Getting key presses in windows & x64 debugging options

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nullbyte

Joined: 10 Jul 2018
Posts: 2

nullbyte 11 Jul 2018, 15:27

Hello,

Sorry for what is probably a moronic n00b question, but I'm having trouble with windows character input. I'd like to register key presses, but the following doesnt work. Do I need to use the Microsoft API instead (as w/ WriteConsole?)

The long term goal would be to do this in an OpenGL window, but I figured a console is a start.

Second, what debuggers do you use in 64 bit Windows land? My favorites (OllyDbg/Immunity) seem to only support 32 bit PEs.

Code:

include 'win64ax.inc'

.code

  start:
         invoke AllocConsole
         invoke GetStdHandle, STD_OUTPUT_HANDLE
         mov [outhandle], eax
         invoke WriteConsole, [outhandle], "Hit a key", 10, numwrite, 0
         mov ah, 01h ; char read
         int 21h ; interrupt
         mov [char], al ; store our char
         invoke WriteConsole, [outhandle], "After int21", 12, numwrite, 0
         invoke WriteConsole, [outhandle], char, 1, numwrite, 0
         invoke Sleep, 2000
         invoke ExitProcess,0
.end start


.data
        outhandle dd ?
        numwrite dd ?
        char db ?

11 Jul 2018, 15:27

Tomasz Grysztar

Joined: 16 Jun 2003
Posts: 8359
Location: Kraków, Poland

Tomasz Grysztar 11 Jul 2018, 15:36

nullbyte wrote:

Sorry for what is probably a moronic n00b question, but I'm having trouble with windows character input. I'd like to register key presses, but the following doesnt work. Do I need to use the Microsoft API instead (as w/ WriteConsole?)

Yes, you have to use the Windows API. DOS interrupt functions do not exist in Windows subsystem (and modern Windows systems do not even have a DOS subsystem anymore).

nullbyte wrote:

Second, what debuggers do you use in 64 bit Windows land? My favorites (OllyDbg/Immunity) seem to only support 32 bit PEs.

FDBG is one developed by a member of this forum (Feryno).

11 Jul 2018, 15:36

nullbyte

Joined: 10 Jul 2018
Posts: 2

nullbyte 12 Jul 2018, 10:30

Thank you Tomasz! I'll check out FDBG.

In case anyone is wondering the same thing:
Seems like for console this works:

ReadConsoleInput(): https://docs.microsoft.com/en-us/windows/console/readconsoleinput
This Stackoverflow provides an example https://stackoverflow.com/questions/15993882/detecting-key-events

and w/ a bit of modification

Code:

      .while
            invoke  ReadConsoleInput, [inhandle], input, 1, count ; read input
            cmp [input.event.VirtScanCode], 51h ; check if our scan code is Q
            je .exit ; if it is jump
            invoke  WriteConsole,[outhandle],input.event.char,1,numwritten,0 ; print character
        .endw

.exit:
        invoke WriteConsole,[outhandle],"You pressed Q",14,numwritten,0
        invoke Sleep, 1000
        invoke ExitProcess, 0

For a window, this seems like the way to go:
https://docs.microsoft.com/en-us/windows/desktop/inputdev/wm-keydown

12 Jul 2018, 10:30

revolution
When all else fails, read the source

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

revolution 12 Jul 2018, 10:34

You can also encode the characters directly:

Code:

cmp [input.event.VirtScanCode], 'Q' ;<--- use the Q character in the code for better readability.

12 Jul 2018, 10:34

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