ftpasswd: tool for ProFTPD's AuthUserFile, AuthGroupFile, UserPassword

## `ftpasswd`: tool for ProFTPD's `AuthUserFile`, `AuthGroupFile`, `UserPassword`

This program is used to create and manage files, correctly formatted, suitable for use with ProFTPD's `AuthUserFile` and `AuthGroupFile` configuration directives. It can also generate password hashes for ProFTPD's `UserPassword` directive.

The most current version of `ftpasswd` is distributed with the ProFTPD source code, under the `contrib/` directory.

## Author

Please contact TJ Saunders <tj at castaglia.org> with any questions, concerns, or suggestions regarding this program.

## Usage

The following describes the common usage of the `ftpasswd` tool. The options supported are described in more detail later.

This script is intended to replace the `genuser.pl` script that is currently distributed with `proftpd`. That script can generate DES-hashed passwords, suitable for use with the `UserPassword` configuration directive, but it is not quite right for `AuthUserFile`s. Another common mistake is to use the `htpasswd` program from Apache to create files for `proftpd`. Apache and ProFTPD both have the same `AuthUserFile` and `AuthGroupFile` directives; the format of the files used by each server is different.

Creating Files
The `ftpasswd` program can create and update files for both `AuthUserFile` and `AuthGroupFile`. When it is used for the first time, the program will create the necessary file. If that file already exists, `ftpasswd` will update it with the new information.

`ftpasswd` must first know what type of file to create. Use either the `--passwd` option (for handling `AuthUserFile`s), or the `--group` option (for handling `AuthGroupFile`s); this is required.

When creating an `AuthUserFile`, the following options are also required: `--name`, `--uid`, `--home`, and `--shell`. This information is required by `proftpd` to authenticate a user. The optional parameters for an `AuthUserFile` include `--gid` (defaults to the given `--uid` argument when not provided) and `--gecos` (not used by `proftpd` at all). For example:

      $ ftpasswd --passwd --name=bob --uid=1001 --home=/home/bob --shell=/bin/false

creates an account for user `bob`. To create a file with a name or location other than the default (which, for `--passwd` mode is `ftpd.passwd`), use the `--file` option. For example, to create the alternate password file in `/usr/local/etc/ftpd/passwd`:

      $ ftpasswd --passwd --file=/usr/local/etc/ftpd/passwd --name=bob --uid=1001 --home=/home/bob \
        --shell=/bin/false

For `AuthGroupFile`s, use `--group`:

      $ ftpasswd --group --name=group-name --gid=group-id --member=user-member1  \
        --member=user-member2 ... --member=user-memberN

The most common change to these files is made to `AuthUserFile`s, to change a user's password. The `--change-password` option was provided just for this scenario:

      $ ftpasswd --passwd --name=user --change-password

Creating Hashes
A less common need is to generate a password hash for some user, to be used in a `UserPassword` directive in the `proftpd.conf`. One could generate a file using `--passwd` and then extract the password hash from the file. Easier, though, is to use `ftpasswd`'s `--hash` option:

      $ ftpasswd --hash

The password will either be prompted for, or it can be given on standard in using `--stdin`.

Automated Use
The `ftpasswd` provides a useful command-line interface to interacting with the authentication files. Many sites would like to be able to remotely manipulate these files, just as `ftpasswd` does, only using a web-based mechanism, perhaps even providing a page to users to change their passwords, instead of requiring use of a shell. Wrapping a shell or Perl script around `ftpasswd` is the logical solution.

To aid such automated wrapper scripts, `ftpasswd` has two features: its return value, and a specific option. The program returns 0 if the requested change was successful, and 1 if there was an error (no such user/group, password matched system password and the `--not-system-password` option was used, etc.). The specific option is `--stdin`: this allows scripts to provide a password to `ftpasswd` without prompting for a password. For example:

      $ echo passwd-variable | ftpasswd opts --stdin

Note that the `--stdin` option does not allow passwords to be passed to the script on the command line, but on `stdin`. This is done as a security measure: the standard Unix `ps` command can be used to show all the processes running on a system including their command line parameters. This means that any user could use `ps` to watch passwords given to `ftpasswd`, if those passwords were to be passed on the command line. Some operating systems (e.g. FreeBSD) allow the sysadmin to prevent users from seeing all processes in this manner; consult your operating system documentation for more information.

There are other issues that arise when using `AuthUserFile`s. This document discusses these issues in greater detail.

## Options

The following is the output from running `ftpasswd --help`:

    usage: ftpasswd [--help] [--hash|--group|--passwd]

      REQUIRED: --passwd, --group, or --hash.  These specify whether ftpasswd is to
      operate on a passwd(5) format file, on a group(5) format file, or simply
      to generate a password hash, respectively.

      If used with --passwd, ftpasswd creates a file in the passwd(5) format,
      suitable for use with proftpd's AuthUserFile configuration directive.
      You will be prompted for the password to use of the user, which will be
      encrypted, and written out as the encrypted string.  New entries are
      appended to the file by default.

      By default, using --passwd will write output to "./ftpd.passwd".

      Error exit values:

      To make it easier for wrapper scripts to interact with ftpasswd, ftpasswd
      will exit with the following error values for the reasons described:

        1       no such user
        2       password matches current password
        4       password matches system password
        8       relative path given for home directory

      Options:

        --file      Write output to specified file, rather than "./ftpd.passwd"

        -F          If the file to be used already exists, delete it and write a
        --force     new one.  By default, new entries will be appended to the file.

        --gecos     Descriptive string for the given user (usually the user's
                    full name).

        --gid       Primary group ID for this user (optional, will default to
                    given --uid value if absent)

        -h          Displays this message
        --help

        --home      Home directory for the user (required)

        --des       Use the DES algorithm for encrypting passwords.  The default
                    is the MD5 algorithm.

        --md5       Use the MD5 algorithm for encrypting passwords.  This is the
                    default.

        --name      Name of the user account (required).  If the name does not
                    exist in the specified output-file, an entry will be created
                    for her.  Otherwise, the given fields will be updated.

        --shell     Shell for the user (required).  Recommended: /bin/false

        --uid       Numerical user ID (required)

        --change-password

                    Update only the password field for a user.  This option
                    requires that the --name and --passwd options be used, but no
                    others.  This also double-checks the given password against
                    the user's current password in the existing passwd file, and
                    requests that a new password be given if the entered password
                    is the same as the current password.

        --delete-user

                    Remove the entry for the given user name from the file.

        -l          Lock the password of the named account.  This option disables a
        --lock      password by changing it to a value which matches no possible
                    encrypted value (it adds a '!' at the beginning of the
                    password).

        --not-previous-password

                    Double-checks the given password against the previous password
                    for the user, and requests that a new password be given if
                    the entered password is the same as the previous password.

        --not-system-password

                    Double-checks the given password against the system password
                    for the user, and requests that a new password be given if
                    the entered password is the same as the system password.  This
                    helps to enforce different passwords for different types of
                    access.

        --sha256    Use the SHA-256 algorithm for encrypting passwords.

        --sha512    Use the SHA-512 algorithm for encrypting passwords.

        --stdin
                    Read the password directly from standard in rather than
                    prompting for it.  This is useful for writing scripts that
                    automate use of ftpasswd.

        -u          Unlock the password of the named account.  This option
        --unlock    re-enables a password by changing the password back to its
                    previous value (to the value before using the -l option).

        --use-cracklib
                    Causes ftpasswd to use Alec Muffet's cracklib routines in
                    order to determine and prevent the use of bad or weak
                    passwords.  The optional path to this option specifies
                    the path to the dictionary files to use -- default path
                    is "/usr/lib/cracklib_dict".  This requires the Perl
                    Crypt::Cracklib module to be installed on your system.

        --version
                    Displays the version of ftpasswd.

      If used with --group, ftpasswd creates a file in the group(5) format,
      suitable for use with proftpd's AuthGroupFile configuration directive.

      By default, using --group will write output to "./ftpd.group".

      Options:

        --delete-group

                    Remove the entry for the given group name from the file.

        --enable-group-passwd

                    Prompt for a group password.  This is disabled by default,
                    as group passwords are not usually a good idea at all.

        --file      Write output to specified file, rather than "./ftpd.group"

        -F          If the file be used already exists, delete it and write a new
        --force     one.  By default, new entries will be appended to the file.

        --gid       Numerical group ID (required)

        -h
        --help      Displays this message

        -m
        --member    User to be a member of the group.  This argument may be used
                    multiple times to specify the full list of users to be members
                    of this group.

        --des       Use the DES algorithm for encrypting passwords.  The default
                    is the MD5 algorithm.

        --md5       Use the MD5 algorithm for encrypting passwords.  This is the
                    default.

        --name      Name of the group (required).  If the name does not exist in
                    the specified output-file, an entry will be created for them.
                    Otherwise, the given fields will be updated.

        --sha256    Use the SHA-256 algorithm for encrypting passwords.

        --sha512    Use the SHA-512 algorithm for encrypting passwords.

        --stdin
                    Read the password directly from standard in rather than
                    prompting for it.  This is useful for writing scripts that
                    automate use of ftpasswd.

        --use-cracklib
                    Causes ftpasswd to use Alec Muffet's cracklib routines in
                    order to determine and prevent the use of bad or weak
                    passwords.  The optional path to this option specifies
                    the path to the dictionary files to use -- default path
                    is "/usr/lib/cracklib_dict".  This requires the Perl
                    Crypt::Cracklib module to be installed on your system.

        --version
                    Displays the version of ftpasswd.

      If used with --hash, ftpasswd generates a hash of a password, as would
      appear in an AuthUserFile.  The hash is written to standard out.
      This hash is suitable for use with proftpd's UserPassword directive.

      Options:

        --des       Use the DES algorithm for encrypting passwords.  The default
                    is the MD5 algorithm.

        --md5       Use the MD5 algorithm for encrypting passwords.  This is the
                    default.

        --sha256    Use the SHA-256 algorithm for encrypting passwords.

        --sha512    Use the SHA-512 algorithm for encrypting passwords.

        --stdin
                    Read the password directly from standard in rather than
                    prompting for it.  This is useful for writing scripts that
                    automate use of ftpasswd.

        --use-cracklib
                    Causes ftpasswd to use Alec Muffet's cracklib routines in
                    order to determine and prevent the use of bad or weak
                    passwords.  The optional path to this option specifies
                    the path to the dictionary files to use -- default path
                    is "/usr/lib/cracklib_dict".  This requires the Perl
                    Crypt::Cracklib module to be installed on your system.

© Copyright 2000-2016 TJ Saunders
All Rights Reserved