How to enable password changing on remote host in roundcube on FreeBSD

Roundcube comes with a password change module, through it's disabled by default. Configuring it to change passwords on another server's passwd database is another matter. The instructions only cover using chpasswd on a Linux server to update the local password database.

On the mail server:

• adduser roundcube, set a shell and create a home directory.
• visudo, adding roundcube ALL = NOPASSWD: /usr/sbin/pw

On the web server:

• chpass www, assigning a shell to allow logins.
• su www, impersonate www.
• ssh-keygen -t rsa, create an RSA private/public key pair.
• scp /home/www/.ssh/id_rsa.pub roundcube@<em>remotehost</em>/~/.ssh/authorized_keys, copying the public key to the mail server to allow passwordless logins.

The chpasswd driver (/www/roundcube/plugins/password/drivers/chpasswd.php will require modification.

function password_save($currpass, $newpass) { 
    $cmd = rcmail::get_instance()->config->get('password_chpasswd_cmd'); 
    $username = $_SESSION['username']; 
    $handle = popen($cmd, "w"); 
 
    fwrite($handle, "$newpass
"); 
    if (pclose($handle) == 0) { return PASSWORD_SUCCESS; }     
    else { 
        raise_error(array( 'code' => 600, 'type' => 'php', 'file' => __FILE__, 'line' => __LINE__, 'message' => "Password plugin: Unable to execute $cmd" ), true, false); 
    } 
    return PASSWORD_ERROR; 
}

And so will this line in /www/roundcube/plugins/password/config.inc.php

// chpasswd Driver options 
// --------------------- 
// Command to use 
$rcmail_config['password_chpasswd_cmd'] = "ssh roundcube@mailhost sudo pw usermod -n {$_SESSION['username']} -h 0 2> /dev/null";