How to use CoInitializeSecurity by using pointer to AppID in pSecDesc parameter?

Hello @Sivalingam Somasundaram ,

To use CoInitializeSecurity with a pointer to an AppID in the first parameter, you need to fulfill two specific requirements:

1. Cast the GUID pointer: You must take the address of your AppID (GUID) and cast it to PSECURITY_DESCRIPTOR for the first parameter.
2. Use the EOAC_APPID flag: You must pass the EOAC_APPID flag in the 8th parameter (dwCapabilities). This flag explicitly indicates to the COM infrastructure that the pSecDesc parameter is a pointer to an AppID GUID. COM will then use this GUID to look up your security settings in the Windows Registry.

Below is a C++ example snippet that I want to demonstrate how to do this:

#include <windows.h>
#include <objbase.h>
#include <iostream>

// Link the COM library for Visual Studio users
#pragma comment(lib, "ole32.lib")

// 1. Define your AppID (Replace with your application's actual GUID)
// Example: {12345678-1234-1234-1234-1234567890AB}
const GUID AppID_MyApp = 
{ 0x12345678, 0x1234, 0x1234, { 0x12, 0x34, 0x12, 0x34, 0x56, 0x78, 0x90, 0xab } };

int main() {
    // Initialize the COM library
    HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);

    if (FAILED(hr)) {
        std::cout << "Failed to initialize COM library." << std::endl;
        return -1;
    }

    // 2. Call CoInitializeSecurity using the AppID pointer
    hr = CoInitializeSecurity(
        (PSECURITY_DESCRIPTOR)&AppID_MyApp, // Parameter 1: Cast the address of your AppID
        -1,                                 // cAuthSvc
        NULL,                               // asAuthSvc
        NULL,                               // pReserved1
        RPC_C_AUTHN_LEVEL_DEFAULT,          // dwAuthnLevel
        RPC_C_IMP_LEVEL_IDENTIFY,           // dwImpLevel
        NULL,                               // pAuthList
        EOAC_APPID,                         // Parameter 8: REQUIRED FLAG to indicate pSecDesc is an AppID
        NULL                                // pReserved3
    );

    if (hr == S_OK) {
        std::cout << "Successfully initialized COM security using AppID!" << std::endl;
    } else if (hr == REGDB_E_CLASSNOTREG) {
        std::cout << "Failed: AppID not found in the Registry (0x80040154)." << std::endl;
    } else {
        std::cout << "Failed with HRESULT: 0x" << std::hex << hr << std::endl;
    }

    // Cleanup COM
    CoUninitialize();
    return 0;
}

Important Registry note is for this to work at runtime and not return REGDB_E_CLASSNOTREG, your AppID must actually exist in the Windows Registry under HKEY_CLASSES_ROOT\AppID\{Your-GUID} with the appropriate security configurations (like AccessPermission or LaunchPermission). If it's not in the registry, COM won't be able to fetch the security settings for your application.

Hope this helps clarify your question. If you found my response helpful, please follow this guide to provide feedback.

Thank you.