Calculate checksum using ASLR - C / C++ / MFC Discussion Boards

Re: Exception when debugging Multithread

«_Superman_»7-Jun-12 19:15

«_Superman_»

7-Jun-12 19:15

It is probably because the thread is in a suspended state and has not started running.

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: Exception when debugging Multithread

ForNow7-Jun-12 23:53

ForNow

7-Jun-12 23:53

I resume the thread

myprog->progsocket->ResumeThread(); // get it going

However one I comment out anything the destroys e.g. EndDialog the Modal Dialog box whose method

I was while creating the CWinThread the exception disappears

I am wondering since I create a UI thread it associates the CWinThread with the modal

Dialog Box and when the modal Dialog Box disappears it destroys anything associated

with it e.g. the CWinThread object and anything releated to that object

code in question don't know whay my pre tags aren't taking

<pre lang='cpp'>

CprogDebug *myprog; // instantiate a Debug Class modless CDialog derived class

myprog = new CprogDebug; // Allocate on the Heap

if (myprog == NULL)
MessageBox("CprogDebug","CprogDebug Error",MB_ICONERROR);

myprog->jobname = jobname; // copy over jobname
myprog->progname = progname; // copy over progname
myprog->proglisting = dlg.GetPathName();
EndDialog(0); // Kill the Dialog
// dlg.~dlg();

myprog->Create(IDD_PROGDBG,NULL); // Attach it to a window

myprog->progsocket = (SockCLeintThread *) AfxBeginThread(RUNTIME_CLASS)
(SockCLeintThread),
THREAD_PRIORITY_NORMAL,
0,CREATE_SUSPENDED);

if (myprog->progsocket == NULL)
MessageBox("Socket","Prog Socket Error",MB_ICONERROR);

myprog->progsocket->sendwindow = (CWnd *) myprog;
// set window to receive TCP/IP messages
myprog->progsocket->m_pActiveWnd = (CWnd *) myprog; // <== point to newwindow
myprog->progsocket->m_pMainWnd = (CWnd *) myprog; // ditto
myprog->progsocket->ipaddr = "192.168.1.4"; // ip address
CHERC_CMDApp *main_app = (CHERC_CMDApp *)AfxGetApp();
int i = 0;
while(main_app->ports[i].busy != 0)
{
i++;
}
myprog->progsocket->port = main_app->ports[i].port; // port
main_app->ports[i].busy = 1;
// Tcpipthread = progsocket->m_nThreadID; // thread id
// myprog.progsocket->thisocket.send_wnd = myprog.progsocket->sendwindow;
myprog->progsocket->thisocket->send_wnd = (CWnd *) myprog;
strcpy((char *)&myprog->progsocket->thread_id,"DebugSocket");
myprog->progsocket->thisocket->thread_no = i; //
myprog->Tcpipthread = myprog->progsocket->m_nThreadID;
myprog->progsocket->ResumeThread();

</pre>

Event though I explictily point to another modless dialog I create on the heap

while in the modless Dialog Box method

Re: Exception when debugging Multithread

ForNow7-Jun-12 23:58

ForNow

7-Jun-12 23:58

sorry in last sentence I meant Eventhough I explictly destroy the <b> modal </b> dialog box

Re: Exception when debugging Multithread

Erudite_Eric7-Jun-12 20:34

Erudite_Eric

7-Jun-12 20:34

Yeah so this is the kind of problem you get when trying to do things outside the 'usual way of doing it'.

So just create your thread normally and implement your own messaging system as I suggested in your earlier post.

==============================

Nothing to say.

Re: Exception when debugging Multithread

Richard MacCutchan7-Jun-12 21:53

Richard MacCutchan

7-Jun-12 21:53

ForNow wrote:
can sone one tell me What the /MD and /MT linker options are

Check the documentation[^].

speaking as ...

Re: Exception when debugging Multithread

Erudite_Eric7-Jun-12 23:35

Erudite_Eric

7-Jun-12 23:35

Nah, thats too hard. It is easier to type an entire question into CP than those two switches into google....

==============================

Nothing to say.

Re: Exception when debugging Multithread

Richard MacCutchan8-Jun-12 0:19

Richard MacCutchan

8-Jun-12 0:19

In this case I went direct to MSDN, so no need for Google. Who said TINA?

speaking as ...

Calculate checksum using ASLR

Giggsey737-Jun-12 8:39

Giggsey73

7-Jun-12 8:39

XML

Hi Guys! I'm a newbie here. I wanna match the PID in Windows Task Manager with the checksum/hash value generated by dynamic base ASLR in Visual Studio 2010? I have already enabled the ASLR in Visual Studio 2010 but no data is received. Any idea how?

<b>Clues:</b>
1. Windows functions CreateToolhelp32Snapshot
2. MODULEENTRY32
3. Windows function OpenProcess

Appreciate it very much guys.

Giggsey

Re: Calculate checksum using ASLR

David Crow7-Jun-12 8:43

David Crow

7-Jun-12 8:43

Giggsey73 wrote:
<b>Clues:</b>
1. Windows functions CreateToolhelp32Snapshot
2. MODULEENTRY32
3. Windows function OpenProcess

Are you wanting to know how to use these functions/structures?

"One man's wage rise is another man's price increase." - Harold Wilson

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Re: Calculate checksum using ASLR

Giggsey737-Jun-12 8:46

Giggsey73

7-Jun-12 8:46

Yes please. I'm rushing in the middle of a project & need to use this functions? I aint got a clue.
Thanx.

Re: Calculate checksum using ASLR

David Crow7-Jun-12 8:55

David Crow

7-Jun-12 8:55

Google was of no help? What exactly did you search for? Did you try this? Another example can be found here.

Re: Calculate checksum using ASLR

Giggsey737-Jun-12 9:08

Giggsey73

7-Jun-12 9:08

Sori, i need to go to sleep. Smile | :)

Will discuss tmrow then.
Good night.

Re: Calculate checksum using ASLR

Giggsey738-Jun-12 8:34

Giggsey73

8-Jun-12 8:34

Hi David. With reference to yday's question,how is it possible to link process_checksum enabled by ASLR in Visual Studio 2010 to the command prompt?

Example:
c:Users\User\Documents\Visual Studio 2010\Projects\process_checksum\Debug>process_checksum.exe

Appreciate it very much.
Giggsey

Re: Calculate checksum using ASLR

Randor 8-Jun-12 9:48

Randor

8-Jun-12 9:48

Giggsey,

I am having trouble comprehending the question you are asking. Don't worry... I know that English is not your mother tongue. Your original question appears to be gibberish. Could you be more specific?

The problem is that the acronym 'ASLR' is security related... pertaining to randomization of DLL base addresses and stack/heap allocation randomizations to help mitigate aurora attacks (heap-spraying) and ROP shell code.

Are you asking how to enable ASLR in your project? If so... you would want to enable /DYNAMICBASE[^]

Best Wishes,
-David Delaune

Re: Calculate checksum using ASLR

Giggsey738-Jun-12 18:48

Giggsey73

8-Jun-12 18:48

Hi. Actually I am a novice to computing.
BTW, I got the cmd line from other sources.

c:Users\User\Documents\Visual Studio 2010\Projects\process_checksum\Debug>process_checksum.exe

By right, if u run the cmd, it will prompt u to enter PID.
Then the following data will be generated:
Name, Path, Image Base, PE Signature,...., and finally hash/checksum value which i'm so desperately looking for.

I have difficulty in finding/linking(whatever) this process_checksum. Bcoz in the end I would be able get the hash or checksum value of the file. That's all.

Many thanks.
Giggsey

Re: Calculate checksum using ASLR

Randor 9-Jun-12 4:36

Randor

9-Jun-12 4:36

Giggsey,

No problem. I completely understand that you are a novice and looking for guidance. It sounds to me as if you need to do quite a bit more research so that you can build a more complete understanding of these topics.

If you are looking to understand more about the PE hash algorithm then you should have a look at the article: An Analysis of the Windows PE Checksum Algorithm[^].

If you want to list the characteristics of arbitrary PE images (executable files) then have a look at the article: XPEInfo - a non-MFC class to get info from PE file[^].

I understand that you are working with a particular Visual Studio project named process_checksum. If you are having trouble compiling the application feel free to describe the exact details of the problem you are having.

I still do not understand the details of your problem. I suspect that it is because you do not know the verbiage to properly form the question.

Best Wishes,
-David Delaune

Re: Calculate checksum using ASLR

Giggsey739-Jun-12 4:52

Giggsey73

9-Jun-12 4:52

Hi David.
Yeah, u r right. I have problem in compiling the application especially. I had read the articles but still a bit confused.
So, what should I be doing then? Can u shed some light into this?
Appreciate it very much.

Giggsey

Re: Calculate checksum using ASLR

Randor 9-Jun-12 5:28

Randor

9-Jun-12 5:28

Giggsey73 wrote:
Yeah, u r right. I have problem in compiling the application especially. I had read the articles but still a bit confused.

So, what should I be doing then? Can u shed some light into this?

No, I cannot help you without knowing the problem. If you are receiving a compilation or linking error then you should paste the error message here.

Best Wishes,
-David Delaune

Re: Calculate checksum using ASLR

Giggsey739-Jun-12 6:51

Giggsey73

9-Jun-12 6:51

I need to create a process_checksum.exe first before I can compile.
How do i go about creating it?

Regards,
Giggesy

Re: Calculate checksum using ASLR

Randor 9-Jun-12 7:04

Randor

9-Jun-12 7:04

Giggsey73 wrote:
I need to create a process_checksum.exe first before I can compile.

<layer>How do i go about creating it?

Giggesy,

I am sorry but I can no longer help you. You continue to give paradoxical statements that are without a clear meaning.

Good luck with your project.

Best Wishes,
-David Delaune

C++ Program without main()

pix_programmer6-Jun-12 22:45

pix_programmer

6-Jun-12 22:45

Hi!
Is it possible to write a program with out main() function in C++?
If yes, Erom where the execution begins for such a program?

Re: C++ Program without main()

Richard MacCutchan6-Jun-12 23:22

Richard MacCutchan

6-Jun-12 23:22

Yes, you can by using the Linker /ENTRY[^] option. However, you will not have the full C library initialised so it is your program's responsibility to set the environment correctly.

speaking as ...

Re: C++ Program without main()

pix_programmer7-Jun-12 0:33

pix_programmer

7-Jun-12 0:33

Richard MacCutchan wrote:
using the Linker /ENTRY[^]

I checked the project property pages. It's also empty. From where it comes?

Re: C++ Program without main()

Richard MacCutchan7-Jun-12 4:53

Richard MacCutchan

7-Jun-12 4:53

Go to the Linker section, click on Advanced, and add your start label name to the Entry Point item.

speaking as ...

Re: C++ Program without main()

Aescleal7-Jun-12 0:12

Aescleal

7-Jun-12 0:12

In standard C++ it isn't possible.

As Richard mentioned you can specify an entry point for MSVC and other linkers allow you to do the same thing but you'll have a few hurdles to jump:

- The parameters to whatever function you define as the entry point will probably not be argc and argv
- Depending on the start-up code you're avoiding static and global objects may not be initialised (no great loss though)
- The language runtime library, even if linked, probably won't be initialised
- Anything that relies on the OS interacting with the language might go screwy (e.g. if new/delete expects allocations to come out of a heap the runtime allocates on start-up)

About the only place I've used this trick, had it work and be useful was back programming for Windows 3.1 when I was trying to keep the size of code down to a minimum and I was willing to pay the price for having an emasculated language. Basically if you're happy programming in assembler and using the OS and your own code for everything then then it may have some use.

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