diff options
Diffstat (limited to 'cmd/crc.c')
-rw-r--r-- | cmd/crc.c | 304 |
1 files changed, 0 insertions, 304 deletions
diff --git a/cmd/crc.c b/cmd/crc.c deleted file mode 100644 index b872e6c..0000000 --- a/cmd/crc.c +++ /dev/null @@ -1,304 +0,0 @@ -#pragma GCC optimize("Ofast") - -#include <endian.h> -#include <stdio.h> -#include <unistd.h> -#include <string.h> -#include <stdlib.h> -#include <sodium.h> -#include <getopt.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]; - - 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); - memcpy(color_data, temp_color_data, length); - searching = 0; - } - free(check_data_buff); - } - - } while(searching == 1); -} - -void build_png_file(struct PNG_FILE_STRUCT *png_file, char *out_file_name) { - FILE *fp; - - fp = fopen(out_file_name, "w"); - - union{ - unsigned char data[sizeof(struct PNG_START_FILE_STRUCT)]; - struct PNG_START_FILE_STRUCT png_data; - }start_data; - - start_data.png_data = png_file->png_start_data; - - // IHDR Data - for(int i = 0; i < sizeof(start_data.data); i++) { - fputc(start_data.data[i], fp); - } - // IDAT Data - for(int i = 0; i < 4; i++) { - fputc(png_file->png_idat_data.idat_length[i], fp); - } - for(int i = 0; i < 4; i++) { - fputc(png_file->png_idat_data.idat_header[i], fp); - } - for(int i = 0; i < be32toh(png_file->png_idat_data.idat_data_length); i++) { - fputc(png_file->png_idat_data.idat_data[i], fp); - } - // Generating CRC - unsigned char full_data[be32toh(png_file->png_idat_data.idat_data_length)+4]; - for(int i = 0; i < 4; i++) { - full_data[i] = png_file->png_idat_data.idat_header[i]; - } - for(int i = 0; i < be32toh(png_file->png_idat_data.idat_data_length); i++) { - full_data[i+4] = png_file->png_idat_data.idat_data[i]; - } - - unsigned int int_crc = crc(full_data, be32toh(png_file->png_idat_data.idat_data_length)); - unsigned char new_crc[4]; - - for(int i = 0; i < 4; i++) { - new_crc[i] = int_crc >> (8*(3-i)) & 0xFF; - fputc(new_crc[i], fp); - } - // IEND Data - unsigned char IEND_DATA[12] = { 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44, 0xAE, 0x42, 0x60, 0x82}; - for(int i = 0; i < 12; i++) { - fputc(IEND_DATA[i], fp); - } - fclose(fp); -} - -int change_idat_content(unsigned char *addr, struct PNG_FILE_STRUCT *png_file, char *message, int accuracy, unsigned long offset, char *out_file_name) { - 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((char*)message)) { - printf("Warning, message exceeds IDAT amount\n"); - exit(EXIT_FAILURE); - } - - int idat_length = check_header_length(addr, offset); - printf("IDAT Length: %d\n", idat_length); - - long size = 1; - 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]; - 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); - - // Compress Data - unsigned char *com_data_buff; - size_t com_data_size = 0; - zlib_compress_data(uncom_data_buff, uncom_data_size, &com_data_buff, &com_data_size); - - png_file->png_idat_data.idat_data = calloc(com_data_size, sizeof(unsigned char)); - - png_file->png_idat_data.idat_data_length = be32toh(com_data_size); - - for(size_t i = 0; i < com_data_size; i++) { - png_file->png_idat_data.idat_data[i] = com_data_buff[i]; - } - - // Build PNG File - build_png_file(png_file, out_file_name); - - free(uncom_data_buff); - free(com_data_buff); - free(idat_data); - free(png_file->png_idat_data.idat_data); - - return 0; -} - -// This is where it all starts -int main(int argc, char **argv) { - FILE *fp; - size_t i = 0; - unsigned long offset = 0; - struct PNG_FILE_STRUCT png_file_data; - char *in_file_name = NULL; - char *out_file_name = NULL; - char *message = NULL; - - static const struct option long_options[] = { - {"help", no_argument, NULL, 'h'}, - {"file", required_argument, NULL, 'f'}, - {"outfile", required_argument, NULL, 'o'}, - {"message", required_argument, NULL, 'm'}, - {0, 0, 0, 0} - }; - - const char* usage = - "Usage: crc [options]\n" - " -h, --help Shows help message\n" - " -f, --file Denotes input file\n" - " -o, --outfile Denotes output file\n" - " -m, --message Encoded message\n" - "\n"; - - int c; - while (1) { - int option_index = 0; - c = getopt_long(argc, argv, "hf:o:m:", long_options ,&option_index); - if(c == -1) { - break; - } - switch(c) { - case 'h': - printf("%s", usage); - exit(EXIT_SUCCESS); - case 'f': - in_file_name = optarg; - break; - case 'o': - out_file_name = optarg; - break; - case 'm': - message = optarg; - break; - } - } - - if(in_file_name == NULL) { - printf("Input file required!\n"); - exit(EXIT_FAILURE); - } else if(out_file_name == NULL) { - printf("Output file required!\n"); - exit(EXIT_FAILURE); - } else if(message == NULL) { - printf("Message required!\n"); - exit(EXIT_FAILURE); - } - - if(sodium_init() == -1) { - return EXIT_FAILURE; - } - - fp = fopen(in_file_name, "rt"); - if (fp == NULL) { - printf("File error\n"); - exit(EXIT_FAILURE); - } - - unsigned char *file_data = file_to_char_array(fp, &i); - fclose(fp); - - populate_start_png(file_data, &png_file_data.png_start_data); - - offset = first_idat(file_data); - - populate_idat_png(file_data, &png_file_data.png_idat_data, offset); - - change_idat_content(file_data, &png_file_data, message, 1, offset, out_file_name); - - free(file_data); -} |