I failed to learn how to create a Windows Driver Kernel...

[night egret]

Hello, I'm learning C/C++ as part of an internship. I've been asked to create a Windows Driver Kernel which has to communicate with a Python application using IOCTL (I'm much better at Python than C/C++). The first step is to carry out a very simple communication where the Python application asks the WDK for a ping and the driver answers "pong" (To carry out a very simple heartbeat).

For my part, I concentrated on C, which should be easier to learn/understand.

Based on what I can see here: https://github.com/microsoft/Windows-driver-samples I set up this little solution:

[sharp gyro]

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[night egret]

NTSTATUS DeviceControlDispatch(PDEVICE_OBJECT DeviceObject, PIRP Irp)
{
    UNREFERENCED_PARAMETER(DeviceObject);
    PIO_STACK_LOCATION irpStack = IoGetCurrentIrpStackLocation(Irp);
    NTSTATUS status = STATUS_SUCCESS;

    switch (irpStack->Parameters.DeviceIoControl.IoControlCode)
    {
    case IOCTL_PING:
        PWCHAR message = L"ping";
        SIZE_T stringLength = wcslen(message);

        RtlCopyMemory(Irp->AssociatedIrp.SystemBuffer, message, (stringLength * sizeof(WCHAR)));
        Irp->IoStatus.Information = (stringLength * sizeof(WCHAR));
        break;
    default:
        status = STATUS_INVALID_PARAMETER;
        break;
    }

    Irp->IoStatus.Status = status;
    IoCompleteRequest(Irp, IO_NO_INCREMENT);
    return status;
}```

In python I do something like this:

```py
driver_path = r"\\.\test"
 
driver_handle = ctypes.windll.kernel32.CreateFileW(
    ctypes.c_wchar_p(driver_path),
    ctypes.c_uint32(0xC0000000),  # GENERIC_READ | GENERIC_WRITE
    ctypes.c_uint32(0),
    None,
    ctypes.c_uint32(3),  # OPEN_EXISTING
    ctypes.c_uint32(0),
    None
)
 
if driver_handle != -1:
    ping_response = ctypes.create_unicode_buffer(256)
    bytes_returned = ctypes.c_ulong(0)
 
    result = ctypes.windll.kernel32.DeviceIoControl(
        driver_handle,
        IOCTL_PING,
        None,
        ctypes.c_ulong(0),
        ping_response,
        ctypes.sizeof(ping_response),
        ctypes.byref(bytes_returned),
        None
    )
    if result != 0:
        print("Ping response:", ping_response.value)```



My problem comes from RtlCopyMemory, that generates me a BSOD, as if my driver was not able to inject in the buffer allocated by python...I would really like to understand my error and I have already posted my problem on several servers / forums (grouping different types of discussion) but nobody knows how to help me ...I would like to understand, for that I made many test but without results.

(I know that learning C/C++ by starting with this kind of project is not a good method but I have no choice, I haven't decided)

[night egret]

bump

[jade halo]

if you have a bsod you could check the crash dump to see what happens

I wouldn't know though

is the pointer address passed into the C "Irp" correct ?

verify that the address allocated in python and C are identical

@night egret

[night egret]

For the moment i can't check it (i will be able in 3 hours, but i will