#! /usr/local/bin/perl

#  Copyright (c) 2006-2008 Frédéric Senault.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. Neither the name of the author or any contributors may be used to
#    endorse or promote products derived from this software without
#    specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AHTOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

use strict;

our %attributes;

my $MAX = 4;
my $FILE = '/etc/news/users';

sub auth_init {
  #
}

sub authenticate {
  my $oc = 0;
  my $ok = 0;
  open(P, '/bin/ps -ax |') && do {
    while(<P>) {
      if(/nnrpd: (\S*)/) {
        if($1 eq $attributes{hostname}) {
          $oc++;
        }
      }
    }
    close(P);
  };
  if($oc > $MAX) {
    sleep(2);
    return ( '502', 'Too many connections from your host' );
  }
  my $p;
  open(F, $FILE) && do {
    while(<F>) {
      if(/^$attributes{username}:([^:]*):/) {
        my $salt;
        $salt = substr($1, 0, 2);
        if(crypt($attributes{password}, $salt) eq $1) {
          $ok = 1;
        }
        last;
      }
    }
    close(F);
  };
  if($ok) {
    return ( '281', 'Ok' );
  } else {
    sleep(2);
    return ( '502', 'Authentication error' );
  }
}