[mod] limiter: trusted proxies (#4911)

Replaces `x_for` functionality with `trusted_proxies`. This allows defining
which IP / ranges to trust extracting the client IP address from X-Forwarded-For
and X-Real-IP headers.

We don't know if the proxy chain will give us the proper client
address (REMOTE_ADDR in the WSGI environment), so we rely on reading the headers
of the proxy before SearXNG (if there is one, in that case it must be added to
trusted_proxies) hoping it has done the proper checks. In case a proxy in the
chain does not check the client address correctly, integrity is compromised and
this should be fixed by whoever manages the proxy, not us.

Closes:

- https://github.com/searxng/searxng/issues/4940
- https://github.com/searxng/searxng/issues/4939
- https://github.com/searxng/searxng/issues/4907
- https://github.com/searxng/searxng/issues/3632
- https://github.com/searxng/searxng/issues/3191
- https://github.com/searxng/searxng/issues/1237

Related:

- https://github.com/searxng/searxng-docker/issues/386
- https://github.com/inetol-infrastructure/searxng-container/issues/81

1 files changed, 8 insertions, 8 deletions

diff --git a/searx/botdetection/ip_lists.py b/searx/botdetection/ip_lists.py
index 2ad1c62d0..77628b577 100644
--- a/searx/botdetection/ip_lists.py
+++ b/searx/botdetection/ip_lists.py
@@ -4,21 +4,22 @@
 Method ``ip_lists``
 -------------------
 
-The ``ip_lists`` method implements IP :py:obj:`block- <block_ip>` and
-:py:obj:`pass-lists <pass_ip>`.
+The ``ip_lists`` method implements :py:obj:`block-list <block_ip>` and
+:py:obj:`pass-list <pass_ip>`.
 
 .. code:: toml
 
    [botdetection.ip_lists]
 
    pass_ip = [
-    '167.235.158.251', # IPv4 of check.searx.space
-    '192.168.0.0/16',  # IPv4 private network
-    'fe80::/10'        # IPv6 linklocal
+     '167.235.158.251', # IPv4 of check.searx.space
+     '192.168.0.0/16',  # IPv4 private network
+     'fe80::/10',       # IPv6 linklocal
    ]
+
    block_ip = [
-      '93.184.216.34', # IPv4 of example.org
-      '257.1.1.1',     # invalid IP --> will be ignored, logged in ERROR class
+     '93.184.216.34',   # IPv4 of example.org
+     '257.1.1.1',       # invalid IP --> will be ignored, logged in ERROR class
    ]
 
 """
@@ -72,7 +73,6 @@ def block_ip(real_ip: IPv4Address | IPv6Address, cfg: config.Config) -> Tuple[bo
 def ip_is_subnet_of_member_in_list(
     real_ip: IPv4Address | IPv6Address, list_name: str, cfg: config.Config
 ) -> Tuple[bool, str]:
-
     for net in cfg.get(list_name, default=[]):
         try:
             net = ip_network(net, strict=False)