CoRegisterClassObject returns error (session 0?)

Question

A customer is running one of our programs, usually run as a service, as an application. The customer is getting the following error on CoRegisterClassObject():

The class is configured to run as a security id different from the caller.

It looks like some type of session 0 error, but why should CoRegisterClassObject() care about session 0? COM should allow both services (session 0) and apps (session > 0) and not care what registers what, shouldn't it?

Also, I don't like the fact that it's not in the list of errors returnable by CoRegisterClassObject(), as per the Microsoft doc webpage.

Answer 1

The error code in question is CO_E_WRONG_SERVER_IDENTITY (0x80004015).

Per this page:

COM security frequently asked questions

Q6 Why does CoRegisterClassObject return CO_E_WRONG_SERVER_IDENTITY? When launching my ATL 1.1 server service as an .exe file, I receive CO_E_WRONG_SERVER_IDENTITY from CoRegisterClassObject. (The class is configured to run as a security ID different from the caller.) This seems to occur whether I skip the CoInitializeSecurity or not. It fails running as a service or as an .exe file.

A. Many services are debugged by running them as console applications in the interactive user identity. Because the service is already registered to run in a different identity (configurable by the Services control panel applet), OLE fails the CoRegisterClassObject and RunningObjectTable::Register(ROTFLAGS_ALLOWANYCLIENT) calls by returning CO_E_WRONG_SERVER_IDENTITY to enforce security and to prevent malicious servers from spoofing the server. To debug by running in the interactive user's identity, make the following changes in the server's registry entries to prevent these failures:

• To prevent CoRegisterClassObject failure, remove the following named value:

[HKEY_CLASSES_ROOT\APPID\{0bf52b15-8cab-11cf-8572-00aa00c006cf}]
"LocalService"="HelloOleServerService"  

• To prevent a IRunningObjectTable::Register(ROTFLAGS_ALLOWANYCLIENT) failure, follow these steps:

1. Remove the following named value:

   [HKEY_CLASSES_ROOT\APPID\{0bf52b15-8cab-11cf-8572-00aa00c006cf}]
   "LocalService"="HelloOleServerService" 
   

2. Then add the following named value:

   [HKEY_CLASSES_ROOT\APPID\{0bf52b15-8cab-11cf-8572-00aa00c006cf}]
   "RunAs"="Interactive User"  
   

You muist restore the modified registry entries after debugging.

I am assuming you would have to replace {0bf52b15-8cab-11cf-8572-00aa00c006cf} with your COM object's actual CLSID instead.