/mandos/trunk

This file documents the next steps to take after installation of the

Debian package, and also contain some notes specific to the Debian

packaging which are not also in the manual.

* Adding a Client Password to the Server

  The server must be given a password to give back to the client on

  boot time.  This password must be a one which can be used to unlock

  the root file system device.  On the *client*, run this command:

	mandos-keygen --password

  It will prompt for a password and output a config file section.

  This output should be copied to the Mandos server and added to the

  file "/etc/mandos/clients.conf" there.

* Testing that it Works (Without Rebooting)

  After the server has been started with this client's key added, it

  is possible to verify that the correct password will be received by

  this client by running the command, on the client:

	MANDOSPLUGINHELPERDIR=/usr/lib/$(dpkg-architecture \

	-qDEB_HOST_MULTIARCH)/mandos/plugin-helpers \

	/usr/lib/$(dpkg-architecture -qDEB_HOST_MULTIARCH \

	)/mandos/plugins.d/mandos-client \

		--pubkey=/etc/keys/mandos/pubkey.txt \

		--seckey=/etc/keys/mandos/seckey.txt \

		--tls-privkey=/etc/keys/mandos/tls-privkey.pem \

		--tls-pubkey=/etc/keys/mandos/tls-pubkey.pem; echo

  This command should retrieve the password from the server, decrypt

  it, and output it to standard output.  There it can be verified to

  be the correct password, before rebooting.

* Emergency Escape

  If it ever should be necessary, the Mandos client can be temporarily

  prevented from running at startup by passing the parameter

  "mandos=off" to the kernel.

* Specifying a Client Network Interface

  At boot time the network interfaces to use will by default be

  automatically detected.  If this should result in incorrect

  interfaces, edit the DEVICE setting in the

  "/etc/initramfs-tools/initramfs.conf" file.  (The default setting is

  empty, meaning it will autodetect the interfaces.)  *If* the DEVICE

  setting is changed, it will be necessary to update the initrd image

  by running this command:

	(For initramfs-tools:)

	update-initramfs -k all -u

	(For dracut:)

	dpkg-reconfigure dracut

  The device can also be overridden at boot time on the Linux kernel

  command line using the sixth colon-separated field of the "ip="

  option; for exact syntax, read the documentation in the file

  "/usr/share/doc/linux-doc-*/Documentation/filesystems/nfs/nfsroot.txt",

  available in the "linux-doc-*" package.

  Note that since the network interfaces are used in the initial RAM

  disk environment, the network interfaces *must* exist at that stage.

  Thus, an interface can *not* be a pseudo-interface such as "br0" or

  "tun0"; instead, only real interfaces (such as "enp1s0" or "eth0")

  can be used. This can be overcome by writing a "network hook"

  program to create an interface (see mandos-client(8mandos)) and

  placing it in "/etc/mandos/network-hooks.d", from where it will be

  copied into the initial RAM disk.  Example network hook scripts can

  be found in "/usr/share/doc/mandos-client/examples/network-hooks.d".

* User-Supplied Plugins

  Any plugins found in "/etc/mandos/plugins.d" will override and add

  to the normal Mandos plugins.  When adding or changing plugins, do

  not forget to update the initial RAM disk image:

	(For initramfs-tools:)

	update-initramfs -k all -u

	(For dracut:)

	dpkg-reconfigure dracut

* Do *NOT* Edit "/etc/crypttab"

  It is NOT necessary to edit "/etc/crypttab" to specify

  "/usr/lib/mandos/plugin-runner" as a keyscript for the root file

  system; if no keyscript is given for the root file system, the

  Mandos client will be the new default way for getting a password for

  the root file system when booting.

* Non-local Connection (Not Using ZeroConf)

  If the "ip=" kernel command line option is used to specify a

  complete IP address and device name, as noted above, it then becomes

  possible to specify a specific IP address and port to connect to,

  instead of using ZeroConf.  The syntax for doing this is

  "mandos=connect:<IP_ADDRESS>:<PORT_NUMBER>" on the kernel command

  line.

  For very advanced users, it is possible to specify "mandos=connect"

  on the kernel command line to make the system only set up the

  network (using the data in the "ip=" option) and not pass any extra

  "--connect" options to mandos-client at boot.  For this to work,

  "--options-for=mandos-client:--connect=<ADDRESS>:<PORT>" needs to be

  manually added to the file "/etc/mandos/plugin-runner.conf" or, if

  dracut is used with systemd, the "--connect=<ADDRESS>:<PORT>"

  options needs to be added to an environment variable in an override

  file for the "ask-password-mandos" service, as detailed in the file

  "/usr/lib/dracut/modules.d/90mandos/ask-password-mandos.service".

* Diffie-Hellman Parameters

  On installation, a file with Diffie-Hellman parameters,

  /etc/keys/mandos/dhparams.pem, will be generated and automatically

  installed into the initial RAM disk image and also used by the

  Mandos Client on boot.  If different parameters are needed for

  policy or other reasons, simply replace the existing dhparams.pem

  file and update the initial RAM disk image.

 -- Teddy Hogeborn <teddy@recompile.se>, Sun,  8 Sep 2024 02:09:20 +0200