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https://github.com/chazmcgarvey/groupsecret

A simple tool for maintaining a shared group secret
https://github.com/chazmcgarvey/groupsecret

ansible-vault encryption perl ssh

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A simple tool for maintaining a shared group secret

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README 

        
# NAME



groupsecret - A simple tool for maintaining a shared group secret



# VERSION



version 0.304



# SYNOPSIS



    groupsecret [--version] [--help] [-f ] [-k ]

                 []



    groupsecret add-key [--embed] [--update]  ...



    groupsecret delete-key | ...



    groupsecret list-keys



    groupsecret set-secret [--keep-passphrase] |-|rand:



    groupsecret [print-secret] [--no-decrypt]



# DESCRIPTION



[groupsecret](https://metacpan.org/pod/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)](http://man.he.net/man1/ansible-vault) password; see ["ansible-vault"](#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"](#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"](#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"](#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"](#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:



     



## set-secret



    groupsecret set-secret path/to/secretfile.txt

    groupsecret set-secret - < 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 , 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"](#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)](http://man.he.net/man1/ssh-keygen))

- [OpenSSL](https://www.openssl.org) (commands: [openssl(1)](http://man.he.net/man1/openssl))



# INSTALL



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

["REQUIREMENTS"](#requirements) installed.



## Using cpanm



You can install groupsecret using [cpanm](https://metacpan.org/pod/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"](#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"](#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"](#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  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)](http://man.he.net/man1/ansible-vault) 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)](http://man.he.net/man1/ansible-playbook) 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](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 



# COPYRIGHT AND LICENSE



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



This is free software, licensed under:



    The MIT (X11) License