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registry: Prevent memory leaks caused by Value.getSpecific getting values with non-channel/non-network values.

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This commit is contained in:
Valentin Lorentz 2020-05-15 23:57:39 +02:00
parent 7e7a7bf936
commit f408f6cc42
1 changed files with 54 additions and 1 deletions
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55
src/registry.py
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@ -36,7 +36,7 @@ import codecs
import string
import textwrap
from . import utils, i18n
from . import utils, i18n, ircutils
from .utils import minisix
_ = i18n.PluginInternationalization()
@ -400,6 +400,59 @@ class Value(Group):
self._name)
else:
channel = None
# It may seem weird to check channel/network validity here,
# but we need to prevent plugins from passing garbage values.
#
# For example, LinkRelay has an inFilter() function that calls
# self.registryValue('...', msg.args[0]) no matter the command. This
# means that, every time it receives a 'PING :<timestamp>' from a
# network (eg. OFTC), it calls
# self.registryValue('...', '<timestamp>'), which calls this
# function.
#
# We then get the proper group, and do .get('<timestamp>'), which
# causes a new variable to be registered.
# And if the values have a high cardinality (eg. with timestamps),
# this creates *a lot* of values, thereby leaking megabytes of memory
# a week.
#
# Ideally, we would want to not register these variables, but it's
# complicated for multiple reasons, including:
#
# 1. if two plugins .get() them, store them for a little while, then
# both set them, we have to take care of it.
# 2. if <group>.network.channel is modified, then we need to register
# both .channel and .network. (and what if two plugins are doing
# this concurrently with different channels?)
# 3. we could also have a task run in the upkeep function, but we have
# issues again with plugins that keep a reference.
#
# All in all, this is not ideal, but afaict, this is the least bad
# solution. And let's hope no one bruteforces valid channel names.
# If you have a better solution, please let us know!
#
# Also, we're setting them to None instead of raising an error in
# order not to break existing plugins.
if channel and not ircutils.isChannel(channel):
from . import log
log.warning(
'Trying to get channel-specific value of %s for channel %s, '
'but it is not a channel. This is a bug, please report it.',
self._name, channel)
channel = None
if network:
from . import world # put here to work around circular dependencies
if world.getIrc(network) is None:
# checking 'world is not None' as part of the workaround for
# circular dependencies (see the end of the file)
from . import log
log.warning(
'Trying to get network-specific value of %s for network %s, '
'but it is not a network. This is a bug, please report it.',
self._name, network)
network = None
if network and channel:
# The complicated case. We want a net+chan specific value,
# which may come in three different ways: