laravel-validation-cpf.php

<?php
Validator::extend('cpf', function($attribute, $value, $params, $validator){
    $cpf = $value;
    $cpf = preg_replace('/[^0-9]/', '', $cpf);
    $cpf = str_pad($cpf, 11, '0', STR_PAD_LEFT);
    if (strlen($cpf) != 11)
        return false;
    $cpfsCheck = [
        '00000000000', 
        '11111111111', 
        '22222222222', 
        '33333333333', 
        '44444444444', 
        '55555555555', 
        '66666666666', 
        '77777777777', 
        '88888888888', 
        '99999999999'
    ];
    if(in_array($value, $cpfsCheck))
        return false;

    for ($t = 9; $t < 11; $t++) {
        for ($d = 0, $c = 0; $c < $t; $c++) {
            $d += $cpf{$c} * (($t + 1) - $c);
        }
        $d = ((10 * $d) % 11) % 10;
        if ($cpf{$c} != $d) {
            return false;
        }
    }
    return true;
});