Implement Haproxy PROXY protocol v1 and v2

Signed-off-by: Frank Villaro-Dixon <frank.villaro@infomaniak.com>

demo/proxy_protocol_untrusted.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+
+# Copyright (C) 2007 Giampaolo Rodola' <g.rodola@gmail.com>.
+# Use of this source code is governed by MIT license that can be
+# found in the LICENSE file.
+
+"""A basic FTP server which uses a DummyAuthorizer for managing 'virtual
+users', setting a limit for incoming connections and a range of passive
+ports. Accepts connections from proxies implementing the PROXY protocol.
+"""
+
+import os
+
+from pyftpdlib.authorizers import DummyAuthorizer
+from pyftpdlib.handlers import FTPHandler
+from pyftpdlib.servers import FTPServer
+
+
+def main():
+    # Instantiate a dummy authorizer for managing 'virtual' users
+    authorizer = DummyAuthorizer()
+
+    # Define a new user having full r/w permissions and a read-only
+    # anonymous user
+    authorizer.add_user('user', '12345', os.getcwd(), perm='elradfmwMT')
+    authorizer.add_anonymous(os.getcwd())
+
+    # Instantiate FTP handler class
+    handler = FTPHandler
+    handler.authorizer = authorizer
+
+    # Define a customized banner (string returned when client connects)
+    handler.banner = "pyftpdlib based ftpd ready."
+
+    # Specify a masquerade address and the range of ports to use for
+    # passive connections.  Decomment in case you're behind a NAT.
+    # handler.masquerade_address = '151.25.42.11'
+    handler.passive_ports = range(20000, 22535)
+
+
+    # Instantiate FTP server class and listen on 0.0.0.0:2121
+    address = ('', 2121)
+    FTPServer.proxy_proto_enabled = True
+    FTPServer.proxy_proto_allow_untrusted = True
+    server = FTPServer(address, handler)
+
+    # set a limit for connections
+    server.max_cons = 256
+    server.max_cons_per_ip = 5
+
+    # start ftp server
+    server.serve_forever()
+
+
+if __name__ == '__main__':
+    main()

docs/api.rst

@@ -379,6 +379,22 @@ Server (acceptor)
     Number of maximum connections accepted for the same IP address (default
     ``0`` == no limit).
 
+  .. data:: proxy_proto_enabled
+
+    Whether to enable the PROXY protocol for incoming connections (default ``False``)
+
+  .. data:: proxy_proto_trusted_nets
+
+    Contains a list of trusted proxies (written as strings) allowed to communicate
+    with the server. Use a /32 (or /128) network mask if you want to declare a
+    single IP, for example ``['10.11.12.13/32', 'fc88::2/128']`` (defaults to ``[]``).
+
+  .. data:: proxy_proto_allow_untrusted
+
+    Whether or not to parse non trusted (as defined by :data:`proxy_proto_trusted_nets`)
+    proxies headers (defaults to ``False``).
+
+
   .. method:: serve_forever(timeout=None, blocking=True, handle_exit=True, worker_processes=1)
 
     Starts the asynchronous IO loop.

pyftpdlib/handlers.py

@@ -1234,6 +1234,7 @@ def __init__(self, conn, server, ioloop=None):
         self.remote_ip = ""
         self.remote_port = ""
         self.started = time.time()
+        self.proxy_proto_obj = self.server.proxy_proto_obj
 
         # private session attributes
         self._last_response = ""
@@ -1294,6 +1295,15 @@ def __init__(self, conn, server, ioloop=None):
                 self.handle_error()
             return
         else:
+            if self.server.proxy_proto_enabled and self.proxy_proto_obj and \
+                    (self.proxy_proto_obj.trusted or self.server.proxy_proto_allow_untrusted):
+                # Override the socket values if PROXY protocol data is
+                # available and comes from a trusted proxy
+                if self.proxy_proto_obj.remote_ip:
+                    self.remote_ip = self.proxy_proto_obj.remote_ip
+                if self.proxy_proto_obj.remote_port:
+                    self.remote_port = self.proxy_proto_obj.remote_port
+
             self.log("FTP session opened (connect)")
 
         # try to handle urgent data inline

pyftpdlib/ioloop.py

@@ -76,6 +76,7 @@ def handle_accepted(self, sock, addr):
 from .log import debug
 from .log import is_logging_configured
 from .log import logger
+from .proxy_proto import ProxyProtocol
 
 
 timer = getattr(time, 'monotonic', time.time)
@@ -977,8 +978,30 @@ def add_channel(self, map=None, events=None):
 class Acceptor(AsyncChat):
     """Same as base AsyncChat and supposed to be used to
     accept new connections.
+
+    All relevant PROXY protocol information is stored in class attributes
+    described below.
+
+     - (bool) proxy_proto_enabled:
+        enable the use of PROXY protocol (defaults to False).
+
+     - (list) proxy_proto_trusted_nets:
+        the IP networks (written as strings) of the proxies you want to
+        trust. Use a /32 (or /128) network mask if you want to declare a
+        single IP (defaults to []).
+
+     - (bool) proxy_proto_allow_untrusted:
+        whether or not to parse untrusted proxies headers (defaults to False).
+
+     - (instance) proxy_proto_obj:
+        the ProxyProtocol instance populated with header's information
     """
 
+    proxy_proto_enabled = False
+    proxy_proto_trusted_nets = []
+    proxy_proto_allow_untrusted = False
+    proxy_proto_obj = None
+
     def add_channel(self, map=None, events=None):
         AsyncChat.add_channel(self, map=map, events=self.ioloop.READ)
 
@@ -1045,6 +1068,21 @@ def handle_accept(self):
                 debug("call: handle_accept(); accept() returned ECONNABORTED",
                       self)
         else:
+            if self.proxy_proto_enabled:
+                # Retrieve a populated PROXY protocol object. If no exception
+                # is raised the returned object is considered valid
+                try:
+                    ProxyProtocol.trusted_networks = self.proxy_proto_trusted_nets
+                    ProxyProtocol.allow_untrusted = self.proxy_proto_allow_untrusted
+                    self.proxy_proto_obj = ProxyProtocol.create(sock)
+                except Exception as e:
+                    logger.error("proxy: {}".format(e))
+                    return
+
+                if self.proxy_proto_obj.trusted or self.proxy_proto_allow_untrusted:
+                    # Could result in a (None, None) tuple
+                    addr = (self.proxy_proto_obj.remote_ip, self.proxy_proto_obj.remote_port)
+
             # sometimes addr == None instead of (ip, port) (see issue 104)
             if addr is not None:
                 self.handle_accepted(sock, addr)