""" Copyright (c) 2015 Ad Schellevis All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -------------------------------------------------------------------------------------- rule downloader module (may need to be extended in the future, this version only processes http(s)) """ import syslog import requests class Downloader(object): def __init__(self, target_dir): self._target_dir = target_dir def filter(self, in_data, filter_type): """ apply input filter to downloaded data :param in_data: raw input data (ruleset) :param filter_type: filter type to use on input data :return: ruleset data """ if filter_type == "drop": return self.filter_drop(in_data) else: return in_data def filter_drop(self, in_data): """ change all alert rules to block :param in_data: raw input data (ruleset) :return: new ruleset """ output = list() for line in in_data.split('\n'): if len(line) > 10: if line[0:5] == 'alert': line = 'drop %s' % line[5:] elif line[0:6] == '#alert': line = '#drop %s' % line[5:] output.append(line) return '\n'.join(output) def download(self, proto, url, filename, input_filter): """ download ruleset file :param proto: protocol (http,https) :param url: download url :param filename: target filename :param input_filter: filter to use on received data before save """ if proto in ('http', 'https'): frm_url = url.replace('//', '/').replace(':/', '://') req = requests.get(url=frm_url) if req.status_code == 200: try: target_filename = '%s/%s' % (self._target_dir, filename) save_data = self.filter(req.text, input_filter) open(target_filename, 'wb').write(save_data) except IOError: syslog.syslog(syslog.LOG_ERR, 'cannot write to %s' % target_filename) return None syslog.syslog(syslog.LOG_INFO, 'download completed for %s' % frm_url) else: syslog.syslog(syslog.LOG_ERR, 'download failed for %s' % frm_url) @staticmethod def is_supported(proto): """ check if protocol is supported :param proto: :return: """ if proto in ['http', 'https']: return True else: return False