughs systems resulted in 
Gligor's expression of a policy requirement for user/kernel.  Rumors 
abound that they were quite serious.  Perhaps a freedom of information 
inquiry may one day find out what they were.

---

For a while while Java was young, and the idea of cell phones running a 
pure Java environment was current, the notion of a purely software 
enforced JVM bassed security arose again.  It seems to have disappeared.

Thread

History of byte addressing John Levine <johnl@iecc.com> - 2011-06-02 19:36 +0000
  Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-02 20:38 +0100
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 08:05 -0700
  Re: History of byte addressing Alex McDonald <blog@rivadpm.com> - 2011-06-03 05:26 -0700
    Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-03 09:48 -0400
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 07:49 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-03 10:56 -0700
  Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-04 10:59 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-04 15:01 -0700
      Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-04 22:53 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:40 -0700
    Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-06-05 06:10 +0000
      Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-05 10:00 -0700
        Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-05 10:04 -0700
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:36 -0700
            Re: History of byte addressing "Paul A. Clayton" <paaronclayton@gmail.com> - 2011-06-05 11:00 -0700
              Re: History of byte addressing Morten Reistad <first@last.name> - 2011-06-05 21:42 +0200
                Re: History of byte addressing anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-06-06 17:03 +0000
                Re: History of byte addressing Andrew Reilly <areilly---@bigpond.net.au> - 2011-06-06 23:55 +0000
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:26 -0700
                Re: History of byte addressing Andrew Reilly <areilly---@bigpond.net.au> - 2011-06-07 05:08 +0000
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-07 03:26 -0700
                Re: History of byte addressing Roberto Waltman <usenet@rwaltman.com> - 2011-07-05 20:00 -0400
                Re: History of byte addressing jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-06 00:15 +0000
              Re: History of byte addressing George Neuner <gneuner2@comcast.net> - 2011-06-05 16:18 -0400
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:10 -0700
              Re: History of byte addressing torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-06-07 10:50 +0200
                Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:02 +0200
              Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 15:51 +0200
            Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-05 13:43 -0600
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:12 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-06 02:04 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-05 23:49 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-06 13:34 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-06 10:49 -0700
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-06 22:42 -0700
                Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-07 07:37 -0400
                Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-07 08:22 -0700
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-11 09:56 -0700
                Re: History of byte addressing EricP <ThatWouldBeTelling@thevillage.com> - 2011-06-11 14:59 -0400
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-11 18:52 -0600
                Re: History of byte addressing "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-12 12:40 -0700
                Re: History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-11 15:05 -0400
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 13:10 -0600
                Re: History of byte addressing George Neuner <gneuner2@comcast.net> - 2011-06-06 16:41 -0400
                Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:13 -0700
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 23:50 -0600
                Re: History of byte addressing Jim Haynes <jhaynes@alumni.uark.edu> - 2011-06-07 10:01 -0500
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-07 13:09 -0600
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-07 14:03 -0600
                Re: History of byte addressing Louis Krupp <lkrupp@nospam.indra.com.invalid> - 2011-06-06 05:16 -0600
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 10:44 -0700
        Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-06-06 05:00 +0000
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-05 22:11 -0700
            Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-06 08:00 +0100
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:16 -0700
            Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 01:01 -0700
              Re: History of byte addressing nmm1@cam.ac.uk - 2011-06-06 08:30 +0100
                Re: History of byte addressing Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-06 10:34 +0200
                Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 03:29 -0700
                Re: History of byte addressing Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-06 15:21 +0200
                Re: History of byte addressing Michael S <already5chosen@yahoo.com> - 2011-06-06 03:23 -0700
                Re: History of byte addressing MitchAlsup <MitchAlsup@aol.com> - 2011-06-07 08:01 -0700
                Re: alignment, was History of byte addressing John Levine <johnl@iecc.com> - 2011-06-06 18:33 +0000
                Re: alignment, was History of byte addressing nmm1@cam.ac.uk - 2011-06-06 19:30 +0100
                Re: alignment, was History of byte addressing Anne & Lynn Wheeler <lynn@garlic.com> - 2011-06-06 15:32 -0400
              Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-06 18:11 -0700
          Re: History of byte addressing Robert Myers <rbmyersusa@gmail.com> - 2011-06-06 06:48 -0700
            Re: History of byte addressing jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-03 16:13 +0000
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-03 09:10 -0700
  Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:23 +0200
    Re: History of byte addressing Stephen Fuld <SFuld@alumni.cmu.edu.invalid> - 2011-06-07 08:26 -0700
  Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:25 +0200
    Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:45 +0200
      Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:48 +0200
      Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 16:59 +0200
        Re: History of byte addressing "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-06-07 17:05 +0200
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-06-18 15:43 -0700
  Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 03:14 -0700
    Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 03:40 -0700
      Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 04:28 -0700
        Re: History of byte addressing nmm1@cam.ac.uk - 2011-07-04 13:38 +0100
          Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 06:47 -0700
            Re: History of byte addressing nmm1@cam.ac.uk - 2011-07-04 14:16 +0100
        Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:53 +0100
      Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:36 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 07:50 -0700
          Re: History of byte addressing John Levine <johnl@iecc.com> - 2011-07-04 19:46 +0000
            Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 15:29 -0700
              Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-05 00:02 +0100
      Re: History of byte addressing Bill Findlay <yaldnif.w@blueyonder.co.uk> - 2011-07-04 15:47 +0100
        Re: History of byte addressing Quadibloc <jsavard@ecn.ab.ca> - 2011-07-04 07:54 -0700

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