forked from zaclys/searxng
105 lines
3.6 KiB
Python
105 lines
3.6 KiB
Python
""".. _botdetection.ip_limit:
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Method ``ip_limit``
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-------------------
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The ``ip_limit`` method counts request from an IP in *sliding windows*. If
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there are to many requests in a sliding window, the request is evaluated as a
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bot request. This method requires a redis DB and needs a HTTP X-Forwarded-For_
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header. To take privacy only the hash value of an IP is stored in the redis DB
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and at least for a maximum of 10 minutes.
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The :py:obj:`.link_token` method can be used to investigate whether a request is
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*suspicious*. To activate the :py:obj:`.link_token` method in the
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:py:obj:`.ip_limit` method add the following to your
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``/etc/searxng/limiter.toml``:
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.. code:: toml
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[botdetection.ip_limit]
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link_token = true
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If the :py:obj:`.link_token` method is activated and a request is *suspicious*
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the request rates are reduced:
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- :py:obj:`BURST_MAX` -> :py:obj:`BURST_MAX_SUSPICIOUS`
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- :py:obj:`LONG_MAX` -> :py:obj:`LONG_MAX_SUSPICIOUS`
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.. _X-Forwarded-For:
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
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"""
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from typing import Optional, Tuple
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import flask
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from searx.tools import config
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from searx import redisdb
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from searx import logger
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from searx.redislib import incr_sliding_window
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from . import link_token
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logger = logger.getChild('botdetection.ip_limit')
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BURST_WINDOW = 20
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"""Time (sec) before sliding window for *burst* requests expires."""
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BURST_MAX = 15
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"""Maximum requests from one IP in the :py:obj:`BURST_WINDOW`"""
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BURST_MAX_SUSPICIOUS = 2
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"""Maximum of suspicious requests from one IP in the :py:obj:`BURST_WINDOW`"""
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LONG_WINDOW = 600
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"""Time (sec) before the longer sliding window expires."""
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LONG_MAX = 150
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"""Maximum requests from one IP in the :py:obj:`LONG_WINDOW`"""
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LONG_MAX_SUSPICIOUS = 10
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"""Maximum suspicious requests from one IP in the :py:obj:`LONG_WINDOW`"""
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API_WONDOW = 3600
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"""Time (sec) before sliding window for API requests (format != html) expires."""
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API_MAX = 4
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"""Maximum requests from one IP in the :py:obj:`API_WONDOW`"""
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def filter_request(request: flask.Request, cfg: config.Config) -> Optional[Tuple[int, str]]:
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redis_client = redisdb.client()
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x_forwarded_for = request.headers.get('X-Forwarded-For', '')
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if not x_forwarded_for:
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logger.error("missing HTTP header X-Forwarded-For")
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if request.args.get('format', 'html') != 'html':
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c = incr_sliding_window(redis_client, 'IP limit - API_WONDOW:' + x_forwarded_for, API_WONDOW)
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if c > API_MAX:
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return 429, "BLOCK %s: API limit exceeded"
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suspicious = False
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if cfg['botdetection.ip_limit.link_token']:
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suspicious = link_token.is_suspicious(request)
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if suspicious:
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c = incr_sliding_window(redis_client, 'IP limit - BURST_WINDOW:' + x_forwarded_for, BURST_WINDOW)
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if c > BURST_MAX_SUSPICIOUS:
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return 429, f"bot detected, too many request from {x_forwarded_for} in BURST_MAX_SUSPICIOUS"
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c = incr_sliding_window(redis_client, 'IP limit - LONG_WINDOW:' + x_forwarded_for, LONG_WINDOW)
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if c > LONG_MAX_SUSPICIOUS:
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return 429, f"bot detected, too many request from {x_forwarded_for} in LONG_MAX_SUSPICIOUS"
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else:
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c = incr_sliding_window(redis_client, 'IP limit - BURST_WINDOW:' + x_forwarded_for, BURST_WINDOW)
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if c > BURST_MAX:
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return 429, f"bot detected, too many request from {x_forwarded_for} in BURST_MAX"
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c = incr_sliding_window(redis_client, 'IP limit - LONG_WINDOW:' + x_forwarded_for, LONG_WINDOW)
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if c > LONG_MAX:
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return 429, f"bot detected, too many request from {x_forwarded_for} in LONG_MAX"
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return None
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