Initial pass of a mass-highlight blocking plugin (#359)

plugins/antispam.py

@@ -0,0 +1,141 @@
+# antispam.py: Basic services-side spamfilters for IRC
+
+from pylinkirc import utils, world, conf
+from pylinkirc.log import log
+
+mydesc = ("Provides anti-spam functionality.")
+sbot = utils.register_service("antispam", default_nick="AntiSpam", desc=mydesc)
+
+def die(irc=None):
+    utils.unregister_service("antispam")
+
+PUNISH_OPTIONS = ['kill', 'ban', 'quiet', 'kick']
+EXEMPT_OPTIONS = ['voice', 'halfop', 'op']
+DEFAULT_EXEMPT_OPTION = 'halfop'
+def _punish(irc, target, channel, reason):
+    """Punishes the target user."""
+    if irc.is_oper(target, allowAuthed=False):
+        log.debug("(%s) antispam: refusing to punish oper %s/%s", irc.name, target, irc.get_friendly_name(target))
+        return
+
+    exempt_level = irc.get_service_option('antispam', 'exempt_level', DEFAULT_EXEMPT_OPTION).lower()
+    c = irc.channels[channel]
+
+    if exempt_level not in EXEMPT_OPTIONS:
+        log.error('(%s) Antispam exempt %r is not a valid setting, '
+                  'falling back to defaults; accepted settings include: %s',
+                  irc.name, exempt_level, ', '.join(EXEMPT_OPTIONS))
+        exempt_level = DEFAULT_EXEMPT_OPTION
+
+    if exempt_level == 'voice' and c.is_voice_plus(target):
+        log.debug("(%s) antispam: refusing to punish voiced and above %s/%s", irc.name, target, irc.get_friendly_name(target))
+        return
+    elif exempt_level == 'halfop' and c.is_halfop_plus(target):
+        log.debug("(%s) antispam: refusing to punish halfop and above %s/%s", irc.name, target, irc.get_friendly_name(target))
+        return
+    elif exempt_level == 'op' and c.is_op_plus(target):
+        log.debug("(%s) antispam: refusing to punish op and above %s/%s", irc.name, target, irc.get_friendly_name(target))
+        return
+
+    my_uid = sbot.uids.get(irc.name)
+
+    punishment = irc.get_service_option('antispam', 'punishment',
+                                        'ban+kill').lower()
+    bans = set()
+    log.debug('(%s) antispam: got %r as punishment for %s/%s', irc.name, punishment,
+              target, irc.get_friendly_name(target))
+
+    def _ban():
+        bans.add(irc.make_channel_ban(target))
+    def _quiet():
+        bans.add(irc.make_channel_ban(target, ban_type='quiet'))
+    def _kick():
+        irc.kick(my_uid, channel, target, reason)
+        irc.call_hooks([my_uid, 'ANTISPAM_KICK', {'channel': channel, 'text': reason, 'target': target,
+                                                  'parse_as': 'KICK'}])
+    def _kill():
+        userdata = irc.users[target]
+        irc.kill(my_uid, target, reason)
+        irc.call_hooks([my_uid, 'ANTISPAM_KILL', {'target': target, 'text': reason,
+                                                  'userdata': userdata, 'parse_as': 'KILL'}])
+
+    kill = False
+    for action in set(punishment.split('+')):
+        if action not in PUNISH_OPTIONS:
+            log.error('(%s) Antispam punishment %r is not a valid setting; '
+                      'accepted settings include: %s OR any combination of '
+                      'these joined together with a "+".',
+                      irc.name, punishment, ', '.join(PUNISH_OPTIONS))
+            return
+        elif action == 'kill':
+            kill = True  # Delay kills so that the user data doesn't disappear.
+        elif action == 'kick':
+            _kick()
+        elif action == 'ban':
+            _ban()
+        elif action == 'quiet':
+            _quiet()
+
+    if bans:  # Set all bans at once to prevent spam
+        irc.mode(my_uid, channel, bans)
+        irc.call_hooks([my_uid, 'ANTISPAM_BAN',
+                        {'target': channel, 'modes': bans, 'parse_as': 'MODE'}])
+    if kill:
+        _kill()
+
+MASSHIGHLIGHT_DEFAULTS = {
+    'min_length': 50,
+    'min_nicks': 5,
+    'reason': "Mass highlight spam is prohibited"
+}
+def handle_masshighlight(irc, source, command, args):
+    """Handles mass highlight attacks."""
+    channel = args['target']
+    text = args['text']
+    mhl_settings = irc.get_service_option('antispam', 'masshighlight',
+                                          MASSHIGHLIGHT_DEFAULTS)
+    my_uid = sbot.uids.get(irc.name)
+
+    if (not irc.connected.is_set()) or (not my_uid):
+        # Break if the network isn't ready.
+        log.debug("(%s) antispam: skipping processing; network isn't ready", irc.name)
+        return
+    elif not irc.is_channel(channel):
+        # Not a channel.
+        log.debug("(%s) antispam: skipping processing; %r is not a channel", irc.name, channel)
+        return
+    elif irc.is_internal_client(source):
+        # Ignore messages from our own clients.
+        log.debug("(%s) antispam: skipping processing message from internal client %s", irc.name, source)
+        return
+    elif channel not in irc.channels or my_uid not in irc.channels[channel].users:
+        # We're not monitoring this channel.
+        log.debug("(%s) antispam: skipping processing message from channel %r we're not in", irc.name, channel)
+        return
+    elif len(text) < mhl_settings.get('min_length', MASSHIGHLIGHT_DEFAULTS['min_length']):
+        log.debug("(%s) antispam: skipping processing message %r; it's too short", irc.name, text)
+        return
+
+    # Strip :, from potential nicks
+    words = [word.rstrip(':,') for word in text.split()]
+
+    userlist = [irc.users[uid].nick for uid in irc.channels[channel].users.copy()]
+    min_nicks = mhl_settings.get('min_nicks', MASSHIGHLIGHT_DEFAULTS['min_nicks'])
+
+    # Don't allow repeating the same nick to trigger punishment
+    nicks_caught = set()
+
+    for word in words:
+        if word in userlist:
+            nicks_caught.add(word)
+        if len(nicks_caught) >= min_nicks:
+            reason = mhl_settings.get('reason', MASSHIGHLIGHT_DEFAULTS['reason'])
+            log.debug('(%s) antispam: calling _punish on %s/%s', irc.name,
+                      source, irc.get_friendly_name(source))
+            _punish(irc, source, channel, reason)
+            break
+
+    log.debug('(%s) antispam: got %s/%s nicks on message to %r', irc.name, len(nicks_caught), min_nicks, channel)
+
+utils.add_hook(handle_masshighlight, 'PRIVMSG')
+utils.add_hook(handle_masshighlight, 'NOTICE')