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[fix] limiter: replace real_ip by IPv4/v6 network 

Closes: https://github.com/searxng/searxng/issues/2477
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
This commit is contained in:
Markus Heiser 2023-06-01 15:41:48 +02:00
parent 38431d2e14
commit 281e36f4b7
12 changed files with 208 additions and 106 deletions
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1
searx/botdetection/__init__.py
View File

@ -24,3 +24,4 @@ X-Forwarded-For
from ._helpers import dump_request
from ._helpers import get_real_ip
from ._helpers import too_many_requests

42
searx/botdetection/_helpers.py
View File

@ -1,11 +1,19 @@
# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
# pylint: disable=missing-module-docstring, invalid-name
from __future__ import annotations
from typing import Optional
from ipaddress import (
IPv4Network,
IPv6Network,
IPv6Address,
ip_address,
ip_network,
)
import flask
import werkzeug
from searx.tools import config
from searx import logger
logger = logger.getChild('botdetection')
@ -13,7 +21,7 @@ logger = logger.getChild('botdetection')
def dump_request(request: flask.Request):
return (
"%s: %s" % (get_real_ip(request), request.path)
request.path
+ " || X-Forwarded-For: %s" % request.headers.get('X-Forwarded-For')
+ " || X-Real-IP: %s" % request.headers.get('X-Real-IP')
+ " || form: %s" % request.form
@ -27,12 +35,30 @@ def dump_request(request: flask.Request):
)
def too_many_requests(request: flask.Request, log_msg: str) -> Optional[werkzeug.Response]:
log_prefix = 'BLOCK %s: ' % get_real_ip(request)
logger.debug(log_prefix + log_msg)
def too_many_requests(network: IPv4Network | IPv6Network, log_msg: str) -> werkzeug.Response | None:
"""Returns a HTTP 429 response object and writes a ERROR message to the
'botdetection' logger. This function is used in part by the filter methods
to return the default ``Too Many Requests`` response.
"""
logger.debug("BLOCK %s: %s", network.compressed, log_msg)
return flask.make_response(('Too Many Requests', 429))
def get_network(real_ip: str, cfg: config.Config) -> IPv4Network | IPv6Network:
"""Returns the (client) network of whether the real_ip is part of."""
ip = ip_address(real_ip)
if isinstance(ip, IPv6Address):
prefix = cfg['real_ip.ipv6_prefix']
else:
prefix = cfg['real_ip.ipv4_prefix']
network = ip_network(f"{real_ip}/{prefix}", strict=False)
# logger.debug("get_network(): %s", network.compressed)
return network
def get_real_ip(request: flask.Request) -> str:
"""Returns real IP of the request. Since not all proxies set all the HTTP
headers and incoming headers can be faked it may happen that the IP cannot
@ -63,7 +89,9 @@ def get_real_ip(request: flask.Request) -> str:
forwarded_for = request.headers.get("X-Forwarded-For")
real_ip = request.headers.get('X-Real-IP')
remote_addr = request.remote_addr
logger.debug("X-Forwarded-For: %s || X-Real-IP: %s || request.remote_addr: %s", forwarded_for, real_ip, remote_addr)
# logger.debug(
# "X-Forwarded-For: %s || X-Real-IP: %s || request.remote_addr: %s", forwarded_for, real_ip, remote_addr
# )
if not forwarded_for:
logger.error("X-Forwarded-For header is not set!")
@ -89,5 +117,5 @@ def get_real_ip(request: flask.Request) -> str:
logger.warning("IP from WSGI environment (%s) is not equal to IP from X-Real-IP (%s)", remote_addr, real_ip)
request_ip = forwarded_for or real_ip or remote_addr or '0.0.0.0'
logger.debug("get_real_ip() -> %s", request_ip)
# logger.debug("get_real_ip() -> %s", request_ip)
return request_ip

16
searx/botdetection/http_accept.py
View File

@ -15,7 +15,12 @@ Accept_ header ..
"""
# pylint: disable=unused-argument
from typing import Optional
from __future__ import annotations
from ipaddress import (
IPv4Network,
IPv6Network,
)
import flask
import werkzeug
@ -23,7 +28,12 @@ from searx.tools import config
from ._helpers import too_many_requests
def filter_request(request: flask.Request, cfg: config.Config) -> Optional[werkzeug.Response]:
def filter_request(
network: IPv4Network | IPv6Network,
request: flask.Request,
cfg: config.Config,
) -> werkzeug.Response | None:
if 'text/html' not in request.accept_mimetypes:
return too_many_requests(request, "HTTP header Accept did not contain text/html")
return too_many_requests(network, "HTTP header Accept did not contain text/html")
return None

16
searx/botdetection/http_accept_encoding.py
View File

@ -16,7 +16,12 @@ bot if the Accept-Encoding_ header ..
"""
# pylint: disable=unused-argument
from typing import Optional
from __future__ import annotations
from ipaddress import (
IPv4Network,
IPv6Network,
)
import flask
import werkzeug
@ -24,8 +29,13 @@ from searx.tools import config
from ._helpers import too_many_requests
def filter_request(request: flask.Request, cfg: config.Config) -> Optional[werkzeug.Response]:
def filter_request(
network: IPv4Network | IPv6Network,
request: flask.Request,
cfg: config.Config,
) -> werkzeug.Response | None:
accept_list = [l.strip() for l in request.headers.get('Accept-Encoding', '').split(',')]
if not ('gzip' in accept_list or 'deflate' in accept_list):
return too_many_requests(request, "HTTP header Accept-Encoding did not contain gzip nor deflate")
return too_many_requests(network, "HTTP header Accept-Encoding did not contain gzip nor deflate")
return None

14
searx/botdetection/http_accept_language.py
View File

@ -12,8 +12,12 @@ if the Accept-Language_ header is unset.
"""
# pylint: disable=unused-argument
from __future__ import annotations
from ipaddress import (
IPv4Network,
IPv6Network,
)
from typing import Optional
import flask
import werkzeug
@ -21,7 +25,11 @@ from searx.tools import config
from ._helpers import too_many_requests
def filter_request(request: flask.Request, cfg: config.Config) -> Optional[werkzeug.Response]:
def filter_request(
network: IPv4Network | IPv6Network,
request: flask.Request,
cfg: config.Config,
) -> werkzeug.Response | None:
if request.headers.get('Accept-Language', '').strip() == '':
return too_many_requests(request, "missing HTTP header Accept-Language")
return too_many_requests(network, "missing HTTP header Accept-Language")
return None

16
searx/botdetection/http_connection.py
View File

@ -13,7 +13,12 @@ the Connection_ header is set to ``close``.
"""
# pylint: disable=unused-argument
from typing import Optional
from __future__ import annotations
from ipaddress import (
IPv4Network,
IPv6Network,
)
import flask
import werkzeug
@ -21,7 +26,12 @@ from searx.tools import config
from ._helpers import too_many_requests
def filter_request(request: flask.Request, cfg: config.Config) -> Optional[werkzeug.Response]:
def filter_request(
network: IPv4Network | IPv6Network,
request: flask.Request,
cfg: config.Config,
) -> werkzeug.Response | None:
if request.headers.get('Connection', '').strip() == 'close':
return too_many_requests(request, "HTTP header 'Connection=close")
return too_many_requests(network, "HTTP header 'Connection=close")
return None

16
searx/botdetection/http_user_agent.py
View File

@ -14,8 +14,13 @@ the User-Agent_ header is unset or matches the regular expression
"""
# pylint: disable=unused-argument
from typing import Optional
from __future__ import annotations
import re
from ipaddress import (
IPv4Network,
IPv6Network,
)
import flask
import werkzeug
@ -50,8 +55,13 @@ def regexp_user_agent():
return _regexp
def filter_request(request: flask.Request, cfg: config.Config) -> Optional[werkzeug.Response]:
def filter_request(
network: IPv4Network | IPv6Network,
request: flask.Request,
cfg: config.Config,
) -> werkzeug.Response | None:
user_agent = request.headers.get('User-Agent', 'unknown')
if regexp_user_agent().match(user_agent):
return too_many_requests(request, f"bot detected, HTTP header User-Agent: {user_agent}")
return too_many_requests(network, f"bot detected, HTTP header User-Agent: {user_agent}")
return None

49
searx/botdetection/ip_limit.py
View File

@ -38,8 +38,12 @@ droped.
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
"""
from __future__ import annotations
from ipaddress import (
IPv4Network,
IPv6Network,
)
from typing import Optional
import flask
import werkzeug
from searx.tools import config
@ -49,7 +53,7 @@ from searx import logger
from searx.redislib import incr_sliding_window, drop_counter
from . import link_token
from ._helpers import too_many_requests, get_real_ip
from ._helpers import too_many_requests
logger = logger.getChild('botdetection.ip_limit')
@ -85,49 +89,58 @@ SUSPICIOUS_IP_MAX = 3
"""Maximum requests from one suspicious IP in the :py:obj:`SUSPICIOUS_IP_WINDOW`."""
def filter_request(request: flask.Request, cfg: config.Config) -> Optional[werkzeug.Response]:
def filter_request(
network: IPv4Network | IPv6Network,
request: flask.Request,
cfg: config.Config,
) -> werkzeug.Response | None:
# pylint: disable=too-many-return-statements
redis_client = redisdb.client()
client_ip = get_real_ip(request)
if network.is_link_local and not cfg['botdetection.ip_limit.filter_link_local']:
logger.debug("network %s is link-local -> not monitored by ip_limit method", network.compressed)
return None
if request.args.get('format', 'html') != 'html':
c = incr_sliding_window(redis_client, 'ip_limit.API_WONDOW:' + client_ip, API_WONDOW)
c = incr_sliding_window(redis_client, 'ip_limit.API_WONDOW:' + network.compressed, API_WONDOW)
if c > API_MAX:
return too_many_requests(request, "too many request in API_WINDOW")
return too_many_requests(network, "too many request in API_WINDOW")
if cfg['botdetection.ip_limit.link_token']:
suspicious = link_token.is_suspicious(request, True)
suspicious = link_token.is_suspicious(network, request, True)
if not suspicious:
# this IP is no longer suspicious: release ip again / delete the counter of this IP
drop_counter(redis_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + client_ip)
drop_counter(redis_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + network.compressed)
return None
# this IP is suspicious: count requests from this IP
c = incr_sliding_window(redis_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + client_ip, SUSPICIOUS_IP_WINDOW)
c = incr_sliding_window(
redis_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + network.compressed, SUSPICIOUS_IP_WINDOW
)
if c > SUSPICIOUS_IP_MAX:
logger.error("BLOCK: too many request from %s in SUSPICIOUS_IP_WINDOW (redirect to /)", client_ip)
logger.error("BLOCK: too many request from %s in SUSPICIOUS_IP_WINDOW (redirect to /)", network)
return flask.redirect(flask.url_for('index'), code=302)
c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + client_ip, BURST_WINDOW)
c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
if c > BURST_MAX_SUSPICIOUS:
return too_many_requests(request, "too many request in BURST_WINDOW (BURST_MAX_SUSPICIOUS)")
return too_many_requests(network, "too many request in BURST_WINDOW (BURST_MAX_SUSPICIOUS)")
c = incr_sliding_window(redis_client, 'ip_limit.LONG_WINDOW' + client_ip, LONG_WINDOW)
c = incr_sliding_window(redis_client, 'ip_limit.LONG_WINDOW' + network.compressed, LONG_WINDOW)
if c > LONG_MAX_SUSPICIOUS:
return too_many_requests(request, "too many request in LONG_WINDOW (LONG_MAX_SUSPICIOUS)")
return too_many_requests(network, "too many request in LONG_WINDOW (LONG_MAX_SUSPICIOUS)")
return None
# vanilla limiter without extensions counts BURST_MAX and LONG_MAX
c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + client_ip, BURST_WINDOW)
c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
if c > BURST_MAX:
return too_many_requests(request, "too many request in BURST_WINDOW (BURST_MAX)")
return too_many_requests(network, "too many request in BURST_WINDOW (BURST_MAX)")
c = incr_sliding_window(redis_client, 'ip_limit.LONG_WINDOW' + client_ip, LONG_WINDOW)
c = incr_sliding_window(redis_client, 'ip_limit.LONG_WINDOW' + network.compressed, LONG_WINDOW)
if c > LONG_MAX:
return too_many_requests(request, "too many request in LONG_WINDOW (LONG_MAX)")
return too_many_requests(network, "too many request in LONG_WINDOW (LONG_MAX)")
return None

61
searx/botdetection/limiter.py
View File

@ -37,14 +37,16 @@ and set the redis-url connection. Check the value, it depends on your redis DB
"""
from typing import Optional, Tuple
from __future__ import annotations
from pathlib import Path
import flask
import pytomlpp as toml
import werkzeug
from searx import logger
from searx.tools import config
from searx.botdetection import (
from searx import logger
from . import (
http_accept,
http_accept_encoding,
http_accept_language,
@ -53,6 +55,16 @@ from searx.botdetection import (
ip_limit,
)
from ._helpers import (
get_network,
get_real_ip,
dump_request,
)
logger = logger.getChild('botdetection.limiter')
CFG: config.Config = None # type: ignore
LIMITER_CFG_SCHEMA = Path(__file__).parent / "limiter.toml"
"""Base configuration (schema) of the botdetection."""
@ -63,40 +75,21 @@ CFG_DEPRECATED = {
# "dummy.old.foo": "config 'dummy.old.foo' exists only for tests. Don't use it in your real project config."
}
CFG = None
def get_cfg() -> config.Config:
global CFG # pylint: disable=global-statement
if CFG is None:
init_cfg(logger)
CFG = config.Config.from_toml(LIMITER_CFG_SCHEMA, LIMITER_CFG, CFG_DEPRECATED)
return CFG
def init_cfg(log):
global CFG # pylint: disable=global-statement
CFG = config.Config(cfg_schema=toml.load(LIMITER_CFG_SCHEMA), deprecated=CFG_DEPRECATED)
def filter_request(request: flask.Request) -> werkzeug.Response | None:
if not LIMITER_CFG.exists():
log.warning("missing config file: %s", LIMITER_CFG)
return
log.info("load config file: %s", LIMITER_CFG)
try:
upd_cfg = toml.load(LIMITER_CFG)
except toml.DecodeError as exc:
msg = str(exc).replace('\t', '').replace('\n', ' ')
log.error("%s: %s", LIMITER_CFG, msg)
raise
is_valid, issue_list = CFG.validate(upd_cfg)
for msg in issue_list:
log.error(str(msg))
if not is_valid:
raise TypeError(f"schema of {LIMITER_CFG} is invalid, can't cutomize limiter configuration from!")
CFG.update(upd_cfg)
def filter_request(request: flask.Request) -> Optional[Tuple[int, str]]:
cfg = get_cfg()
real_ip = get_real_ip(request)
network = get_network(real_ip, cfg)
if network.is_link_local:
return None
if request.path == '/healthz':
return None
@ -104,7 +97,7 @@ def filter_request(request: flask.Request) -> Optional[Tuple[int, str]]:
for func in [
http_user_agent,
]:
val = func.filter_request(request, CFG)
val = func.filter_request(network, request, cfg)
if val is not None:
return val
@ -118,8 +111,8 @@ def filter_request(request: flask.Request) -> Optional[Tuple[int, str]]:
http_user_agent,
ip_limit,
]:
val = func.filter_request(request, CFG)
val = func.filter_request(network, request, cfg)
if val is not None:
return val
logger.debug(f"OK {network}: %s", dump_request(flask.request))
return None

22
searx/botdetection/limiter.toml
View File

@ -1,8 +1,22 @@
[botdetection.ip_limit]
link_token = false
[real_ip]
# Number of values to trust for X-Forwarded-For.
x_for = 1
# The prefix defines the number of leading bits in an address that are compared
# to determine whether or not an address is part of a (client) network.
ipv4_prefix = 32
ipv6_prefix = 48
[botdetection.ip_limit]
# To get unlimited access in a local network, by default link-lokal addresses
# (networks) are not monitored by the ip_limit
filter_link_local = false
# acrivate link_token method in the ip_limit method
link_token = false

54
searx/botdetection/link_token.py
View File

@ -6,7 +6,7 @@ Method ``link_token``
The ``link_token`` method evaluates a request as :py:obj:`suspicious
<is_suspicious>` if the URL ``/client<token>.css`` is not requested by the
client. By adding a random component (the token) in the URL a bot can not send
client. By adding a random component (the token) in the URL, a bot can not send
a ping by request a static URL.
.. note::
@ -35,6 +35,11 @@ And in the HTML template from flask a stylesheet link is needed (the value of
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For
"""
from __future__ import annotations
from ipaddress import (
IPv4Network,
IPv6Network,
)
import string
import random
@ -43,7 +48,11 @@ import flask
from searx import logger
from searx import redisdb
from searx.redislib import secret_hash
from ._helpers import get_real_ip
from ._helpers import (
get_network,
get_real_ip,
)
TOKEN_LIVE_TIME = 600
"""Livetime (sec) of limiter's CSS token."""
@ -60,29 +69,26 @@ TOKEN_KEY = 'SearXNG_limiter.token'
logger = logger.getChild('botdetection.link_token')
def is_suspicious(request: flask.Request, renew: bool = False):
"""Checks if there is a valid ping for this request, if not this request is
rated as *suspicious*. If a valid ping exists and argument ``renew`` is
``True`` the expire time of this ping is reset to :py:obj:`PING_LIVE_TIME`.
def is_suspicious(network: IPv4Network | IPv6Network, request: flask.Request, renew: bool = False):
"""Checks whether a valid ping is exists for this (client) network, if not
this request is rated as *suspicious*. If a valid ping exists and argument
``renew`` is ``True`` the expire time of this ping is reset to
:py:obj:`PING_LIVE_TIME`.
"""
redis_client = redisdb.client()
if not redis_client:
return False
ping_key = get_ping_key(request)
ping_key = get_ping_key(network, request)
if not redis_client.get(ping_key):
logger.warning(
"missing ping (IP: %s) / request: %s",
get_real_ip(request),
ping_key,
)
logger.warning("missing ping (IP: %s) / request: %s", network.compressed, ping_key)
return True
if renew:
redis_client.set(ping_key, 1, ex=PING_LIVE_TIME)
logger.debug("found ping for client request: %s", ping_key)
logger.debug("found ping for (client) network %s -> %s", network.compressed, ping_key)
return False
@ -92,27 +98,31 @@ def ping(request: flask.Request, token: str):
The expire time of this ping-key is :py:obj:`PING_LIVE_TIME`.
"""
from . import limiter # pylint: disable=import-outside-toplevel, cyclic-import
redis_client = redisdb.client()
if not redis_client:
return
if not token_is_valid(token):
return
ping_key = get_ping_key(request)
logger.debug("store ping for: %s", ping_key)
cfg = limiter.get_cfg()
real_ip = get_real_ip(request)
network = get_network(real_ip, cfg)
ping_key = get_ping_key(network, request)
logger.debug("store ping_key for (client) network %s (IP %s) -> %s", network.compressed, real_ip, ping_key)
redis_client.set(ping_key, 1, ex=PING_LIVE_TIME)
def get_ping_key(request: flask.Request):
"""Generates a hashed key that fits (more or less) to a client (request).
At least X-Forwarded-For_ is needed to be able to assign the request to an
IP.
"""
def get_ping_key(network: IPv4Network | IPv6Network, request: flask.Request) -> str:
"""Generates a hashed key that fits (more or less) to a *WEB-browser
session* in a network."""
return (
PING_KEY
+ "["
+ secret_hash(
get_real_ip(request) + request.headers.get('Accept-Language', '') + request.headers.get('User-Agent', '')
network.compressed + request.headers.get('Accept-Language', '') + request.headers.get('User-Agent', '')
)
+ "]"
)

7
searx/plugins/limiter.py
View File

@ -8,7 +8,6 @@ import flask
from searx import redisdb
from searx.plugins import logger
from searx.botdetection import limiter
from searx.botdetection import dump_request
name = "Request limiter"
description = "Limit the number of request"
@ -20,10 +19,7 @@ logger = logger.getChild('limiter')
def pre_request():
"""See :ref:`flask.Flask.before_request`"""
ret_val = limiter.filter_request(flask.request)
if ret_val is None:
logger.debug("OK: %s" % dump_request(flask.request))
return ret_val
return limiter.filter_request(flask.request)
def init(app: flask.Flask, settings) -> bool:
@ -32,6 +28,5 @@ def init(app: flask.Flask, settings) -> bool:
if not redisdb.client():
logger.error("The limiter requires Redis")
return False
limiter.init_cfg(logger)
app.before_request(pre_request)
return True