Spencer/PNG_CC
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2021-10-07 00:08:52 -04:00
parent 74a37cd640
commit 4976751876
3 changed files with 88 additions and 47 deletions
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114
crc.c
View File

@@ -14,18 +14,16 @@
const long idat_signature = 1229209940;
const long iend_signature = 1229278788;
int zlib_compress_data(unsigned char *data_chunk, size_t file_length) {
FILE *zlib_decompress_data(unsigned char *data_chunk, size_t file_length) {
int ret;
unsigned int have;
z_stream strm;
unsigned char out[CHUNK];
unsigned char in[CHUNK];
printf("Len: %zu\n", file_length);
errno=0;
FILE *data_stream = fmemopen(data_chunk, file_length-1, "r");
FILE *of = fopen("wow.wow", "w");
FILE *data_stream = fmemopen(data_chunk, file_length, "r");
FILE *of = open_memstream(NULL, NULL);
if(data_stream == NULL) {
perror("F MEM OPEN");
}
@@ -37,20 +35,20 @@ int zlib_compress_data(unsigned char *data_chunk, size_t file_length) {
strm.next_in = Z_NULL;
ret = inflateInit(&strm);
if(ret != Z_OK) {
return ret;
return NULL;
}
do {
strm.avail_in = fread(in, 1, CHUNK, data_stream);
if(ferror(data_stream)) {
(void)inflateEnd(&strm);
return Z_ERRNO;
return NULL;
}
if(strm.avail_in == 0) {
break;
}
strm.next_in = in;
do {
strm.avail_out = CHUNK;
strm.next_out = out;
@@ -64,7 +62,7 @@ int zlib_compress_data(unsigned char *data_chunk, size_t file_length) {
(void)inflateEnd(&strm);
printf("Error: %d\n", ret);
printf("MSG: %s\n", (char*)strm.msg);
return ret;
return NULL;
}
have = CHUNK - strm.avail_out;
fwrite(out, 1, have, of);
@@ -73,9 +71,8 @@ int zlib_compress_data(unsigned char *data_chunk, size_t file_length) {
(void)inflateEnd(&strm);
printf("String: %s\n", out);
return 1;
return of;
}
unsigned long first_idat(unsigned char *addr) {
@@ -125,6 +122,31 @@ int update_file_crc(unsigned char *addr, unsigned long offset , unsigned int crc
}
}
void random_data_change(unsigned char *color_data, int width, int length) {
int searching = 1;
width = 16;
int color_range = 3;
unsigned char temp_color_data[length];
memcpy(temp_color_data, color_data, length);
do {
// Creating temporary data set
memcpy(temp_color_data, color_data, length);
// Generating random byte to change
int random_num = randombytes_uniform(length);
// Checking for index break
if(random_num % ((width * color_range) + 1)) {
if(color_data[random_num] == 255) {
//temp_color_data[random_num]--;
} else {
//temp_color_data[random_num]++;
}
}
} while(searching == 1);
}
int change_idat_content(unsigned char *addr, char *message, int accuracy, unsigned long offset) {
//printf("Starting IDAT Tranform\n");
if(accuracy > 4) {
@@ -160,33 +182,41 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
for(int i = 0; i <= idat_length; i++) {
temp_idat_data[i] = idat_data[i];
}
int r = randombytes_uniform(5) + 1;
int j = randombytes_uniform(idat_length);
//int r = randombytes_uniform(5) + 1;
//int j = randombytes_uniform(idat_length);
temp_idat_data[j] = (temp_idat_data[j] + r) % 255;
unsigned char crc_check[size+4];
unsigned int idat_header[] = { 0x49, 0x44, 0x41, 0x54 };
for(int i = 0; i < 4; i++) {
crc_check[i] = idat_header[i];
}
for(int i = 0; i < idat_byte_length; i++) {
crc_check[i] = temp_idat_data[i+4];
}
unsigned int crcnum = crc(crc_check, idat_length);
//printf("New CRC: %08X\n", crcnum);
//printf("Test: %X\n", crcnum >> (8*3));
unsigned int checked_crc = crcnum >> (8*3);
rounds++;
if(checked_crc == 61) {
zlib_compress_data(temp_idat_data, idat_byte_length);
printf("Found %d in %d rounds\n", checked_crc ,rounds);
//temp_idat_data[j] = (temp_idat_data[j] + r) % 255;
//unsigned char crc_check[size+4];
//unsigned int idat_header[] = { 0x49, 0x44, 0x41, 0x54 };
//for(int i = 0; i < 4; i++) {
// crc_check[i] = idat_header[i];
//}
//for(int i = 0; i < idat_byte_length; i++) {
// crc_check[i] = temp_idat_data[i+4];
//}
//unsigned int crcnum = crc(crc_check, idat_length);
//unsigned int checked_crc = crcnum >> (8*3);
//rounds++;
//if(checked_crc == 61) {
// Setting TEMP IDAT DATA BACK TO ORIGINAL
// TO STOP DECOMPRESSION CORRUPTION
//temp_idat_data[j] = addr[offset+8+j];
// Decompressing Data
FILE *uncom_data = zlib_decompress_data(temp_idat_data, idat_byte_length);
size_t uncom_data_size = 0;
unsigned char *uncom_data_array = file_to_char_array(uncom_data, &uncom_data_size);
printf("UnCom: %zu\n", uncom_data_size);
random_data_change(uncom_data_array, 16, uncom_data_size);
//printf("Found %d in %d rounds\n", checked_crc ,rounds);
//printf("Full CRC: %08X\n", crcnum);
//printf("Original: %02X\n", idat_data[j]);
//printf("Change offset: %d to hex: %02X\n", j, temp_idat_data[j]);
addr[offset+8+j] = temp_idat_data[j];
update_file_crc(addr, offset, crcnum);
//addr[offset+8+j] = temp_idat_data[j];
//update_file_crc(addr, offset, crcnum);
prop_found = 1;
}
//}
}
return 0;
@@ -194,28 +224,18 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
int main() {
FILE *fp;
unsigned int c;
unsigned long file_data_cap = 8;
unsigned char* file_data = calloc(file_data_cap, sizeof(unsigned char));
size_t i = 0;
unsigned long offset = 0;
char message[1];
if(sodium_init() == -1) {
return EXIT_FAILURE;
}
fp = fopen("./1.png", "rt");
for(size_t i = 0;(c = fgetc(fp)) != EOF; i++) {
if(i == file_data_cap) {
file_data_cap *= 2;
file_data = reallocarray(file_data, file_data_cap, sizeof(unsigned char));
if(file_data == NULL) {
perror("FAILED ARRAY RESIZE");
return EXIT_FAILURE;
}
}
file_data[i] = c;
}
unsigned char *file_data = file_to_char_array(fp, &i);
fclose(fp);
offset = first_idat(file_data);
change_idat_content(file_data, message, 1, offset);
//create_cc_file(file_data, i);

20
crc_util.c
View File

@@ -41,3 +41,23 @@ int create_cc_file(unsigned char *addr, unsigned long file_length) {
}
fclose(fp);
}
unsigned char* file_to_char_array(FILE *in_file, size_t* size) {
unsigned int c;
unsigned long file_data_cap = 8;
unsigned char* file_data = calloc(file_data_cap, sizeof(unsigned char));
for(size_t i = 0;(c = fgetc(in_file)) != EOF; i++) {
if(i == file_data_cap) {
file_data_cap *= 2;
file_data = reallocarray(file_data, file_data_cap, sizeof(unsigned char));
if(file_data == NULL) {
perror("FAILED ARRAY RESIZE");
return NULL;
}
}
file_data[i] = c;
*size += 1;
}
return file_data;
}

1
crc_util.h
View File

@@ -4,3 +4,4 @@ extern const long png_signature[8];
int check_header_length(unsigned char *addr, long offset);
int check_file_header(char *addr);
int create_cc_file(unsigned char *addr, unsigned long file_length);
unsigned char* file_to_char_array(FILE *in_file, size_t* size);