/*****************************************************************************
corruotingData.c: Interposition library to capture function calls from the libc
	and attack the system by corrupting data thta is stored or taked from a file
	using the fwrite and fread functions, and corrupoting data in when the malloc
	operation is called

By:
	Miguel Torres
	Computer Science, Mississippi State University
	July 2002

Based on:
	Profiling and tracind gynamic library usage via interposition (Timothy Curry)
	Generation of application level audit data via library interposition (Kuperman and
		Spafford, 1999)
	The Thesis work by German Florez at the CCSR at Mississippi State University
******************************************************************************/
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <unistd.h>
#include <time.h>
#include <string.h>

#include "signal.h"
#include <sys/utsname.h>

// For Random Generation
#include "randomlib.h"
// Sets the Seeds for the random generator
#define RANDOM (double)random()/RAND_MAX
//#define RANDOM (double)random((time(NULL))%31328)/RAND_MAX

#define INIT_RANDS \
	srand(time(NULL)); \
    	RandomInitialise((int)(time(NULL)*RANDOM)%31328,(int)(time(NULL)*RANDOM)%30081);

// Frecuency to attack
#define  PERCENTAJE    2 

#define TRUE 1
#define FALSE 0

static int DoProfile=TRUE;


#ifdef ATTACK

/*Description Writes to a stream.
fwrite appends n items of data each of length size bytes to the given output file. 
The data written begins at ptr. 
The total number of bytes written is (n x size). ptr in the declarations is a pointer to any object.
*/
size_t fwrite(const void *ptr, size_t size, size_t n, FILE *stream)
{
	// The actual function
	typedef size_t(*function_type) (const void *ptr, size_t size, size_t n, FILE *stream);
	static function_type function=NULL;
	static char* function_name="fwrite";
	// Sets the seed for the random number generator 
	size_t  retval;

    static int first_time=TRUE;
	if (!function){
		function = (function_type) dlsym(RTLD_NEXT,function_name);
	}

	#ifdef PRINT_OUTPUT
		printf("_W %d\n",DoProfile);
		fflush(stdout);
	#endif

	if (DoProfile){
		#ifdef PRINT_OUTPUT
			printf("_WProfiling\n");
			fflush(stdout);
		#endif
		/*
		** Seed the random number generator with the current time
		** of day if we haven't done so yet.
		*/
		if( first_time ){
			first_time = FALSE;
			// Random Generation
			INIT_RANDS
		}
		if(RandomInt(0,100)<PERCENTAJE){
			if(ptr){
				//Corromper
				//(char*)ptr[rand() % n][rand() % size]='0'
				;
				//Cambiar tamanno de la memoria a almacenar
				//size+= (size/2) - (rand()%(size-1)); 
				n+= (n/2) - (RandomInt(0,n-1)); 
				#ifdef PRINT_OUTPUT
					printf("_WAttacked\n");
					fflush(stdout);
				#endif
			}
			#ifdef PRINT_OUTPUT
				printf("_WRandom\n");
				fflush(stdout);
			#endif
		}
		//execute the funtion and then profile
		retval = ((*function)(ptr,size,n,stream)); 
	}
	else //do not profile, only execute
		retval = ((*function)(ptr,size,n,stream)); 

	return (retval);
}



/*
Reads data from a stream.
fread reads n items of data each of length size bytes from the given input stream into a block pointed to by ptr. 
The total number of bytes read is (n * size).
*/
size_t fread(void *ptr, size_t size, size_t n, FILE *stream)
{
	typedef size_t(*function_type) (const void *ptr, size_t size, size_t n, FILE *stream);
	static function_type function=NULL;
	static char* function_name="fread";
	// Sets the seed for the random number generator 

	static int first_time=TRUE;
	size_t  retval;

	if (!function){
		function = (function_type) dlsym(RTLD_NEXT,function_name);
	}

	#ifdef PRINT_OUTPUT
		printf("_R %d\n",DoProfile);
		fflush(stdout);
	#endif

	if (DoProfile){
		/*
		** Seed the random number generator with the current time
		** of day if we haven't done so yet.
		*/
		#ifdef PRINT_OUTPUT
			printf("_RProfiling %d\n",DoProfile);
			fflush(stdout);
		#endif

		if( first_time ){
			first_time = FALSE;
			// Random Generation
			INIT_RANDS
		}
		if(RandomInt(0,100)<PERCENTAJE){
			if(ptr){
				//Changes the size of the allocated memory
				//size+= (size/2) - (rand()%(size-1)); 
				n+= RandomInt(-(n-1),n-1); 
				#ifdef PRINT_OUTPUT
					printf("_RAttacking\n");
					fflush(stdout);
				#endif
			}
			#ifdef PRINT_OUTPUT
				printf("_RRandom\n");
				fflush(stdout);
			#endif
		}
		//execute the funtion and then profile
		retval = ((*function)(ptr,size,n,stream)); 
	}
	else //do not profile, only execute
		retval = ((*function)(ptr,size,n,stream)); 

	return (retval);
}


/*
malloc allocates a block of size bytes from the memory heap. 
It allows a program to allocate memory explicitly as it's needed, 
and in the exact amounts needed.
*/

void*  malloc (size_t size)
{
	typedef void*(*function_type) (size_t size);
	static function_type function=NULL;
	static char* function_name="malloc";

	static int first_time=TRUE;
	void*  retval;

	if (!function){
		function = (function_type) dlsym(RTLD_NEXT,function_name);
	}

	#ifdef PRINT_OUTPUT
		printf("_MA %d\n",DoProfile);
		fflush(stdout);
	#endif

	if (DoProfile){
		#ifdef PRINT_OUTPUT
			printf("_MAProfiling %d\n",DoProfile);
			fflush(stdout);
		#endif
		/*
		** Seed the random number generator with the current time
		** of day if we haven't done so yet.
		*/
		if( first_time ){
			first_time = FALSE;
			// Random Generation
			INIT_RANDS
		}
		int r;
		if((r=RandomInt(0,100))<PERCENTAJE){
			size+= RandomInt(-(size-1),size-1);
			#ifdef PRINT_OUTPUT
				printf("_MAAttacking\n");
				fflush(stdout);
			#endif
		}
#ifdef PRINT_OUTPUT
		printf("%d\n",r);
		fflush(stdout);
#endif
		//execute the funtion and then profile
		retval = ((*function)(size)); 

	}
	else //do not profile, only execute
		retval = ((*function)(size)); 


	return (retval);
}


/*
Copies a block of n bytes.
memcpy is available on UNIX System V systems.
memcpy copies a block of n bytes from src to dest. 
If src and dest overlap, the behavior of memcpy is undefined.
*/
void *memcpy(void *dest, const void *src, size_t n)
{
	typedef void*(*function_type) (void *dest, const void *src, size_t n);
	static function_type function=NULL;
	static char* function_name="memcpy";
	void*  retval;

	static int first_time=TRUE;
	if (!function){
		function = (function_type) dlsym(RTLD_NEXT,function_name);
	}

	#ifdef PRINT_OUTPUT
		printf("_MC %d\n",DoProfile);
		fflush(stdout);
	#endif

	if (DoProfile){
		#ifdef PRINT_OUTPUT
			printf("_MCProfiling %d\n",DoProfile);
			fflush(stdout);
		#endif
		/*
		** Seed the random number generator with the current time
		** of day if we haven't done so yet.
		*/
		if( first_time ){
			first_time = FALSE;
			// Random Generation
			INIT_RANDS
		}
		if(RandomInt(0,100)<PERCENTAJE){
			if(src){
				n+= RandomInt(-(n-1),n-1);
				#ifdef PRINT_OUTPUT
					printf("_MCAttacking\n");
					fflush(stdout);
				#endif
			}
			#ifdef PRINT_OUTPUT
				printf("_MCRandom\n");
				fflush(stdout);
			#endif
		}
		//execute the funtion and then profile
		retval = ((*function)(dest, src, n)); 
	}
	else //do not profile, only execute
		retval = ((*function)(dest, src, n)); 

	return (retval);
}

#endif