UEFI Create User

Question

I try to use this code

      Status = gBS->OpenProtocol(handles[i], &gEfiUserManagerProtocolGuid, (void **) &mUserManager, gImageHandle, NULL, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
  switch (Status)
  {
  case EFI_SUCCESS:           Print(L"OpenProtocol _____ OK!\n\r");  break;
  case EFI_INVALID_PARAMETER: Print(L"OpenProtocol _____ EFI_INVALID_PARAMETER!\n\r"); break;
  case EFI_UNSUPPORTED:       Print(L"OpenProtocol _____ EFI_UNSUPPORTED!\n\r");       break;
  default:                    Print(L"OpenProtocol _____ Status =  %d  \n\r",Status);  break;
  }

  Status = mUserManager->Create(mUserManager, &User);
  switch (Status)
  {
  case EFI_SUCCESS:           Print(L"Create _____ create successfully!\n\r");    break;
  case EFI_ACCESS_DENIED:     Print(L"Create _____ EFI_ACCESS_DENIED!\n\r");      break;
  case EFI_UNSUPPORTED:       Print(L"Create _____ EFI_UNSUPPORTED!\n\r");        break;
  case EFI_INVALID_PARAMETER: Print(L"Create _____ EFI_INVALID_PARAMETER!\n\r");  break;
  default:                    Print(L"Create _____ Status =  %d  \n\r",Status);   break;
  }

Status return EFI_SUCCESS, computer go to reboot. Next time i try to create user, status return EFI_ACCESS_DENIED. Where user profile storing? How to create user at second time?

CodeRush CodeRush · Accepted Answer · 2014-11-08T06:54:24

I think you are creating a user with limited rights by default which can't create any other users that is why you have EFI_ACCESS_DENIED in return.

Here is the related quote from UEFI 2.4 Rev B specs, page 1837:

If the current user profile does not permit creation of new user profiles then EFI_ACCESS_DENIED will be returned. If creation of new user profiles is not supported, then EFI_UNSUPPORTED is returned.

Here you can find an example of using the protocol you are trying to use.

User profiles are stored in non-volatile memory that must be protected from tampering, so it's implementation-defined thing, but all implementations I know are using NVRAM.

UEFI Create User

1 Answers