Secure Function Pointer and Callbacks in Windows Programming

// UnsafeFP.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<windows.h>
#define INFO_BUFFER_SIZE 32767


/****************************************************************
GetComputerDetailes	 - 
Arguments	 - arr. Not used!
			 - n Not used!
Retrun		 - Display computer information to hacker
*******************************************************************/
void GetComputerDetailes(int arr[], int n) {
     
	TCHAR  infoBuf[INFO_BUFFER_SIZE];
  DWORD  bufCharCount = INFO_BUFFER_SIZE;
 
  // display the name of the computer. 
  bufCharCount = INFO_BUFFER_SIZE;
  if( !GetComputerName( infoBuf, &bufCharCount ) )
    printf( "GetComputerName Failed!"); 
  printf("\nComputer name:      %s", infoBuf ); 
 
  // display the user name. 
  bufCharCount = INFO_BUFFER_SIZE;
  if( !GetUserName( infoBuf, &bufCharCount ) )
	   printf( "GetUserName Failed!"); 
  printf("\nUser name:          %s", infoBuf ); 
 
  // display the system directory. 
  if( !GetSystemDirectory( infoBuf, INFO_BUFFER_SIZE ) )
	   printf( "GetSystemDirectory Failed!"); 
  printf("\nSystem Directory:   %s", infoBuf ); 
 
  // display the Windows directory. 
  if( !GetWindowsDirectory( infoBuf, INFO_BUFFER_SIZE ) )
	   printf( "GetWindowsDirectory Failed!"); 
  printf("\nWindows Directory:  %s \n", infoBuf ); 


}


/****************************************************************
Display		 -	Display the array of integer
Arguments	 - Array of integer
			 - Number of array elements
Retrun		 - void. Display in Console
*******************************************************************/
void Display(int arr[], int n) {
	for(int i=0;i<n;i++)
		printf("%d ",arr[i]);
	printf("\n");

}


// Declare function pointer
typedef void (*FunctionPointer)(int arr[], int);
FunctionPointer fpdisplay = &Display;

int _tmain(int argc, _TCHAR* argv[])
{
	// Declare and define the variable
	int arr[]={1,9,8,4,6,5,3,7,2};
	int searchval = 6;
	int result = 0;
	
	printf("Display function pointer address : %d\n \n",fpdisplay);

	// Hacker get the address of global Display address
	fpdisplay = &GetComputerDetailes;  // Open Computer Details.

	// Our display information try to display array of integers.
	printf("Display Array Before sort using function pointer: ");
	if(fpdisplay)
		(*fpdisplay)(arr,9);
	
	
	return 0;
}