файл \catalog\controller\product\product.php метод write()
//проверка имени
if ((utf8_strlen($this->request->post['name']) < 3) || (utf8_strlen($this->request->post['name']) > 25)) {
$json['error'] = $this->language->get('error_name');
}
//проверка сообщения
if ((utf8_strlen($this->request->post['text']) < 25) || (utf8_strlen($this->request->post['text']) > 1000)) {
$json['error'] = $this->language->get('error_text');
}
//проверка рейтинга
if (empty($this->request->post['rating']) || $this->request->post['rating'] < 0 || $this->request->post['rating'] > 5) {
$json['error'] = $this->language->get('error_rating');
}