From: iang@cs.berkeley.edu (Ian Goldberg)
Date: Fri, 9 Aug 1996 10:49:22 +0800
To: cypherpunks@toad.com
Subject: Re: Fixes to loop.c et al. for DES,IDEA,stego now done
In-Reply-To: <199608062350.QAA10693@abraham.cs.berkeley.edu>
Message-ID: <4ue0dk$2g4@abraham.cs.berkeley.edu>
MIME-Version: 1.0
Content-Type: text/plain


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In article <Pine.LNX.3.91.890918054255.204A-100000@HellSpawn>,
Damien Lucifer  <root@hellspawn.Berkeley.EDU> wrote:
>
>
>On Tue, 6 Aug 1996, Ian Goldberg wrote:
>> This directory contains patches to the Linux kernel to enable encryption and
>> steganography of filesystems. Encryption allows you to have a scrambled
>> partition or file that, with the proper pass phrase, you can mount, just
>> like a normal filesystem. Steganography allows you to hide a filesystem in
>> the low bits of, say, an audio file. You can even combine these two to hide
>> a scrambled filesystem in the low bits of an audio file (see the example,
>> below).
>
>
<snip>
>So the question on my mind, is can the loop device(s) be 
>multi-threaded? I decided to be clever one evening and moved all my home 
>directories to cfs directories.. unfortunatly when two instances of the 
>same user try to hit their CFS home directory at once, the whole machine 
>goes flubflub and and needs to be rebooted. Single threading didnt seem 
>like such a terrible thing when I installed cfs, but lately its become 
>rather restrictive and ugly to deal with. Please tell me theres a better 
>way. :) 

Well, unlike CFS, loop.c is part of the Linux kernel, which is single-threaded,
so I guess loop.c is also single-threaded.  However, I took care that deadlocks
be avoided (mounting a loop device as another loop device (for example,
hiding an encrypted filesystem as stego) caused me to think a bit, but I'm
fairly confident that it works now).

   - Ian

[For those that missed it, the URL is

ftp://ftp.csua.berkeley.edu/pub/cypherpunks/filesystems/linux/index.html

mirror site:

ftp://csclub.uwaterloo.ca/pub/linux-stego/index.html
]

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