outguess.patch

diff --git a/src/jpg.c b/src/jpg.c
index 173deaa..24dc100 100644
--- a/src/jpg.c
+++ b/src/jpg.c
@@ -49,6 +49,7 @@
 #include "jpg.h"
 
 #include "jpeg-6b-steg/jmorecfg.h"
+#include "jpeg-6b-steg/jerror.h"
 
 void jpeg_dummy_dest (j_compress_ptr cinfo);
 
@@ -611,6 +612,44 @@ write_JPEG_file (FILE *outfile, image *image)
  * will go away automatically when the JPEG object is cleaned up.
  */
 
+// From Carl Staelin, https://stackoverflow.com/questions/5280756/libjpeg-ver-6b-jpeg-stdio-src-vs-jpeg-mem-src
+
+/* Read JPEG image from a memory segment */
+static void init_source (j_decompress_ptr cinfo) {}
+static boolean fill_input_buffer (j_decompress_ptr cinfo)
+{
+    ERREXIT(cinfo, JERR_INPUT_EMPTY);
+return TRUE;
+}
+static void skip_input_data (j_decompress_ptr cinfo, long num_bytes)
+{
+    struct jpeg_source_mgr* src = (struct jpeg_source_mgr*) cinfo->src;
+
+    if (num_bytes > 0) {
+        src->next_input_byte += (size_t) num_bytes;
+        src->bytes_in_buffer -= (size_t) num_bytes;
+    }
+}
+static void term_source (j_decompress_ptr cinfo) {}
+static void jpeg_mem_src (j_decompress_ptr cinfo, void* buffer, long nbytes)
+{
+    struct jpeg_source_mgr* src;
+
+    if (cinfo->src == NULL) {   /* first time for this JPEG object? */
+        cinfo->src = (struct jpeg_source_mgr *)
+            (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+            sizeof(struct jpeg_source_mgr));
+    }
+
+    src = (struct jpeg_source_mgr*) cinfo->src;
+    src->init_source = init_source;
+    src->fill_input_buffer = fill_input_buffer;
+    src->skip_input_data = skip_input_data;
+    src->resync_to_restart = jpeg_resync_to_restart; /* use default method */
+    src->term_source = term_source;
+    src->bytes_in_buffer = nbytes;
+    src->next_input_byte = (JOCTET*)buffer;
+}
 
 /*
  * Sample routine for JPEG decompression.  We assume that the source file name
@@ -619,7 +658,7 @@ write_JPEG_file (FILE *outfile, image *image)
 
 
 image *
-read_JPEG_file (FILE *infile)
+read_JPEG_file (uint8_t* file_content, size_t file_size)
 {
   /* This struct contains the JPEG decompression parameters and pointers to
    * working space (which is allocated as needed by the JPEG library).
@@ -649,7 +688,7 @@ read_JPEG_file (FILE *infile)
 
   /* Step 2: specify data source (eg, a file) */
 
-  jpeg_stdio_src(&cinfo, infile);
+  jpeg_mem_src(&cinfo, file_content, file_size);
 
   /* Step 3: read file parameters with jpeg_read_header() */
 
diff --git a/src/jpg.h b/src/jpg.h
index b099643..73ed2df 100644
--- a/src/jpg.h
+++ b/src/jpg.h
@@ -40,7 +40,7 @@ void init_JPEG_handler(char *parameters);
 int preserve_jpg(bitmap *, int);
 
 void write_JPEG_file (FILE *outfile, image *image);
-image *read_JPEG_file (FILE *infile);
+image *read_JPEG_file (uint8_t*, size_t);
 
 void bitmap_from_jpg(bitmap *bitmap, image *image, int flags);
 void bitmap_to_jpg(image *image, bitmap *bitmap, int flags);
diff --git a/src/outguess.c b/src/outguess.c
index 44f12cd..65e421f 100644
--- a/src/outguess.c
+++ b/src/outguess.c
@@ -45,6 +45,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <emscripten/emscripten.h>
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/mman.h>
@@ -780,31 +782,14 @@ munmap_file(u_char *data, int len)
 #endif /* HAVE_MMAP */
 }
 
-int
-main(int argc, char **argv)
+struct return_information {
+  uint8_t* message;
+  size_t message_length;
+};
+
+struct return_information* EMSCRIPTEN_KEEPALIVE
+outguess_main(char* image_filename, uint8_t* image_data, size_t image_data_size, char* key, int use_error_correction)
 {
-	char version[] = "OutGuess 0.4 Universal Stego 1999-2021 Niels Provos and others";
-	char usage[] = "%s\n\n%s [options] [<input file> [<output file>]]\n"
-		"\t-h           print this usage help text and exit\n"
-		"\t-[sS] <n>    iteration start, capital letter for 2nd dataset\n"
-		"\t-[iI] <n>    iteration limit\n"
-		"\t-[kK] <key>  key\n"
-		"\t-[dD] <name> filename of dataset\n"
-		"\t-[eE]        use error correcting encoding\n"
-		"\t-p <param>   parameter passed to destination data handler\n"
-		"\t-r           retrieve message from data\n"
-		"\t-x <n>       number of key derivations to be tried\n"
-		"\t-m           mark pixels that have been modified\n"
-		"\t-t           collect statistic information\n"
-		"\t-F[+-]       turns statistical steganalysis foiling on/off.\n"
-		"\t             The default is on.\n"
-#ifdef FOURIER
-		"\t-f           fourier transform modified image\n"
-#endif /* FOURIER */
-		;
-
-	char *progname;
-	FILE *fin = stdin, *fout = stdout;
 	image *image;
 	handler *srch = NULL, *dsth = NULL;
 	char *param = NULL;
@@ -814,322 +799,71 @@ main(int argc, char **argv)
 	int j, ch, derive = 0;
 	stegres cumres, tmpres;
 	config cfg1, cfg2;
-	u_char *data = NULL, *data2 = NULL;
+	u_char *data = NULL;
 	int datalen;
-	char *key = "Default key", *key2 = NULL;
 	struct arc4_stream as, tas;
-	char mark = 0, doretrieve = 0;
-	char doerror = 0, doerror2 = 0;
-	char *cp;
-	int extractonly = 0, foil = 1;
-#ifdef FOURIER
-	char dofourier = 0;
-#endif /* FOURIER */
-
-	progname = argv[0];
+	char doretrieve = 0;
+	char doerror = 0;
+
+  struct return_information* rv = malloc(sizeof(struct return_information));
+  if (rv == NULL)
+    return NULL;
+  rv->message = NULL;
+  rv->message_length = 0;
+
 	steg_stat = 0;
 
 	memset(&cfg1, 0, sizeof(cfg1));
 	memset(&cfg2, 0, sizeof(cfg2));
 
-        if (strchr(argv[0], '/'))
-                cp = strrchr(argv[0], '/') + 1;
-        else
-                cp = argv[0];
-	if (!strcmp("outguess-extract", cp)) {
-		extractonly = 1;
-		doretrieve = 1;
-		argv++;
-		argc--;
-		goto aftergetop;
-	}
+  /* outguess options */
+  doretrieve = 1;
+  doerror = use_error_correction;
 
-	/* read command line arguments */
-	while ((ch = getopt(argc, argv, "heErmftp:s:S:i:I:k:d:D:K:x:F:")) != -1)
-		switch((char)ch) {
-		case 'h':
-			fprintf(stderr, usage, version, argv[0]);
-			exit(0);
-		case 'F':
-			if (optarg[0] == '-')
-				foil = 0;
-			break;
-		case 'k':
-			key = optarg;
-			break;
-		case 'K':
-			key2 = optarg;
-			break;
-		case 'p':
-			param = optarg;
-			break;
-		case 'x':
-			derive = atoi(optarg);
-			break;
-		case 'i':
-			cfg1.siter = atoi(optarg);
-			break;
-		case 'I':
-			cfg2.siter = atoi(optarg);
-			break;
-		case 'r':
-			doretrieve = 1;
-			break;
-		case 't':
-			steg_stat++;
-			break;
-		case 's':
-			cfg1.siterstart = atoi(optarg);
-			break;
-		case 'S':
-			cfg2.siterstart = atoi(optarg);
-			break;
-#ifdef FOURIER
-		case 'f':
-			dofourier = 1;
-			break;
-#endif /* FOURIER */
-		case 'm':
-			mark = 1; /* Mark bytes we modified with 255 */
-			break;
-		case 'd':
-			data = optarg;
-			break;
-		case 'D':
-			data2 = optarg;
-			break;
-		case 'e':
-			doerror = 1;
-			break;
-		case 'E':
-			doerror2 = 1;
-			break;
-		default:
-			fprintf(stderr, usage, version, argv[0]);
-			exit(1);
-		}
-
-	argc -= optind;
-	argv += optind;
-
- aftergetop:
-	if ((argc != 2 && argc != 0) ||
-	    (extractonly && argc != 2) ||
-	    (!doretrieve && !extractonly && data == NULL)) {
-		fprintf(stderr, usage, version, progname);
-		exit(1);
-	}
-
-	if (argc == 2) {
-		srch = get_handler(argv[0]);
-		if (srch == NULL) {
-			fprintf(stderr, "Unknown data type of %s\n", argv[0]);
-			exit (1);
-		}
-		if (!doretrieve) {
-			dsth = get_handler(argv[1]);
-			if (dsth == NULL) {
-				fprintf(stderr, "Unknown data type of %s\n",
-					argv[1]);
-				exit (1);
-			}
-		}
-		fin = fopen(argv[0], "rb");
-		if (fin == NULL) {
-			fprintf(stderr, "Can't open input file '%s': ",
-				argv[0]);
-			perror("fopen");
-			exit(1);
-		}
-		fout = fopen(argv[1], "wb");
-		if (fout == NULL) {
-			fprintf(stderr, "Can't open output file '%s': ",
-				argv[1]);
-			perror("fopen");
-			exit(1);
-		}
-	} else {
-		fin = stdin;
-		fout = stdout;
-
-		srch = dsth = get_handler(".ppm");
+	srch = get_handler(image_filename);
+	if (srch == NULL) {
+		fprintf(stderr, "Unknown data type of %s\n", image_filename);
+    return rv;
 	}
 
 	/* Initialize Golay-Tables for 12->23 bit error correction */
-	if (doerror || doerror2) {
+	if (doerror) {
 		fprintf(stderr, "Initialize encoding/decoding tables\n");
 		init_golay();
 	}
 
-	fprintf(stderr, "Reading %s....\n", argv[0]);
-	image = srch->read(fin);
+	fprintf(stderr, "Reading %s....\n", image_filename);
+	image = srch->read(image_data, image_data_size);
 
-	if (extractonly) {
-		int bits;
-		/* Wen extracting get the bitmap from the source handler */
-		srch->get_bitmap(&bitmap, image, STEG_RETRIEVE);
+	srch->get_bitmap(&bitmap, image, STEG_RETRIEVE);
 
-		fprintf(stderr, "Writing %d bits\n", bitmap.bits);
-		bits = htonl(bitmap.bits);
-		fwrite(&bits, 1, sizeof(int), fout);
-		fwrite(bitmap.bitmap, bitmap.bytes, sizeof(char), fout);
-		exit (1);
-	} else if (doretrieve)
-		/* Wen extracting get the bitmap from the source handler */
-		srch->get_bitmap(&bitmap, image, STEG_RETRIEVE);
-	else {
-		/* Initialize destination data handler */
-		dsth->init(param);
-		/* When embedding the destination format determines the bits */
-		dsth->get_bitmap(&bitmap, image, 0);
-	}
 	fprintf(stderr, "Extracting usable bits:   %d bits\n", bitmap.bits);
 
 	if (doerror)
 		cfg1.flags |= STEG_ERROR;
 
-	if (!doretrieve) {
-		if (mark)
-			cfg1.flags |= STEG_MARK;
-		if (foil) {
-			dsth->preserve(&bitmap, -1);
-			if (bitmap.maxcorrect)
-				fprintf(stderr,
-					"Correctable message size: %zu bits, %0.2f%%\n",
-					bitmap.maxcorrect,
-					(float)100*bitmap.maxcorrect/bitmap.bits);
-		}
-
-		do_embed(&bitmap, data, key, strlen(key), &cfg1, &cumres);
-
-		if (key2 && data2) {
-			char derivekey[128];
-			int i;
-
-			/* Flags from first configuration are being copied */
-			cfg2.flags = cfg1.flags;
-			if (doerror2)
-				cfg2.flags |= STEG_ERROR;
-			else
-				cfg2.flags &= ~STEG_ERROR;
-
-			for (j = -1, i = 0; i <= derive && j < 0; i++) {
-#ifdef HAVE_SNPRINTF
-				snprintf(derivekey, 128, "%s%d", key2, i);
-#else /* YOU SUCK */
-				sprintf(derivekey, "%s%d", key2, i);
-#endif /* HAVE_SNPRINTF */
-				if (i == 0)
-					derivekey[strlen(key2)] = '\0';
-
-				j = do_embed(&bitmap, data2,
-					     derivekey, strlen(derivekey),
-					     &cfg2, &tmpres);
-			}
-
-			if (j < 0) {
-				fprintf(stderr, "Failed to find embedding.\n");
-				exit (1);
-			}
-
-			cumres.changed += tmpres.changed;
-			cumres.bias += tmpres.bias;
-		}
-
-		if (foil) {
-			int i, count;
-			double mean, dev;
-			int n;
-			u_char cbit;
-			u_char *pbits = bitmap.bitmap;
-			u_char *bdata = bitmap.data;
-			u_char *plocked = bitmap.locked;
-
-			memset(steg_offset, 0, sizeof(steg_offset));
-			steg_foil = steg_foilfail = 0;
-
-			for (i = 0; i < bitmap.bits; i++) {
-				if (!TEST_BIT(plocked, i))
-					continue;
-
-				cbit = TEST_BIT(pbits, i) ? 1 : 0;
-
-				if (cbit == (bdata[i] & 0x01))
-					continue;
-
-				n = bitmap.preserve(&bitmap, i);
-				if (n > 0) {
-					/* Actual modificaton */
-					n = abs(n - i);
-					if (n > MAX_SEEK)
-						n = MAX_SEEK;
-
-					steg_offset[n - 1]++;
-				}
-			}
-
-			/* Indicates that we are done with the image */
-			bitmap.preserve(&bitmap, bitmap.bits);
-
-			/* Calculate statistics */
-			count = 0;
-			mean = 0;
-			for (i = 0; i < MAX_SEEK; i++) {
-				count += steg_offset[i];
-				mean += steg_offset[i] * (i + 1);
-			}
-			mean /= count;
-
-			dev = 0;
-			for (i = 0; i < MAX_SEEK; i++) {
-				const double sq = (i + 1 - mean) * (i + 1 - mean);
-				dev += steg_offset[i] * sq;
-			}
-
-			fprintf(stderr, "Foiling statistics: "
-				"corrections: %d, failed: %d, "
-				"offset: %f +- %f\n",
-				steg_foil, steg_foilfail,
-				mean, sqrt(dev / (count - 1)));
-		}
-
-		fprintf(stderr, "Total bits changed: %d (change %d + bias %d)\n",
-			cumres.changed + cumres.bias,
-			cumres.changed, cumres.bias);
-		fprintf(stderr, "Storing bitmap into data...\n");
-		dsth->put_bitmap (image, &bitmap, cfg1.flags);
-
-#ifdef FOURIER
-		if (dofourier)
-			fft_image(image->x, image->y, image->depth,
-				  image->img);
-#endif /* FOURIER */
-
-		fprintf(stderr, "Writing %s....\n", argv[1]);
-		dsth->write(fout, image);
-	} else {
-		/* Initialize random data stream */
-		arc4_initkey(&as,  "Encryption", key, strlen(key));
-		tas = as;
+	/* Initialize random data stream */
+	arc4_initkey(&as,  "Encryption", key, strlen(key));
+	tas = as;
 
-		iterator_init(&iter, &bitmap, key, strlen(key));
+	iterator_init(&iter, &bitmap, key, strlen(key));
 
-		encdata = steg_retrieve(&datalen, &bitmap, &iter, &as,
-					cfg1.flags);
+	encdata = steg_retrieve(&datalen, &bitmap, &iter, &as,
+				cfg1.flags);
 
-		data = decode_data(encdata, &datalen, &tas, cfg1.flags);
-		free(encdata);
+	data = decode_data(encdata, &datalen, &tas, cfg1.flags);
+	free(encdata);
 
-		fwrite(data, datalen, sizeof(u_char), fout);
-		free(data);
-	}
+  // The JS code must free `rv` and `data`
+  rv->message = data;
+  rv->message_length = datalen; 
 
 	free(bitmap.bitmap);
 	free(bitmap.locked);
 
 	free_pnm(image);
 
-	return 0;
+	return rv;
 }
 
 
diff --git a/src/pnm.c b/src/pnm.c
index c015f16..07ad1c8 100644
--- a/src/pnm.c
+++ b/src/pnm.c
@@ -77,19 +77,33 @@ preserve_pnm(bitmap *bitmap, int off)
 
 /* skip whitespace and comments in PGM/PPM headers */
 void
-skip_white(FILE *f)
+skip_white(char** data, size_t* size)
 {
 	int c;
 
-	do {
-		while (isspace(c = getc(f)));
-		if (c == '#')
-			while ((c = getc(f)) != '\n' && c != EOF);
+  while (*size > 0) {
+    do {
+      c = **data;
+      data++;
+      size--;
+    } while (isspace(c) && *size > 0);
+
+    if (*size == 0)
+      return;
+
+		if (c == '#') {
+      do {
+        c = **data;
+        data++;
+        size--;
+			} while (c != '\n' && *size > 0);
+    }
 		else {
-			ungetc(c, f);
+      data--;
+      size++;
 			return;
 		}
-	} while (c != EOF);
+	}
 }
 
 void
@@ -161,45 +175,81 @@ bitmap_from_pnm(bitmap *bitmap, image *image, int flags)
 
 
 image *
-read_pnm(FILE *fin)
+read_pnm(uint8_t* file_bytes, size_t file_size)
 {
 	image *image;
-	char magic[10];
 	int v;
 
+  char* file_content = (char*)file_bytes;
+
 	image = checkedmalloc(sizeof(*image));
 	memset(image, 0, sizeof(*image));
 
-	const char* const getsRet = fgets(magic, 10, fin);
-	if (getsRet == NULL) {
+  char* magic = (char*)file_content;
+
+	if (file_size < 10) {
 		fprintf(stderr, "Failed to read the magic value of the image!\n");
-		fprintf(stderr, "This suggest either an I/O error, ");
-		fprintf(stderr, "or that the file is invalid.\n");
+		fprintf(stderr, "This suggest	that the file is invalid.\n");
 		exit(1);
 	}
 	if (magic[0] != 'P' || !isdigit(magic[1]) || magic[2] != '\n') {
 		fprintf(stderr, "Unsupported input file type!\n");
 		exit(1);
 	}
-	skip_white(fin);
-	int nScanned = fscanf(fin, "%d", &image->x);
-	if (nScanned != 1) {
-		fprintf(stderr, "Failed to read image width!\n");
-		exit(1);
-	}
-	skip_white(fin);
-	nScanned = fscanf(fin, "%d", &image->y);
-	if (nScanned != 1) {
-		fprintf(stderr, "Failed to read image height!\n");
-		exit(1);
-	}
-	skip_white(fin);
-	nScanned = fscanf(fin, "%d", &image->max);
-	if (nScanned != 1) {
-		fprintf(stderr, "Failed to read image max pixel value!\n");
-		exit(1);
-	}
-	getc(fin);
+  file_content += 10;
+  file_size -= 10;
+	skip_white(&file_content, &file_size);
+ 
+  char* file_content_pre = file_content;
+  if (file_size == 0) {
+    fprintf(stderr, "Failed to read image width!\n");
+    exit(1);
+  }
+  int scanned = strtol(file_content, &file_content, 10);
+  if (file_content_pre == file_content) {
+    fprintf(stderr, "Failed to read image width!\n");
+    exit(1);
+  }
+  image->x = scanned;
+  file_size -= (uintptr_t)(file_content - file_content_pre);
+
+	skip_white(&file_content, &file_size);
+
+  file_content_pre = file_content;
+  if (file_size == 0) {
+    fprintf(stderr, "Failed to read image height!\n");
+    exit(1);
+  }
+  scanned = strtol(file_content, &file_content, 10);
+  if (file_content_pre == file_content) {
+    fprintf(stderr, "Failed to read image height!\n");
+    exit(1);
+  }
+  image->y = scanned;
+  file_size -= (uintptr_t)(file_content - file_content_pre);
+
+	skip_white(&file_content, &file_size);
+
+  file_content_pre = file_content;
+  if (file_size == 0) {
+    fprintf(stderr, "Failed to read image max pixel value!\n");
+    exit(1);
+  }
+  scanned = strtol(file_content, &file_content, 10);
+  if (file_content_pre == file_content) {
+    fprintf(stderr, "Failed to read image max pixel value!\n");
+    exit(1);
+  }
+  image->max = scanned;
+  file_size -= (uintptr_t)(file_content - file_content_pre);
+
+  if (file_size == 1) {
+    fprintf(stderr, "Unexpected EOF!\n");
+    exit(1);
+  }
+  file_size--;
+  file_content++;
+
 	if (image->max > 255 || image->max <= 0 || image->x <= 1 ||
 	    image->y <= 1) {
 		fprintf(stderr, "Unsupported value range!\n");
@@ -228,39 +278,40 @@ read_pnm(FILE *fin)
 	case '2': /* PGM ASCII */
 	case '3': /* PPM ASCII */
 		for (size_t i = 0; i < image->x * image->y * image->depth; i++) {
-			skip_white(fin);
-			nScanned = fscanf(fin, "%d", &v);
-			if (nScanned != 1) {
-				fprintf(stderr, "Failed to read image pixel value!\n");
-				exit(1);
-			}
+			skip_white(&file_content, &file_size);
+
+      file_content_pre = file_content;
+      if (file_size == 0) {
+        fprintf(stderr, "Failed to read image pixel value!\n");
+        exit(1);
+      }
+      scanned = strtol(file_content, &file_content, 10);
+      if (file_content_pre == file_content) {
+        fprintf(stderr, "Failed to read image pixel value!\n");
+        exit(1);
+      }
+      v = scanned;
+      file_size -= (uintptr_t)(file_content - file_content_pre);
+
 			if (v < 0 || v > image->max) {
 				fprintf(stderr, "Out of range value %d!\n", v);
 				exit(1);
 			}
+
 			(image->img)[i] = v;
 		}
 		break;
 	case '5': /* PGM binary */
 	case '6': /* PPM binary */
-		if (fread(image->img, image->x * image->depth, image->y, fin)
-				!= image->y)
+		if (file_size < image->x * image->depth * image->y)
 		{
 			fprintf(stderr, "Failed to read PPM image data!\n");
-			fprintf(stderr, "This suggest either an I/O error, ");
-			fprintf(stderr, "or that the file is invalid.\n");
+			fprintf(stderr, "This suggest that the file is invalid.\n");
 			exit(1);
 		}
-		break;
-	}
+    memcpy(image->img, file_content, image->x * image->depth * image->y);
 
-	if (ferror(fin)) {
-		perror("Error occurred while reading input file");
-		exit(1);
-	}
-	if (feof(fin)) {
-		fprintf(stderr, "Unexpected end of input file!\n");
-		exit(1);
+		break;
 	}
 
 	return image;
diff --git a/src/pnm.h b/src/pnm.h
index e2cb7c8..2581d1e 100644
--- a/src/pnm.h
+++ b/src/pnm.h
@@ -55,7 +55,7 @@ typedef struct _handler {
 	char *extension;				/* Extension name */
 	char *extension_alternative;		/* Extension name */
 	void (*init)(char *);
-	image *(*read)(FILE *);
+	image *(*read)(uint8_t*, size_t);
 	void (*write)(FILE *, image *);
 	void (*get_bitmap)(bitmap *, image *, int);
 	void (*put_bitmap)(image *, bitmap *, int);
@@ -64,7 +64,7 @@ typedef struct _handler {
 
 extern handler pnm_handler;
 
-void skip_white(FILE *f);
+void skip_white(char**, size_t*);
 
 void init_pnm(char *);
 
@@ -73,7 +73,7 @@ int preserve_pnm(bitmap *, int);
 void bitmap_to_pnm(image *img, bitmap *bitmap, int flags);
 void bitmap_from_pnm(bitmap *bitmap, image *image, int flags);
 
-image *read_pnm(FILE *fin);
+image *read_pnm(uint8_t*, size_t);
 void write_pnm(FILE *fout, image *image);
 
 void free_pnm(image *image);