/* * headstripper * File: main.c * (c) 2019 Jonas Gunz himself(at)jonasgunz.de * * License: MIT * */ #include #include #include #include #include #define _VERSION 0 #define _SUBVERSION 2 #ifdef _DEBUG #warning "Compiling in DEBUG mode" #endif #ifdef _DEBUG #define DEBUG_PRINTF( ... ) { printf ( __VA_ARGS__ ); } #else #define DEBUG_PRINTF( ... ) { } #endif //Magic values #define _MAGIC_JPG 0xD8FF //JPG Magic Value #define _MAGIC_PNG 0x5089 #define _MAGIC_PNG_FULL 0x0A1A0A0D474E5089 //89 50 4E 47 0D 0A 1A 0A #define _MAGIC_TFF 0x2A00 //TIFF Magic Value //JPG #define _JPG_SOI 0xFFD8 #define _JPG_APP0 0xFFE0 #define _JPG_CX 0xFFC0 #define _JPG_DQT 0xFFDB #define _JPG_DRI 0xFFDD #define _JPG_SOS 0xFFDA //Start of image data #define _JPG_EOI 0xFFD9 //End of image //Stuff to ignore #define _JPG_EXIF 0xFFE1 //EXIF #define _JPG_COM 0xFFFE //Comments #define _JPG_COPY 0xFFEE //Copyright notice //PNG //Essential chunks #define _PNG_IHDR 0x52444849 #define _PNG_IDAT 0x54414449 #define _PNG_IEND 0x444E4549 #define _PNG_PLTE 0x45544C50 //Aux chunks #define _PNG_tRNS 0x534e5274 #define _PNG_gAMA 0x414d4167 #define _PNG_cHRM 0x4d524863 #define _PNG_sRGB 0x42475273 #define _PNG_iCCP 0x50434369 #define _PNG_sBIT 0x54494273 int strip_jpg(char *_filename); int strip_png(char *_filename); int strip_tiff(char *_filename); //String combine char* strcmb(char *_str1, char *_str2); int main(int argc, char* argv[]) { FILE *image; uint16_t magic; if(argc < 2) { printf("Wrong number of arguments!\nUsage: %s \n", argv[0]); exit(1); } printf("headstripper v%i.%i\n", _VERSION, _SUBVERSION); DEBUG_PRINTF("==DEBUG BUILD==\n"); for(unsigned int cntr = 1; cntr < argc; cntr++) { char *filename = argv[cntr]; //Read magic val image = fopen(filename, "rb"); if(!image) { printf("Unable to open \"%s\": %i\n", argv[1], errno); exit(2); } fread(&magic, 2, 1, image); fclose(image); switch(magic) { case _MAGIC_JPG: printf("%s: JPG\n", filename); strip_jpg(filename); break; case _MAGIC_PNG: printf("%s: PNG\n", filename); strip_png(filename); break; case _MAGIC_TFF: printf("%s: TIFF\n", filename); strip_tiff(filename); break; default: printf("%s: Bad/Unknown Filetype\n", filename); exit(1); break; }; } return 0; } //This function assumes a valid JFIF container file! No file validation is performed int strip_jpg(char *_filename) { FILE *in; FILE *out; char *f__outfile = strcmb("strip.", _filename); in = fopen(_filename, "rb"); out = fopen(f__outfile, "wb"); //Feelin' lazy. Might add debug later, idk if(!in) return 1; if(!out) { printf("Unable to open for writing %s: %i\n", f__outfile, errno); return 1; } uint16_t magic_num = 0xD8FF; fwrite(&magic_num, 1, 2, out); uint16_t segment = 0xFFD8; while(1) { unsigned char c = fgetc(in); segment = (segment << 8) + (c & 0x00FF); if(segment == _JPG_APP0 || segment == _JPG_DQT || segment == _JPG_DRI || (segment & 0xFFF0) == (_JPG_CX & 0xFFF0)) { unsigned char l1 = fgetc(in); unsigned char l2 = fgetc(in); uint16_t seg_len = (( l1 << 8 ) & 0xff00) + l2; DEBUG_PRINTF("Segment %X, size %uB @%liB\n", segment, seg_len, ftell(in)); char *f__buffer = malloc(seg_len - 2); fread(f__buffer, 1, seg_len - 2, in); fputc(segment >> 8, out); fputc(segment, out); fputc(seg_len >> 8, out); fputc(seg_len, out); fwrite(f__buffer, 1, seg_len - 2, out); free(f__buffer); } else if(segment == _JPG_EXIF || segment == _JPG_COM || segment == _JPG_COPY ) { unsigned char l1 = fgetc(in); unsigned char l2 = fgetc(in); uint16_t seg_len = (( l1 << 8 ) & 0xff00) + l2; DEBUG_PRINTF("Ignoring segment %X, size %uB @%liB\n", segment, seg_len, ftell(in)); char *f__buffer = malloc(seg_len - 2); fread(f__buffer, 1, seg_len - 2, in); free(f__buffer); } else if(segment == _JPG_SOS) { DEBUG_PRINTF("SOS @%li\n", ftell(in)); uint16_t endseg = _JPG_SOS; fputc(segment >> 8, out); fputc(segment, out); while(1) { unsigned char cc = fgetc(in); endseg = (endseg << 8) + (cc & 0x00FF); if(endseg == _JPG_EOI) break; else fputc(cc, out); } DEBUG_PRINTF("ENDSEG @%li\n", ftell(in)); fwrite(&endseg, 1, 2, out); break; } if(feof(in)) { DEBUG_PRINTF("Reached EOF before ENDSEG @%li\n", ftell(in)); break; } } fclose(in); fclose(out); free(f__outfile); return 0; } int strip_png(char *_filename) { FILE *in; FILE *out; char *f__outfile = strcmb("strip.", _filename); in = fopen(_filename, "rb"); out = fopen(f__outfile, "wb"); if(!in) return 1; if(!out) { printf("Unable to open for writing %s: %i\n", f__outfile, errno); return 1; } uint64_t magic_num = _MAGIC_PNG_FULL; fwrite(&magic_num, 1, 8, out); uint32_t read_buff = 0; uint32_t chunk_len = 0; while(1) { //Heavy shifting chunk_len = ((chunk_len << 8) & 0xFFFFFF00) + ( read_buff & 0x000000FF ); unsigned char c = fgetc(in); read_buff = ((read_buff >> 8) & 0x00FFFFFF) + (((uint32_t)c << 24) & 0xFF000000); //Whitelist only important PNG chunks if( read_buff == _PNG_IHDR || read_buff == _PNG_IDAT || read_buff == _PNG_PLTE || // read_buff == _PNG_sBIT || // read_buff == _PNG_tRNS || // read_buff == _PNG_gAMA || // read_buff == _PNG_cHRM || // read_buff == _PNG_sRGB || // read_buff == _PNG_iCCP || // read_buff == _PNG_sRGB || read_buff == _PNG_IEND ) { char *f__buffer = malloc( chunk_len ); uint32_t crc; #ifdef _DEBUG //*Ghetto music plays* uint64_t chunk_str = 0; chunk_str += read_buff; printf("CHUNK %s SIZE %uB @%li\n", (char*)(&chunk_str), chunk_len, ftell(in) ); #endif fread(f__buffer, 1, chunk_len, in); fread(&crc, 1, 4, in); //Flip chunk_len... uint32_t lencpy = chunk_len; for (int i = 0; i < 4; i++) { fputc(lencpy >> 24, out); lencpy <<= 8; } fwrite(&read_buff, 1, sizeof(read_buff), out); fwrite(f__buffer, 1, chunk_len, out); fwrite(&crc, 1, 4, out); free(f__buffer); if(read_buff == _PNG_IEND) break; } if(feof(in)) { DEBUG_PRINTF("Reached EOF before IEND @%li\n", ftell(in) ); break; } } fclose(in); fclose(out); free(f__outfile); return 1; } int strip_tiff(char *_filename) { printf("TIFF Unimplemented.\n"); return 1; } char* strcmb(char *_str1, char *_str2) { char *f__return = malloc(strlen(_str1) + strlen(_str2) + 1); strcpy( f__return, _str1); strcpy(&f__return[ strlen(_str1) ], _str2); return f__return; }