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Now, of course the initial RAM disk image is not on the encrypted
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root file system, so anyone who had physical access could take the
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Mandos client computer offline and read the disk with their own
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tools to get the authentication keys used by a client. *But*, by
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then the Mandos server should notice that the original server has
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been offline for too long, and will no longer give out the encrypted
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key. The timing here is the only real weak point, and the method,
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frequency and timeout of the server’s checking can be adjusted to
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any desired level of paranoia
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server offline and read the disk with their own tools to get the
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authentication keys used by a client. *But*, by then the Mandos
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server should notice that the original server has been offline for
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too long, and will no longer give out the encrypted key. The timing
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here is the only real weak point, and the method, frequency and
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timeout of the server’s checking can be adjusted to any desired
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(The encrypted keys on the Mandos server is on its normal file
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system, so those are safe, provided the root file system of *that*
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to do. An attacker would have to physically disassemble the client
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computer, extract the key from the initial RAM disk image, and then
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connect to a *still online* Mandos server to get the encrypted key,
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and do all this *before* the Mandos server timeout kicks in and the
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Mandos server refuses to give out the key to anyone.
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all *before* the Mandos server timeout kicks in and the Mandos
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server refuses to give out the key to anyone.
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Now, as the typical procedure seems to be to barge in and turn off
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and grab *all* computers, to maybe look at them months later, this
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is not likely. If someone does that, the whole system *will* lock
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Now, as the typical SOP seems to be to barge in and turn off and
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grab *all* computers, to maybe look at them months later, this is
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not likely. If someone does that, the whole system *will* lock
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itself up completely, since Mandos servers are no longer running.
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For sophisticated attackers who *could* do the clever thing, *and*
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on your door and the sudden absence of all the servers in your
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server room. Which it does nicely.
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In the early designs, the mandos-client(8mandos) program (which
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retrieves a password from the Mandos server) also prompted for a
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password on the terminal, in case a Mandos server could not be
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found. This duality of purpose was seen to be too complex to be a
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viable way to continue. Instead, the programs are now separated
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into mandos-client(8mandos) and password-prompt(8mandos), and a
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plugin-runner(8mandos) exist to run them both in parallel, allowing
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the first plugin to succeed to provide the password. This opened up
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for any number of additional plugins to run, all competing to be the
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first to find a password and provide it to the plugin runner.
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Three additional plugins are provided:
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This prompts for a password when using usplash(8).
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This prompts for a password when using splashy(8).
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* askpass-fifo(8mandos)
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To provide compatibility with the "askpass" program from
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cryptsetup, this plugin listens to the same FIFO as askpass would
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More plugins could easily be written and added by the system
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administrator; see the section called "WRITING PLUGINS" in
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plugin-runner(8mandos) to learn the plugin requirements.
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Copyright © 2008,2009 Teddy Hogeborn
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Copyright © 2008,2009 Björn Påhlsson
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Copyright (C) 2008 Teddy Hogeborn
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This program is free software: you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation, either version 3 of the
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removed
README
