驅動開發：內核封裝WSK網絡通信接口

本章LyShark將帶大家學習如何在內核中使用標準的Socket套接字通信接口，我們都知道Windows應用層下可直接調用WinSocket來實現網絡通信，但在內核模式下應用層API接口無法使用，內核模式下有一套專有的WSK通信接口，我們對WSK進行封裝，讓其與應用層調用規範保持一致，並實現內核與內核直接通過Socket通信的案例。

當然在早期如果需要實現網絡通信一般都會採用TDI框架，但在新版本Windows10系統上雖然依然可以使用TDI接口，但是LyShark並不推薦使用，因爲微軟已經對接口擱置了，爲了使WSK通信更加易用，我們需要封裝內核層中的通信API，新建LySocket.hpp頭文件，該文件中封裝了WSK通信API接口，其封裝格式與應用層接口保持了高度一致，當需要在內核中使用Socket通信時可直接引入本文件。

我們需要使用WDM驅動程序，並配置以下參數。

• 配置屬性 -> 連接器 -> 輸入-> 附加依賴 -> $(DDK_LIB_PATH)\Netio.lib
• 配置屬性 -> C/C++ -> 常規 -> 設置 警告等級2級 (警告視爲錯誤關閉)

配置好以後，我們就開始吧，先來看看服務端如何實現！

對於服務端來說，驅動通信必須保證服務端開啓多線程來處理異步請求，不然驅動加載後系統會處於等待狀態，而一旦等待則系統將會卡死，那麼對於服務端DriverEntry入口說我們不能讓其等待，必須使用PsCreateSystemThread來啓用系統線程，該函數屬於WDM的一部分，官方定義如下；

NTSTATUS PsCreateSystemThread(
  [out]           PHANDLE            ThreadHandle,
  [in]            ULONG              DesiredAccess,
  [in, optional]  POBJECT_ATTRIBUTES ObjectAttributes,
  [in, optional]  HANDLE             ProcessHandle,
  [out, optional] PCLIENT_ID         ClientId,
  [in]            PKSTART_ROUTINE    StartRoutine,
  [in, optional]  PVOID              StartContext
);

我們使用PsCreateSystemThread函數開闢線程TcpListenWorker在線程內部執行如下流程啓動驅動服務端，由於我們自己封裝實現了標準接口組，所以使用起來幾乎與應用層無任何差異了。

• CreateSocket 創建套接字
• Bind 綁定套接字
• Accept 等待接收請求
• Receive 用於接收返回值
• Send 用於發送返回值

// 署名權
// right to sign one's name on a piece of work
// PowerBy: LyShark
// Email: [email protected]

#include "LySocket.hpp"

PETHREAD m_EThread = NULL;

// 線程函數
// PowerBy: LySHark
VOID TcpListenWorker(PVOID Context)
{
	WSK_SOCKET* paccept_socket = NULL;
	SOCKADDR_IN LocalAddress = { 0 };
	SOCKADDR_IN RemoteAddress = { 0 };
	NTSTATUS status = STATUS_UNSUCCESSFUL;

	// 創建套接字
	PWSK_SOCKET TcpSocket = CreateSocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, WSK_FLAG_LISTEN_SOCKET);
	if (TcpSocket == NULL)
	{
		return;
	}

	// 設置綁定地址
	LocalAddress.sin_family = AF_INET;
	LocalAddress.sin_addr.s_addr = INADDR_ANY;
	LocalAddress.sin_port = HTON_SHORT(8888);

	status = Bind(TcpSocket, (PSOCKADDR)&LocalAddress);
	if (!NT_SUCCESS(status))
	{
		return;
	}

	// 循環接收
	while (1)
	{
		CHAR* read_buffer = (CHAR*)ExAllocatePoolWithTag(NonPagedPool, 2048, "read");
		paccept_socket = Accept(TcpSocket, (PSOCKADDR)&LocalAddress, (PSOCKADDR)&RemoteAddress);
		if (paccept_socket == NULL)
		{
			continue;
		}

		// 接收數據
		memset(read_buffer, 0, 2048);
		int read_len = Receive(paccept_socket, read_buffer, 2048, 0);
		if (read_len != 0)
		{
			DbgPrint("[內核A] => %s \n", read_buffer);

			// 發送數據
			char send_buffer[2048] = "Hi, lyshark.com B";
			Send(paccept_socket, send_buffer, strlen(send_buffer), 0);

			// 接收確認包
			memset(read_buffer, 0, 2048);
			Receive(paccept_socket, read_buffer, 2, 0);
		}

		// 清理堆
		if (read_buffer != NULL)
		{
			ExFreePool(read_buffer);
		}

		// 關閉當前套接字
		if (paccept_socket)
		{
			CloseSocket(paccept_socket);
		}
	}

	if (TcpSocket)
	{
		CloseSocket(TcpSocket);
	}
	PsTerminateSystemThread(STATUS_SUCCESS);
	return;
}

// 關閉套接字
VOID UnDriver(PDRIVER_OBJECT driver)
{
	WSKCleanup();
	KeWaitForSingleObject(m_EThread, Executive, KernelMode, FALSE, NULL);
	if (m_EThread != NULL)
	{
		ObDereferenceObject(m_EThread);
	}
}

NTSTATUS DriverEntry(IN PDRIVER_OBJECT Driver, PUNICODE_STRING RegistryPath)
{
	DbgPrint("hello lyshark.com \n");

	// 初始化
	WSKStartup();

	HANDLE hThread = NULL;
	NTSTATUS status = STATUS_UNSUCCESSFUL;

	// 創建系統線程
	status = PsCreateSystemThread(&hThread, THREAD_ALL_ACCESS, NULL, NULL, NULL, TcpListenWorker, NULL);
	if (!NT_SUCCESS(status))
	{
		return status;
	}

	// 獲取線程EProcess結構
	status = ObReferenceObjectByHandle(hThread, THREAD_ALL_ACCESS, NULL, KernelMode, (PVOID*)&m_EThread, NULL);
	if (NT_SUCCESS(status) == FALSE)
	{
		return status;
	}

	ZwClose(hThread);
	Driver->DriverUnload = UnDriver;
	return STATUS_SUCCESS;
}

對於客戶端來說，只需要創建套接字並連接到指定地址即可，這個過程大體上可以總結爲如下；

• CreateSocket 創建套接字
• Bind 綁定套接字
• Connect 鏈接服務端驅動
• Send 發送數據到服務端
• Receive 接收數據到服務端

// 署名權
// right to sign one's name on a piece of work
// PowerBy: LyShark
// Email: [email protected]

#include "LySocket.hpp"

VOID UnDriver(PDRIVER_OBJECT driver)
{
	// 卸載並關閉Socket庫
	WSKCleanup();
}

NTSTATUS DriverEntry(IN PDRIVER_OBJECT Driver, PUNICODE_STRING RegistryPath)
{
	DbgPrint("hello lyshark.com \n");
	// 初始化
	WSKStartup();

	NTSTATUS      status = STATUS_SUCCESS;
	SOCKADDR_IN   LocalAddress = { 0, };
	SOCKADDR_IN   RemoteAddress = { 0, };

	// 創建套接字
	PWSK_SOCKET TcpSocket = CreateSocket(AF_INET, SOCK_STREAM, IPPROTO_TCP, WSK_FLAG_CONNECTION_SOCKET);
	if (TcpSocket == NULL)
	{
		Driver->DriverUnload = UnDriver;
		return STATUS_SUCCESS;
	}

	LocalAddress.sin_family = AF_INET;
	LocalAddress.sin_addr.s_addr = INADDR_ANY;
	status = Bind(TcpSocket, (PSOCKADDR)&LocalAddress);

	// 綁定失敗則關閉驅動
	if (!NT_SUCCESS(status))
	{
		CloseSocket(TcpSocket);

		Driver->DriverUnload = UnDriver;
		return STATUS_SUCCESS;
	}

	// 初始化服務端地址與端口信息
	ULONG address[4] = { 127, 0, 0, 1 };

	RemoteAddress.sin_family = AF_INET;
	RemoteAddress.sin_addr.s_addr = change_uint(address[0], address[1], address[2], address[3]);
	RemoteAddress.sin_port = HTON_SHORT(8888);

	status = Connect(TcpSocket, (PSOCKADDR)&RemoteAddress);

	// 連接服務端,如果失敗則關閉驅動
	if (!NT_SUCCESS(status))
	{
		CloseSocket(TcpSocket);
		Driver->DriverUnload = UnDriver;
		return STATUS_SUCCESS;
	}

	// 發送數據
	char send_buffer[2048] = "hello lyshark.com A";
	Send(TcpSocket, send_buffer, strlen(send_buffer), 0);

	// 接收數據
	CHAR* read_buffer = (CHAR*)ExAllocatePoolWithTag(NonPagedPool, 2048, "read");

	memset(read_buffer, 0, 1024);
	Receive(TcpSocket, read_buffer, 2048, 0);
	DbgPrint("[內核B] => %s \n", read_buffer);

	// 發送確認包
	Send(TcpSocket, "ok", 2, 0);

	// 釋放內存
	ExFreePool(read_buffer);
	CloseSocket(TcpSocket);
	Driver->DriverUnload = UnDriver;
	return STATUS_SUCCESS;
}

編譯兩個驅動程序，首先運行server.sys驅動，運行後該驅動會在後臺等待客戶端連接，接着運行client.sys屏幕上可輸出如下提示，說明通信已經建立了。