Version 0.304

[chaz/groupsecret] / README

NAME

    groupsecret - A simple tool for maintaining a shared group secret

VERSION

    version 0.304

SYNOPSIS

        groupsecret [--version] [--help] [-f <filepath>] [-k <privatekey_path>]
                    <command> [<args>]
    
        groupsecret add-key [--embed] [--update] <publickey_path> ...
    
        groupsecret delete-key <fingerprint>|<publickey_path> ...
    
        groupsecret list-keys
    
        groupsecret set-secret [--keep-passphrase] <path>|-|rand:<num_bytes>
    
        groupsecret [print-secret] [--no-decrypt]

DESCRIPTION

    groupsecret is a program that makes it easy for groups to share a
    secret between themselves without exposing the secret to anyone else.
    It could be used, for example, by a team to share an ansible-vault(1)
    password; see "ansible-vault" for more about this particular use case.

    The goal of this program is to be easy to use and have few dependencies
    (or only have dependencies users are likely to already have installed).

    groupsecret works by encrypting a secret with a symmetric cipher
    protected by a secure random passphrase which is itself encrypted by
    one or more SSH2 RSA public keys. Only those who have access to one of
    the corresponding private keys are able to decrypt the passphrase and
    access the secret.

    The encrypted secret and passphrase are stored in a single keyfile. You
    can even commit the keyfile in a public repo or in a private repo where
    some untrusted users may have read access; the secret is locked away to
    all except those with a private key to a corresponding public key that
    has been added to the keyfile.

    The keyfile is just a YAML file, so it's human-readable (except of
    course for the encrypted parts). This make it easy to add to version
    control and work with diffs. You can edit the keyfile by hand if you
    learn its very simple structure, but this program makes it even easier
    to manage the keyfile.

OPTIONS

 --version

    Print the program name and version to STDOUT, and exit.

    Alias: -v

 --help

    Print the synopsis to STDOUT, and exit.

    Alias: -h

 --file=path

    Specify a path to a keyfile which stores a secret and keys.

    Defaults to the value of the environment variable "GROUPSECRET_KEYFILE"
    or groupsecret.yml.

    Alias: -f

 --private-key=path

    Specify a path to a PEM private key. This is used by some commands to
    decrypt the passphrase that protects the secret and is ignored by
    commands that don't need it.

    Defaults to the value of the environment variable
    "GROUPSECRET_PRIVATE_KEY" or ~/.ssh/id_rsa.

    Alias: -k

COMMANDS

 add-key

        groupsecret add-key path/to/mykey_rsa.pub

    Adds one or more SSH2 RSA public keys to a keyfile. This allows the
    secret contained within the keyfile to be accessed by whoever has the
    corresponding private key.

    If the --embed option is used, the public keys will be embeded in the
    keyfile. This may be a useful way to make sure the actual keys are
    available in the future since they could be needed to encrypt a new
    passphrase if it ever needs to be changed. Keys that are not embedded
    will be searched for in the filesystem; see "GROUPSECRET_PATH".

    If the --update option is used and a key with the same fingerprint is
    added, the new key will replace the existing key. The default behavior
    is to skip existing keys.

    If the keyfile is storing a secret, the passphrase protecting the
    secret will need to be decrypted so that access to the secret can be
    shared with the new key(s).

    Alias: add-keys

 delete-key

        groupsecret delete-key MD5:89:b3:fb:76:6c:f9:56:8e:a8:1a:df:ba:1c:ba:7d:05
        groupsecret delete-key path/to/mykey_rsa.pub

    Deletes one or more keys from a keyfile. This prevents the secret
    contained within the keyfile from being accessed by whoever has the
    corresponding private key.

    Of course, if the owners of the key(s) being removed have already had
    access to the keyfile prior to their keys being removed, the secret is
    already exposed to them. It usually makes sense to follow up this
    command with a "set-secret" command in order to change the secret.

    Aliases: delete-keys, remove-key, remove-keys

 list-keys

        groupsecret list-keys

    Prints the keys that have access to the secret contained in the keyfile
    to STDOUT, one per line in the following format:

        <fingerprint> <comment>

 set-secret

        groupsecret set-secret path/to/secretfile.txt
        groupsecret set-secret - <<END
        > it's a secret to everybody
        > END
        groupsecret set-secret rand:48

    Set or update the secret contained in a keyfile. The argument allows
    you to add a secret from a file, from <STDIN>, or from a stream of
    secure random bytes.

    If the keyfile already contains a secret, it will be replaced by the
    new secret. A keyfile can only contain one secret at a time. If you
    think you want to store more than one secret at a time, store a tarball
    instead.

    By default, this will also change the passphrase protecting the secret
    and re-encrypt the passphrase for each key currently in the keyfile.
    This requires all of the public keys to be available (see
    "GROUPSECRET_PATH"). If for some reason you want to protect the new
    secret with the current passphrase, use the --keep-passphrase option;
    this can be done without the public keys being available, but it will
    require a private key to decrypt the passphrase.

    Aliases: change-secret, update-secret

 print-secret

        groupsecret print-secret
        groupsecret print-secret --no-decrypt

    Print the secret contained in the keyfile to STDOUT.

    If the --no-decrypt option is used, the secret will be printed in its
    encrypted form.

    This requires a private key.

    Aliases: (no command), show-secret

REQUIREMENTS

      * OpenSSH <https://www.openssh.com> (commands: ssh-keygen(1))

      * OpenSSL <https://www.openssl.org> (commands: openssl(1))

INSTALL

    There are a few ways to install groupsecret to your system. First, make
    sure you first have the "REQUIREMENTS" installed.

 Using cpanm

    You can install groupsecret using cpanm. If you have a local perl
    (plenv, perlbrew, etc.), you can just do this:

        cpanm App::GroupSecret

    to install the groupsecret executable and its Perl module dependencies.
    The executable will be installed to your perl's bin path, like
    ~/perl5/perlbrew/bin/groupsecret.

    If you're installing to your system perl, you can do:

        cpanm --sudo App::GroupSecret

    to install the groupsecret executable to a system directory, like
    /usr/local/bin/groupsecret (depending on your perl).

 For developers

    If you're a developer and want to hack on the source, clone the
    repository and pull the dependencies:

        git clone https://github.com/chazmcgarvey/groupsecret.git
        cd groupsecret
        cpanm Dist::Zilla
        dzil authordeps --missing | cpanm
        dzil listdeps --author --develop --missing | cpanm

ENVIRONMENT

 GROUPSECRET_KEYFILE

    If set, this program will use the value as a path to the keyfile. The
    "--file=path" option takes precedence if used.

 GROUPSECRET_PRIVATE_KEY

    If set, this program will use the value as a path to private key used
    for decryption. The "--private-key=path" option takes precedence if
    used.

 GROUPSECRET_PATH

    The value of this variable should be a colon-separated list of
    directories in which to search for public keys. By default, the actual
    keys are not embedded in keyfiles, but they may be needed to encrypt a
    new passphrase if it ever needs to be changed. Keys that are not
    embedded will be searched for in the filesystem based on the value of
    this environment variable.

    Defaults to .:keys:$HOME/.ssh.

EXAMPLES

 ansible-vault

    Ansible Vault <http://docs.ansible.com/ansible/latest/vault.html> is a
    great way to securely store secret configuration variables for use in
    your playbooks. Vaults are secured using a password, which is okay if
    you're the only one who will need to unlock the Vault, but as soon as
    you add team members who also need to access the Vault you are then
    faced with how to manage knowledge of the password. When a team member
    leaves, you'll also need to change the Vault password which means
    you'll need a way to communicate the change to other team members who
    also have access. This becomes a burden to manage.

    You can use groupsecret to manage this very easily by storing the Vault
    password in a groupsecret keyfile. That way, you can add or remove keys
    and change the secret (the Vault password) at any time without
    affecting the team members that still have access. Team members always
    use their own SSH2 RSA keys to unlock the Vault, so no new password
    ever needs to be communicated out.

    To set this up, first create a keyfile with the public keys of everyone
    on your team:

        groupsecret -f vault-password.yml add-keys keys/*_rsa.pub

    Then set the secret in the keyfile to a long random number:

        groupsecret -f vault-password.yml set-secret rand:48

    This will be the Ansible Vault password. You can see it if you want
    using the "print-secret" command, but you don't need to.

    Then we'll take advantage of the fact that an Ansible Vault password
    file can be an executable program that prints the Vault password to
    STDOUT. Create a file named vault-password with the following script,
    and make it executable (chmod +x vault-password):

        #!/bin/sh
        # Use groupsecret <https://github.com/chazmcgarvey/groupsecret> to access the Vault password
        exec ${GROUPSECRET:-groupsecret} -f vault-password.yml print-secret

    Commit both vault-password and vault-password.yml to your repository.

    Now use ansible-vault(1) to add files to the Vault:

        ansible-vault --vault-id=vault-password encrypt foo.yml bar.yml baz.yml

    These examples show the Ansible 2.4+ syntax, but it can be adapted for
    earlier versions. The significant part of this command is
    --vault-id=vault-password which refers to the executable script we
    created earlier. You can use that argument with other ansible-vault
    commands to view or edit the encrypted files.

    You can also pass that same argument to ansible-playbook(1) in order to
    use the Vault in playbooks that refer to the encrypted variables:

        ansible-playbook -i myinventory --vault-id=vault-password site.yml

    What this does is execute vault-password which executes groupsecret to
    print the secret contained in the vault-password.yml file (which is
    actually the Vault password) to STDOUT. In order to do this,
    groupsecret will decrypt the keyfile passphrase using any one of the
    private keys that have associated public keys added to the keyfile.

    That's it! Pretty easy.

    If and when you need to change the Vault password (such as when a team
    member leaves), you can follow this procedure which is probably mostly
    self-explanatory:

        groupsecret -f vault-password.yml delete-key keys/revoked/jdoe_rsa.pub
        groupsecret -f vault-password.yml print-secret >old-vault-password.txt
        groupsecret -f vault-password.yml set-secret rand:48
        echo "New Vault password: $(groupsecret -f vault-password.yml)"
        ansible-vault --vault-id=old-vault-password.txt rekey foo.yml bar.yml baz.yml
        # You will be prompted for the new Vault password which you can copy from the output above.
        rm -f old-vault-password.txt

    This removes access to the keyfile secret and to the Ansible Vault.
    Don't forget that you may also want to change the variables being
    protected by the Vault. After all, those secrets are the actual things
    we're protecting by doing all of this, and an exiting team member may
    have decided to take a copy of those variables for himself before
    leaving.

BUGS

    Please report any bugs or feature requests on the bugtracker website
    https://github.com/chazmcgarvey/groupsecret/issues

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

AUTHOR

    Charles McGarvey <chazmcgarvey@brokenzipper.com>

COPYRIGHT AND LICENSE

    This software is Copyright (c) 2017 by Charles McGarvey.

    This is free software, licensed under:

      The MIT (X11) License