annotate debian/README.Debian @ 1930:299f4f19ba19

Add /usr/sbin and /sbin to default root PATH When dropbear is used in a very restricted environment (such as in a initrd), the default user shell is often also very restricted and doesn't take care of setting the PATH so the user ends up with the PATH set by dropbear. Unfortunately, dropbear always sets "/usr/bin:/bin" as default PATH even for the root user which should have /usr/sbin and /sbin too. For a concrete instance of this problem, see the "Remote Unlocking" section in this tutorial: https://paxswill.com/blog/2013/11/04/encrypted-raspberry-pi/ It speaks of a bug in the initramfs script because it's written "blkid" instead of "/sbin/blkid"... this is just because the scripts from the initramfs do not expect to have a PATH without the sbin directories and because dropbear is not setting the PATH appropriately for the root user. I'm thus suggesting to use the attached patch to fix this misbehaviour (I did not test it, but it's easy enough). It might seem anecdotic but multiple Kali users have been bitten by this. From https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=903403
author Raphael Hertzog <hertzog@debian.org>
date Mon, 09 Jul 2018 16:27:53 +0200
parents fe6bca95afa7
children
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1 Dropbear for Debian
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2 -------------------
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4 This package will attempt to listen on port 22. If the OpenSSH
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5 package ("ssh") is installed, the file /etc/default/dropbear
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6 will be set up so that the server does not start by default.
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8 You can run Dropbear concurrently with OpenSSH 'sshd' by
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9 modifying /etc/default/dropbear so that "NO_START" is set to
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10 "0" and changing the port number that Dropbear runs on. Follow
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11 the instructions in the file.
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13 This package suggests you install the "ssh" package. This package
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14 provides the "ssh" client program, as well as the "/usr/bin/scp"
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15 binary you will need to be able to retrieve files from a server
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16 running Dropbear via SCP.
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18 Replacing OpenSSH "sshd" with Dropbear
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19 --------------------------------------
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21 You will still want to have the "ssh" package installed, as it
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22 provides the "ssh" and "scp" binaries. When you install this
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23 package, it checks for existing OpenSSH host keys and if found,
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24 converts them to the Dropbear format.
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26 If this appears to have worked, you should be able to change over
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27 by following these steps:
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29 1. Stop the OpenSSH server
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30 % /etc/init.d/ssh stop
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31 2. Prevent the OpenSSH server from starting in the future
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32 % touch /etc/ssh/sshd_not_to_be_run
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33 3. Modify the Dropbear defaults file, set NO_START to 0 and
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34 ensure DROPBEAR_PORT is set to 22.
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35 % editor /etc/default/dropbear
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36 4. Restart the Dropbear server.
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37 % /etc/init.d/dropbear restart
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39 See the Dropbear homepage for more information:
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40 http://matt.ucc.asn.au/dropbear/dropbear.html
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41