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relay: implement kick/mode/topic war prevention (#23)
This adds cachetools as a dependency for Relay.
This commit is contained in:
James Lu
parent
042d11d7ba
commit
94cd1d8f22
@ -13,6 +13,11 @@ from pylinkirc.coremods import permissions
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CHANNEL_DELINKED_MSG = "Channel delinked."
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RELAY_UNLOADED_MSG = "Relay plugin unloaded."
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try:
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import cachetools
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except ImportError as e:
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raise ImportError("PyLink Relay requires cachetools as of PyLink 2.1: https://pypi.org/project/cachetools/") from e
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try:
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import unidecode
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except ImportError:
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@ -27,6 +32,11 @@ relayservers = defaultdict(dict)
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spawnlocks = defaultdict(threading.Lock)
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spawnlocks_servers = defaultdict(threading.Lock)
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# Claim bounce cache to prevent kick/mode/topic loops
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__claim_bounce_timeout = conf.conf.get('relay', {}).get('claim_bounce_timeout', 5)
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claim_bounce_cache = cachetools.TTLCache(float('inf'), __claim_bounce_timeout)
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claim_bounce_cache_lock = threading.Lock()
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dbname = conf.get_database_name('pylinkrelay')
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datastore = structures.PickleDataStore('pylinkrelay', dbname)
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db = datastore.store
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@ -646,9 +656,32 @@ def remove_channel(irc, channel):
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del relayusers[remoteuser][irc.name]
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irc.quit(user, 'Left all shared channels.')
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def _claim_should_bounce(irc, channel):
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"""
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Returns whether we should bounce the next action that fails CLAIM.
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This is used to prevent kick/mode/topic wars with services.
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"""
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with claim_bounce_cache_lock:
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if irc.name not in claim_bounce_cache: # Nothing in the cache to worry about
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return True
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limit = irc.get_service_option('relay', 'claim_bounce_limit', default=15)
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if limit < 0: # Disabled
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return True
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elif limit < 5: # Anything below this is just asking for desyncs...
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log.warning('(%s) relay: the minimum supported value for relay::claim_bounce_limit is 5.', irc.name)
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limit = 5
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success = claim_bounce_cache[irc.name] <= limit
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ttl = claim_bounce_cache.ttl
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if not success:
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log.warning("(%s) relay: %s received more than %s claim bounces in %s seconds - your channel may be desynced!",
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irc.name, channel, limit, ttl)
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return success
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def check_claim(irc, channel, sender, chanobj=None):
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"""
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Checks whether the sender of a kick/mode change passes CLAIM checks for
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Checks whether the sender of a kick/mode/topic change passes CLAIM checks for
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a given channel. This returns True if any of the following criteria are met:
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1) No relay exists for the channel in question.
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@ -669,13 +702,23 @@ def check_claim(irc, channel, sender, chanobj=None):
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log.debug('(%s) relay.check_claim: sender modes (%s/%s) are %s (mlist=%s)', irc.name,
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sender, channel, sender_modes, mlist)
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# XXX: stop hardcoding modes to check for and support mlist in isHalfopPlus and friends
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return (not relay) or irc.name == relay[0] or not db[relay]['claim'] or \
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success = (not relay) or irc.name == relay[0] or not db[relay]['claim'] or \
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irc.name in db[relay]['claim'] or \
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(any([mode in sender_modes for mode in ('y', 'q', 'a', 'o', 'h')])
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(any([mode in sender_modes for mode in {'y', 'q', 'a', 'o', 'h'}])
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and not irc.is_privileged_service(sender)) \
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or irc.is_internal_client(sender) or \
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irc.is_internal_server(sender)
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# Increment claim_bounce_cache, checked in _claim_should_bounce()
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if not success:
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with claim_bounce_cache_lock:
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if irc.name not in claim_bounce_cache:
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claim_bounce_cache[irc.name] = 1
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else:
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claim_bounce_cache[irc.name] += 1
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return success
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def get_supported_umodes(irc, remoteirc, modes):
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"""Given a list of user modes, filters out all of those not supported by the
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remote network."""
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@ -1318,7 +1361,7 @@ def handle_join(irc, numeric, command, args):
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if modechar and not irc.is_privileged_service(numeric):
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modes.append(('-%s' % modechar, user))
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if modes:
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if modes and _claim_should_bounce(irc, channel):
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log.debug('(%s) relay.handle_join: reverting modes on BURST: %s', irc.name, irc.join_modes(modes))
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irc.mode(irc.sid, channel, modes)
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@ -1695,17 +1738,16 @@ def handle_kick(irc, source, command, args):
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del relayusers[(irc.name, target)][remoteirc.name]
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remoteirc.quit(real_target, 'Left all shared channels.')
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# Kick was a relay client but sender does not pass CLAIM restrictions. Bounce a rejoin unless we've reached our limit.
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if is_relay_client(irc, target) and not check_claim(irc, channel, kicker):
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if _claim_should_bounce(irc, channel):
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homenet, real_target = get_orig_user(irc, target)
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homeirc = world.networkobjects.get(homenet)
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homenick = homeirc.users[real_target].nick if homeirc else '<ghost user>'
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homechan = get_remote_channel(irc, homeirc, channel)
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log.debug('(%s) relay.handle_kick: kicker %s is not opped... We should rejoin the target user %s', irc.name, kicker, real_target)
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# Home network is not in the channel's claim AND the kicker is not
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# opped. We won't propograte the kick then.
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# TODO: make the check slightly more advanced: i.e. halfops can't
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# kick ops, admins can't kick owners, etc.
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# FIXME: make the check slightly more advanced: i.e. halfops can't kick ops, admins can't kick owners, etc.
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modes = get_prefix_modes(homeirc, irc, homechan, real_target)
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# Join the kicked client back with its respective modes.
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@ -1838,20 +1880,21 @@ def handle_mode(irc, numeric, command, args):
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for named_modepair in modedelta_modes]))
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if not check_claim(irc, target, numeric, chanobj=oldchan):
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if _claim_should_bounce(irc, target):
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# Mode change blocked by CLAIM.
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reversed_modes = irc.reverse_modes(target, modes, oldobj=oldchan)
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if irc.is_privileged_service(numeric):
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# Special hack for "U-lined" servers - ignore changes to SIMPLE modes and
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# attempts to op u-lined clients (trying to change status for others
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# attempts to op its own clients (trying to change status for others
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# SHOULD be reverted).
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# This is for compatibility with Anope's DEFCON for the most part, as well as
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# silly people who try to register a channel multiple times via relay.
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reversed_modes = [modepair for modepair in reversed_modes if
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# Mode is a prefix mode but target isn't ulined, revert
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# Include prefix modes if target isn't also U-lined
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((modepair[0][-1] in irc.prefixmodes and not
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irc.is_privileged_service(modepair[1]))
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# Tried to set a list mode, revert
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# Include all list modes (bans, etc.)
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or modepair[0][-1] in irc.cmodes['*A'])
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]
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modes.clear() # Clear the mode list so nothing is relayed below
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@ -1920,7 +1963,7 @@ def handle_topic(irc, numeric, command, args):
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remoteirc.topic_burst(rsid, remotechan, topic)
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iterate_all(irc, _handle_topic_loop, extra_args=(numeric, command, args))
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elif oldtopic: # Topic change blocked by claim.
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elif oldtopic and _claim_should_bounce(irc, channel): # Topic change blocked by claim.
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irc.topic_burst(irc.sid, channel, oldtopic)
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utils.add_hook(handle_topic, 'TOPIC')
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