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> Windows > Problems with 64-bit |
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revolution 24 Feb 2011, 07:37
Your parameters for CreateWindowExA are pushed in reverse order.
Also you should align all the structures you pass to the APIs to at least mod 8. |
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24 Feb 2011, 07:37 |
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Hornet52 24 Feb 2011, 08:08
Pushed in reverse? I thought in the fastcall convention additional parameters were pushed on the stack left-to-right?
I was actually sure about the structures and was more worried if the api's would actually recognize that they're padded, thanks for the tip though |
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24 Feb 2011, 08:08 |
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revolution 24 Feb 2011, 13:29
If you want your code to work as expected then I suggest you push your parameters in the reverse of what you currently have them.
It is important to align your structures. If you don't you can sometimes get unexpected failures during the API calls. Padding of internal parameters of structures is also required, it is not detected by the APIs, the API functions just assume it is done properly. |
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24 Feb 2011, 13:29 |
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Hornet52 24 Feb 2011, 18:44
Well I tried pushing the parameters in reverse order (see below) but it doesn't work as I exactly expect. No error is thrown from what I can tell but the process just dies silently.
Code: Main: sub RSP, 0x08 ;align stack, (for call which subs 0x08) mov RCX, 0x00 ;Get hInstance for class etc. sub RSP, 0x20 call QWORD [GetModuleHandleA] add RSP, 0x20 mov [WNDCLASSEX.hInstance], RAX mov RCX, 0x00 mov RDX, 0x7F00 ;Get a cursor for application sub RSP, 0x20 call QWORD [LoadCursorA] add RSP, 0x20 mov [WNDCLASSEX.hCursor], RAX mov RCX, 0x00000096 ;Colour background RGB(150,0,0) sub RSP, 0x20 call QWORD [CreateSolidBrush] add RSP, 0x20 mov [WNDCLASSEX.hbrBackground], RAX lea RCX, [WNDCLASSEX] ;Register windows class sub RSP, 0x20 call QWORD [RegisterClassExA] add RSP, 0x20 mov RCX, 0x00 lea RDX, [String.ClassName] lea R8, [String.WindowName] mov R9, 0x10CF0000 ;WS_OVERLAPPEDWINDOW | WS_VISIBLE push QWORD 0x00 ;Create Window push QWORD [WNDCLASSEX.hInstance] push QWORD 0x00 push QWORD 0x00 push QWORD 0x01F4 push QWORD 0x01F4 push QWORD 0x64 push QWORD 0x64 sub RSP, 0x20 call QWORD [CreateWindowExA] add RSP, 0x60 ;cleanup stack or RAX, RAX jz PostError MessageLoop: lea RCX, [MSG] xor RDX, RDX xor R8, R8 xor R9, R9 sub RSP, 0x20 call QWORD [GetMessageA] add RSP, 0x20 cmp EAX, 0xFFFFFFFF ;check for GetMessage error je PostError or EAX, EAX jz WM_QUIT ;check for quiting lea RCX, [MSG] sub RSP, 0x20 call QWORD [TranslateMessage] add RSP, 0x20 lea RCX, [MSG] sub RSP, 0x20 call QWORD [DispatchMessageA] add RSP, 0x20 jmp MessageLoop WndProc: push RBP ;[RBP+0x28] LParam mov RBP, RSP ;[RBP+0x20] WParam push RBX ;[RBP+0x18] Message (dword) push RSI ;[RBP+0x10] Hwnd push RDI ;[RBP+0x08] Callback address push R12 ;[RBP+0x00] Last RBP push R13 push R14 push R15 mov [RBP+0x10], RCX mov [RBP+0x18], RDX mov [RBP+0x20], R8 mov [RBP+0x28], R9 cmp EDX, 0x02 je WM_DESTROY cmp EDX, 0x012 je WM_QUIT .Default: sub RSP, 0x20 call QWORD [DefWindowProcA] ;params should be setup from input add RSP, 0x20 .Return: pop R15 pop R14 pop R13 pop R12 pop RDI pop RSI pop RBX pop RBP ret WM_DESTROY: mov RCX, 0x00 sub RSP, 0x20 call QWORD [PostQuitMessage] add RSP, 0x20 jmp WndProc.Return WM_QUIT: mov RCX, [MSG.wParam] sub RSP, 0x20 call QWORD [ExitProcess] add RSP, 0x20 PostError: ;Make better error handler later mov RCX, 0x00 lea RDX, [String.ErrorMsg] mov R8, 0x00 mov R9, 0x10 sub RSP, 0x20 call QWORD [MessageBoxA] add RSP, 0x20 jmp WM_QUIT ;===================.data=================== ALIGN 0x08, db 0x00 WNDCLASSEX: .cbSize dd 0x50 ;80 bytes (same everytime) .style dd 0x03 ;CS_HREDRAW | CS_VREDRAW, redraw .lpfnWndProc dq WndProc .cbClsExtra dd 0x00 .cbWndExtra dd 0x00 .hInstance dq 0x00 ;Will be set in Main .hIcon dq 0x00 ;No Icon .hCursor dq 0x00 ;Will be set in Main .hbrBackground dq 0x00 ;Will be set in Main .lpszMenuName dq 0x00 .lpszClassName dq String.ClassName ;"Main Class" .hIconSm dq 0x00 ALIGN 0x08, db 0x00 MSG: .hwnd dq 0x00 .message dd 0x00 .padQ1 dd 0x00 .wParam dq 0x00 .lParam dq 0x00 .time dd 0x00 .ptx dd 0x00 .pty dd 0x00 .padQ2 dd 0x00 String: .ClassName: db "Main Class", 0x00 .WindowName: db "Basic Window", 0x00 .Hello: db "Hello World!", 0x00 .ErrorMsg: db "Fatal Error! Application closing", 0x00 |
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24 Feb 2011, 18:44 |
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b1528932 24 Feb 2011, 21:19
why dont you make macro for those pushes?
And why use pushes at all. Subtract sp, and mov. or even rep movs. Keep in ming that if u use guard page you have to limit ammount of arguments 'pushed'. Code: mov RCX, 0x00 lea RDX, [String.ClassName] lea R8, [String.WindowName] mov R9, 0x10CF0000 ;WS_OVERLAPPEDWINDOW | WS_VISIBLE push QWORD 0x00 ;Create Window push QWORD [WNDCLASSEX.hInstance] push QWORD 0x00 push QWORD 0x00 push QWORD 0x01F4 push QWORD 0x01F4 push QWORD 0x64 push QWORD 0x64 sub RSP, 0x20 call QWORD [CreateWindowExA] push in reverse order and use virtual macro to allocate uninitialized data. YOu setup stack frame at the beggining, call bp - XX a WNDCLASS and access it like a struct. |
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24 Feb 2011, 21:19 |
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asmhack 25 Feb 2011, 01:28
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25 Feb 2011, 01:28 |
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Hornet52 25 Feb 2011, 20:01
@asmhack: Thanks for the link, it actually answered a number of questions for me. A small error still remains (possibly with stack alignment), but I've started to look through some more (albeit poorly written 64bit material) which hopefully should lead to a solution.
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25 Feb 2011, 20:01 |
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