asked on

Unable to set a hook to a process created in winlogon

Hi,

I am having a problem not being able to hook into a process created by CreateProcess:

STARTUPINFO si;
PROCESS_INFORMATION pi;

ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
si.lpDesktop = "Winsta0\\Winlogon";
ZeroMemory( &pi, sizeof(pi) );

if(!CreateProcess( NULL,
TEXT("Notepad.exe"),
NULL,
NULL,
TRUE,
0,
NULL,
NULL,
&si,
&pi )
)
return false;

if(!g_hHook_Keyboard)
{
g_lpHookProc_Keyboard = (HOOKPROC) HookProcKeyboard;
b_Success_Keyboard = (NULL != (g_hHook_Keyboard = ::SetWindowsHookEx (WH_KEYBOARD, g_lpHookProc_Keyboard, (HINSTANCE)pi.hProcess, NULL)));
}

It returns "false" for "b_Success_Keyboard"

Any help will be appreciated..
Thanks a lot.

jkr

You need to change your process'/threads window station and desktop using the appropriate APIs ('SetProcessWindowStation()'/'SetThreadDesktop()') to the one the process that you want to hook is using, otherwise it won't work.

ewong_111

ASKER

jkr..

I have inserted the follow code before the "if(!g_hHook_Keyboard)"

      HWINSTA h_Winsta = OpenWindowStation((LPCTSTR)"Winsta0", TRUE, GENERIC_ALL);
      if (!SetProcessWindowStation(h_Winsta)) AfxMessageBox("SetProcessWindowStation Failed");

      HDESK h_Desk = OpenDesktop((LPCTSTR)"Winlogon", 0, TRUE, GENERIC_ALL);
      if (!SetThreadDesktop(h_Desk)) AfxMessageBox("SetThreadDesktop Failed");

but unfortunately it still returns "false" for "b_Success_Keyboard"

      if (b_Success_Keyboard) AfxMessageBox("Success on Keyboard Hook");
      else AfxMessageBox("Failed on Keyboard Hook");

but now the AfxMessageBox is showing up in the "Winlogon" desktop now.
Any more ideas?
Thanks a lot.

ASKER CERTIFIED SOLUTION

jkr

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ewong_111

ASKER

so, what kind of hook will be allowed there?
and is it true for Screen-saver also?
Thanks again..

jkr

Actually, what is it that you have to hook the logon desktop for? To know the purpose might help to find a suggestion around that :o)

ewong_111

ASKER

jkr,

Thanks a lot for your help, but you have already answered this question in another question I posted.
https://www.experts-exchange.com/questions/21174306/Keep-track-of-users-logging-on-and-off.html
I guess you just have too many questions each day to answer that you didn't notice it right?
Thanks again for your motivation for helping..

:D

jkr

Well, I thought these were two completely separate issues :o)