Add nickname_checker.py module

See: network-health/team#329 for details.

nickname_checker.py

+#!/usr/bin/env python3
+# Copyright 2013-2021, Damian Johnson and The Tor Project
+# See LICENSE for licensing information
+
+"""
+Simple script that checks to see if there has been a sudden influx of new
+relays with a specific nickname. If so then this sends an email notification.
+"""
+
+import os
+import re
+import time
+import traceback
+
+import util
+
+from stem.descriptor.remote import DescriptorDownloader
+
+EMAIL_SUBJECT = 'Possible Sybil Attack - By Nickname'
+
+EMAIL_BODY = """\
+ALERT: %i new relays have appeared with nickname matching '%s'.
+
+"""
+
+RELAY_ENTRY = """\
+* %s (%s)
+  Address: %s:%i
+  Version: %s
+  Exit Policy: %s
+"""
+
+NICKNAME_FILE = util.get_path('data', 'nickname')
+
+log = util.get_logger('nickname_checker')
+
+
+def main():
+  nicknames_to_check = load_nicknames()
+  downloader = DescriptorDownloader(timeout = 60, validate = True)
+
+  dry_run = False
+
+  if not nicknames_to_check:
+    log.debug("We don't have any nicknames so stop. No notifications will be sent.")
+    return
+
+  query = downloader.get_consensus()
+  query.run(True)
+
+  if query.error:
+    log.warning("Unable to retrieve the consensus: %s" % query.error)
+    return
+
+  # Build a dictionnary with the loaded nicknames with each an empty table
+  # that will contain match relays.
+  matches = {}
+  for name in nicknames_to_check:
+      if name not in matches:
+          matches[name] = []
+
+  num_found = 0
+  for entry in query:
+      # For each nickname, match it as a regex.
+      for nickname in nicknames_to_check:
+          if re.search(nickname, entry.nickname):
+              matches[nickname].append(entry)
+              num_found += 1
+
+  log.debug("%i new relays found" % num_found)
+
+  if not dry_run and num_found > 0 :
+    log.debug("Sending a notification...")
+    send_email(matches)
+
+def send_email(matches):
+  # Constructs a mapping of nicknames to router status entries so we can
+  # provide a listing that's sorted by nicknames.
+
+  for nickname in matches:
+      relays = matches[nickname]
+      if len(relays) == 0:
+          # Ignore empty relays for the nickname.
+          continue
+      relay_entries = []
+      for relay in relays:
+        relay_entries.append(RELAY_ENTRY % (relay.nickname, relay.fingerprint, \
+                relay.address, relay.or_port, relay.version, relay.exit_policy))
+
+      try:
+        body = EMAIL_BODY % (len(relays), nickname)
+        body += "\n".join(relay_entries)
+
+        util.send(EMAIL_SUBJECT, body = body)
+      except Exception as exc:
+        log.warning("Unable to send email: %s" % exc)
+
+def load_nicknames():
+  log.debug("Loading nicknames...")
+
+  if not os.path.exists(NICKNAME_FILE):
+    log.debug("  '%s' doesn't exist" % NICKNAME_FILE)
+    return set()
+
+  try:
+    with open(NICKNAME_FILE) as nickname_file:
+      nicknames = nickname_file.read().strip()
+
+      if not nicknames:
+        log.debug("  '%s' is empty" % NICKNAME_FILE)
+        return set()
+
+      nicknames = nicknames.splitlines()
+
+      log.debug("  %i nicknames found" % len(nicknames))
+      return set(nicknames)
+  except Exception as exc:
+    log.debug("  unable to read '%s': %s" % (NICKNAME_FILE, exc))
+    return set()
+
+if __name__ == '__main__':
+  try:
+    main()
+  except:
+    msg = "nickname_checker.py failed with:\n\n%s" % traceback.format_exc()
+    log.error(msg)
+    util.send("Script Error", body = msg, to = [util.ERROR_ADDRESS])