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CSRF
<?php
class csrf {
public function get_token_id() {
if(isset($_SESSION['token_id'])) {
return $_SESSION['token_id'];
} else {
$token_id = $this->random(10);
$_SESSION['token_id'] = $token_id;
return $token_id;
}
}
public function get_token() {
if(isset($_SESSION['token_value'])) {
return $_SESSION['token_value'];
} else {
$token = hash('sha256', $this->random(500));
$_SESSION['token_value'] = $token;
return $token;
}
}
public function check_valid($method) {
if($method == 'post' || $method == 'get') {
$post = $_POST;
$get = $_GET;
if(isset(${$method}[$this->get_token_id()]) && (${$method}[$this->get_token_id()] == $this->get_token())) {
return true;
} else {
return false;
}
} else {
return false;
}
}
private function random($len) {
if (function_exists('openssl_random_pseudo_bytes')) {
$byteLen = intval(($len / 2) + 1);
$return = substr(bin2hex(openssl_random_pseudo_bytes($byteLen)), 0, $len);
} elseif (@is_readable('/dev/urandom')) {
$f=fopen('/dev/urandom', 'r');
$urandom=fread($f, $len);
fclose($f);
$return = '';
}
if (empty($return)) {
for ($i=0;$i<$len;++$i) {
if (!isset($urandom)) {
if ($i%2==0) {
mt_srand(time()%2147 * 1000000 + (double)microtime() * 1000000);
}
$rand=48+mt_rand()%64;
} else {
$rand=48+ord($urandom[$i])%64;
}
if ($rand>57)
$rand+=7;
if ($rand>90)
$rand+=6;
if ($rand==123) $rand=52;
if ($rand==124) $rand=53;
$return.=chr($rand);
}
}
return $return;
}
}
?>
<?php
session_start();
include 'csrf.class.php';
$csrf = new csrf();
// Generate Token Id and Valid
$token_id = $csrf->get_token_id();
$token_value = $csrf->get_token($token_id);
?>
<form action="submit.php" method="post">
<input type="hidden" name="<?= $token_id; ?>" value="<?= $token_value; ?>" />
<input type="submit" value="Login"/>
</form>
<?php
session_start();
include 'csrf.class.php';
$csrf = new csrf();
// Generate Token Id and Valid
$token_id = $csrf->get_token_id();
$token_value = $csrf->get_token($token_id);
if($csrf->check_valid('post')) {
var_dump($_POST[$token_id]);
} else {
echo 'Not Valid';
}
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