Bring back SSL option validation on startup by introducing handlers.validate_ssl_options

Author: zuohaocheng

pyftpdlib/handlers.py

@@ -3469,17 +3469,7 @@ def verify_certs_callback(self, connection, x509,
 
         def get_ssl_context(self):
             if self.ssl_context is None:
-                if self.certfile is None:
-                    raise ValueError("at least certfile must be specified")
-                self.ssl_context = SSL.Context(self.ssl_protocol)
-                if self.ssl_protocol != SSL.SSLv2_METHOD:
-                    self.ssl_context.set_options(SSL.OP_NO_SSLv2)
-                else:
-                    warnings.warn("SSLv2 protocol is insecure", RuntimeWarning)
-                self.ssl_context.use_certificate_chain_file(self.certfile)
-                if not self.keyfile:
-                    self.keyfile = self.certfile
-                self.ssl_context.use_privatekey_file(self.keyfile)
+                self.ssl_context = self.validate_ssl_options()
                 if self.client_certfile is not None:
                     from OpenSSL.SSL import VERIFY_CLIENT_ONCE
                     from OpenSSL.SSL import VERIFY_FAIL_IF_NO_PEER_CERT
@@ -3488,16 +3478,32 @@ def get_ssl_context(self):
                                                 VERIFY_FAIL_IF_NO_PEER_CERT |
                                                 VERIFY_CLIENT_ONCE,
                                                 self.verify_certs_callback)
-                    from OpenSSL.SSL import OP_NO_TICKET
-                    from OpenSSL.SSL import SESS_CACHE_OFF
-                    self.ssl_context.load_verify_locations(
-                        self.client_certfile)
-                    self.ssl_context.set_session_cache_mode(SESS_CACHE_OFF)
-                    self.ssl_options = self.ssl_options | OP_NO_TICKET
-                if self.ssl_options:
-                    self.ssl_context.set_options(self.ssl_options)
             return self.ssl_context
 
+        @classmethod
+        def validate_ssl_options(cls):
+            if cls.certfile is None:
+                raise ValueError("at least certfile must be specified")
+            ssl_context = SSL.Context(cls.ssl_protocol)
+            if cls.ssl_protocol != SSL.SSLv2_METHOD:
+                ssl_context.set_options(SSL.OP_NO_SSLv2)
+            else:
+                warnings.warn("SSLv2 protocol is insecure", RuntimeWarning)
+            ssl_context.use_certificate_chain_file(cls.certfile)
+            if not cls.keyfile:
+                cls.keyfile = cls.certfile
+            ssl_context.use_privatekey_file(cls.keyfile)
+            if cls.client_certfile is not None:
+                from OpenSSL.SSL import OP_NO_TICKET
+                from OpenSSL.SSL import SESS_CACHE_OFF
+                ssl_context.load_verify_locations(
+                    cls.client_certfile)
+                ssl_context.set_session_cache_mode(SESS_CACHE_OFF)
+                cls.ssl_options = cls.ssl_options | OP_NO_TICKET
+            if cls.ssl_options:
+                ssl_context.set_options(cls.ssl_options)
+            return ssl_context
+
         # --- overridden methods
 
         def flush_account(self):

pyftpdlib/servers.py

@@ -104,8 +104,8 @@ def __init__(self, address_or_socket, handler, ioloop=None, backlog=100):
         self.ip_map = []
         # in case of FTPS class not properly configured we want errors
         # to be raised here rather than later, when client connects
-        # if hasattr(handler, 'get_ssl_context'):
-        #     handler.get_ssl_context(handler)
+        if hasattr(handler, 'validate_ssl_options'):
+            handler.validate_ssl_options()
         if callable(getattr(address_or_socket, 'listen', None)):
             sock = address_or_socket
             sock.setblocking(0)

pyftpdlib/test/test_functional_ssl.py

@@ -370,15 +370,15 @@ def try_protocol_combo(self, server_protocol, client_protocol):
     #     for proto in protos:
     #         self.try_protocol_combo(ssl.PROTOCOL_TLSv1, proto)
 
-    # On OSX TLS_FTPHandler.get_ssl_context()._context does not exist.
+    # On OSX TLS_FTPHandler.validate_ssl_options()._context does not exist.
     @unittest.skipIf(OSX, "can't get options on OSX")
     def test_ssl_options(self):
         from OpenSSL import SSL
         from OpenSSL._util import lib
         from pyftpdlib.handlers import TLS_FTPHandler
         try:
             TLS_FTPHandler.ssl_context = None
-            ctx = TLS_FTPHandler.get_ssl_context()
+            ctx = TLS_FTPHandler.validate_ssl_options()
             # Verify default opts.
             with contextlib.closing(socket.socket()) as s:
                 s = SSL.Connection(ctx, s)
@@ -392,7 +392,7 @@ def test_ssl_options(self):
             # ssl_proto is set to SSL.SSLv23_METHOD).
             TLS_FTPHandler.ssl_context = None
             TLS_FTPHandler.ssl_options = None
-            ctx = TLS_FTPHandler.get_ssl_context()
+            ctx = TLS_FTPHandler.validate_ssl_options()
             with contextlib.closing(socket.socket()) as s:
                 s = SSL.Connection(ctx, s)
                 opts = lib.SSL_CTX_get_options(ctx._context)