Spencer/PNG_CC
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Pin
2021-10-05 00:32:06 -04:00
parent 6cae1ecc58
commit 74a37cd640
3 changed files with 146 additions and 57 deletions
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154
crc.c
View File

@@ -1,38 +1,81 @@
#include <stdio.h>
#include <zlib.h>
#include <assert.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sodium.h>
#include "crc_util.h"
#include "CRCLib.h"
#include "crc.h"
const long png_signature[8] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
#define CHUNK 8
const long idat_signature = 1229209940;
const long iend_signature = 1229278788;
const int working = 1;
int check_file_header(char *addr) {
int signature_match = 0;
for( int i = 0; i < 8; i++ ) {
if (addr[i] != png_signature[i]) {
signature_match = 1;
}
int zlib_compress_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");
if(data_stream == NULL) {
perror("F MEM OPEN");
}
printf("Sig Match: %d\n", signature_match);
return signature_match;
}
int check_header_length(unsigned char *addr, long offset) {
unsigned int res = 0;
for( int i = 0; i < 4; i++ ) {
res |= addr[offset+i];
if (i < 3) {
res <<= 8;
}
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = 0;
strm.next_in = Z_NULL;
ret = inflateInit(&strm);
if(ret != Z_OK) {
return ret;
}
return res;
do {
strm.avail_in = fread(in, 1, CHUNK, data_stream);
if(ferror(data_stream)) {
(void)inflateEnd(&strm);
return Z_ERRNO;
}
if(strm.avail_in == 0) {
break;
}
strm.next_in = in;
do {
strm.avail_out = CHUNK;
strm.next_out = out;
ret = inflate(&strm, Z_NO_FLUSH);
assert(ret != Z_STREAM_ERROR);
switch(ret) {
case Z_NEED_DICT:
ret = Z_DATA_ERROR;
case Z_DATA_ERROR:
case Z_MEM_ERROR:
(void)inflateEnd(&strm);
printf("Error: %d\n", ret);
printf("MSG: %s\n", (char*)strm.msg);
return ret;
}
have = CHUNK - strm.avail_out;
fwrite(out, 1, have, of);
} while(strm.avail_out == 0);
} while(ret != Z_STREAM_END);
(void)inflateEnd(&strm);
printf("String: %s\n", out);
return 1;
}
unsigned long first_idat(unsigned char *addr) {
@@ -83,7 +126,7 @@ int update_file_crc(unsigned char *addr, unsigned long offset , unsigned int crc
}
int change_idat_content(unsigned char *addr, char *message, int accuracy, unsigned long offset) {
printf("Starting IDAT Tranform\n");
//printf("Starting IDAT Tranform\n");
if(accuracy > 4) {
printf("Warning, accuracy cannot be larger than 4");
return EXIT_FAILURE;
@@ -97,20 +140,24 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
}
int idat_length = check_header_length(addr, offset);
printf("IDAT: %d\n", idat_length);
printf("IDAT Length: %d\n", idat_length);
int prop_found = 0;
long size = 1;
long rounds = 0;
unsigned int* idat_data = malloc(size * sizeof(unsigned int));
for(int i = 0; i < idat_length; i++) {
size_t idat_byte_length = 0;
unsigned char* idat_data = calloc(size, sizeof(unsigned char));
for(size_t i = 0; i <= idat_length; i++) {
if(i == size) {
size *= 2;
idat_data = reallocarray(idat_data, size, sizeof(unsigned char));
}
idat_data[i] = addr[i+offset+8];
size++;
int* new_idat_data = realloc(idat_data, size * sizeof(unsigned int));
idat_byte_length = i;
}
unsigned int temp_idat_data[size];
unsigned char temp_idat_data[idat_byte_length];
while(prop_found == 0) {
for(int i = 0; i < idat_length; i++) {
for(int i = 0; i <= idat_length; i++) {
temp_idat_data[i] = idat_data[i];
}
int r = randombytes_uniform(5) + 1;
@@ -122,7 +169,7 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
for(int i = 0; i < 4; i++) {
crc_check[i] = idat_header[i];
}
for(int i = 0; i < size; 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);
@@ -131,10 +178,11 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
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);
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]);
//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);
prop_found = 1;
@@ -144,39 +192,31 @@ int change_idat_content(unsigned char *addr, char *message, int accuracy, unsign
return 0;
}
int create_cc_file(unsigned char *addr, unsigned long file_length) {
FILE *fp;
fp = fopen("png2.png", "w");
if(fp == NULL) {
return EXIT_FAILURE;
}
for(int i = 0; i < file_length; i++){
fputc(addr[i], fp);
}
fclose(fp);
}
int main() {
FILE *fp;
unsigned int c;
unsigned char* myArray = calloc(1000, sizeof(unsigned char));
unsigned long i = 0;
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");
while((c = fgetc(fp)) != EOF) {
myArray[i] = c;
i++;
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;
}
fclose(fp);
offset = first_idat(myArray);
change_idat_content(myArray, message, 2, offset);
create_cc_file(myArray, i);
//int crcnum = crc(myArray, 19);
//printf("%08X\n", crcnum);
offset = first_idat(file_data);
change_idat_content(file_data, message, 1, offset);
//create_cc_file(file_data, i);
}

43
crc_util.c Normal file
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@@ -0,0 +1,43 @@
#include <stdio.h>
#include <stdlib.h>
#include "crc_util.h"
const long png_signature[8] = { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
int check_header_length(unsigned char *addr, long offset) {
unsigned int res = 0;
for( int i = 0; i < 4; i++ ) {
res |= addr[offset+i];
if (i < 3) {
res <<= 8;
}
}
return res;
}
int check_file_header(char *addr) {
int signature_match = 0;
for( int i = 0; i < 8; i++ ) {
if (addr[i] != png_signature[i]) {
signature_match = 1;
}
}
printf("Sig Match: %d\n", signature_match);
return signature_match;
}
int create_cc_file(unsigned char *addr, unsigned long file_length) {
FILE *fp;
fp = fopen("png2.png", "w");
if(fp == NULL) {
return EXIT_FAILURE;
}
for(int i = 0; i < file_length; i++){
fputc(addr[i], fp);
}
fclose(fp);
}

6
crc_util.h Normal file
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@@ -0,0 +1,6 @@
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);