135 lines
3 KiB
NASM
135 lines
3 KiB
NASM
title WINHOOK.ASM - SetWindowsHook() and friends
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ifdef WOW
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NOEXTERNS equ 1
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SEGNAME equ <TEXT>
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endif
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.xlist
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include user.inc
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.list
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swappro = 0
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; include NEW_SEG1 struc used in GetProcModule
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include newexe.inc
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ExternFP <GetCodeInfo>
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ExternFP <GetExePtr>
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ExternFP <GetCurrentTask>
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ExternFP <SetWindowsHookInternal>
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createSeg _%SEGNAME,%SEGNAME,WORD,PUBLIC,CODE
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createSeg _DATA,DATA,WORD,PUBLIC,DATA,DGROUP
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defgrp DGROUP,DATA
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;===========================================================================
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sBegin %SEGNAME
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assumes CS,%SEGNAME
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assumes DS,DATA
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assumes ES,NOTHING
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;============================================================================
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;
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; HANDLE FAR PASCAL GetProcModule(FARPROC lpfn);
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;
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; This function returns the module handle corresponding to a given
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; hook proc address.
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;
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; CAUTION: This uses the undocumented feature of "GetCodeInfo()" that it
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; returns the module handle in ES register.
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;
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cProc GetProcModule, <PUBLIC, FAR>
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ParmD lpfn
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LocalV seginfofromkernel, %size NEW_SEG1+2
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cBegin
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; Turns out GetCodeInfo
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;
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pushd lpfn ; GetCodeInfo(lpfn, &seginfo)
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lea ax,seginfofromkernel
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push ss
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push ax
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call GetCodeInfo
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or ax,ax ; AX is BOOL fSuccess (even though windows.h says void)
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mov ax,es ; ES contains the module handle according
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; to David Weise...
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jnz gpmexit ; We're ok
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; hack. Excel global allocs some memory, puts
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; code into it and passes it to us. The GetCodeInfo fails in this
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; case so we need to get the module handle for a globalalloced
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; chunk of memory.
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push word ptr lpfn+2
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call GetExePtr
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gpmexit:
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ifdef DEBUG
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or ax,ax
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jnz gpm900
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DebugErr DBF_ERROR, "Invalid Hook Proc Addr"
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xor ax,ax
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gpm900:
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endif
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cEnd
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;==============================================================================
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;
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; FARPROC FAR PASCAL SetWindowsHook(int idHook, FARPROC lpfn)
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; {
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; SetWindowsHookEx2(idHook,
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; (HOOKPROC)lpfn,
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; GetProcModule(lpfn),
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; (idHook == WH_MSGFILTER ? GetCurrentTask() : NULL));
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; }
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;
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cProc ISetWindowsHook,<FAR, PUBLIC, LOADDS>
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ParmW idHook
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ParmD lpfn
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LocalW hmodule
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LocalW htask
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cBegin
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; Check if some apps are trying to unhook a hook using SetWindowsHook()
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mov bx, seg_lpfn
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cmp bx, HHOOK_MAGIC
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jz swhHookMagic
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cmp idHook,WH_MSGFILTER
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jnz swh10
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call GetCurrentTask
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jmp swhMakeCall
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swhHookMagic:
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; Now, it is clear that this app wants to unhook by calling SetWindowsHook()
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; All Micrographix apps do this trick to unhook their keyboard hooks.
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; Fix for Bug #7972 -- SANKAR -- 05/30/91 --
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; Let us unhook the node passed in thro lpfn;
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ifdef DEBUG
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DebugErr <DBF_WARNING>, "SetWindowsHook called to unhook: use UnhookWindowsHook"
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endif
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xor ax,ax
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jmps swhMakeCall
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swh10:
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pushd lpfn
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call GetProcModule
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swhMakeCall:
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push ax
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push idHook
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pushd lpfn
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call SetWindowsHookInternal
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swhExit:
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cEnd
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sEnd %SEGNAME
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END
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