#!/usr/bin/perl -wT

############################################################
# login -  a perlscript to make a secure login to any site #
#                                                          #
# Requirements:                                            #
# - a server running a cgi-capable webserver               #
#   with perl being installed                              #
#   and mysql (tested with apache & linux)                 #
# - perlmodules DBI, DBD::mysql, CGI                       #
# - any use for this :)                                    #
#                                                          #
# This script is able to run at any place if you know how  #
# to configure your webserver. It runs from the cgi-bin-   #
# directory without any further configuration.             #
# If its name conflicts with your files, simply rename it  #
# and change the url at the "user config" a few lines down #
#                                                          #
# Prerequisite is to execute the sql-statements from the   #
# usertrack.sql file like this (as root):                  #
# mysqladmin create usertrack                              #
# mysql usertrack < usertrack.sql                          #
# Note that you have to modify this file for your own      #
# needs (including dbuser und dbpassword).                 #
#                                                          #
# The special features of this script are:                 #
# -no use of cookies                                       #
# -no hints about existing users from its reaction.        #
# -only one handshake of password transfer.                #
# -each request creates a new key in konjunction with the  #
#  username.                                               #
# -automated logout by reloading after a specified timeout.#
#                                                          #
############################################################

use strict;
use DBI;
DBI->trace(1);
use CGI;
use CGI::Carp qw(fatalsToBrowser);

######################
# user config starts #

my $reloadpage = "http://localhost/cgi-bin/login"; # url of this script
my $timeout    = "20";                             # seconds before logout
my $dbhost="localhost";
my $dbuser="gunny";
my $dbpass="RaZoRbLaCk";
my $dbname="usertrack";

# user config ends   #
######################

my $q = new CGI;
my $dbquery;
my $sth;
my $dbh;
my @row;
my $dbpassword;
my $short;
my $vname;
my $nname;
my $password;
my $currentstate;
my $state;
my $time = time() . rand 65535;

sub getrow {
 $dbquery = qq~
               SELECT * FROM users WHERE short='$short'
              ~;
 $sth=$dbh->prepare($dbquery);
 $sth->execute;
 @row = $sth->fetchrow_array;
 $sth->finish;
}

sub putpassword {
 $dbquery = qq~
               UPDATE users SET password='$password' WHERE vname='$vname' AND nname='$nname'
              ~;
 $sth=$dbh->prepare($dbquery);
 $sth->execute;
 $sth->finish;
}

sub putstate {
 $dbquery = qq~
               UPDATE users SET state='$currentstate' WHERE vname='$vname' AND nname='$nname'
              ~;
 $sth=$dbh->prepare($dbquery);
 $sth->execute;
 $sth->finish;
}

sub login {
print <<EOF;
<h4 align=center>Loginprompt:</h4>
<table align=center border=1 cellpadding=8  bgcolor=#CCFFFF>
<form method="post" enctype="application/x-www-form-urlencoded">
<input type=hidden name="currentstate" value=$time>
<tr><td align=center>login-name:<br><input type=text name='short'></td></tr>
<tr><td align=center>password:<br><input type=password name='password'></td></tr>
<tr><td align=center><input type=submit name="login">
<input type=reset value="Reset"></td></tr>
</form></table></center><hr>
EOF
}

sub html_end {
if ($vname) {
print <<EOF;
<h4 align=center></h4>
<table align=center border=1 cellpadding=8  bgcolor=#CCFFFF>
<form method="post" enctype="application/x-www-form-urlencoded">
</table>
<input type=submit>
<input type=reset>
<input type=hidden name=vname value=$vname>
<input type=hidden name=nname value=$nname>
<input type=hidden name=currentstate value=$currentstate>
<input type=hidden name=state value=$state>
<input type=hidden name=short value=$short>
</form></center><hr>
<center>Hallo $vname $nname</center><br>
EOF
 }
  print $q->end_html;
  $dbh->disconnect;
  exit;
}

################################################################################
#                                    main                                      #
################################################################################

# start database connectin and die if it fails
$dbh = DBI->connect("DBI:mysql:$dbname:$dbhost", $dbuser, $dbpass)|| die "Couldn't connect to db $dbname at $dbhost $DBI::errstr";

# safe control data
$short=$q->param('short');               # used to identify user all the time after login
$password=$q->param('password');         # only used at loginprocedure
$currentstate=$q->param('currentstate'); # new state if this script is invoked, created from the script
$state=$q->param('state');               # old state to verify connection coming from the database
$vname=$q->param('vname');               # data to present all the time after login and to keep contact(!)
$nname=$q->param('nname');               # data to present all the time after login

if (# user has given login-name
    ($short) and
    # was not logged in before
    (not $state)
   ) {
 # fetch user's data
 getrow;
 if (@row) {
  (undef,undef,$vname,$nname,$dbpassword,undef)=@row;
  if (# no password was given
      (not $password) or
      # password given does not match password at table
      (not ($dbpassword eq $password))
     ) {
       # erase all data to disable control
       $q->delete_all();
       undef @row;
       undef $vname;
       undef $nname;
       undef $state;
       undef $currentstate;
  }
 }
putstate;
getrow;
(undef,undef,undef,undef,undef,$state)=@row;
}

# start the html-code
# the java-script is not nescessary but focusses the cursor to the form
print $q->header();
print <<EOF;
<html>
<head>
<title>User-Tracking</title>
<meta http-equiv="refresh" content="$timeout; URL=$reloadpage">
<SCRIPT LANGUAGE="JavaScript"><!--
 function setFocus() {
     document.forms[0].elements[1].focus();
 }
 //--></SCRIPT>
</head>
<body  onLoad="setTimeout('setFocus()',1)">
</head>
<h1>User-Tracking</h1>
EOF

if (not $vname) {
    login;
    html_end;
}

# this is, where the keycode is compared to enshure it is the right user requesting this
getrow;
(undef,undef,undef,undef,undef,$state)=@row;
if ($currentstate eq $state) {
 $currentstate=$time;
 putstate;
 getrow;
 (undef,undef,undef,undef,undef,$state)=@row;
}
 elsif ($vname) {
       print "Your connections has been hijacked!!!<br>";
       print "...or the server has a current problem.<br>";
       print "Anyway, report this to the webmaster.<br>";
       print $q->end_html;
       $dbh->disconnect;
       exit;
}

# space to put in your own code

# stop html-code and exit the script
html_end;

##</code><code>##

DROP TABLE IF EXISTS users;
CREATE TABLE users (
ID INT PRIMARY KEY AUTO_INCREMENT,
short varchar(10) NOT NULL,
vname VARCHAR(50) NOT NULL,
nname VARCHAR(50) NOT NULL,
password char(16) DEFAULT '' NOT NULL,
state char(50) DEFAULT '' NOT NULL,
UNIQUE short (short)
);

INSERT INTO users VALUES ('','admin','Micky','Mouse','admin','');
INSERT INTO users VALUES ('','user1','Donald','Duck','daisy','');
INSERT INTO users VALUES ('','user2','Dagobert','Duck','gold','');

GRANT SELECT, INSERT, UPDATE, DELETE ON usertrack.* TO gunny@localhost IDENTIFIED BY 'RaZoRbLaCk'