Using ProFTPD and its SQL module for MySQL, it is possible to give FTP access to non system users.
By doing so, one can give access to a Virtual User which is only allowed to use the FTP service.

This Tutorial will show how to create and populate the user and group tables as well as configure proftpd in order to use the MySQL backend.

In order to achieve this, we will:

1. have to create a local user and group that people login in through will be run as.
2. create a database for proftpd as well as grant permissions to the proftp database user.
3. populate the database.
4. and finally, configure proftpd.

1. Requirements:

as we will be running proftpd server and we will authenticate using a mysql database, we need to install both components plus the mysql module for proftpd:

# apt-get install proftpd proftpd-mysql mysql-server

On Ubuntu and Debian, the default root password for MySQL is empty. You might want to change it by typing:

# mysqladmin -u root password 'hereismypassword'

2. Local user and group:

In our example, the ftp user uid and group gid will be 3001 (this value will be used later on). The local user we are going to create will have /dev/null as home and a shell of /bin/false.

To create the group and user type:

# groupadd -G 3001 ftpgroup
# useradd -s /bin/false -d /bin/null -c "proftpd user" --uid 3001 -g ftpgroup ftpuser

3. MySQL Database:

Now, it is time to create the database, grant a user permissions and finally create the tables.

The database will be called proftpddb and user proftpuser will be able to connect from localhost using password proftpdpassword.

3.1 Create the database:

Log into mysql as root:

# mysql -u root -p

And create the database proftpddb:

mysql> CREATE DATABASE proftpddb;
Query OK, 1 row affected (0.00 sec)

mysql> GRANT USAGE ON *.* TO proftpduser@localhost IDENTIFIED BY 'proftpdpassword';
Query OK, 0 rows affected (0.00 sec)

mysql> GRANT SELECT, INSERT, UPDATE, DELETE ON proftpddb.* TO 'proftpduser'@'localhost';
Query OK, 0 rows affected (0.00 sec)

mysql> quit

After we create the database and gave access to a specific user we have to create the tables that are going to host our groups and users.

3.2. Creating database tables:

There is different ways of creating the tables. Either interactively through mysql command line or by using a sql dump file.
In this tutorial we will create a dump file and inject it directly from the shell command line.

Copy the following text in a file called proftpd-mysql.sql:

CREATE TABLE ftpgroup (
 groupname varchar(16) NOT NULL default '',
 gid smallint(6) NOT NULL default '3000',
 members varchar(16) NOT NULL default '',
 KEY groupname (groupname)
 ) TYPE=MyISAM COMMENT='ProFTPd group table';

 

 CREATE TABLE ftpuser (
 id int(10) unsigned NOT NULL auto_increment,
 userid varchar(32) NOT NULL default '',
 passwd varchar(80) NOT NULL default '',
 uid smallint(6) NOT NULL default '3000',
 gid smallint(6) NOT NULL default '3000',
 homedir varchar(255) NOT NULL default '',
 shell varchar(16) NOT NULL default '/sbin/nologin',
 count int(11) NOT NULL default '0',
 accessed datetime NOT NULL default '0000-00-00 00:00:00',
 modified datetime NOT NULL default '0000-00-00 00:00:00',
 PRIMARY KEY (id),
 UNIQUE KEY userid (userid)
 ) TYPE=MyISAM COMMENT='ProFTPd user table';

Save it and finally type:

# mysql -u root -p proftpddb < proftpd-mysql.sql

Note that this must be done as root since proftpduser does not have credentials for creating tables in database proftpddb.

Finally, we are going to create our first virtual ftp user and group.

3.3. First user and group:

In order to create our first user and password, we are going to connect using the database user access we have just created:

# mysql -u proftpduser -p proftpddb

and create your first group:

mysql> INSERT INTO `ftpgroup` (`groupname`, `gid`, `members`) VALUES ('ftpgroup', 3001, 'ftpuser');

and your first user which is going to belong to this group:

mysql> INSERT INTO `ftpuser` (`id`, `userid`, `passwd`, `uid`, `gid`, `homedir`, `shell`, `count`, `accessed`, `modified`) VALUES (1, 'firstuser', PASSWORD('userpassword'), 3001, 3001, '/var/proftp/firstuser', '/sbin/nologin', 0, '', '');

In order to have your user able to copy and delete files to their home dir, you have to create /var/proftp and give proftpuser/proftpgroup write access to it:

# mkdir /var/proftp
# chown ftpuser:ftpgroup /var/proftp
# chmod 775 /var/proftp

Well, now, we still need to configure proFTPd to use our newly create mysql database as a backend.