Added a middleware to repel anonymous proxy and tor clients

dpaste/middleware.py

@@ -0,0 +1,54 @@
+import socket
+
+tor_bl = (
+    '{remote_addr}.{server_port}.{server_ip}'
+    '.ip-port.exitlist.torproject.org')
+open_proxy_bl = ('{remote_addr}.dnsbl.proxybl.org')
+rev_ip = lambda ip: '.'.join(reversed(ip.split('.')))
+
+
+def in_blacklist(request, bl, ip=None):
+    ip = ip or request.META['REMOTE_ADDR']
+    try:
+        server_ip = socket.gethostbyname(request.META['SERVER_NAME'])
+    except socket.gaierror:
+        return
+    bl_name = bl.format(
+        remote_addr=rev_ip(ip),
+        server_port=request.META['SERVER_PORT'],
+        server_ip=rev_ip(server_ip)
+    )
+    try:
+        lookup = socket.gethostbyname(bl_name)
+    except socket.gaierror as s:
+        if s.errno == -5:
+            return False
+        return
+    except Exception:
+        return
+    return lookup == '127.0.0.2'
+
+
+class SuspiciousIPMiddleware(object):
+
+    def process_request(self, request):
+
+        def check_tor():
+            if not hasattr(request, '_is_tor_exit_node'):
+                request._is_tor_exit_node = in_blacklist(request, tor_bl)
+            return request._is_tor_exit_node
+
+        request.is_tor_exit_node = check_tor
+
+        def check_open_proxy():
+            if not hasattr(request, '_is_open_proxy'):
+                request._is_open_proxy = in_blacklist(
+                    request, open_proxy_bl)
+            return request._is_open_proxy
+
+        request.is_open_proxy = check_open_proxy
+
+        def check_suspicious():
+            return request.is_tor_exit_node() or request.is_open_proxy()
+
+        request.is_suspicious = check_suspicious