DeviceIoControl input buffer question

[Mattzimmerer]

The following is a snippet from an exe that is communicating with my driver. I am trying to pass a buffer to my driver by using DeviceIoControl. The problem is I've never done this before, so I don't even know if I am on the right track. I guess I just need the starting address of my input struct. (struct input {int a;int b;int c;};) The problem seems to be that I cannot put the address of my bInput into a DWORD. Am I going about this right? When I check out the contents of pInput, it seems to b a DWORD with the actual struct attached after... Im just confused

unsigned long Returned,*pReturned = &Returned;
input bInput;
bInput.a = 1;
bInput.b = 2;
bInput.c = 3;
int test = sizeof(bInput);
input *pInput = &bInput;

 DeviceIoControl(
      hFile,			// Device handle
      IOCTL\_MZ\_READMEMORY,          // Code
      NULL,				// Buffer TO driver
      0,			// Size of InBuffer
      NULL,				// Buffer FROM driver
      0,				// Size of OutBuffer
      pReturned,			// Bytes output
      (LPOVERLAPPED) NULL);		// Overlapped struc

note: right now my DeviceIoControl call is not using any buffer. I plan on passing the starting address of bInput and the size of bInput.

[Lost User]

The input and output buffers are defined here[^] as being LPVOID, which effectively means a pointer to something; what it really contains is between you and the driver. So to call this function passing your buffer address (suitably cast) all you need to code is something like:

 DeviceIoControl(
      hFile,			// Device handle
      IOCTL\_MZ\_READMEMORY,          // Code
      (LPVOID)&bInput,		// Buffer TO driver
      sizeof bInput,		// Size of InBuffer
      (LPVOID)&bOutput,		// Buffer FROM driver
      sizeof bOutput,		// Size of OutBuffer
      pReturned,			// Bytes output
      (LPOVERLAPPED) NULL);		// Overlapped struc

And don't forget to check the return status.

[Mattzimmerer]

Thanks!

[Lost User]

Mattzimmerer wrote:

my driver

You wrote a driver and you cant get devioctl to work! :omg:

Morality is indistinguishable from social proscription

[Mattzimmerer]

Thanks sir, your tons of help. No it works now... maybe you should try helpful comments instead of (in my perception) being boastful. Surely you have asked for help to understand certain things... Obviously in not doing this professionally, its a side project in developing a game hacking tool! :-D

[Lost User]

I saw though that someone else had solved your problem and felt like having a bit of a dig! :)

Morality is indistinguishable from social proscription

[Mattzimmerer]

Yea, lol this stuff is pretty out there if you have only been exposed to userspace programming. Now onto assembly language!