#!perl -Tw

=head1 NAME

auth_flat_file - simple CRAM MD5 auth plugin using a flat password file

=head1 SYNOPSIS

in config/plugins:

  auth/auth_flat_file

in config/flat_auth_pw

  username1:password1
  username2:password2
  ...

=head1 DESCRIPTION

This plugin implements a very simple authentication plugin using a flat password
file containing username and password separated by colons.

Note that this plugin enforces the use of a full email address (including
@domain) as the username. There's no particular reason for this so feel free
to modify the code to suit your setup.

The password is stored on disk unencrypted, however authentication uses a HMAC
algorithm so no password is transfered in the clear.

=cut

use Digest::HMAC_MD5 qw(hmac_md5_hex);

sub register {
    my ( $self, $qp ) = @_;

    $self->register_hook("auth-cram-md5", "auth_flat_file");
}

sub auth_flat_file {
    my ( $self, $transaction, $method, $user, $passClear, $passHash, $ticket ) =
      @_;

    my ( $pw_name, $pw_domain ) = split "@", lc($user);

    unless ( defined $pw_domain ) {
        return DECLINED;
    }

    $self->log(LOGINFO, "Authentication for: $pw_name\@$pw_domain");

    my ($auth_line) = grep {/^$pw_name\@$pw_domain:/} $self->qp->config('flat_auth_pw');
    
    unless (defined $auth_line) {
        return DECLINED;
    }
    
    my ($auth_user, $auth_pass) = split(/:/, $auth_line, 2);
    
    # at this point we can assume the user name matched
    if (
        ( defined $passClear
            and $auth_pass eq $passClear ) or
        ( defined $passHash
            and $passHash eq hmac_md5_hex($ticket, $auth_pass) )
      )
    {
        return ( OK, "authflat/$method" );
    }
    else {
        return ( DENY, "authflat/$method - wrong password" );
    }
}