| #!/usr/bin/env python3 |
| # -*- coding: utf-8 -*- |
| # Licensed to the Apache Software Foundation (ASF) under one or more |
| # contributor license agreements. See the NOTICE file distributed with |
| # this work for additional information regarding copyright ownership. |
| # The ASF licenses this file to You under the Apache License, Version 2.0 |
| # (the "License"); you may not use this file except in compliance with |
| # the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| import asyncio |
| import aiohttp |
| import aiohttp.web |
| import aiohttp.client_exceptions |
| import urllib.parse |
| import yaml |
| import time |
| import re |
| import asfpy.syslog |
| import typing |
| import multidict |
| import spamfilter |
| |
| # Shadow print with our syslog wrapper |
| print = asfpy.syslog.Printer(stdout=True, identity="aardvark") |
| |
| |
| # Some defaults to keep this running without a yaml |
| DEFAULT_PORT = 4321 |
| DEFAULT_BACKEND = "http://localhost:8080" |
| DEFAULT_IPHEADER = "x-forwarded-for" |
| DEFAULT_BLOCK_MSG = "No Cookie!" |
| DEFAULT_DEBUG = False |
| DEFAULT_NAIVE = True |
| DEFAULT_SPAM_NAIVE_THRESHOLD = 60 |
| MINIMUM_SCAN_LENGTH = 16 # We don't normally scan form data elements with fewer than 16 chars |
| |
| |
| class Aardvark: |
| def __init__(self, config_file: str = "aardvark.yaml"): |
| """ Load and parse the config """ |
| |
| # Type checking hints for mypy |
| self.scan_times: typing.List[float] |
| self.last_batches: typing.List[float] |
| self.processing_times: typing.List[float] |
| self.offenders: typing.Set[str] |
| self.spamurls: typing.Set[re.Pattern] |
| self.postmatches: typing.Set[re.Pattern] |
| self.multispam_auxiliary: typing.Set[re.Pattern] |
| self.multispam_required: typing.Set[re.Pattern] |
| |
| # Init vars with defaults |
| self.config = {} # Our config, unless otherwise specified in init |
| self.debug = False # Debug prints, spammy! |
| self.block_msg = DEFAULT_BLOCK_MSG |
| self.proxy_url = DEFAULT_BACKEND # Backend URL to proxy to |
| self.port = DEFAULT_PORT # Port we listen on |
| self.ipheader = DEFAULT_IPHEADER # Standard IP forward header |
| self.last_batches = [] # Last batches of requests for stats |
| self.scan_times = [] # Scan times for stats |
| self.processing_times = [] # Request proxy processing times for stats |
| self.postmatches = set() # SPAM POST data simple matches |
| self.spamurls = set() # Honey pot URLs |
| self.ignoreurls = set() # URLs we should not scan |
| self.multispam_required = set() # Multi-Match required matches |
| self.multispam_auxiliary = set() # Auxiliary Multi-Match strings |
| self.offenders = set() # List of already known offenders (block right out!) |
| self.naive_threshold = DEFAULT_SPAM_NAIVE_THRESHOLD |
| self.enable_naive = DEFAULT_NAIVE |
| |
| # If config file, load that into the vars |
| if config_file: |
| self.config = yaml.safe_load(open(config_file, "r")) |
| self.debug = self.config.get("debug", self.debug) |
| self.proxy_url = self.config.get("proxy_url", self.proxy_url) |
| self.port = int(self.config.get("port", self.port)) |
| self.ipheader = self.config.get("ipheader", self.ipheader) |
| self.block_msg = self.config.get("spam_response", self.block_msg) |
| self.enable_naive = self.config.get("enable_naive_scan", self.enable_naive) |
| self.naive_threshold = self.config.get("naive_spam_threshold", self.naive_threshold) |
| for pm in self.config.get("postmatches", []): |
| r = re.compile(bytes(pm, encoding="utf-8"), flags=re.IGNORECASE) |
| self.postmatches.add(r) |
| for su in self.config.get("spamurls", []): |
| r = re.compile(su, flags=re.IGNORECASE) |
| self.spamurls.add(r) |
| self.ignoreurls = self.config.get("ignoreurls", []) |
| multimatch = self.config.get("multimatch", {}) |
| if multimatch: |
| for req in multimatch.get("required", []): |
| r = re.compile(bytes(req, encoding="utf-8"), flags=re.IGNORECASE) |
| self.multispam_required.add(r) |
| for req in multimatch.get("auxiliary", []): |
| r = re.compile(bytes(req, encoding="utf-8"), flags=re.IGNORECASE) |
| self.multispam_auxiliary.add(r) |
| if self.enable_naive: |
| print("Loading Naïve Bayesian spam filter...") |
| self.spamfilter = spamfilter.BayesScanner() |
| |
| def scan_simple(self, request_url: str, post_data: bytes = None): |
| """Scans post data for spam""" |
| bad_items = [] |
| |
| # Check for honey pot URLs |
| for su in self.spamurls: |
| if su.match(request_url): |
| bad_items.append(f"Request URL '{request_url}' matches honey pot URL '{su.pattern}'") |
| |
| # Standard POST data simple matches |
| for pm in self.postmatches: |
| if pm.search(post_data): |
| bad_items.append("Found offending match in POST data: " + str(pm.pattern, encoding="utf-8")) |
| |
| # Multimatch check where one _required_ match is needed, PLUS one or more _auxiliary_ matches. |
| # Thus, "phone support" does not match, but "for phone support, call 1-234-453-2383" will. |
| for req in self.multispam_required: |
| if req.search(post_data): |
| for aux in self.multispam_auxiliary: |
| if aux.search(post_data): |
| bad_items.append( |
| f"Found multi-match in POST data: '%s' + '%s'" |
| % (str(req.pattern, encoding="utf-8"), str(aux.pattern, encoding="utf-8")) |
| ) |
| |
| return bad_items |
| |
| def scan_dict(self, post_dict: multidict.MultiDictProxy): |
| """Scans form data dicts for spam""" |
| bad_items = [] |
| for k, v in post_dict.items(): |
| if v and isinstance(v, str) and len(v) >= MINIMUM_SCAN_LENGTH: |
| b = bytes(v, encoding="utf-8") |
| bad_items.extend(self.scan_simple(f"formdata::{k}", b)) |
| # Use the naïve scanner as well? |
| if self.enable_naive: |
| res = self.spamfilter.scan_text(v) |
| if res >= self.naive_threshold: |
| bad_items.append(f"Form element {k} has spam score of {res}, crosses threshold of {self.naive_threshold}!") |
| return bad_items |
| |
| async def proxy(self, request: aiohttp.web.Request): |
| """Handles each proxy request""" |
| request_url = "/" + request.match_info["path"] |
| now = time.time() |
| target_url = urllib.parse.urljoin(self.proxy_url, request_url) |
| if self.ipheader: |
| remote_ip = request.headers.get(self.ipheader, request.remote) |
| else: |
| remote_ip = request.remote |
| if self.debug: |
| print(f"Proxying request to {target_url}...") # This can get spammy, default is to not show it. |
| |
| # Debug output for syslog |
| self.last_batches.append(time.time()) |
| if len(self.last_batches) >= 5000: |
| diff = self.last_batches[-1] - self.last_batches[0] |
| diff += 0.01 |
| self.last_batches = [] |
| print("Last 5k anti spam scans done at %.2f req/sec" % (5000 / diff)) |
| if self.processing_times: |
| avg = sum(self.processing_times) / len(self.processing_times) |
| self.processing_times = [] |
| print("Average request proxy response time is %.2f ms" % (avg * 1000.0)) |
| if self.scan_times: |
| avg = sum(self.scan_times) / len(self.scan_times) |
| self.scan_times = [] |
| print("Average request scan time is %.2f ms" % (avg * 1000.0)) |
| |
| # Read POST data and query string |
| post_dict = await request.post() # Request data as key/value pairs if applicable |
| post_data = None |
| if not post_dict: |
| post_data = await request.read() # Request data as a blob if not valid form data |
| get_data = request.rel_url.query |
| |
| # Perform scan! |
| bad_items = [] |
| |
| # Check if offender is in out registry already |
| if remote_ip in self.offenders: |
| bad_items.append("Client is on the list of bad offenders.") |
| else: |
| bad_items = [] |
| if post_data: |
| bad_items.extend(self.scan_simple(request_url, post_data)) |
| elif post_dict: |
| bad_items.extend(self.scan_dict(post_dict)) |
| # If this URL is actually to be ignored, forget all we just did! |
| if bad_items: |
| for iu in self.ignoreurls: |
| if iu in request_url: |
| print(f"Spam was detected from {remote_ip} but URL '{request_url} is on ignore list, so...") |
| bad_items = [] |
| break |
| |
| if bad_items: |
| print(f"Request from {remote_ip} to '{request_url}' contains possible spam:") |
| for item in bad_items: |
| print(f"[{remote_ip}]: {item}") |
| |
| # Done with scan, log how long that took |
| self.scan_times.append(time.time() - now) |
| |
| # If bad items were found, don't proxy, return empty response |
| if bad_items: |
| self.offenders.add(remote_ip) |
| self.processing_times.append(time.time() - now) |
| return aiohttp.web.Response(text=self.block_msg, status=403) |
| |
| async with aiohttp.ClientSession() as session: |
| try: |
| req_headers = request.headers.copy() |
| if post_dict: |
| del req_headers["content-length"] |
| async with session.request( |
| request.method, |
| target_url, |
| headers=req_headers, |
| params=get_data, |
| data=post_dict or post_data, |
| timeout=30, |
| ) as resp: |
| result = resp |
| raw = await result.read() |
| headers = result.headers.copy() |
| # We do NOT want chunked T-E! Leave it to aiohttp |
| if "Transfer-Encoding" in headers: |
| del headers["Transfer-Encoding"] |
| self.processing_times.append(time.time() - now) |
| return aiohttp.web.Response(body=raw, status=result.status, headers=headers) |
| except aiohttp.client_exceptions.ClientConnectorError as e: |
| print("Could not connect to backend: " + str(e)) |
| self.processing_times.append(time.time() - now) |
| |
| self.processing_times.append(time.time() - now) |
| return aiohttp.web.Response(text=self.block_msg, status=403) |
| |
| |
| async def main(): |
| aar = Aardvark() |
| app = aiohttp.web.Application() |
| app.router.add_route("*", "/{path:.*?}", aar.proxy) |
| runner = aiohttp.web.AppRunner(app) |
| |
| await runner.setup() |
| site = aiohttp.web.TCPSite(runner, "localhost", aar.port) |
| print("Starting Aardvark Anti Spam Proxy") |
| await site.start() |
| print(f"Started on port {aar.port}") |
| while True: |
| await asyncio.sleep(60) |
| |
| |
| if __name__ == "__main__": |
| try: |
| loop = asyncio.get_event_loop() |
| loop.run_until_complete(main()) |
| except KeyboardInterrupt: |
| pass |
