Merge pull request #3344 from volundmush/ip_from_request

Overhaul IP Matching

evennia/server/portal/webclient_ajax.py

@@ -31,7 +31,7 @@ from evennia.server import session
 from evennia.utils import utils
 from evennia.utils.ansi import parse_ansi
 from evennia.utils.text2html import parse_html
-from evennia.utils.utils import to_bytes
+from evennia.utils.utils import to_bytes, ip_from_request
 
 _CLIENT_SESSIONS = utils.mod_import(settings.SESSION_ENGINE).SessionStore
 _RE_SCREENREADER_REGEX = re.compile(
@@ -197,16 +197,7 @@ class AjaxWebClient(resource.Resource):
         csessid = self.get_client_sessid(request)
         browserstr = self.get_browserstr(request)
 
-        remote_addr = request.getClientIP()
-
-        if remote_addr in settings.UPSTREAM_IPS and request.getHeader("x-forwarded-for"):
-            addresses = [x.strip() for x in request.getHeader("x-forwarded-for").split(",")]
-            addresses.reverse()
-
-            for addr in addresses:
-                if addr not in settings.UPSTREAM_IPS:
-                    remote_addr = addr
-                    break
+        remote_addr = ip_from_request(request)
 
         host_string = "%s (%s:%s)" % (
             _SERVERNAME,

evennia/settings_default.py

@@ -90,7 +90,8 @@ WEBSERVER_PORTS = [(4001, 4005)]
 # Interface addresses to listen to. If 0.0.0.0, listen to all. Use :: for IPv6.
 WEBSERVER_INTERFACES = ["0.0.0.0"]
 # IP addresses that may talk to the server in a reverse proxy configuration,
-# like NginX.
+# like NginX or Varnish. These can be either specific IPv4 or IPv6 addresses,
+# or subnets in CIDR format - like 192.168.0.0/24 or 2001:db8::/32.
 UPSTREAM_IPS = ["127.0.0.1"]
 # The webserver uses threadpool for handling requests. This will scale
 # with server load. Set the minimum and maximum number of threads it
@@ -1031,6 +1032,7 @@ MIDDLEWARE = [
     "django.middleware.csrf.CsrfViewMiddleware",
     "django.contrib.admindocs.middleware.XViewMiddleware",
     "django.contrib.flatpages.middleware.FlatpageFallbackMiddleware",
+    "evennia.web.utils.middleware.OriginIpMiddleware",
     "evennia.web.utils.middleware.SharedLoginMiddleware",
 ]
 

evennia/utils/tests/test_utils.py

@@ -773,3 +773,15 @@ class TestJustify(TestCase):
         result = utils.justify(line, align="c", width=30)
 
         self.assertIn(ANSI_RED, str(result))
+
+
+class TestMatchIP(TestCase):
+    """
+    test utils.match_ip
+    """
+
+    def test_match_ip(self):
+        self.assertFalse(utils.match_ip("192.168.0.1", "10.0.0.0/24"))
+        self.assertTrue(utils.match_ip("192.168.0.1", "192.168.0.0/24"))
+        self.assertTrue(utils.match_ip("192.168.0.1", "192.168.0.1"))
+        self.assertFalse(utils.match_ip("192.168.0.1", "10.0.0.1"))

evennia/utils/utils.py

@@ -11,6 +11,7 @@ import importlib
 import importlib.machinery
 import importlib.util
 import inspect
+import ipaddress
 import math
 import os
 import random
@@ -2942,3 +2943,78 @@ def str2int(number):
             # invalid number-word, raise ValueError
             raise ValueError(f"String {original_input} cannot be converted to int.")
     return sum(sums)
+
+
+def match_ip(address, pattern) -> bool:
+    """
+    Check if an IP address matches a given pattern. The pattern can be a single IP address
+    such as 8.8.8.8 or a CIDR-formatted subnet like 10.0.0.0/8
+
+    IPv6 is supported to, with CIDR-subnets looking like 2001:db8::/48
+
+    Args:
+        address (str): The source address being checked.
+        pattern (str): The single IP address or subnet to check against.
+
+    Returns:
+        result (bool): Whether it was a match or not.
+    """
+    try:
+        # Convert the given IP address to an IPv4Address or IPv6Address object
+        ip_obj = ipaddress.ip_address(address)
+    except ValueError:
+        # Invalid IP address format
+        return False
+
+    try:
+        # Check if pattern is a single IP or a subnet
+        if "/" in pattern:
+            # It's (hopefully) a subnet in CIDR notation
+            network = ipaddress.ip_network(pattern, strict=False)
+            if ip_obj in network:
+                return True
+        else:
+            # It's a single IP address
+            if ip_obj == ipaddress.ip_address(pattern):
+                return True
+    except ValueError:
+        return False
+    return False
+
+
+def ip_from_request(request, exclude=None) -> str:
+    """
+    Retrieves the IP address from a web Request, while respecting X-Forwarded-For and
+    settings.UPSTREAM_IPS.
+
+    Args:
+        request (django Request or twisted.web.http.Request): The web request.
+        exclude: (list, optional): A list of IP addresses to exclude from the check. If left none,
+            then settings.UPSTREAM_IPS will be used.
+
+    Returns:
+        ip (str): The IP address the request originated from.
+    """
+    if exclude is None:
+        exclude = settings.UPSTREAM_IPS
+
+    if hasattr(request, "getClientIP"):
+        # It's a twisted request.
+        remote_addr = request.getClientIP()
+        forwarded = request.getHeader("x-forwarded-for")
+    else:
+        # it's a Django request.
+        remote_addr = request.META.get("REMOTE_ADDR")
+        forwarded = request.META.get("HTTP_X_FORWARDED_FOR")
+
+    addresses = [remote_addr]
+
+    if forwarded:
+        addresses.extend(x.strip() for x in forwarded.split(","))
+
+    for addr in reversed(addresses):
+        if all(not match_ip(addr, pattern) for pattern in exclude):
+            return addr
+
+    logger.log_warn("ip_from_request: No valid IP address found in request. Using remote_addr.")
+    return remote_addr

evennia/web/utils/middleware.py

@@ -1,7 +1,21 @@
 from django.contrib.auth import authenticate, login
 
 from evennia.accounts.models import AccountDB
-from evennia.utils import logger
+from evennia.utils import logger, ip_from_request
+
+
+class OriginIpMiddleware:
+    """
+    This Django Middleware simply sets the request.origin_ip attribute to what is
+    respected by the Evennia Server, taking into account settings.UPSTREAM_IPS.
+    """
+
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
+        request.origin_ip = ip_from_request(request)
+        return self.get_response(request)
 
 
 class SharedLoginMiddleware(object):