例子驱动通信基础架构

1.Ring0编写驱动层代码：

//codemsg.h 定义通信控制代码
#ifndef _DEFINE_H_
#define _DEFINE_H_

// _number:    0 -> 2047 : reserved for Microsoft 微软保留
//             2047 -> 4095 : reserved for OEMs 用户自己定义     
#define CODEMSG(_number) CTL_CODE(FILE_DEVICE_UNKNOWN, _number , METHOD_BUFFERED,
                                FILE_READ_DATA | FILE_WRITE_DATA)       
//定义控制码
#define INIT_FILE_NAME 2047

#endif

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//Ring0.h
#ifndef _KERNEL_MODULE_H_
#define _KERNEL_MODULE_H_

#include <ntifs.h>
#include "codemsg.h"

//设备对象的名称
#define DEVICE L"\Device\www.AntiGameProtect.com"

//链接符号的名称
#define DOSDEVICE L"\DosDevices\www.AntiGameProtect.com"

PDEVICE_OBJECT DriverDeviceObject;

#endif

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//Ring0.c
#include "Ring0.h"

//驱动卸载例程函数，在这里释放一些资源。
VOID DriverUnload(PDRIVER_OBJECT DriverObject)
{
	UNICODE_STRING DeviceName;
	UNICODE_STRING DosDeviceName; 

	//删除符号链接
	RtlInitUnicodeString(&DosDeviceName, DOSDEVICE);
	IoDeleteSymbolicLink(&DosDeviceName );

	//删除驱动对象
	if(DriverDeviceObject != NULL)
		IoDeleteDevice(DriverDeviceObject);

	DbgPrint("驱动卸载成功！
");
}

//默认的例程处理函数
NTSTATUS IODispatch(PDEVICE_OBJECT DeviceObject, PIRP Irp)
{
	Irp->IoStatus.Status = STATUS_SUCCESS;
	IoCompleteRequest(Irp, IO_NO_INCREMENT);

	return STATUS_SUCCESS;
}

//验证一个WCHAR内容的指针能否够訪问
BOOLEAN ValidateWCHARString(WCHAR *pwzStr, ULONG_PTR Length)
{
	ULONG i;

	__try
	{
		//第一步推断指针和大小是否为NULL，是的话就不是必需验证了
		if (*pwzStr == NULL || Length == 0)
		{
			return FALSE;
		}

		//以length长度循环检查指针pwzStr里面的值
		for (i = 0; i < Length; i++)
		{
			//检查内存能否够訪问。
			if (!MmIsAddressValid((PUCHAR)pwzStr + i))
			{
				//仅仅要有一个字节是不可读取，就失败
				return FALSE;
			}
		}

	}__except(EXCEPTION_EXECUTE_HANDLER)
	{
		//触发了异常
		return FALSE;
	}

	return TRUE;
}

//IRP通信例程处理函数
NTSTATUS IOManager(PDEVICE_OBJECT DeviceObject, PIRP Irp)
{   
	//获取当前IrpStack，通过读取其结构成员，取出我们须要的控制码IRPcode
	PIO_STACK_LOCATION StackLocation = IoGetCurrentIrpStackLocation(Irp);

	//获取控制码IRPcode
	ULONG IRPcode = StackLocation->Parameters.DeviceIoControl.IoControlCode;  

	WCHAR *buf;
	SIZE_T size;
	WCHAR *pwzCopyBuf = NULL;

	//获取应用层传进来的内存缓冲区
	buf = (WCHAR*)Irp->AssociatedIrp.SystemBuffer;

	//内存缓冲区的字节长度
	size  = (SIZE_T)Irp->Size;

	//设置Irp的状态
	Irp->IoStatus.Status = STATUS_SUCCESS; 

	switch(IRPcode)
	{
		case CODEMSG(INIT_FILE_NAME):

		//从应用层传进来的buf，你无法预知这个值能否够訪问，所以，这里要验证我们传递进来的buf的有效性，才干够在驱动层訪问buf
		//所以，这里我写了一个ValidateWCHARString来验证这个变量
		__try{
			//推断Buffer的有效性
			if (ValidateWCHARString(buf, size))
			{

				//提示-应用层数据传到了驱动层
				DbgPrint("Buf ==> %ws:%d
", buf, size);

				//申请内存。相似应用层的new，并给于标识'fp'
				pwzCopyBuf = (WCHAR*)ExAllocatePoolWithTag(NonPagedPool, size, 'fp');

				//假设申请内存成功
				if (pwzCopyBuf)
				{
					//内存初始化
					memset(pwzCopyBuf, 0, size);

					//copy到我们新申请的内存
					memcpy(pwzCopyBuf,buf,size);

					//显示从应用层获取到的字符串信息
					DbgPrint("CopyBuf ==> %ws
", pwzCopyBuf);

					//在驱动以下用C语言来写，就要遵守windows的规则。申请的内存，必须要释放。
					//要记得释放内存
					ExFreePool(pwzCopyBuf);
				}
			}
		}
		__except (EXCEPTION_EXECUTE_HANDLER)
		{
			//获取异常的状态码
			Irp->IoStatus.Status = GetExceptionCode();
		}
		break;

	default:
		Irp->IoStatus.Status = STATUS_INVALID_DEVICE_REQUEST;                       

	}

	//设置Irp的返回码
	IoCompleteRequest(Irp, IO_NO_INCREMENT);

	return Irp->IoStatus.Status;
}


//驱动的入口函数DriverEntry
NTSTATUS DriverEntry(PDRIVER_OBJECT DriverObject,PUNICODE_STRING theRegistryPath)
{
	UNICODE_STRING DeviceName;
	UNICODE_STRING DosDeviceName; 
	NTSTATUS status;

	//初始化驱动符号名
	//UNICODE_STRING是一个结构体，相似win32里面的结构体。比方SYSTEMTIME
	//在Win系统下，内核的结构体都是能够通过windbg或者wrk获得
	/*
	lkd> dt_unicode_string
	nt!_UNICODE_STRING
	+0x000 Length           : Uint2B //文本长度
	+0x002 MaximumLength    : Uint2B //最大长度
	+0x004 Buffer           : Ptr32 Uint2B //文本内容。是unicode类型，即WCHAR
	*/

	//设备名称字符串
	RtlInitUnicodeString(&DeviceName, DEVICE);
	//符号链接字符串
	RtlInitUnicodeString(&DosDeviceName, DOSDEVICE);

	//创建设备对象
	status = IoCreateDevice(
		DriverObject,        // ptr to caller object
		0,                   // extension device allocated byte number
		&DeviceName,         // device name 
		FILE_DEVICE_UNKNOWN, 
		0,                   // no special caracteristics
		FALSE,               // we can open many handles in same time
		&DeviceObject);		 // [OUT] ptr to the created object

	if (!NT_SUCCESS(status))
	{
		return STATUS_NO_SUCH_DEVICE;
	}
	//相同也须要一个符号链接。不然会影响到驱动和应用层的通信
	status = IoCreateSymbolicLink(&DosDeviceName,&DeviceName);
	if(!NT_SUCCESS(status))
	{
		IoDeleteDevice(DriverDeviceObject);
		return STATUS_NO_SUCH_DEVICE;
	}   

	//设置驱动卸载例程函数
	DriverObject->DriverUnload = DriverUnload;

	//IRP_MJ_CREATE。响应的是应用层函数CreateFile，应用层调用这个函数就会进入这个例程
	DriverObject->MajorFunction[IRP_MJ_CREATE] = IODispatch;

	//以下的分别相应应用层CloseHandle、ReadFile、WriteFile函数
	DriverObject->MajorFunction[IRP_MJ_CLOSE]  = IODispatch;
	DriverObject->MajorFunction[IRP_MJ_READ]   = IODispatch;
	DriverObject->MajorFunction[IRP_MJ_WRITE]  = IODispatch;

	//一般我们跟应用层通信，都是通过IRP_MJ_DEVICE_CONTROL例程，这个例程相应的是应用层下的DeviceIoControl
	DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = IOManager; //DeviceIoControl()

	//设置通信方式--直接方式I/O  
	DeviceObject->Flags |= DO_BUFFERED_IO;
	//设置文件字对齐  
	DeviceObject->AlignmentRequirement = FILE_WORD_ALIGNMENT;

	//设备初始化完成能够工作了  
	DeviceObject->Flags &= ~DO_DEVICE_INITIALIZING;

	//提示驱动载入成功
	DbgPrint("Hello Driver !
");

	return STATUS_SUCCESS;
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2.Ring3应用层代码的编写：

//Ring3.cpp
#include <windows.h>
#include <stdio.h>

//包括控制码的头文件
#include "..Ring0codemsg.h"

//向驱动发送请求
BOOL CallDriver(char *ID,char *lpBuffer)
{
	HANDLE service = 0;
	HANDLE device = 0;
	char ret[1024];
	WCHAR ToSend[512];
	DWORD code = -1;
	DWORD bytes;

	//通过符号连接打开设备对象
	device = CreateFile("\\.\www.AntiGameProtect.com", GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
	if( !device || device==INVALID_HANDLE_VALUE )
	{   
		printf("打开驱动失败，驱动载入不成功. %d
",GetLastError());
		return FALSE; 
	}

	//推断输入的命令是否是"-file"
	if(!strcmp(ID,"-file"))
	{
		//相应我们驱动以下的控制码。

		code = INIT_FILE_NAME; 
	}

	//推断驱动的控制码是否有效
	if (code == -1)
	{
		printf("无效的ID
");
		return FALSE; 
	}

	//将ascii码lpBuffer字符串转unicode码字符串ToSend
	MultiByteToWideChar(CP_ACP, 0, lpBuffer, -1, ToSend, sizeof(ToSend));

	DeviceIoControl(device,
		CODEMSG(code),         //驱动的控制码
		ToSend,                //输入缓冲区
		(wcslen(ToSend)+1)*2,  //输入缓冲区的大小
		&ret,                  //输出缓冲区
		sizeof(ret),           //输出缓冲区的大小
		&bytes,                //返回的字节数
		NULL);

	//关闭驱动文件
	CloseHandle(device);

	printf("完毕！
");

	return TRUE;
}

//main函数
void main(int argc,char *argv[])
{
	//推断用户输入的合法性
	if (argc != 3)
	{
		printf("Example：%s ID CommandLine
",argv[0]);
		return;
	}

	//调用驱动的代码
	CallDriver(argv[1], argv[2]);

	return;
}

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