Monkeysphere User README
You don't have to be an OpenSSH or OpenPGP expert to use the
Monkeysphere. However, you should be comfortable using secure shell
(ssh), and you should already have GnuPG installed and an OpenPGP key
pair before you begin.
As a regular user on a system where the monkeysphere package is
installed, you probably want to do a few things:
Keep your keyring up-to-date
Regularly refresh your GnuPG keyring from the keyservers. This can be
done with a simple cronjob. An example of crontab line to do this is:
0 12 * * * /usr/bin/gpg --refresh-keys > /dev/null 2>&1
This would refresh your keychain every day at noon.
Keeping your known_hosts file in sync with your keyring
With your keyring updated, you want to make sure that OpenSSH can
still see the most recent trusted information about who the various
hosts are. This can be done with the monkeysphere-ssh-proxycommand
(see next section) or with the update-known_hosts command:
$ monkeysphere update-known_hosts
This command will check to see if there is an OpenPGP key for
each (non-hashed) host listed in the known_hosts file, and then add
the key for that host to the known_hosts file if one is found. This
command could be added to a crontab as well, if desired.
Using monkeysphere-ssh-proxycommand(1)
The best way to handle host keys is to use the monkeysphere ssh proxy
command. This command will make sure the known_hosts file is
up-to-date for the host you are connecting to with ssh. The best way
to integrate this is to add the following line to the "Host *" section
of your ~/.ssh/config file:
ProxyCommand monkeysphere-ssh-proxycommand %h %p
The "Host *" section specifies what ssh options to use for all
connections. If you don't already have a "Host *" line, you can add it
by entering:
Host *
On a line by itself. Add the ProxyCommand line just below it.
Once you've completed this step - you are half-way there. You will now
be able to verify servers participating in the monkeysphere provided
their keys have been signed by someone that you trust.
FIXME: We should setup a way for someone to download a test gpg key and
then connect to a test server that is signed by this gpg key so users
can establish that they are setup correctly.
The remaining steps will complete the second half: allow servers to
verify you based on your OpenPGP key.
Setting up an OpenPGP authentication key
First things first: you'll need to create a new subkey for your
current key, if you don't already have one. If your OpenPGP key is
keyid $GPGID, you can set up such a subkey relatively easily with:
$ monkeysphere gen-subkey $GPGID
Typically, you can find out what your keyid is by running:
$ gpg --list-secret-keys
The first line (starting with sec) will include your key length followed
by the type of key (e.g. 1024D) followed by a slash and then your keyid.
Using your OpenPGP authentication key for SSH
Once you have created an OpenPGP authentication key, you will need to
feed it to your ssh agent.
Currently (2008-08-23), gnutls does not support this operation. In order
to take this step, you will need to upgrade to a patched version of
gnutls. You can easily upgrade a Debian system by adding the following
to /etc/apt/sources.list.d/monkeysphere.list:
deb http://monkeysphere.info/debian experimental gnutls
deb-src http://monkeysphere.info/debian experimental gnutls
Next, run aptitude update; aptitude install libgnuttls26.
With the patched gnutls installed, you can feed your authentication sub
key to your ssh agent by running:
$ monkeysphere subkey-to-ssh-agent
FIXME: using the key with a single session?
Miscellaneous
Users can also maintain their own authorized_keys files, for users
that would be logging into their accounts. This is primarily useful
for accounts on hosts that are not already systematically using the
monkeysphere for user authentication. If you're not sure whether this
is the case for your host, ask your system administrator.
If you want to do this as a regular user, use the
update-authorized_keys command:
$ monkeysphere update-authorized_keys
This command will take all the user IDs listed in the
~/.config/monkeysphere/authorized_user_ids file and check to see if
there are acceptable keys for those user IDs available. If so, they
will be added to the ~/.ssh/authorized_keys file.
You must have indicated reasonable ownertrust in some key for this
account, or no keys will be found with trusted certification paths.
If you find this useful, you might want to place a job like this in
your crontab so that revocations and rekeyings can take place
automatically.
