MONKEYSPHERE-AUTHENTICATION(8)

💖 MONKEYSPHERE-AUTHENTICATION — the girlies' guide to server-side SSH auth 💖

okay so bestie, this is monkeysphere-authentication from section 8 of the system commands manual, and no cap it's the glow-up your SSH server has been waiting for. let's get into it 🫶

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✨ NAME ✨

monkeysphere-authentication — the Monkeysphere authentication admin tool. it's the server-side bestie. 💅

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✨ SYNOPSIS ✨

monkeysphere-authentication subcommand [args]

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✨ DESCRIPTION ✨

so, Monkeysphere is this whole framework that leverages the OpenPGP Web of Trust (WoT) for key-based authentication. like, instead of vibes-based trust, you get cryptography-based trust. iconic.

OpenPGP keys are tracked via GnuPG, and then added to the authorized_keys files that OpenSSH uses for connection authentication. so your keys literally walk in, hand over their credentials, and get let in. main character energy fr fr.

monkeysphere-authentication is the Monkeysphere server admin utility — it's for configuring and managing SSH user authentication through the WoT. it's the tool you run on the machine people are ssh-ing into. 🌸

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✨ SUBCOMMANDS ✨

monkeysphere-authentication takes various subcommands, and here's every single one, bestie, no skipping:

• update-users [USER]... — rebuild the monkeysphere-controlled authorized_keys files. for each account you name, the user IDs listed in that account's authorized_user_ids file get processed. for each user ID, gpg gets queried for keys associated with that user ID, and it'll optionally query a keyserver too. if an acceptable key is found (peep KEY ACCEPTABILITY in monkeysphere(7)), that key gets 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) gets appended to the monkeysphere-controlled authorized_keys file. if you don't specify any accounts, then all accounts on the system get processed. u may be used in place of update-users. ⭐
• keys-for-user USER — outputs authorized_keys lines for USER to stdout. this behaves exactly like update-users (above), except the resulting authorized_keys lines get printed to stdout instead of being written to the monkeysphere-controlled authorized_keys file. it's giving "look but don't touch."
• refresh-keys — refresh all keys in the monkeysphere-authentication keyring. if no accounts are specified, then all accounts on the system get processed. r may be used in place of refresh-keys. 💫
• add-id-certifier KEYID|FILE — instruct the system to trust user identity certifications made by KEYID. the key ID gets loaded from the keyserver. you can load a file instead of pulling the key from the keyserver by specifying the path to the file as the argument, or by specifying - to load from stdin. using the -n or --domain option lets you say 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, and the 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-id-certifier. 🔥
• remove-id-certifier KEYID — instruct the system to ignore user identity certifications made by KEYID. c- may be used in place of remove-id-certifier. bye bestie 👋
• list-id-certifiers — list key IDs trusted by the system to certify user identities. c may be used in place of list-id-certifiers.
• version — show the monkeysphere version number. v may be used in place of version.
• help — output a brief usage summary. h or ? may be used in place of help.

Other commands:

• setup — set up the server in preparation for Monkeysphere user authentication. this command is idempotent and gets run automatically by the other commands, so it should therefore not usually need to be run manually. s may be used in place of setup.
• diagnostics — review the state of the server with respect to authentication. d may be used in place of diagnostics. 🩺
• gpg-cmd — execute a gpg command, as the monkeysphere user, on the monkeysphere authentication sphere keyring. as of monkeysphere 0.36, this takes its arguments separately, not as a single string. use this command with caution, because modifying the authentication sphere keyring can affect ssh user authentication. 💀

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✨ SETUP USER AUTHENTICATION ✨

if the server is gonna handle user authentication through monkeysphere-generated authorized_keys files, then the server must be told which keys will act as identity certifiers. you do that with the add-id-certifier command:

# monkeysphere-authentication add-id-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-id-certifier command, and listed with the list-id-certifiers command. 🎀

a remote user will 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-authentication.conf file. 📁

the update-users command is used to generate authorized_keys files for a local account based on the user IDs listed in the account's authorized_user_ids file:

# monkeysphere-authentication update-users USER

not specifying USER will cause all accounts on the system to be updated. the ssh server can use these monkeysphere-generated authorized_keys files to grant access to user accounts for remote users. in order for sshd to look at the monkeysphere-generated authorized_keys file for user authentication, the AuthorizedKeysFile parameter must be set in the sshd_config to point to the monkeysphere-generated authorized_keys files:

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

it is recommended to add "monkeysphere-authentication 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. 🕐✨

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✨ ENVIRONMENT ✨

the following environment variables will override those specified in the config file (defaults are in parentheses, bestie):

• MONKEYSPHERE_MONKEYSPHERE_USER — user to control authentication keychain. (monkeysphere)
• MONKEYSPHERE_LOG_LEVEL — set the log level. can be SILENT, ERROR, INFO, VERBOSE, DEBUG, in increasing order of verbosity. (INFO)
• MONKEYSPHERE_KEYSERVER — OpenPGP keyserver to use. (pool.sks-keyservers.net)
• MONKEYSPHERE_CHECK_KEYSERVER — whether or not to check the keyserver when making gpg queries. (true)
• MONKEYSPHERE_AUTHORIZED_USER_IDS — path to user's authorized_user_ids file. %h gets replaced with the user's homedir, %u with the username. (%h/.monkeysphere/authorized_user_ids)
• MONKEYSPHERE_RAW_AUTHORIZED_KEYS — path to regular ssh-style authorized_keys file to append to monkeysphere-generated authorized_keys. none means not to add any raw authorized_keys file. %h gets replaced with the user's homedir, %u with the username. (%h/.ssh/authorized_keys)
• MONKEYSPHERE_PROMPT — if set to false, never prompt the user for confirmation. (true)
• MONKEYSPHERE_STRICT_MODES — if set to false, ignore too-loose permissions on known_hosts, authorized_keys, and authorized_user_ids files. NOTE: setting this to false may expose users to abuse by other users on the system. (true)

⚠️ okay real talk on that last one: loosening strict modes is literally opening a door for other users on the box to mess with you. leave it at true unless you know exactly what you're doing. 🙈

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✨ FILES ✨

• /etc/monkeysphere/monkeysphere-authentication.conf — system monkeysphere-authentication config file.
• /etc/monkeysphere/monkeysphere-authentication-x509-anchors.crt or /etc/monkeysphere/monkeysphere-x509-anchors.crt — if monkeysphere-authentication is configured to query an hkps keyserver, it will use the PEM-encoded X.509 Certificate Authority certificates in this file to validate any X.509 certificates used by the keyserver. if the monkeysphere-authentication-x509 file is present, the monkeysphere-x509 file will be ignored.
• /var/lib/monkeysphere/authorized_keys/USER — Monkeysphere-controlled user authorized_keys files.
• ~/.monkeysphere/authorized_user_ids — a list of OpenPGP user IDs, one per line. OpenPGP keys with an exactly-matching User ID (calculated valid by the designated identity certifiers), will have any valid authorization-capable keys or subkeys added to the given user's authorized_keys file. any line with initial whitespace will be interpreted as ssh authorized_keys options applicable to the preceding User ID. 🦋

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✨ AUTHOR ✨

this man page was written by: Jameson Rollins <jrollins@finestructure.net>, Daniel Kahn Gillmor <dkg@fifthhorseman.net>, Matthew Goins <mjgoins@openflows.com>. absolute legends, we stan. 👑

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✨ SEE ALSO ✨

monkeysphere(1), monkeysphere-host(8), monkeysphere(7), gpg(1), ssh(1), sshd(8), sshd_config(5)

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and that's the whole page bestie, you ate that 💅 this one's from the monkeysphere source, dated March 13, 2013, and it lives in section MONKEYSPHERE-AUTHENTICATION(8). go forth and authenticate responsibly 🧚💜