Windows NT Driver >> Assembly >> IOCTL
METHOD_IN_DIRECT、METHOD_OUT_DIRECT
參考資訊:
1. Four-F
2. Source Code
METHOD_IN_DIRECT、METHOD_OUT_DIRECT的概念就是直接Mapping User Buffer,然後驅動程式使用該Mapped的MDL(Memory Description List)操作,相較於METHOD_BUFFERED,因為不須I/O Manager更新回User Buffer,因此,效率會比較好,而相比File的DO_DIRECT_IO,IOCTL細分成IN和OUT兩種,這是因為IOCTL有區分Input和Output Buffer的緣故,因此,會有方向性的考量,Microsoft針對這部份的描述,僅說明MDL描述會有讀寫存取方向的區分,但是司徒實際測試,發現DeviceIoControl()的Input和Output Buffer是可以混用的,意思就是Input Buffer可以充當Input或Output Buffer使用,而Output Buffer也可以充當Input或Output Buffer使用,只要驅動程式跟User Application定義好即可,當然,METHOD_IN_DIRECT和METHOD_OUT_DIRECT也是可以混用的,關於這部份的細節,有興趣的使用者可以研讀WRK代碼,不過,深怕未知問題可能發生,建議還是依照Microsoft規定去撰寫驅動程式會比較保險。
Microsoft針對I/O部份的說明:
buffer-descriptions-for-i-o-control-codes
記憶體指標:
Buffer | Length | |
---|---|---|
Input | (Irp) AssociatedIrp.SystemBuffer |
(IrpStack) Parameters.DeviceIoControl.InputBufferLength |
Output | (MDL) MmGetSystemAddressForMdlSafe |
(IrpStack) Parameters.DeviceIoControl.OutputBufferLength |
main.asm
.386p .model flat, stdcall option casemap:none include c:\masm32\include\w2k\ntstatus.inc include c:\masm32\include\w2k\ntddk.inc include c:\masm32\include\w2k\ntoskrnl.inc include c:\masm32\include\w2k\ntddkbd.inc include c:\masm32\include\wxp\wdm.inc include c:\masm32\Macros\Strings.mac includelib c:\masm32\lib\wxp\i386\ntoskrnl.lib public DriverEntry OurDeviceExtension struct pNextDev PDEVICE_OBJECT ? szBuffer byte 255 dup(?) OurDeviceExtension ends IOCTL_GET equ CTL_CODE(FILE_DEVICE_UNKNOWN, 800h, METHOD_OUT_DIRECT, FILE_ANY_ACCESS) IOCTL_SET equ CTL_CODE(FILE_DEVICE_UNKNOWN, 801h, METHOD_IN_DIRECT, FILE_ANY_ACCESS) .const DEV_NAME word "\","D","e","v","i","c","e","\","M","y","D","r","i","v","e","r",0 SYM_NAME word "\","D","o","s","D","e","v","i","c","e","s","\","M","y","D","r","i","v","e","r",0 MSG_GET byte "IOCTL_GET",0 MSG_SET byte "IOCTL_SET",0 .code IrpOpenClose proc pOurDevice:PDEVICE_OBJECT, pIrp:PIRP IoGetCurrentIrpStackLocation pIrp movzx eax, (IO_STACK_LOCATION PTR [eax]).MajorFunction .if eax == IRP_MJ_CREATE invoke DbgPrint, $CTA0("IRP_MJ_CREATE") .elseif eax == IRP_MJ_CLOSE invoke DbgPrint, $CTA0("IRP_MJ_CLOSE") .endif mov eax, pIrp and (_IRP PTR [eax]).IoStatus.Information, 0 mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS fastcall IofCompleteRequest, pIrp, IO_NO_INCREMENT mov eax, STATUS_SUCCESS ret IrpOpenClose endp IrpIOCTL proc pOurDevice:PDEVICE_OBJECT, pIrp:PIRP local dwLen: DWORD local pdx:PTR OurDeviceExtension local pBuf:DWORD and dwLen, 0 mov eax, pOurDevice push (DEVICE_OBJECT PTR [eax]).DeviceExtension pop pdx IoGetCurrentIrpStackLocation pIrp mov eax, (IO_STACK_LOCATION PTR [eax]).Parameters.DeviceIoControl.IoControlCode .if eax == IOCTL_GET invoke DbgPrint, offset MSG_GET mov eax, pIrp MmGetSystemAddressForMdlSafe (_IRP ptr [eax]).MdlAddress, LowPagePriority push eax pop pBuf mov eax, pdx invoke strcpy, pBuf, addr (OurDeviceExtension PTR [eax]).szBuffer mov eax, pdx invoke strlen, addr (OurDeviceExtension PTR [eax]).szBuffer inc eax push eax pop dwLen .elseif eax == IOCTL_SET invoke DbgPrint, offset MSG_SET IoGetCurrentIrpStackLocation pIrp push (IO_STACK_LOCATION PTR [eax]).Parameters.DeviceIoControl.InputBufferLength pop dwLen mov eax, pIrp push (_IRP PTR [eax]).AssociatedIrp.SystemBuffer pop pBuf mov eax, pdx invoke memcpy, addr (OurDeviceExtension PTR [eax]).szBuffer, pBuf, dwLen invoke DbgPrint, $CTA0("Buffer: %s, Length: %d"), pBuf, dwLen .endif mov eax, pIrp mov (_IRP PTR [eax]).IoStatus.Status, STATUS_SUCCESS push dwLen pop (_IRP PTR [eax]).IoStatus.Information fastcall IofCompleteRequest, pIrp, IO_NO_INCREMENT mov eax, STATUS_SUCCESS ret IrpIOCTL endp Unload proc pOurDriver:PDRIVER_OBJECT local szSymName:UNICODE_STRING invoke RtlInitUnicodeString, addr szSymName, offset SYM_NAME invoke IoDeleteSymbolicLink, addr szSymName mov eax, pOurDriver invoke IoDeleteDevice, (DRIVER_OBJECT PTR [eax]).DeviceObject ret Unload endp DriverEntry proc pOurDriver:PDRIVER_OBJECT, pOurRegistry:PUNICODE_STRING local pOurDevice:PDEVICE_OBJECT local suDevName:UNICODE_STRING local szSymName:UNICODE_STRING mov eax, pOurDriver mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_CREATE * (sizeof PVOID)], offset IrpOpenClose mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_CLOSE * (sizeof PVOID)], offset IrpOpenClose mov (DRIVER_OBJECT PTR [eax]).MajorFunction[IRP_MJ_DEVICE_CONTROL * (sizeof PVOID)], offset IrpIOCTL mov (DRIVER_OBJECT PTR [eax]).DriverUnload, offset Unload invoke RtlInitUnicodeString, addr suDevName, offset DEV_NAME invoke RtlInitUnicodeString, addr szSymName, offset SYM_NAME invoke IoCreateDevice, pOurDriver, sizeof OurDeviceExtension, addr suDevName, FILE_DEVICE_UNKNOWN, 0, FALSE, addr pOurDevice .if eax == STATUS_SUCCESS mov eax, pOurDevice or (DEVICE_OBJECT PTR [eax]).Flags, DO_BUFFERED_IO and (DEVICE_OBJECT PTR [eax]).Flags, not DO_DEVICE_INITIALIZING invoke IoCreateSymbolicLink, addr szSymName, addr suDevName .endif ret DriverEntry endp end DriverEntry .end
IrpIOCTL()收到IOCTL_SET時,Driver複製User Buffer的內容到szBuffer,而收到IOCTL_GET時,將szBuffer內容又複製回User Buffer,完成暫存的功能,IoStatus.Information的數值就是OutBufferSize回傳的長度。
app.asm
.386p .model flat, stdcall option casemap:none include c:\masm32\include\windows.inc include c:\masm32\include\masm32.inc include c:\masm32\include\user32.inc include c:\masm32\include\msvcrt.inc include c:\masm32\include\kernel32.inc include c:\masm32\include\w2k\ntddkbd.inc include c:\masm32\Macros\Strings.mac includelib c:\masm32\lib\user32.lib includelib c:\masm32\lib\masm32.lib includelib c:\masm32\lib\msvcrt.lib includelib c:\masm32\lib\kernel32.lib IOCTL_GET equ CTL_CODE(FILE_DEVICE_UNKNOWN, 800h, METHOD_OUT_DIRECT, FILE_ANY_ACCESS) IOCTL_SET equ CTL_CODE(FILE_DEVICE_UNKNOWN, 801h, METHOD_IN_DIRECT, FILE_ANY_ACCESS) .const DEV_NAME db "\\.\MyDriver",0 MSG_ERR db "failed to open mydriver",0 MSG_SEND db "I am error",0 MSG_WR db "SET: %s, %d",10,13,0 MSG_RD db "GET: %s, %d",10,13,0 .data? hFile dd ? dwRet dd ? szBuffer db 255 dup(?) .code start: invoke CreateFile, offset DEV_NAME, GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0 .if eax == INVALID_HANDLE_VALUE invoke crt_printf, offset MSG_ERR invoke ExitProcess, -1 .endif mov hFile, eax invoke crt_memset, offset szBuffer, 0, 255 invoke StrLen, offset MSG_SEND inc eax mov dwRet, eax invoke crt_printf, offset MSG_WR, offset MSG_SEND, dwRet invoke DeviceIoControl, hFile, IOCTL_SET, offset MSG_SEND, dwRet, NULL, 0, offset dwRet, NULL push 0 pop dwRet invoke DeviceIoControl, hFile, IOCTL_GET, NULL, 0, offset szBuffer, 255, offset dwRet, NULL invoke crt_printf, offset MSG_RD, offset szBuffer, dwRet invoke CloseHandle, hFile invoke ExitProcess, 0 end start
結果