monkeysphere-server

Langue: en

Version: 328548 (ubuntu - 08/07/09)

Section: 8 (Commandes administrateur)

NAME

monkeysphere-server - Monkeysphere server admin user interface

SYNOPSIS

monkeysphere-server subcommand [args]

DESCRIPTION

Monkeysphere is a framework to leverage the OpenPGP web of trust for OpenSSH authentication. OpenPGP keys are tracked via GnuPG, and added to the authorized_keys and known_hosts files used by OpenSSH for connection authentication.

monkeysphere-server is the Monkeysphere server admin utility.

SUBCOMMANDS

monkeysphere-server takes various subcommands:

update-users [ACCOUNT]...
Rebuild the monkeysphere-controlled authorized_keys files. For each specified account, the user ID's listed in the account's authorized_user_ids file are processed. For each user ID, gpg will be queried for keys associated with that user ID, optionally querying a keyserver. If an acceptable key is found (see KEY ACCEPTABILITY in monkeysphere(7)), the key is added to the account's monkeysphere-controlled authorized_keys file. If the RAW_AUTHORIZED_KEYS variable is set, then a separate authorized_keys file (usually ~USER/.ssh/authorized_keys) is appended to the monkeysphere-controlled authorized_keys file. If no accounts are specified, then all accounts on the system are processed. `u' may be used in place of `update-users'.
gen-key [HOSTNAME]
Generate a OpenPGP key for the host. If HOSTNAME is not specified, then the system fully-qualified domain name will be user. An alternate key bit length can be specified with the `-l' or `--length' option (default 2048). An expiration length can be specified with the `-e' or `--expire' option (prompt otherwise). The expiration format is the same as that of extend-key, below. A key revoker fingerprint can be specified with the `-r' or `--revoker' option. `g' may be used in place of `gen-key'.
extend-key EXPIRE
Extend the validity of the OpenPGP key for the host until EXPIRE from the present. If EXPIRE is not specified, then the user will be prompted for the extension term. Expiration is specified like GnuPG does:
          0 = key does not expire
       <n>  = key expires in n days
       <n>w = key expires in n weeks
       <n>m = key expires in n months
       <n>y = key expires in n years
 
`e' may be used in place of `extend-key'.
add-hostname HOSTNAME
Add a hostname user ID to the server host key. `n+' may be used in place of `add-hostname'.
revoke-hostname HOSTNAME
Revoke a hostname user ID from the server host key. `n-' may be used in place of `revoke-hostname'.
show-key
Output gpg information about host's OpenPGP key. `s' may be used in place of `show-key'.
publish-key
Publish the host's OpenPGP key to the keyserver. `p' may be used in place of `publish-key'.
diagnostics
Review the state of the server with respect to the MonkeySphere in general and report on suggested changes. Among other checks, this includes making sure there is a valid host key, that the key is published, that the sshd configuration points to the right place, and that there are at least some valid identity certifiers. `d' may be used in place of `diagnostics'.
add-identity-certifier KEYID
Instruct system to trust user identity certifications made by KEYID. Using the `-n' or `--domain' option allows you to indicate that you only trust the given KEYID to make identifications within a specific domain (e.g. "trust KEYID to certify user identities within the @example.org domain"). A certifier trust level can be specified with the `-t' or `--trust' option (possible values are `marginal' and `full' (default is `full')). A certifier trust depth can be specified with the `-d' or `--depth' option (default is 1). `c+' may be used in place of `add-identity-certifier'.
remove-identity-certifier KEYID
Instruct system to ignore user identity certifications made by KEYID. `c-' may be used in place of `remove-identity-certifier'.
list-identity-certifiers
List key IDs trusted by the system to certify user identities. `c' may be used in place of `list-identity-certifiers'.
gpg-authentication-cmd
Execute a gpg command on the gnupg-authentication keyring as the monkeysphere user. This takes a single command (multiple gpg arguments need to be quoted). Use this command with caution, as modifying the gnupg-authentication keyring can affect ssh user authentication.
help
Output a brief usage summary. `h' or `?' may be used in place of `help'.

SETUP

In order to start using the monkeysphere, you must first generate an OpenPGP key for the server and convert that key to an ssh key that can be used by ssh for host authentication. This can be done with the gen-key subcommand:

$ monkeysphere-server gen-key

To enable host verification via the monkeysphere, you must then publish the host's key to the Web of Trust using the publish-key command to push the key to a keyserver. You must also modify the sshd_config on the server to tell sshd where the new server host key is located:

HostKey /var/lib/monkeysphere/ssh_host_rsa_key

In order for users logging into the system to be able to identify the host via the monkeysphere, at least one person (e.g. a server admin) will need to sign the host's key. This is done using standard OpenPGP keysigning techniques, usually: pul the key from the keyserver, verify and sign the key, and then re-publish the signature. Once an admin's signature is published, users logging into the host can use it to validate the host's key.

If the server will also handle user authentication through monkeysphere-generated authorized_keys files, the server must be told which keys will act as identity certifiers. This is done with the add-identity-certifier command:

$ monkeysphere-server add-identity-certifier KEYID

where KEYID is the key ID of the server admin, or whoever's certifications should be acceptable to the system for the purposes of authenticating remote users. You can run this command multiple times to indicate that multiple certifiers are trusted. You may also specify a filename instead of a key ID, as long as the file contains a single OpenPGP public key. Certifiers can be removed with the remove-identity-certifier command, and listed with the list-identity-certifiers command.

Remote users will then be granted access to a local account based on the appropriately-signed and valid keys associated with user IDs listed in that account's authorized_user_ids file. By default, the authorized_user_ids file for an account is ~/.monkeysphere/authorized_user_ids. This can be changed in the monkeysphere-server.conf file.

The update-users command can then be used to generate authorized_keys file for local accounts based on the authorized user IDs listed in the account's authorized_user_ids file:

$ monkeysphere-server update-users USER

Not specifying USER will cause all accounts on the system to updated. sshd can then use these monkeysphere generated authorized_keys files to grant access to user accounts for remote users. You must also tell sshd to look at the monkeysphere-generated authorized_keys file for user authentication by setting the following in the sshd_config:

AuthorizedKeysFile /var/lib/monkeysphere/authorized_keys/%u

It is recommended to add "monkeysphere-server update-users" to a system crontab, so that user keys are kept up-to-date, and key revocations and expirations can be processed in a timely manner.

ENVIRONMENT

The following environment variables will override those specified in the monkeysphere-server.conf configuration file (defaults in parentheses):

MONKEYSPHERE_MONKEYSPHERE_USER
User to control authentication keychain (monkeysphere).
MONKEYSPHERE_LOG_LEVEL
Set the log level (INFO). Can be SILENT, ERROR, INFO, VERBOSE, DEBUG, in increasing order of verbosity.
MONKEYSPHERE_KEYSERVER
OpenPGP keyserver to use (subkeys.pgp.net).
MONKEYSPHERE_AUTHORIZED_USER_IDS
Path to user authorized_user_ids file (%h/.monkeysphere/authorized_user_ids).
MONKEYSPHERE_RAW_AUTHORIZED_KEYS
Path to user-controlled authorized_keys file. `-' means not to add user-controlled file (%h/.ssh/authorized_keys).

FILES

/etc/monkeysphere/monkeysphere-server.conf
System monkeysphere-server config file.
/etc/monkeysphere/monkeysphere.conf
System-wide monkeysphere config file.
/etc/monkeysphere/gnupg-host.conf
Monkeysphere host GNUPG home gpg.conf
/etc/monkeysphere/gnupg-authentication.conf
Monkeysphere authentication GNUPG home gpg.conf
/var/lib/monkeysphere/authorized_keys/USER
Monkeysphere-generated user authorized_keys files.
/var/lib/monkeysphere/ssh_host_rsa_key
Copy of the host's private key in ssh format, suitable for use by sshd.
/var/lib/monkeysphere/gnupg-host
Monkeysphere host GNUPG home directory.
/var/lib/monkeysphere/gnupg-authentication
Monkeysphere authentication GNUPG home directory.

AUTHOR

Written by Jameson Rollins <jrollins@fifthhorseman.net>, Daniel Kahn Gillmor <dkg@fifthhorseman.net>

SEE ALSO

monkeysphere(1), monkeysphere(7), gpg(1), ssh(1)