A Win32 console keypress example (Updated)

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revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20454
Location: In your JS exploiting you and your system

revolution 02 Apr 2024, 11:04

This might help.

Code:

struc   COORD {
        .x      dw      ?
        .y      dw      ?
}struct COORD

struc   UCHAR {
    virtual
        .AsciiChar      db      ?
    end virtual
        .UnicodeChar    dw      ?
}struct UCHAR

struc   KEY_EVENT_RECORD {
        .bKeyDown               dd      ?
        .wRepeatCount           dw      ?
        .wVirtualKeyCode        dw      ?
        .wVirtualScanCode       dw      ?
        .uChar                  UCHAR
        .dwControlKeyState      dd      ?
}struct KEY_EVENT_RECORD

struc   MOUSE_EVENT_RECORD {
        .dwMousePosition        COORD
        .dwButtonState          dd      ?
        .dwControlKeyState      dd      ?
        .dwEventFlags           dd      ?
}struct MOUSE_EVENT_RECORD

struc   WINDOW_BUFFER_SIZE_RECORD {
        .dwSize COORD
}struct WINDOW_BUFFER_SIZE_RECORD

struc   MENU_EVENT_RECORD {
        .dwCommandId    dd      ?
}struct MENU_EVENT_RECORD

struc   FOCUS_EVENT_RECORD {
        .bSetFocus      dd      ?
}struct FOCUS_EVENT_RECORD

struc   IREVENT {
    virtual
        .MouseEvent             MOUSE_EVENT_RECORD
        .WindowBufferSizeEvent  WINDOW_BUFFER_SIZE_RECORD
        .MenuEvent              MENU_EVENT_RECORD
        .FocusEvent             FOCUS_EVENT_RECORD
    end virtual
        .KeyEvent               KEY_EVENT_RECORD
}struct IREVENT

struc   INPUT_RECORD {
        .EventType      dw      ?,?
        .Event          IREVENT
}struct INPUT_RECORD

02 Apr 2024, 11:04

MatQuasar

Joined: 25 Oct 2023
Posts: 105

MatQuasar 02 Apr 2024, 16:28

revolution wrote:

This might help.

Code:

struc   COORD {
        .x      dw      ?
        .y      dw      ?
}struct COORD

struc   UCHAR {
    virtual
        .AsciiChar      db      ?
    end virtual
        .UnicodeChar    dw      ?
}struct UCHAR

struc   KEY_EVENT_RECORD {
        .bKeyDown               dd      ?
        .wRepeatCount           dw      ?
        .wVirtualKeyCode        dw      ?
        .wVirtualScanCode       dw      ?
        .uChar                  UCHAR
        .dwControlKeyState      dd      ?
}struct KEY_EVENT_RECORD

struc   MOUSE_EVENT_RECORD {
        .dwMousePosition        COORD
        .dwButtonState          dd      ?
        .dwControlKeyState      dd      ?
        .dwEventFlags           dd      ?
}struct MOUSE_EVENT_RECORD

struc   WINDOW_BUFFER_SIZE_RECORD {
        .dwSize COORD
}struct WINDOW_BUFFER_SIZE_RECORD

struc   MENU_EVENT_RECORD {
        .dwCommandId    dd      ?
}struct MENU_EVENT_RECORD

struc   FOCUS_EVENT_RECORD {
        .bSetFocus      dd      ?
}struct FOCUS_EVENT_RECORD

struc   IREVENT {
    virtual
        .MouseEvent             MOUSE_EVENT_RECORD
        .WindowBufferSizeEvent  WINDOW_BUFFER_SIZE_RECORD
        .MenuEvent              MENU_EVENT_RECORD
        .FocusEvent             FOCUS_EVENT_RECORD
    end virtual
        .KeyEvent               KEY_EVENT_RECORD
}struct IREVENT

struc   INPUT_RECORD {
        .EventType      dw      ?,?
        .Event          IREVENT
}struct INPUT_RECORD

Good!

02 Apr 2024, 16:28

MatQuasar

Joined: 25 Oct 2023
Posts: 105

MatQuasar 13 Apr 2024, 15:25

Another example modified from code posted by a 'fasm' Discord user.

GetKeyState API function : "Press "0" to quit"

Code:

format PE console
include 'win32a.inc'

msg db 'Key pressed',13,10
len = $ - msg
msgg db 'Press 0 to quit',13,10
lenn = $ - msgg
stdout dd ?

entry $

  invoke GetStdHandle,STD_OUTPUT_HANDLE
  mov [stdout],eax

  invoke WriteConsole,[stdout], msgg, lenn, 0, 0
  mov ebx, '0'

.again:
  invoke GetKeyState,ebx

  bt eax,15
  jnc .again

  invoke WriteConsole,[stdout], msg, len, 0, 0
  invoke ExitProcess,0

data import
library kernel,'kernel32.dll',user32,'user32.dll'
import  kernel, WriteConsole,'WriteConsoleA',GetStdHandle,'GetStdHandle', ExitProcess, 'ExitProcess'
import  user32, GetKeyState,'GetKeyState',GetAsyncKeyState,'GetAsyncKeyState'
end data

13 Apr 2024, 15:25

bitRAKE

Joined: 21 Jul 2003
Posts: 4075
Location: vpcmpistri

bitRAKE 28 Apr 2024, 09:26

MatQuasar wrote:

Two undefined "db ? " added. Is it because needed by alignment , which is 32-bit?

Yeap. My example has complete console API definitions, but in this specific case the UNION contains a DWORD - which forces the alignment.

MatQuasar wrote:

And what about this:

Code:

00000000 _KEY_EVENT_RECORD::$0E79EC4DAC98A4AB202537FA8C3F69FC union ; (sizeof=0x2, align=0x2, copyof_156)
00000000                                         ; XREF: KEY_EVENT_RECORD/r
00000000 UnicodeChar     dw ?
00000000 AsciiChar       db ?
00000000 _KEY_EVENT_RECORD::$0E79EC4DAC98A4AB202537FA8C3F69FC ends

Is the size of struct 3 bytes or 4 bytes?

UNION is only as large as the biggest entry - in this case - only two bytes:

Code:

struct KEY_EVENT_RECORD
        bKeyDown                dd ?
        wRepeatCount            dw ?
        wVirtualKeyCode         dw ?
        wVirtualScanCode        dw ?
        union
                UnicodeChar     dw ?
                AsciiChar       db ?
        ends
        dwControlKeyState       dd ?
ends

... note the offsets - both values start on the same (relative) byte (0).

_________________
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28 Apr 2024, 09:26

bitRAKE

Joined: 21 Jul 2003
Posts: 4075
Location: vpcmpistri

bitRAKE 28 Apr 2024, 09:35

Note: revolution's structure isn't correct:

Code:

struc   IREVENT {
    virtual
        .MouseEvent             MOUSE_EVENT_RECORD
        .WindowBufferSizeEvent  WINDOW_BUFFER_SIZE_RECORD
        .MenuEvent              MENU_EVENT_RECORD
        .FocusEvent             FOCUS_EVENT_RECORD
    end virtual
        .KeyEvent               KEY_EVENT_RECORD
}struct IREVENT

... each of these event items would need to be in their own VIRTUAL (except the largest one) because they overlap on the same space.

That's why I produced a comprehensive example to demonstrate the errors or validity of my understanding.

28 Apr 2024, 09:35

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 20454
Location: In your JS exploiting you and your system

revolution 28 Apr 2024, 09:46

Thanks. The virtual blocks should be independent.

Code:

struc   IREVENT {
    virtual
        .MouseEvent             MOUSE_EVENT_RECORD
    end virtual
    virtual
        .WindowBufferSizeEvent  WINDOW_BUFFER_SIZE_RECORD
    end virtual
    virtual
        .MenuEvent              MENU_EVENT_RECORD
    end virtual
    virtual
        .FocusEvent             FOCUS_EVENT_RECORD
    end virtual
        .KeyEvent               KEY_EVENT_RECORD
}struct IREVENT

28 Apr 2024, 09:46

MatQuasar

Joined: 25 Oct 2023
Posts: 105

MatQuasar 28 Apr 2024, 10:08

bitRAKE wrote:

Yeap. My example has complete console API definitions, but in this specific case the UNION contains a DWORD - which forces the alignment.

Thank you so much, for confirming my doubts. I always think it is best to refer to the structure disassembled by a disassembler such as IDA Freeware.

bitRAKE wrote:

That's why I produced a comprehensive example to demonstrate the errors or validity of my understanding.

That is a fine example although I don't understand macro. I am impressed with your "never-say-die" attitude in the console event examples (two of them).

28 Apr 2024, 10:08

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