c - 内核驱动程序接收到结构体，但它仍然为空

Question

我有一个内核驱动程序，我正在尝试让 ReadFile 工作。这是我的司机调度功能:

NTSTATUS DriverDispatch(PDEVICE_OBJECT DriverObject, PIRP irp)
{
UNREFERENCED_PARAMETER(DriverObject);
PIO_STACK_LOCATION io;
PGAME_INFO info;
NTSTATUS status = STATUS_SUCCESS;

io = IoGetCurrentIrpStackLocation(irp);
irp->IoStatus.Information = 0;

if (io->MajorFunction == IRP_MJ_WRITE)
{
    io = IoGetCurrentIrpStackLocation(irp);

    CHAR buffer[14] = "Got request\r\n";
    ULONG cb = 14;

    ZwWriteFile(handle, NULL, NULL, NULL, &ioStatusBlock, buffer, cb, NULL, NULL);

    if (io)
    {
        info = (PGAME_INFO)irp->AssociatedIrp.SystemBuffer;
        if (info)
        {
            HANDLE Pid = info->pid;
            cb = 20;

            ZwWriteFile(handle, NULL, NULL, NULL, &ioStatusBlock, Pid, cb, NULL, NULL);

            status = STATUS_SUCCESS;
        }
        else
        {
            CHAR buffer2[20] = "Struct was null\r\n";
            cb = 20;

            ZwWriteFile(handle, NULL, NULL, NULL, &ioStatusBlock, buffer2, cb, NULL, NULL);
        }
    }
    else
    {
        CHAR buffer3[31] = "PIO_STACK_LOCATION is null\r\n";
        cb = 31;

        ZwWriteFile(handle, NULL, NULL, NULL, &ioStatusBlock, buffer3, cb, NULL, NULL);
    }

    irp->IoStatus.Information = sizeof(GAME_INFO);
}
else 
{
    status = STATUS_SUCCESS;
}

irp->IoStatus.Status = status;

IoCompleteRequest(irp, IO_NO_INCREMENT);
return status;
}

这是我正在使用的结构:

typedef struct _GAME_INFO {
HANDLE pid;
}GAME_INFO, *PGAME_INFO;

还有我的用户模式应用程序:

int main()
{
GAME_INFO GameInfo;

HANDLE hDevice = CreateFile("\\\\.\\Driver", GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

if (hDevice == INVALID_HANDLE_VALUE)
{
    printf("\nError: Unable to connect to the driver (%d)\n", GetLastError());
    getchar();
    return -1;
}

getchar();

GameInfo.pid = (HANDLE)1234;
DWORD written;

if (!WriteFile(hDevice, &GameInfo, sizeof(GAME_INFO), &written, NULL))
{
    printf("\nError: Unable to write data to the driver (%d)\n", GetLastError());

    CloseHandle(hDevice);
    getchar();
    return -1;
}
else 
{
    printf("%lu", written);
    getchar();
}

CloseHandle(hDevice);
return 0;
}

驱动程序正在接收请求，但由于某种原因该结构为空。我对内核驱动程序和 C 语言都很陌生，所以请随时纠正我的任何问题

Answer 1

根据一些来回，这似乎是因为驱动程序 IO 设置为直接而不是缓冲。 direct 没有系统缓冲区，因为它实际上没有缓冲，因此该字段预计为 NULL。

接收代码需要通过 MDL 来工作。

参见https://learn.microsoft.com/en-us/windows-hardware/drivers/kernel/using-mdls为起点。