wip

Signed-off-by: Pin <wf6DJd8a3xSSCZbn@protonmail.com>

cmd/crc.c

@@ -0,0 +1,190 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sodium.h>
+#include "crc_util.h"
+#include "CRCLib.h"
+#include "crc.h"
+#include "compress_util.h"
+
+const long idat_signature = 1229209940;
+const long iend_signature = 1229278788;
+
+unsigned long first_idat(unsigned char *addr) {
+	int idat_found = 0;
+	unsigned long offset = 8;
+	int jump_offset = 0;
+	int header_type = 0;
+	while(idat_found == 0) {
+		jump_offset = check_header_length(addr, offset);
+		header_type = check_header_length(addr, offset+4);
+		if(header_type == idat_signature) {
+			idat_found = 1;
+		} else {
+			offset = offset + jump_offset + 12;
+		}
+	}
+	return offset;
+}
+
+int total_idat(unsigned char *addr) {
+	int iend_found = 0;
+	int found_idat = 0;
+	unsigned long offset = 8;
+	int jump_offset = 0;
+	int header_type = 0;
+	while(iend_found == 0) {
+		jump_offset = check_header_length(addr, offset);
+		header_type = check_header_length(addr, offset+4);
+		if(header_type == iend_signature) {
+			iend_found = 1;
+		} else {
+			if(header_type == idat_signature) {
+				found_idat++;
+			}
+			offset = offset + jump_offset + 12;
+		}
+	}
+	return found_idat;
+}
+
+int update_file_crc(unsigned char *addr, unsigned long offset , unsigned int crc_num) {
+	int startCRC = 8 + offset + check_header_length(addr, offset);
+	unsigned char new_crc;
+	for(int i = 0; i < 4; i++) {
+		new_crc = crc_num >> (8*(3-i)) & 0xFF;
+		addr[startCRC+i] = new_crc;
+	}
+	return 0;
+}
+
+void random_data_change(unsigned char *color_data, int width, int length) {
+	int searching = 1;
+	size_t rounds = 0;
+	width = 16;
+	int color_range = 3;	
+	unsigned char temp_color_data[length];
+
+	memcpy(temp_color_data, color_data, length);
+
+	do {
+		rounds++;
+		// 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]++;
+			}
+			unsigned char *check_data_buff = NULL;
+			size_t check_data_length = 0;
+			zlib_compress_data(temp_color_data, length, &check_data_buff, &check_data_length);
+
+			unsigned char full_data[check_data_length+4];
+			full_data[0] = 0x49;
+			full_data[1] = 0x44;
+			full_data[2] = 0x41;
+			full_data[3] = 0x54;
+			for(int i = 0; i < check_data_length; i++) {
+				full_data[i+4] = check_data_buff[i];
+			}
+			unsigned int temp_crc = crc(full_data, check_data_length);
+			if ((temp_crc >> (8*3)) == 10 ) {
+				printf("Found in %zu rounds!\n", rounds);
+				searching = 0;
+			}
+			free(check_data_buff);
+		}
+	
+	} while(searching == 1);
+}
+
+int change_idat_content(unsigned char *addr, unsigned char *message, int accuracy, unsigned long offset) {
+	//printf("Starting IDAT Tranform\n");
+	if(accuracy > 4) {
+		printf("Warning, accuracy cannot be larger than 4");
+		return EXIT_FAILURE;
+	}
+	if(accuracy > 2) {
+		printf("Notice, this could take a long time...");
+	}
+	if(total_idat(addr) < strlen(message)) {
+		printf("Warning, message exceeds IDAT amount");
+		return EXIT_FAILURE;
+	}
+
+	int idat_length = check_header_length(addr, offset);
+	printf("IDAT Length: %d\n", idat_length);
+
+	int prop_found = 0;
+	long size = 1;
+	long rounds = 0;
+	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];
+		idat_byte_length = i;
+	}
+	unsigned char temp_idat_data[idat_byte_length];
+	while(prop_found == 0) {
+		for(int i = 0; i <= idat_length; i++) {
+			temp_idat_data[i] = idat_data[i];
+		}
+		// Decompressing Data
+		unsigned char *uncom_data_buff = NULL;
+		size_t uncom_data_size = 0;
+		zlib_decompress_data(temp_idat_data, idat_byte_length, &uncom_data_buff, &uncom_data_size);
+
+		random_data_change(uncom_data_buff, 16, uncom_data_size);
+
+		free(uncom_data_buff);
+
+		//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);
+		prop_found = 1;
+	}
+
+	free(idat_data);
+
+	return 0;
+}
+
+// This is where it all starts
+int main() {
+	FILE *fp;
+	size_t i = 0;
+	unsigned long offset = 0;
+	unsigned char *message = malloc(sizeof(char));
+	message[0] = '\0';
+
+	if(sodium_init() == -1) {
+		return EXIT_FAILURE;
+	}
+
+	fp = fopen("./1.png", "rt");
+	if (fp == NULL) {
+		return EXIT_FAILURE;
+	}
+
+	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);
+	free(file_data);
+	free(message);
+	//create_cc_file(file_data, i);
+}