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2021-10-22 10:01:22 -04:00
parent 968ca756c3
commit 83dda0ef00
3 changed files with 145 additions and 58 deletions
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4
Makefile
View File

@@ -4,10 +4,10 @@ OUTPUT_DIR = ./bin
OUTPUT = -o ${OUTPUT_DIR}/PROG
build: output_dir
gcc -Wall ${LIBRARIES} ${SOURCES} ${OUTPUT:PROG=crc}
gcc -Wall -pthread ${LIBRARIES} ${SOURCES} ${OUTPUT:PROG=crc}
debug: output_dir
gcc -Wall -g ${LIBRARIES} ${SOURCES} ${OUTPUT:PROG=crc}
gcc -Wall -g -pthread ${LIBRARIES} ${SOURCES} ${OUTPUT:PROG=crc}
output_dir:
mkdir -p ${OUTPUT_DIR}

187
cmd/crc.c
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@@ -7,6 +7,7 @@
#include <stdlib.h>
#include <sodium.h>
#include <getopt.h>
#include <pthread.h>
#include "crc_util.h"
#include "CRCLib.h"
#include "crc.h"
@@ -65,11 +66,118 @@ int update_file_crc(unsigned char *addr, unsigned long offset , unsigned int crc
return 0;
}
static void random_window_bit_change(unsigned char *data, int width, int rounds, int color_range, size_t length) {
size_t random_num = 0;
for (int i = 0; i < rounds; i++) {
random_num = randombytes_uniform(length);
do {
random_num = randombytes_uniform(length);
} while((random_num % ((width * color_range) + 1)) == 0);
if(data[random_num] == 255) {
data[random_num]--;
} else {
data[random_num]++;
}
}
return;
}
static int verify_crc_chunks(unsigned char *data, size_t data_length, int crc_depth, unsigned int max_data_length) {
unsigned char* testing_chunk;
unsigned int crc_check = 0;
unsigned int test_data_length = 0;
for(int i = 0; i < crc_depth; i++) {
if((max_data_length * (i+1)) > data_length) {
test_data_length = (data_length - (max_data_length * i));
testing_chunk = calloc(test_data_length+4, sizeof(unsigned char));
} else {
test_data_length = max_data_length;
testing_chunk = calloc(test_data_length+4, sizeof(unsigned char));
}
testing_chunk[0] = 0x49;
testing_chunk[1] = 0x44;
testing_chunk[2] = 0x41;
testing_chunk[3] = 0x54;
for(int j = 0; j < test_data_length; j++) {
testing_chunk[j+4] = data[(max_data_length*i)+j];
}
crc_check = crc(testing_chunk, test_data_length);
if(i == 2) {
printf("THIRD: %08X\n", crc_check);
} else if(i == 1) {
printf("SECOND: %08X\n", crc_check);
}
if ((crc_check >> (8*3)) != 10 ) {
free(testing_chunk);
return 1;
}
}
free(testing_chunk);
printf("FOUND: %08X\n", crc_check);
return 0;
}
static int crc_embed_data(unsigned char *data, unsigned int data_length, int bit_width, int color_range, unsigned int sliding_window) {
unsigned char *check_data;
size_t check_data_length = 0;
random_window_bit_change(data, bit_width, 3, color_range, sliding_window);
// Compressing data for test
zlib_compress_data(data, data_length, &check_data, &check_data_length);
int match_crc = verify_crc_chunks(check_data, check_data_length, 3, 8192);
if(match_crc == 0) {
free(check_data);
return 0;
}
free(check_data);
return 1;
}
void *random_data_change_thread_call(void *w) {
struct EMBED_THREAD_STRUCT *data = w;
unsigned char* temp_color_data = calloc(data->uncom_data_len, sizeof(unsigned char));
int searching = 1;
do {
// Creating temporary data set
memcpy(temp_color_data, data->data, data->uncom_data_len);
if(data->uncom_data_len > 800000) {
data->data_len = 150000;
} else {
data->data_len = data->uncom_data_len;
}
if(data->uncom_data_len > 16000) {
data->win_size = 9000;
} else {
data->win_size = data->uncom_data_len;
}
searching = crc_embed_data(temp_color_data, data->data_len, data->width, data->color_range, data->win_size);
if (searching == 0) {
pthread_mutex_lock(data->mutex_lock);
//pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
*data->searching = searching;
memcpy(data->data, temp_color_data, data->uncom_data_len);
//pthread_cancel(data->thread_id);
pthread_mutex_unlock(data->mutex_lock);
}
} while(*data->searching == 1);
free(temp_color_data);
return NULL;
}
void random_data_change(unsigned char *color_data, unsigned char *width, size_t length) {
int searching = 1;
size_t rounds = 0;
unsigned char* full_data;
int data_array_size = 0;
unsigned int sliding_window = 0;
unsigned int compress_data_length = 0;
// Needs to be turned into a variable
int color_range = 3;
// Union for width type cast
@@ -77,60 +185,27 @@ void random_data_change(unsigned char *color_data, unsigned char *width, size_t
uint32_t width_int;
unsigned char width_array[4];
}w;
// Temp data array for crc testing
unsigned char* temp_color_data = calloc(length, sizeof(unsigned char));
memcpy(w.width_array, width, 4);
do {
rounds++;
// Creating temporary data set
memcpy(temp_color_data, color_data, length);
// Generating random byte to change
size_t random_num = randombytes_uniform(100000);
//size_t random_num = randombytes_uniform(length);
// Checking for index break
if(random_num % ((be32toh(w.width_int) * color_range) + 1)) {
if(color_data[random_num] == 255) {
temp_color_data[random_num]--;
} else {
temp_color_data[random_num]++;
}
// Compressing data for test
unsigned char *check_data_buff = NULL;
size_t check_data_length = 0;
zlib_compress_data(temp_color_data, 50000, &check_data_buff, &check_data_length);
//zlib_compress_data(temp_color_data, length, &check_data_buff, &check_data_length);
// Temp data array for crc testing
//unsigned char* temp_color_data = calloc(length, sizeof(unsigned char));
if(check_data_length > 8192) {
data_array_size = 8192;
full_data = calloc(8196, sizeof(unsigned char));
} else {
data_array_size = check_data_length;
full_data = calloc(check_data_length+4, sizeof(unsigned char));
}
//int num_threads = 1;
struct EMBED_THREAD_STRUCT t_data;
t_data.searching = &searching;
t_data.data = color_data;
t_data.data_len = compress_data_length;
t_data.uncom_data_len = length;
t_data.width = be32toh(w.width_int);
t_data.color_range = color_range;
t_data.win_size = sliding_window;
pthread_t tid;
t_data.thread_id = tid;
for(int i = 0; i < 28; i++) {
pthread_create(&tid, NULL, random_data_change_thread_call, &t_data);
}
pthread_join(tid, NULL);
full_data[0] = 0x49;
full_data[1] = 0x44;
full_data[2] = 0x41;
full_data[3] = 0x54;
for(int i = 0; i < data_array_size; i++) {
full_data[i+4] = check_data_buff[i];
}
unsigned int temp_crc = crc(full_data, data_array_size);
printf("%08X\n", temp_crc);
if ((temp_crc >> (8*3)) == 10 ) {
printf("RAND Key: %zu\n", random_num);
printf("Found in %zu rounds!\n", rounds);
memcpy(color_data, temp_color_data, length);
searching = 0;
}
free(check_data_buff);
}
} while(searching == 1);
free(temp_color_data);
return;
}
@@ -200,7 +275,7 @@ int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, c
exit(EXIT_FAILURE);
}
size_t size = 1;
size_t size = 8;
size_t idat_byte_length = 0;
unsigned char* idat_data = calloc(size, sizeof(unsigned char));
for(size_t i = 0; i < total_idat(addr); i++) {
@@ -229,7 +304,7 @@ int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, c
// Start data testing
random_data_change(uncom_data_buff, png_file->png_start_data.file_width, uncom_data_size);
return 0;
//return 0;
// Compress Data
unsigned char *com_data_buff;
size_t com_data_size = 0;
@@ -244,7 +319,7 @@ int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, c
}
// Build PNG File
//build_png_file(png_file, out_file_name);
build_png_file(png_file, out_file_name);
// Freeing used memory
free(uncom_data_buff);

12
include/crc_util.h
View File

@@ -33,6 +33,18 @@ struct PNG_FILE_STRUCT {
struct PNG_IDAT_FILE_STRUCT png_idat_data;
};
struct EMBED_THREAD_STRUCT {
pthread_mutex_t *mutex_lock;
pthread_t thread_id;
int *searching;
unsigned char *data;
unsigned int data_len;
size_t uncom_data_len;
int width;
int color_range;
unsigned int win_size;
};
extern const long png_signature[8];
unsigned long check_header_length(unsigned char *addr, long offset);