forked from zaclys/searxng
130 lines
4.2 KiB
Python
130 lines
4.2 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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# lint: pylint
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# pyright: basic
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"""Some bot protection / rate limitation
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To monitor rate limits and protect privacy the IP addresses are getting stored
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with a hash so the limiter plugin knows who to block. A redis database is
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needed to store the hash values.
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Enable the plugin in ``settings.yml``:
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- ``server.limiter: true``
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- ``redis.url: ...`` check the value, see :ref:`settings redis`
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"""
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import hmac
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import re
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from flask import request
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from searx.shared import redisdb
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name = "Request limiter"
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description = "Limit the number of request"
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default_on = False
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preference_section = 'service'
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re_bot = re.compile(
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r'('
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+ r'[Cc][Uu][Rr][Ll]|[wW]get|Scrapy|splash|JavaFX|FeedFetcher|python-requests|Go-http-client|Java|Jakarta|okhttp'
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+ r'|HttpClient|Jersey|Python|libwww-perl|Ruby|SynHttpClient|UniversalFeedParser|Googlebot|GoogleImageProxy'
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+ r'|bingbot|Baiduspider|yacybot|YandexMobileBot|YandexBot|Yahoo! Slurp|MJ12bot|AhrefsBot|archive.org_bot|msnbot'
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+ r'|MJ12bot|SeznamBot|linkdexbot|Netvibes|SMTBot|zgrab|James BOT|Sogou|Abonti|Pixray|Spinn3r|SemrushBot|Exabot'
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+ r'|ZmEu|BLEXBot|bitlybot'
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+ r')'
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)
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def is_accepted_request(inc_get_counter) -> bool:
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# pylint: disable=too-many-return-statements
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user_agent = request.headers.get('User-Agent', '')
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x_forwarded_for = request.headers.get('X-Forwarded-For', '')
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if request.path == '/image_proxy':
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if re_bot.match(user_agent):
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return False
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return True
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if request.path == '/search':
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c_burst = inc_get_counter(interval=20, keys=[b'IP limit, burst', x_forwarded_for])
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c_10min = inc_get_counter(interval=600, keys=[b'IP limit, 10 minutes', x_forwarded_for])
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if c_burst > 15 or c_10min > 150:
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return False
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if re_bot.match(user_agent):
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return False
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if len(request.headers.get('Accept-Language', '').strip()) == '':
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return False
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if request.headers.get('Connection') == 'close':
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return False
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accept_encoding_list = [l.strip() for l in request.headers.get('Accept-Encoding', '').split(',')]
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if 'gzip' not in accept_encoding_list or 'deflate' not in accept_encoding_list:
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return False
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if 'text/html' not in request.accept_mimetypes:
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return False
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if request.args.get('format', 'html') != 'html':
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c = inc_get_counter(interval=3600, keys=[b'API limit', x_forwarded_for])
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if c > 4:
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return False
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return True
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def create_inc_get_counter(redis_client, secret_key_bytes):
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lua_script = """
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local slidingWindow = KEYS[1]
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local key = KEYS[2]
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local now = tonumber(redis.call('TIME')[1])
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local id = redis.call('INCR', 'counter')
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if (id > 2^46)
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then
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redis.call('SET', 'count', 0)
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end
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redis.call('ZREMRANGEBYSCORE', key, 0, now - slidingWindow)
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redis.call('ZADD', key, now, id)
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local result = redis.call('ZCOUNT', key, 0, now+1)
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redis.call('EXPIRE', key, slidingWindow)
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return result
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"""
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script_sha = redis_client.script_load(lua_script)
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def inc_get_counter(interval, keys):
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m = hmac.new(secret_key_bytes, digestmod='sha256')
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for k in keys:
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m.update(bytes(str(k), encoding='utf-8') or b'')
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m.update(b"\0")
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key = m.digest()
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return redis_client.evalsha(script_sha, 2, interval, key)
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return inc_get_counter
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def create_pre_request(get_aggregation_count):
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def pre_request():
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if not is_accepted_request(get_aggregation_count):
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return '', 429
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return None
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return pre_request
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def init(app, settings):
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if not settings['server']['limiter']:
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return False
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logger.debug("init limiter DB") # pylint: disable=undefined-variable
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if not redisdb.init():
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logger.error("init limiter DB failed!!!") # pylint: disable=undefined-variable
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return False
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redis_client = redisdb.client()
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secret_key_bytes = bytes(settings['server']['secret_key'], encoding='utf-8')
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inc_get_counter = create_inc_get_counter(redis_client, secret_key_bytes)
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app.before_request(create_pre_request(inc_get_counter))
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return True
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