Path: utzoo!utgpu!watserv1!watmath!att!rutgers!ucsd!helios.ee.lbl.gov!lbl.gov!jnmoyne
From: jnmoyne@lbl.gov (Jean-Noel MOYNE)
Newsgroups: comp.sys.amiga
Subject: Re: Security on AUX: remote shells
Message-ID: <6181@helios.ee.lbl.gov>
Date: 14 Jul 90 00:09:18 GMT
References: <1858@ns-mx.uiowa.edu>
Sender: usenet@helios.ee.lbl.gov
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Organization: Lawrence Berkeley Laboratory
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X-Local-Date: 13 Jul 90 17:09:18 PDT


   Oh, men you're going into deep yogurt !! (-: 

   Doing a classic login/password on AUX: to give access to a SHELL is 
realy easy. But just after, if you're still aware of security .... 

   The problem is that Amigados is a good multitasking OS, but definitely 
a single-user OS !!!  There is absolutely nothing like security in 
Amigados. The problem is not the Handler, AUX: is fine and all right, the 
problem is the SHELL and the DOS. First of all it's very easy to make a 
requester pop-up by a CLI command, and once the requester is here you can 
say goodbye to your SHELL, to your user, and to your tty (and it's realy 
hard for you, since you only have one tty !!!). I mean: just type "cd 
XISIIDKLSKLM:" on your remote shell and if you don't have the volume 
XISIIDKLSKLM mounted .. your server is out. (try to click cancel or to 
send left-amiga-v from a terminal) (-: 

    But that's easy to fix, just set the pr_Window pointer to -1L in your 
process struct (just do a FinkTask(0L) to find the struct, and every 
system requester will be canceled automatiquely. (you can use a DP prog 
called KillReq for that or just program 4 lines of C)

    Of course, it doesn't prevent you from programs opening a Window .. 
and waiting the Input from this Window. The cure: (yeah, call Rambo now ! 
(-: ) Patch OpenWindow with a big strike of SetFunction between the eyes, 
so that it returns NULL each time. And pray for the programs to be well 
written and not be too confuse by the fact he couldn't open the window.

  So, now you have a shell which is not too easy to mess up. Then you go 
back to the security. You might want to have protected directories or 
files (which come back to: having users and file protection). How to do 
that ? The first solution you see is: make my onw shell (like c-shell and 
all the others), maybe start from the source of a DP shell, and customize 
it for my needs, and of course make the people using this shell only 
(easy). You have a lot of work on this one, and you might still be able to 
do something valuable, for example using some of the unused space in the 
FileInfo struct (such as a part of the name which is 103 bytes long if I 
remember me right), or you can use the comment field to put you stuff (and 
not let the users have access to a command that modify or list the comment 
(like list ). 

     But if there is an upload facility, or a programming facility (C 
compiler or other) in your system .. then you're not sure .. because with 
a modified SHELL, you can control the user, but not the programs he is 
using, and the programs have the same power to access every single file in 
the system (exept if the file is locked which is not a solution).


      No, the only valuable solution is: re-do Amigados, so that it is 
multi-user !!! Not kidding, that's the best way !! 

     But let Commodore do that for us ... By the way wouldn't it be a nice 
idea Mr Commodore ?? You're system is so nicely multitasking that you can 
let it becomme multi-users just by typing "newshell aux:" ... it has gone 
too fast for the old Tripos project .. 

    JNM