From 0367e6dd66d47a78484e12e76119d9662356bf48 Mon Sep 17 00:00:00 2001

From: Stanislav Laznicka <slaznick@redhat.com>

Date: Fri, 26 May 2017 08:37:36 +0200

Subject: [PATCH] Avoid possible endless recursion in RPC call

This commit removes recursion in RPCClient.forward() which may lack

end condition.

https://pagure.io/freeipa/issue/6796

Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>

---

 ipalib/rpc.py | 95 +++++++++++++++++++++++++++++++++--------------------------

 1 file changed, 54 insertions(+), 41 deletions(-)

diff --git a/ipalib/rpc.py b/ipalib/rpc.py

index e23ca3d061645b2695a9e0deaa0b7d666f986e0e..297ed80414fae3d8b27558567425fec704f3e862 100644

--- a/ipalib/rpc.py

+++ b/ipalib/rpc.py

@@ -1088,50 +1088,63 @@ class RPCClient(Connectible):

         :param kw: Keyword arguments to pass to remote command.

         """

         server = getattr(context, 'request_url', None)

-        self.log.info("Forwarding '%s' to %s server '%s'",

-                      name, self.protocol, server)

         command = getattr(self.conn, name)

         params = [args, kw]

-        try:

-            return self._call_command(command, params)

-        except Fault as e:

-            e = decode_fault(e)

-            self.debug('Caught fault %d from server %s: %s', e.faultCode,

-                server, e.faultString)

-            if e.faultCode in errors_by_code:

-                error = errors_by_code[e.faultCode]

-                raise error(message=e.faultString)

-            raise UnknownError(

-                code=e.faultCode,

-                error=e.faultString,

-                server=server,

-            )

-        except SSLError as e:

-            raise NetworkError(uri=server, error=str(e))

-        except ProtocolError as e:

-            # By catching a 401 here we can detect the case where we have

-            # a single IPA server and the session is invalid. Otherwise

-            # we always have to do a ping().

-            session_cookie = getattr(context, 'session_cookie', None)

-            if session_cookie and e.errcode == 401:

-                # Unauthorized. Remove the session and try again.

-                delattr(context, 'session_cookie')

-                try:

-                    principal = getattr(context, 'principal', None)

-                    delete_persistent_client_session_data(principal)

-                except Exception as e:

-                    # This shouldn't happen if we have a session but it isn't fatal.

-                    pass

-                # Create a new serverproxy with the non-session URI

-                serverproxy = self.create_connection(os.environ.get('KRB5CCNAME'), self.env.verbose, self.env.fallback, self.env.delegate)

-                setattr(context, self.id, Connection(serverproxy, self.disconnect))

-                return self.forward(name, *args, **kw)

-            raise NetworkError(uri=server, error=e.errmsg)

-        except socket.error as e:

-            raise NetworkError(uri=server, error=str(e))

-        except (OverflowError, TypeError) as e:

-            raise XMLRPCMarshallError(error=str(e))

+        # we'll be trying to connect multiple times with a new session cookie

+        # each time should we be getting UNAUTHORIZED error from the server

+        max_tries = 5

+        for try_num in range(0, max_tries):

+            self.log.info("[try %d]: Forwarding '%s' to %s server '%s'",

+                          try_num+1, name, self.protocol, server)

+            try:

+                return self._call_command(command, params)

+            except Fault as e:

+                e = decode_fault(e)

+                self.debug('Caught fault %d from server %s: %s', e.faultCode,

+                           server, e.faultString)

+                if e.faultCode in errors_by_code:

+                    error = errors_by_code[e.faultCode]

+                    raise error(message=e.faultString)

+                raise UnknownError(

+                    code=e.faultCode,

+                    error=e.faultString,

+                    server=server,

+                )

+            except ProtocolError as e:

+                # By catching a 401 here we can detect the case where we have

+                # a single IPA server and the session is invalid. Otherwise

+                # we always have to do a ping().

+                session_cookie = getattr(context, 'session_cookie', None)

+                if session_cookie and e.errcode == 401:

+                    # Unauthorized. Remove the session and try again.

+                    delattr(context, 'session_cookie')

+                    try:

+                        principal = getattr(context, 'principal', None)

+                        delete_persistent_client_session_data(principal)

+                    except Exception as e:

+                        # This shouldn't happen if we have a session

+                        # but it isn't fatal.

+                        self.debug("Error trying to remove persisent session "

+                                   "data: {err}".format(err=e))

+

+                    # Create a new serverproxy with the non-session URI

+                    serverproxy = self.create_connection(

+                        os.environ.get('KRB5CCNAME'), self.env.verbose,

+                        self.env.fallback, self.env.delegate)

+

+                    setattr(context, self.id,

+                            Connection(serverproxy, self.disconnect))

+                    # try to connect again with the new session cookie

+                    continue

+                raise NetworkError(uri=server, error=e.errmsg)

+            except (SSLError, socket.error) as e:

+                raise NetworkError(uri=server, error=str(e))

+            except (OverflowError, TypeError) as e:

+                raise XMLRPCMarshallError(error=str(e))

+        raise NetworkError(

+            uri=server,

+            error=_("Exceeded number of tries to forward a request."))

 class xmlclient(RPCClient):

-- 

2.9.4