C / C++ / MFC

DLL Security (.NET Securing)

27-Jun-03 5:04

Try opening the file in another editor and resaving it. If one particular line became corrupted for some reason, and you're copying and pasting it, then you might be pasting more corrupted lines.

Or type the line by hand in again - just type below the current line and delete the old one. I'd do this. If it works for one line, then you can copy and paste that one.

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

About irregular window

tinberdxq26-Jun-03 17:45

tinberdxq

26-Jun-03 17:45

I will made a UI by MFC; The UI just like media player9 ,
I use the function SetWindowRgn, but when the panel zoomed what can I get the ner rgn Confused | :confused:

A man can do what he want but not wants what he want

flip26-Jun-03 17:16

flip

26-Jun-03 17:16

Hi peoples,

Given a Dll generated with VS C++ 6.0, no .h file for that dll and no documentation.
How easy is it too,

[1] - Find the number of parameters for the function
[2] - Find the types of those arguments

I have heard about securing dlls with public/private key cryptography with .NET.
Is it worth the effort? If I have a DLL which is the core of my system is it
relatively easy to link it into a new application and use it effectively?

Thanks.

Ryan Binns26-Jun-03 19:10

26-Jun-03 19:10

flip wrote:
How easy is it too,

[1] - Find the number of parameters for the function
[2] - Find the types of those arguments

Simple answer. You can't. Not unless you want to disassemble the DLL code and step through the assembly code by hand to see what it does.

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

flip26-Jun-03 19:22

flip

26-Jun-03 19:22

Yes, and thats exactly the question.

How easy is it to do that? Is it practically impossible or relatively fairly simple.

If it has been done before (ever) then I probably do not want to expose a core component of the system as a dll (or even an encrypted dll).

Also can I still compile a dll in VC 6 and then encrypt it later or do I have to use
.NET to encrypt it at each build?

Can anyone provide a link to dll Securing for .NET?

Ryan Binns26-Jun-03 19:32

26-Jun-03 19:32

flip wrote:
How easy is it to do that? Is it practically impossible or relatively fairly simple.

Fairly impossible would be an understatement Smile | :)

. It is extremely difficult.

I haven't ever tried to encrypt a DLL, and I haven't used .NET, so I can't help with the rest Smile | :)

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

flip26-Jun-03 19:37

flip

26-Jun-03 19:37

How easy is it to do that? Is it practically impossible or relatively fairly simple.

R - Fairly impossible would be an understatement . It is extremely difficult.

Ok good. Thats what I thought.

R - I haven't ever tried to encrypt a DLL, and I haven't used .NET, so I can't help with the rest

Same here.

I am trying to avoid .NET since nothing in the program needs it.
If I was using .NET technologies - then things would be different.

I just dont see the need to have to switch over to .NET just to ensure the dlls are
encrypted when I am happy with VC 6.

Ryan

Ryan Binns26-Jun-03 19:42

26-Jun-03 19:42

There's an article here on CP somewhere about encrypting an EXE file. Perhaps you could modify that to work with a DLL...

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

Toni7826-Jun-03 20:56

Toni78

26-Jun-03 20:56

As Ryan said you have to disassemble the DLL code to find the number of parameters. There are certain patterns to determine the number of parameters, for instance before a function is called, its parameters are pushed into the stack

push eax<br />
push ecx<br />
call DllFunc

which in C++ translates to DllFunc( ecx, eax).
At the end of the function you could have something like this:
ret 000X - where X is a number (4, 8, C etc.), which will tell you the number of parameters, and 4 means one parameter, 8 means two and so on.
After the function has returned, if you see code like this:
add esp, 0X - where X again is a number that tells you the number of parameters. This is an adjustment done to the stack after a function returns.
There are more hints out there but you have to study some assembly to figure out most of them.

Finding the types of those arguments is very difficult and sometimes impossible. You need to know something about the function.

// Afterall, I realized that even my comment lines have bugs

When one cannot invent, one must at least improve (in bed).-My latest fortune cookie

Ryan Binns26-Jun-03 21:04

26-Jun-03 21:04

Toni78 wrote:
push eax
push ecx
call DllFunc
which in C++ translates to DllFunc( ecx, eax).

Sometimes, but not always. I've looked at the output from some compilers, and sometimes they push the registers simply to save their value across the function call. I don't think this happens with the MS compiler, but other compilers do it. Also, the compiler may perform processing in between the pushes, and it may use the stack for doing that processing, so it can be very complex. But I agree, looking at the instructions before the call is the easiest way.

The problem is that in his situation he want to know if you can work out the parameters from the DLL - no calling code. That is substantially more difficult because you have to look at what each parameter is used for and what is done with them. And then, as you said, finding the types of the parameters is almost impossible Smile | :)

Re: Structures and Classes

Toni7826-Jun-03 21:37

Toni78

26-Jun-03 21:37

Ryan Binns wrote:
Sometimes, but not always.

I couldn't agree more. However, I was just trying to give him some pointers and I thought this could help.
When it comes to the types of the parameters, simple data types such as int, char, char*, etc can be detected "easily" but structures and classes are such a pain (or undetectable).

// Afterall, I realized that even my comment lines have bugs

When one cannot invent, one must at least improve (in bed).-My latest fortune cookie

__FUNCTION__ Macro

ROK_RShadow26-Jun-03 16:27

ROK_RShadow

26-Jun-03 16:27

I was currently reading an article in my linux mag about the wonderful uses of the assert function. I personally use this function and variations of it a lot. My question arises when I caught a side bar of the article about some preprocessor macros.

The sidebar explains how assert is so great because of the __LINE__ and __FILE__ macros. However it also explains two useful macros that are available under the GNU C compiler. __FUNCTION__ and __PRETTY_FUNCTION__. The first being for C compilers it returns the functions name. Since C++ mangles function names do to overloading the second returns the full function name (i.e. "void CMyClass::myfunc(int, double)" ). However these do not seem to be available under Microsoft's or Borland's compiler, and a long search through MSDN doesn't reveal anything similar. Is there a way to produce similar output with the MS compiler?

Re: __FUNCTION__ Macro

Andrew Walker26-Jun-03 17:14

Andrew Walker

26-Jun-03 17:14

A good place to start is current_function.hpp in the boost library. Boost tends to be a good place to start for information and patterns which work around differences in compilers.

#ifndef BOOST_CURRENT_FUNCTION_HPP_INCLUDED
#define BOOST_CURRENT_FUNCTION_HPP_INCLUDED

#if _MSC_VER >= 1020
#pragma once
#endif

//
//  boost/current_function.hpp - BOOST_CURRENT_FUNCTION
//
//  Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
//
//  Permission to copy, use, modify, sell and distribute this software
//  is granted provided this copyright notice appears in all copies.
//  This software is provided "as is" without express or implied
//  warranty, and with no claim as to its suitability for any purpose.
//
//  http://www.boost.org/libs/utility/current_function.html
//

namespace boost
{

namespace detail
{

inline void current_function_helper()
{

#if defined(__GNUC__) || (defined(__MWERKS__) && (__MWERKS__ >= 0x3000))

# define BOOST_CURRENT_FUNCTION __PRETTY_FUNCTION__

#elif defined(__FUNCSIG__)

# define BOOST_CURRENT_FUNCTION __FUNCSIG__

#elif defined(__BORLANDC__) && (__BORLANDC__ >= 0x550)

# define BOOST_CURRENT_FUNCTION __FUNC__

#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901)

# define BOOST_CURRENT_FUNCTION __func__

#else

# define BOOST_CURRENT_FUNCTION "(unknown)"

#endif

}

} // namespace detail

} // namespace boost

#endif // #ifndef BOOST_CURRENT_FUNCTION_HPP_INCLUDED

If you can keep you head when all about you
Are losing theirs and blaming it on you;
If you can dream - and not make dreams your master;
If you can think - and not make thoughts you aim;
Yours is the Earth and everything that's in it.

Rudyard Kipling

Re: __FUNCTION__ Macro

Jim A. Johnson26-Jun-03 17:21

Jim A. Johnson

26-Jun-03 17:21

__FUNCTION__ is available in VS.NET; it returns the undecorated name of the function.

Registry in C++ Website

yashraj121526-Jun-03 15:27

yashraj1215

26-Jun-03 15:27

Hey everyone, I just wanted to inform you of a great great website that really helped me out with reading and writing to the registry using C++. It took me many hours to find a website with simple explanations and examples like this.

http://www4.ncsu.edu:8030/~jgbishop/codetips/general/registry_access_advanced.html

Check it out...

Structures and Classes

yashraj121526-Jun-03 15:24

yashraj1215

26-Jun-03 15:24

I have a book on C++, but it does not explain structures and classes very well. Could someone please tell me what they are, what they're used for, and the differences between them?

Thanks a lot.

Johnny ²26-Jun-03 19:53

Johnny ²

26-Jun-03 19:53

Take a look here for structures and here for classes. At the most basic level, structures are an old C-concept and just contain data, whilst a class is C++ and contains both data and functions relevant to that data. Classes also provide for the whole object-oriented design, so go with them where possible.

show dialog in dll

gucy26-Jun-03 15:01

gucy

26-Jun-03 15:01

i want to show a dialog in regular dll which is dynamicaly linked to mfc.
the exported func is :
//dynamicly
extern "C" __declspec( dllexport ) void Trade1()
{
AFX_MANAGE_STATE(AfxGetStaticModuleState())
CDlgLogon dlg;
dlg.DoModal ();
}
which does not work.
if i set the dll staticly linked to mfc .it works well
//staticly
extern "C" __declspec( dllexport ) void Trade1()
{
CDlgLogon dlg;
dlg.DoModal ();
}
is that means i can't use mfc in static library?

gucy

Ryan Binns26-Jun-03 15:28

26-Jun-03 15:28

Where is your dialog template? In the DLL or in the application. The second one (which you said works) would load it from the application, but the first one (which you said doesn't work) would try to load it from the DLL, and should work if the dialog template was in the DLL.

If you want the first one to work, the dialog template must be in the DLL, not in the application.

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

gucy26-Jun-03 15:36

gucy

26-Jun-03 15:36

hi,
The dialog template is in dll in both of the two funcion.

gucy

Ryan Binns26-Jun-03 15:40

26-Jun-03 15:40

If you use AFX_MANAGE_STATE() in the bottom one, does it still work?

Ryan

Being little and getting pushed around by big guys all my life I guess I compensate by pushing electrons and holes around. What a bully I am, but I do enjoy making subatomic particles hop at my bidding - Roger Wright (2^nd April 2003, The Lounge)

Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late - John Nichol "Point Of Impact"

gucy26-Jun-03 15:48

gucy

26-Jun-03 15:48

yes,if i add the macro to the second one,it still work.it does not depent on the macro.

gucy

Ryan Binns26-Jun-03 16:01