[wechall] PHP 0818

Source Analysis

<?php
chdir('../../../');
define('GWF_PAGE_TITLE', 'PHP 0818');
require_once('challenge/html_head.php');
if (false === ($chall = WC_Challenge::getByTitle(GWF_PAGE_TITLE))) {
    $chall = WC_Challenge::dummyChallenge(GWF_PAGE_TITLE, 3, 'challenge/noother/php0818/index.php', false);
}
$chall->showHeader();
# ------ 8< ------ 8< ------ 8< ------ 8< ------ #
if (isset($_POST['answer']))
{
    if (noother_says_correct(Common::getPostString('number')))
    {
        $chall->onChallengeSolved(GWF_Session::getUserID());
    }
    else
    {
        echo GWF_HTML::error('PHP 0818', $chall->lang('err_wrong'), false);
    }
}
function noother_says_correct($number)
{
    $one = ord('1');
    $nine = ord('9');
    # Check all the input characters!
    for ($i = 0; $i < strlen($number); $i++)
    {
        # Disallow all the digits!
        $digit = ord($number{$i});
        if ( ($digit >= $one) && ($digit <= $nine) )
        {
            # Aha, digit not allowed!
            return false;
        }
    }

    # Allow the magic number ...
    return $number == "3735929054";
}
# ------ 8< ------ 8< ------ 8< ------ 8< ------ #
?>
<div class="box box_c">
    <form action="php0818.php" method="post" enctype="application/x-www-form-urlencoded">
        <div><?php echo $chall->lang('your_magic_number'); ?>: <input type="text" name="number" value="" size="10" /></div>
        <div><input type="submit" name="answer" value="<?php echo $chall->lang('btn_submit'); ?>" /></div>
    </form>
</div>
<?php
# Foo-Tah!
echo $chall->copyrightFooter();
require_once('challenge/html_foot.php');
?>

solve

• 3735929054의 16진수 값