Description:
------------
I'm running nginx which communicates via FastCGI to php-fpm. The filter_input() function doesn't validate any of the variables which are sent via FastCGI within the global $_SERVER array.

Test script:
---------------
<?php

foreach ($_SERVER as $variable_name => $value) {
  var_dump($value);
  var_dump(filter_input(INPUT_SERVER, $variable_name, FILTER_UNSAFE_RAW));
}

?>

Expected result:
----------------
The filter_input() function should validate the variable within the $_SERVER array. I know that filter_input() can't be used if you set something in your code but in my opinion it should accept the data that was sent via FastCGI. Otherwise the function is pretty useless for non Apache users.

Actual result:
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Always returns NULL.