Question

I am trying to set security of PROCESS_TERMINATE. This is the code:

   CreateProcess("C:\\ADP\\SQLBase\\dbntsrv.exe", NULL, NULL, NULL, FALSE, CREATE_NO_WINDOW, NULL, "C:\\ADP\\SQLBase", &si, &pi);       

if(SetSecurityInfo(pi.hProcess, SE_KERNEL_OBJECT, PROCESS_TERMINATE, NULL, NULL, NULL, NULL) == ERROR_SUCCESS)
{
    MessageBox(NULL, "process_terminate granted", NULL, MB_OK);
}
else
{
    MessageBox(NULL, "process_terminate not granted", NULL, MB_OK);
}



                    //--------------------- Permission to query for info to use GetExitCode -------------------------
if(SetSecurityInfo(pi.hProcess, SE_KERNEL_OBJECT, PROCESS_QUERY_INFORMATION, NULL, NULL, NULL, NULL) == ERROR_SUCCESS)
{
    MessageBox(NULL, "process_query_information granted", NULL, MB_OK);
}
else
{
    MessageBox(NULL, "process_query_information not granted", NULL, MB_OK);
}


LPDWORD lpExitCode;
GetExitCodeProcess(pi.hProcess, lpExitCode);

Here SetSecurityInfo for for PROCESS_TERMINATE fails and I get an Unhandled Exception..(KERNEL32.dll):Access Violation for

GetExitCodeProcess(pi.hProcess, lpExitCode);

Why does this happen? Thank You

Answer 1

The access violation is because of this code:

LPDWORD lpExitCode;
GetExitCodeProcess(pi.hProcess, lpExitCode);

Here you declare that lpExitCode is a pointer, but you don’t make it point at anything. When GetExitCodeProcess tries to write to *lpExitCode it results in an access violation.

The correct approach is like this:

DWORD ExitCode;
GetExitCodeProcess(pi.hProcess, &ExitCode);

I also don’t believe that you need to call SetSecurityInfo at all. The process handle that CreateProcess returns should have sufficient rights.

You will need to wait for the spawned process to terminate before you can expect to get an exit code. This is because GetExitCodeProcess is asynchronous. You can wait like this:

WaitForSingleObject(pi.hProcess);
//now you can call GetExitCodeProcess and expect an answer.

And do remember to check all your API calls for errors.