#!/usr/local/bin/perl
#
# CC-Verify script for Visa, MasterCard, Amex and Novus Cards
# Written 29 June 1996 by Spider (spider@servtech.com)
# http://w3works.com
# http://www.servtech.com/public/spider
#
# Loosely based on a re-post of original by Melvyn Myers 
# (initial author unknown) but this revision covers all 13, 
# 15 and 16 digit cards using the Mod 10 algorithm.

##############################################################################
# COPYRIGHT NOTICE                                                           #
# Copyright 1996 Dave Paris (aka Spider)  All Rights Reserved.               #
#                                                                            #
# The Validator may be used and modified free of charge by anyone so long as #
# this copyright notice and the comments above remain intact.  By using this #
# code you agree to indemnify Dave Paris from any liability that might       #  
# arise from it's use.                                                       #  
#                                                                            #
# Selling the code for this program without prior written consent is         #
# expressly forbidden.  In other words, please ask first before you try and  #
# make money off of my program.                                              #
#                                                                            #
# Obtain permission before redistributing this software over the Internet or #
# in any other medium.  In all cases copyright and header must remain intact.#
# This Copyright is in full effect in any country that has International     #
# Trade Agreements with the United States of America.                        #
##############################################################################

# Get the input
read(STDIN, $buffer, $ENV{'CONTENT_LENGTH'});

# Split the name-value pairs
@pairs = split(/&/, $buffer);

foreach $pair (@pairs)
{
    ($name, $value) = split(/=/, $pair);

    # Un-Webify plus signs and %-encoding
    $value =~ tr/+/ /;
    $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;

    # Stop people from using subshells to execute commands
    # Not a big deal when using sendmail, but very important
    # when using UCB mail (aka mailx).
      $value =~ s/~!/ ~!/g;

    # Uncomment for debugging purposes
    # print "Setting $name to $value<P>";

    $FORM{$name} = $value;
    if ($value =~ /\<\!--\#(.*)\s+(.*)\s?=\s?(.*)--\>/) { &kill_input; }
    if ($value =~ /[;><\*`\|]/) { &kill_input; }    
}

print "Content-type: text/html\n\n";

if ($FORM{'payby'} eq "yes") {
    &no_data unless $FORM{'cardholder'};
    &no_data unless $FORM{'cardnumber'};
    &no_data unless $FORM{'cardexp'};
    &CC_Verify;
} else {
    print "Thanks\n";
# You may choose to place something else here, like calling a printable form subroutine
    exit;
}

    
sub CC_Verify {

$cardnumber = $FORM{'cardnumber'}; 

# Remove any spaces or dashes in card number
$cardnumber =~ s/ //g;
$cardnumber =~ s/-//g;
$length = length($cardnumber);

# Make sure that only numbers exist
if (!($cardnumber =~ /^[0-9]*$/)) {
 &invalid_cc;
 }

# Verify correct length for each card type
if ($FORM{'cardtype'} eq "visa") { &vlen; }
if ($FORM{'cardtype'} eq "mastercard") { &mclen; }
if ($FORM{'cardtype'} eq "amex") { &alen; }
if ($FORM{'cardtype'} eq "novus") { &nlen; }

sub vlen {
    &invalid_cc unless (($length ==13) || ($length == 16));
}
sub mclen {
    &invalid_cc unless ($length == 16);    
}
sub alen {
    &invalid_cc unless ($length == 15);    
}
sub nlen {
    &invalid_cc unless ($length == 16);    
}

# Now Verify via Mod 10 for each one
if ($FORM{'cardtype'} eq "visa") { &vver; }
if ($FORM{'cardtype'} eq "mastercard") { &ver16; }
if ($FORM{'cardtype'} eq "amex") { &ver15; }
if ($FORM{'cardtype'} eq "novus") { &ver16; }

# pick one for Visa
sub vver {
	if ($length == 13) { &ver13; }
	if ($length == 16) { &ver16; }
}

# For 13 digit cards
sub ver13 {
        $cc0 = substr($cardnumber,0,1);
        $cc1 = substr($cardnumber,1,1);
        $cc2 = substr($cardnumber,2,1);
        $cc3 = substr($cardnumber,3,1);
        $cc4 = substr($cardnumber,4,1);
        $cc5 = substr($cardnumber,5,1);
        $cc6 = substr($cardnumber,6,1);
        $cc7 = substr($cardnumber,7,1);
        $cc8 = substr($cardnumber,8,1);
        $cc9 = substr($cardnumber,9,1);
        $cc10 = substr($cardnumber,10,1);
        $cc11 = substr($cardnumber,11,1);
        $cc12 = substr($cardnumber,12,1);

        $cc1a = $cc1 * 2;
        $cc3a = $cc3 * 2;
        $cc5a = $cc5 * 2;
        $cc7a = $cc7 * 2;
        $cc9a = $cc9 * 2;
        $cc11a = $cc11 * 2;

        if ($cc1a >= 10) {
            $cc1b = substr($cc1a,0,1);
            $cc1c = substr($cc1a,1,1);
            $cc1 = $cc1b+$cc1c;
        } else {
            $cc1 = $cc1a;
        }
        if ($cc3a >= 10) {
            $cc3b = substr($cc3a,0,1);
            $cc3c = substr($cc3a,1,1);
            $cc3 = $cc3b+$cc3c;
        } else {
            $cc3 = $cc3a;
        }
        if ($cc5a >= 10) {
            $cc5b = substr($cc5a,0,1);
            $cc5c = substr($cc5a,1,1);
            $cc5 = $cc5b+$cc5c;
        } else {
            $cc5 = $cc5a;
        }
        if ($cc7a >= 10) {
            $cc7b = substr($cc7a,0,1);
            $cc7c = substr($cc7a,1,1);
            $cc7 = $cc7b+$cc7c;
        } else {
            $cc7 = $cc7a;
        }
        if ($cc9a >= 10) {
            $cc9b = substr($cc9a,0,1);
            $cc9c = substr($cc9a,1,1);
            $cc9 = $cc9b+$cc9c;
        } else {
            $cc9 = $cc9a;
        }
        if ($cc11a >= 10) {
            $cc11b = substr($cc11a,0,1);
            $cc11c = substr($cc11a,1,1);
            $cc11 = $cc11b+$cc11c;
        } else {
            $cc11 = $cc11a;
        }

        $val = $cc0+$cc1+$cc2+$cc3+$cc4+$cc5+$cc6+$cc7+$cc8+$cc9+$cc10+$cc11+$cc12;
        if (substr($val,1,1) !=0 ) {
            &invalid_cc;
        }
	}

# For 16 digit cards
sub ver16 {
        $cc0 = substr($cardnumber,0,1);
        $cc1 = substr($cardnumber,1,1);
        $cc2 = substr($cardnumber,2,1);
        $cc3 = substr($cardnumber,3,1);
        $cc4 = substr($cardnumber,4,1);
        $cc5 = substr($cardnumber,5,1);
        $cc6 = substr($cardnumber,6,1);
        $cc7 = substr($cardnumber,7,1);
        $cc8 = substr($cardnumber,8,1);
        $cc9 = substr($cardnumber,9,1);
        $cc10 = substr($cardnumber,10,1);
        $cc11 = substr($cardnumber,11,1);
        $cc12 = substr($cardnumber,12,1);
        $cc13 = substr($cardnumber,13,1);
        $cc14 = substr($cardnumber,14,1);
        $cc15 = substr($cardnumber,15,1);

        $cc0a = $cc0 * 2;
        $cc2a = $cc2 * 2;
        $cc4a = $cc4 * 2;
        $cc6a = $cc6 * 2;
        $cc8a = $cc8 * 2;
        $cc10a = $cc10 * 2;
        $cc12a = $cc12 * 2;
        $cc14a = $cc14 * 2;

        if ($cc0a >= 10) {
            $cc0b = substr($cc0a,0,1);
            $cc0c = substr($cc0a,1,1);
            $cc0 = $cc0b+$cc0c;
        } else {
            $cc0 = $cc0a;
        }
        if ($cc2a >= 10) {
            $cc2b = substr($cc2a,0,1);
            $cc2c = substr($cc2a,1,1);
            $cc2 = $cc2b+$cc2c;
        } else {
            $cc2 = $cc2a;
        }
        if ($cc4a >= 10) {
            $cc4b = substr($cc4a,0,1);
            $cc4c = substr($cc4a,1,1);
            $cc4 = $cc4b+$cc4c;
        } else {
            $cc4 = $cc4a;
        }
        if ($cc6a >= 10) {
            $cc6b = substr($cc6a,0,1);
            $cc6c = substr($cc6a,1,1);
            $cc6 = $cc6b+$cc6c;
        } else {
            $cc6 = $cc6a;
        }
        if ($cc8a >= 10) {
            $cc8b = substr($cc8a,0,1);
            $cc8c = substr($cc8a,1,1);
            $cc8 = $cc8b+$cc8c;
        } else {
            $cc8 = $cc8a;
        }
        if ($cc10a >= 10) {
            $cc10b = substr($cc10a,0,1);
            $cc10c = substr($cc10a,1,1);
            $cc10 = $cc10b+$cc10c;
        } else {
            $cc10 = $cc10a;
        }
        if ($cc12a >= 10) {
            $cc12b = substr($cc12a,0,1);
            $cc12c = substr($cc12a,1,1);
            $cc12 = $cc12b+$cc12c;
        } else {
            $cc12 = $cc12a;
        }
        if ($cc14a >= 10) {
            $cc14b = substr($cc14a,0,1);
            $cc14c = substr($cc14a,1,1);
            $cc14 = $cc14b+$cc14c;
        } else {
            $cc14 = $cc14a;
        }

        $val = $cc0+$cc1+$cc2+$cc3+$cc4+$cc5+$cc6+$cc7+$cc8+$cc9+$cc10+$cc11+$cc12+$cc13+$cc14+$cc15;
        if (substr($val,1,1) !=0 ) {
            &invalid_cc;
        }
    }


# For 15 digit (Amex) cards
sub ver15 {
        $cc0 = substr($cardnumber,0,1);
        $cc1 = substr($cardnumber,1,1);
        $cc2 = substr($cardnumber,2,1);
        $cc3 = substr($cardnumber,3,1);
        $cc4 = substr($cardnumber,4,1);
        $cc5 = substr($cardnumber,5,1);
        $cc6 = substr($cardnumber,6,1);
        $cc7 = substr($cardnumber,7,1);
        $cc8 = substr($cardnumber,8,1);
        $cc9 = substr($cardnumber,9,1);
        $cc10 = substr($cardnumber,10,1);
        $cc11 = substr($cardnumber,11,1);
        $cc12 = substr($cardnumber,12,1);
        $cc13 = substr($cardnumber,13,1);
        $cc14 = substr($cardnumber,14,1);

        $cc1a = $cc1 * 2;
        $cc3a = $cc3 * 2;
        $cc5a = $cc5 * 2;
        $cc7a = $cc7 * 2;
        $cc9a = $cc9 * 2;
        $cc11a = $cc11 * 2;
        $cc13a = $cc13 * 2;

        if ($cc1a >= 10) {
            $cc1b = substr($cc1a,0,1);
            $cc1c = substr($cc1a,1,1);
            $cc1 = $cc1b+$cc1c;
        } else {
            $cc1 = $cc1a;
        }
        if ($cc3a >= 10) {
            $cc3b = substr($cc3a,0,1);
            $cc3c = substr($cc3a,1,1);
            $cc3 = $cc3b+$cc3c;
        } else {
            $cc3 = $cc3a;
        }
        if ($cc5a >= 10) {
            $cc5b = substr($cc5a,0,1);
            $cc5c = substr($cc5a,1,1);
            $cc5 = $cc5b+$cc5c;
        } else {
            $cc5 = $cc5a;
        }
        if ($cc7a >= 10) {
            $cc7b = substr($cc7a,0,1);
            $cc7c = substr($cc7a,1,1);
            $cc7 = $cc7b+$cc7c;
        } else {
            $cc7 = $cc7a;
        }
        if ($cc9a >= 10) {
            $cc9b = substr($cc9a,0,1);
            $cc9c = substr($cc9a,1,1);
            $cc9 = $cc9b+$cc9c;
        } else {
            $cc9 = $cc9a;
        }
        if ($cc11a >= 10) {
            $cc11b = substr($cc11a,0,1);
            $cc11c = substr($cc11a,1,1);
            $cc11 = $cc11b+$cc11c;
        } else {
            $cc11 = $cc11a;
        }
        if ($cc13a >= 10) {
            $cc13b = substr($cc13a,0,1);
            $cc13c = substr($cc13a,1,1);
            $cc13 = $cc13b+$cc13c;
        } else {
            $cc13 = $cc13a;
        }

        $val = $cc0+$cc1+$cc2+$cc3+$cc4+$cc5+$cc6+$cc7+$cc8+$cc9+$cc10+$cc11+$cc12+$cc13+$cc14;
        if (substr($val,1,1) !=0 ) {
            &invalid_cc;
        }
    }


}

#####
#
# This Section For Anything Past CC Validation
#
#####
print "Thank You\!  Your Card Has Passed Validation.  It will now be submitted for Charge Authorization.\n";
exit;

sub invalid_cc {
    print "The Credit Card number you've supplied does not pass verification.  Please \n";
    print "use your <B>Back</B> button and verify that the number you've entered is correct \n";
    print "and contains no additional characters other than spaces or hyphens.\n";
    exit;
}

sub kill_input {
    print "Content-type: text/html\n\n";
    $value = "";
    print "<CENTER><H1><FONT COLOR=\"\#FF0000\">CGI Alert</FONT></H1></CENTER>\n";
    print "<CENTER><H3>It appears as though you've tried to \n";
    print "execute a system command via a SSI tag or shell metacharacter. \n";
    print "Please use your <B>Back</B> button, remove the tags or characters and re-submit. \n";
    print "Thanks\!</H3></CENTER>\n";
    exit;
}

sub no_data {
    print "It would seem that you've forgotten to fill in one or more of \n";
    print "the required fields.  Please use your <B>Back</B> button to \n";
    print "do that now.  Thanks\!\n";
    exit;
}