PyLink/plugins/antispam.py

# antispam.py: Basic services-side spamfilters for IRC

import ircmatch

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', 'block']
EXEMPT_OPTIONS = ['voice', 'halfop', 'op']
DEFAULT_EXEMPT_OPTION = 'halfop'
def _punish(irc, target, channel, punishment, reason):
    """Punishes the target user. This function returns True if the user was successfully punished."""
    if target not in irc.users:
        log.warning("(%s) antispam: got target %r that isn't a user?", irc.name, target)
        return False
    elif 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 False

    target_nick = irc.get_friendly_name(target)

    if channel:
        c = irc.channels[channel]
        exempt_level = irc.get_service_option('antispam', 'exempt_level', DEFAULT_EXEMPT_OPTION).lower()

        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, target_nick)
            return False
        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, target_nick)
            return False
        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, target_nick)
            return False

    my_uid = sbot.uids.get(irc.name)
    # XXX workaround for single-bot protocols like Clientbot
    if irc.pseudoclient and not irc.has_cap('can-spawn-clients'):
        my_uid = irc.pseudoclient.uid

    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():
        if target not in irc.users:
            log.debug('(%s) antispam: not killing %s/%s; they already left', irc.name, target,
                      irc.get_friendly_name(target))
            return
        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
    successful_punishments = 0
    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 == 'block':
            # We only need to increment this for this function to return True
            successful_punishments += 1
        elif action == 'kill':
            kill = True  # Delay kills so that the user data doesn't disappear.
        # XXX factorize these blocks
        elif action == 'kick' and channel:
            try:
                _kick()
            except NotImplementedError:
                log.warning("(%s) antispam: Kicks are not supported on this network, skipping; "
                            "target was %s/%s", irc.name, target_nick, channel)
            else:
                successful_punishments += 1
        elif action == 'ban' and channel:
            try:
                _ban()
            except (ValueError, NotImplementedError):
                log.warning("(%s) antispam: Bans are not supported on this network, skipping; "
                            "target was %s/%s", irc.name, target_nick, channel)
            else:
                successful_punishments += 1
        elif action == 'quiet' and channel:
            try:
                _quiet()
            except (ValueError, NotImplementedError):
                log.warning("(%s) antispam: Quiet is not supported on this network, skipping; "
                            "target was %s/%s", irc.name, target_nick, channel)
            else:
                successful_punishments += 1

    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:
        try:
            _kill()
        except NotImplementedError:
            log.warning("(%s) antispam: Kills are not supported on this network, skipping; "
                        "target was %s/%s", irc.name, target_nick, channel)
        else:
            successful_punishments += 1

    if not successful_punishments:
        log.warning('(%s) antispam: Failed to punish %s with %r, target was %s', irc.name,
                    target_nick, punishment, channel or 'a PM')

    return bool(successful_punishments)

MASSHIGHLIGHT_DEFAULTS = {
    'min_length': 50,
    'min_nicks': 5,
    'reason': "Mass highlight spam is prohibited",
    'punishment': 'kick+ban',
    'enabled': False
}
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)

    if not mhl_settings.get('enabled', False):
        return

    my_uid = sbot.uids.get(irc.name)

    # XXX workaround for single-bot protocols like Clientbot
    if irc.pseudoclient and not irc.has_cap('can-spawn-clients'):
        my_uid = irc.pseudoclient.uid

    if (not irc.connected.is_set()) or (not my_uid):
        # Break if the network isn't ready.
        log.debug("(%s) antispam.masshighlight: skipping processing; network isn't ready", irc.name)
        return
    elif not irc.is_channel(channel):
        # Not a channel - mass highlight blocking only makes sense within channels
        log.debug("(%s) antispam.masshighlight: 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.masshighlight: skipping processing message from internal client %s", irc.name, source)
        return
    elif source not in irc.users:
        log.debug("(%s) antispam.masshighlight: ignoring message from non-user %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.masshighlight: 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.masshighlight: skipping processing message %r; it's too short", irc.name, text)
        return

    if irc.get_service_option('antispam', 'strip_formatting', True):
        text = utils.strip_irc_formatting(text)

    # 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()

    punished = False
    for word in words:
        if word in userlist:
            nicks_caught.add(word)
        if len(nicks_caught) >= min_nicks:
            # Get the punishment and reason.
            punishment = mhl_settings.get('punishment', MASSHIGHLIGHT_DEFAULTS['punishment']).lower()
            reason = mhl_settings.get('reason', MASSHIGHLIGHT_DEFAULTS['reason'])

            log.info("(%s) antispam: punishing %s => %s for mass highlight spam",
                     irc.name,
                     irc.get_friendly_name(source),
                     channel)
            punished = _punish(irc, source, channel, punishment, reason)
            break

    log.debug('(%s) antispam.masshighlight: got %s/%s nicks on message to %r', irc.name,
              len(nicks_caught), min_nicks, channel)
    return not punished  # Filter this message from relay, etc. if it triggered protection

utils.add_hook(handle_masshighlight, 'PRIVMSG', priority=1000)
utils.add_hook(handle_masshighlight, 'NOTICE', priority=1000)

TEXTFILTER_DEFAULTS = {
    'reason': "Spam is prohibited",
    'punishment': 'kick+ban+block',
    'watch_pms': 'false',
    'enabled': False
}
def handle_textfilter(irc, source, command, args):
    """Antispam text filter handler."""
    target = args['target']
    text = args['text']
    txf_settings = irc.get_service_option('antispam', 'textfilter',
                                          TEXTFILTER_DEFAULTS)

    if not txf_settings.get('enabled', False):
        return

    my_uid = sbot.uids.get(irc.name)

    # XXX workaround for single-bot protocols like Clientbot
    if irc.pseudoclient and not irc.has_cap('can-spawn-clients'):
        my_uid = irc.pseudoclient.uid

    if (not irc.connected.is_set()) or (not my_uid):
        # Break if the network isn't ready.
        log.debug("(%s) antispam.textfilters: skipping processing; network isn't ready", irc.name)
        return
    elif irc.is_internal_client(source):
        # Ignore messages from our own clients.
        log.debug("(%s) antispam.textfilters: skipping processing message from internal client %s", irc.name, source)
        return
    elif source not in irc.users:
        log.debug("(%s) antispam.textfilters: ignoring message from non-user %s", irc.name, source)
        return

    if irc.is_channel(target):
        channel_or_none = target
        if target not in irc.channels or my_uid not in irc.channels[target].users:
            # We're not monitoring this channel.
            log.debug("(%s) antispam.textfilters: skipping processing message from channel %r we're not in", irc.name, target)
            return
    else:
        channel_or_none = None
        watch_pms = txf_settings.get('watch_pms', TEXTFILTER_DEFAULTS['watch_pms'])

        if watch_pms == 'services':
            if not irc.get_service_bot(target):
                log.debug("(%s) antispam.textfilters: skipping processing; %r is not a service bot (watch_pms='services')", irc.name, target)
                return
        elif watch_pms == 'all':
            log.debug("(%s) antispam.textfilters: checking all PMs (watch_pms='all')", irc.name)
            pass
        else:
            # Not a channel.
            log.debug("(%s) antispam.textfilters: skipping processing; %r is not a channel and watch_pms is disabled", irc.name, target)
            return

    # Merge together global and local textfilter lists.
    txf_globs = set(conf.conf.get('antispam', {}).get('textfilter_globs', [])) | \
                set(irc.serverdata.get('antispam_textfilter_globs', []))

    punishment = txf_settings.get('punishment', TEXTFILTER_DEFAULTS['punishment']).lower()
    reason = txf_settings.get('reason', TEXTFILTER_DEFAULTS['reason'])

    if irc.get_service_option('antispam', 'strip_formatting', True):
        text = utils.strip_irc_formatting(text)

    punished = False
    for filterglob in txf_globs:
        if ircmatch.match(1, filterglob, text):
            log.info("(%s) antispam: punishing %s => %s for text filter %r",
                     irc.name,
                     irc.get_friendly_name(source),
                     irc.get_friendly_name(target),
                     filterglob)
            punished = _punish(irc, source, channel_or_none, punishment, reason)
            break

    return not punished  # Filter this message from relay, etc. if it triggered protection

utils.add_hook(handle_textfilter, 'PRIVMSG', priority=999)
utils.add_hook(handle_textfilter, 'NOTICE', priority=999)