.data
AppName db "DeviceIoControl",0
VxDName db "\\.\shellmsg.vxd",0
Success db "The VxD is successfully loaded!",0
Failure db "The VxD is not loaded!",0
Unload db "The VxD is now unloaded!",0
MsgTitle db "DeviceIoControl Example",0
MsgText db "I'm called from a VxD!",0
InBuffer dd offset MsgTitle
dd offset MsgText
.data?
hVxD dd ?
.code
start:
invoke CreateFile,addr VxDName,0,0,0,0,FILE_FLAG_DELETE_ON_CLOSE,0
.if eax!=INVALID_HANDLE_VALUE
mov hVxD,eax
invoke MessageBox,NULL,addr Success,addr AppName,MB_OK+MB_ICONINFORMATION
invoke DeviceIoControl,hVxD,1,addr InBuffer,8,NULL,NULL,NULL,NULL
invoke CloseHandle,hVxD
invoke MessageBox,NULL,addr Unload,addr AppName,MB_OK+MB_ICONINFORMATION
.else
invoke MessageBox,NULL,addr Failure,NULL,MB_OK+MB_ICONERROR
.endif
invoke ExitProcess,NULL
end start

下面这段源代码是由 vxdloader.asm 调用的动态VxD。
; ShellMsg.asm

.386p
include vmm.inc
include vwin32.inc
include shell.inc

DECLARE_VIRTUAL_DEVICE SHELLMSG,1,0, SHELLMSG_Control,\
UNDEFINED_DEVICE_ID, UNDEFINED_INIT_ORDER

Begin_control_dispatch SHELLMSG
Control_Dispatch w32_DeviceIoControl, OnDeviceIoControl
End_control_dispatch SHELLMSG

VxD_PAGEABLE_DATA_SEG
pTitle dd ?
pMessage dd ?
VxD_PAGEABLE_DATA_ENDS

VxD_PAGEABLE_CODE_SEG
BeginProc OnDeviceIoControl
assume esi:ptr DIOCParams
.if [esi].dwIoControlCode==DIOC_Open
xor eax,eax
.elseif [esi].dwIoControlCode==1
mov edi,[esi].lpvInBuffer
;-----------------------------------
; copy the message title to buffer
;-----------------------------------
VMMCall _lstrlen, <[edi]>
inc eax
push eax
VMMCall _HeapAllocate,<eax,HEAPZEROINIT>
mov pTitle,eax
pop eax
VMMCall _lstrcpyn,<pTitle,[edi],eax>
;-----------------------------------
; copy the message text to buffer
;-----------------------------------
VMMCall _lstrlen, <[edi+4]>
inc eax
push eax
VMMCall _HeapAllocate,<eax,HEAPZEROINIT>
mov pMessage,eax
pop eax
VMMCall _lstrcpyn,<pMessage,[edi+4],eax>
mov edi,pTitle
mov ecx,pMessage
mov eax,MB_OK
VMMCall Get_Sys_VM_Handle
VxDCall SHELL_sysmodal_Message
VMMCall _HeapFree,pTitle,0
VMMCall _HeapFree,pMessage,0
xor eax,eax
.endif
ret
EndProc OnDeviceIoControl
VxD_PAGEABLE_CODE_ENDS

end

分析：
我们从VxDLoader.asm开始。

(编辑:anna sui)