Thread: GetTokenInformation() confusion

Here is the code:
http://blogs.msdn.com/junfeng/archiv...matically.aspx

HRESULT IsUserAdmin(BOOL *pIsAdmin)
{
int b;
HANDLE hProcess = NULL;
HANDLE hProcessToken = NULL;
HANDLE hLinkedToken = NULL;
BOOL fIsAdmin = FALSE;
DWORD dwLength = 0;
OSVERSIONINFO osver = {sizeof(OSVERSIONINFO)};
HRESULT hr = S_OK;

*pIsAdmin = FALSE;

// get handle to our process token
hProcess = GetCurrentProcess();
if (!OpenProcessToken(hProcess, TOKEN_QUERY, &hProcessToken))
{
hr = HRESULT_FROM_WIN32(GetLastError());
goto Exit;
}

// get admin SID
char AdminSID[SECURITY_MAX_SID_SIZE];
dwLength = sizeof(AdminSID);
if(!CreateWellKnownSid(WinBuiltinAdministratorsSid , NULL, &AdminSID, &dwLength))
{
hr = HRESULT_FROM_WIN32(GetLastError());
goto Exit;
}

// check to see if the current token contains admin SID
if (!CheckTokenMembership( NULL, &AdminSID, &fIsAdmin))
{
hr = HRESULT_FROM_WIN32(GetLastError());
goto Exit;
}

if (fIsAdmin)
{
// printf("The user is in admin group, and the process is elevated.\n");
*pIsAdmin = TRUE;
goto Exit;
}

// if the current token does not contain admin SID, it does not mean
// that the current user is not admin. In Vista by default the token of
// users in administrator group has the the admin SID filtered. We nee
// to use the unfiltered token to do the check.
if (!GetVersionEx(&osver))
{
hr = HRESULT_FROM_WIN32(GetLastError());
goto Exit;
}

// XP and below, we are done.
if (osver.dwMajorVersion < 6)
{
// printf("The user is not in admin group.\n");
goto Exit;
}

// get handle to linked token (will have one if we are lua)
if (!GetTokenInformation( hProcessToken,
TokenLinkedToken,
(VOID*) &hLinkedToken,
sizeof(HANDLE),
&dwLength) )
{
b = GetLastError();
if ( b == ERROR_NO_SUCH_LOGON_SESSION
|| b == ERROR_PRIVILEGE_NOT_HELD)
{
// printf("The user is not in admin group.\n");
goto Exit;
}

hr = HRESULT_FROM_WIN32(b); // a real error
goto Exit;
}

if (!CheckTokenMembership( hLinkedToken, &AdminSID, &fIsAdmin))
{
hr = HRESULT_FROM_WIN32(GetLastError());
goto Exit;
}

if (fIsAdmin)
{
// printf("The user is in admin group, and the process is not elevated.\n");
*pIsAdmin = TRUE;
}
else
{
// printf("The user is not in admin group.\n");
}

Exit:
if (hProcess)
{
CloseHandle(hProcess);
}

if (hProcessToken)
{
CloseHandle(hProcessToken);
}

if (hLinkedToken)
{
CloseHandle(hLinkedToken);
}

return hr;
}