Renamed images can now be read, key is now hashed before use

Makefile

@@ -7,7 +7,7 @@ MAN=albumfs.1
 
 CFLAGS=-Wall -D_FILE_OFFSET_BITS=8
 PKG=`pkg-config fuse --cflags --libs`
-LIBS=-lpng -lm
+LIBS=-lpng -lm -lssl -lcrypto
 
 all: objects $(NAME)
 	rm ${OBJECTS}

README

@@ -8,24 +8,25 @@
 key encrypted LSB steganography PNG album filesystem in userspace
 
 Create, access, and modify a key encrypted LSB steganography filesystem in userspace using a directory of PNG images.  Filesystem state is only preserved after safely closing the filesystem via unmount or Ctrl+C.  A filesystem may only use images with the same dimensions as the root image provided.
+
 A filesystem requires a name, key, root image, and storage images.  To access a filesystem the correct key, filesystem name, and root image must be given.  All data is XOR'd with the key as it is read and written from the images.  The root image stores the filesystem name, consumed and total space, image and file count, image filenames, and file meta data.  All images added to the filesystem while formatting or expanding are found in the same directory as the root image.
+
 Formatting a filesystem wipes each avialable least signifigant bit in the images provided, similarly removing a file wipes its data and shifts the filesystem if there is a hole.  All files in the filesystem have permissions of 644 and cannot be edited, but can be read, renamed, deleted, and copied.
 
 
 DEPENDENCIES:
 	- libfuse-dev
-	- pkg-config
 	- libpng12-dev
+	- libssl-dev
+	- pkg-config
 
 
 COMPILE:
 	- make all
 	- sudo make install
-	- make clean
 
 
 KNOWN BUGS:
-	- Filesystem cannot survive image renames
 	- Filesystem does not support  directories
 
 
@@ -53,6 +54,6 @@ EXAMPLES:
 
 
 TODO:
-	- Replace use of name for image tracking with sum
+	- Use different way to write to root image so offset can be unsigned
 	- Support directories
 	- Add option for live updating

afs.c

@@ -518,8 +518,9 @@ void writeRoot() {
 
     // Write png_data for each valid image
     for (y = 0; y < afs->img_count; y++) {
-        writeBytes((void *) afs->images[y]->filename, MAX_FILENAME, offset);
-        offset = offset - MAX_FILENAME;
+        getMD5(afs->images[y]->filename, afs->images[y]->md5);
+        writeBytes((void *) afs->images[y]->md5, sizeof(afs->images[y]->md5), offset);
+        offset = offset -sizeof(afs->images[y]->md5);
     }
 
     // Write file_meta for each file
@@ -533,6 +534,8 @@ void writeRoot() {
 
 /* Read filesystem_meta and png_data from root img */
 void readRoot() {
+    DIR *FD;
+    struct dirent *dir;
     int y;
     int offset = -1;
     char name[64];
@@ -555,18 +558,35 @@ void readRoot() {
     printf("Found filesystem %s [%0.2f/%0.2f] %d files in %d images\n", name, afs->consumed, afs->capacity, afs->file_count, afs->img_count);
 
     png_data **dir_images = malloc((sizeof(png_data*) * afs->img_count));
+    FD = opendir(afs->img_dir);
+    if (!FD) {
+        fprintf(stderr, "Cannot open directory %s", afs->img_dir);
+        free(afs);
+        exit(1);
+    }
 
     // Read png_data for each valid image
     for (y = 0; y < afs->img_count; y++) {
         png_data *new_img = malloc(sizeof(png_data));
-        readBytes((void *) new_img->filename, MAX_FILENAME, offset);
-        offset = offset - MAX_FILENAME;
-        dir_images[y] = new_img;
-        if (!read_png(new_img, afs->img_dir)) {
-            fprintf(stderr, "Filesystem is missing image %s!", new_img->filename);
-            exit(1);
+        char tmp[strlen(new_img->md5)];
+        readBytes((void *) new_img->md5, sizeof(new_img->md5), offset);
+        offset = offset - sizeof(new_img->md5);
+        while ((dir = readdir(FD)) != NULL) {
+            memset(tmp, 0, sizeof(new_img->md5));
+            getMD5(dir->d_name, tmp);;
+            if (strncmp(tmp, new_img->md5, sizeof(new_img->md5)) == 0) {
+                strcpy(new_img->filename, dir->d_name);
+                if (!read_png(new_img, afs->img_dir)) {
+                    fprintf(stderr, "Filesystem is missing image %s!", new_img->filename);
+                    exit(1);
+                }
+                dir_images[y] = new_img;
+                break;
+            }
         }
+        seekdir(FD, 0);
     }
+    closedir(FD);
     afs->images = dir_images;
 
     afs_file **files = malloc((sizeof(afs_file*) * afs->file_count));

albumfs.1

@@ -1,12 +1,14 @@
 .\" Manpage for albumfs.
-.TH ALBUMFS 1 "Dec 2015" "0.1.2" "User Commands"
+.TH ALBUMFS 1 "Dec 2015" "0.1.3" "User Commands"
 .SH NAME
 albumfs \- key encrypted LSB steganography PNG album filesystem in userspace
 .SH SYNOPSIS
 albumfs [OPTIONS]... [PATH/TO/ROOTIMAGE.PNG]
 .SH DESCRIPTION
 Create, access, and modify a LSB steganography filesystem in userspace using a directory of PNG images.  Filesystem state is only preserved after safely closing the filesystem via unmount or Ctrl+C.  A filesystem may only use images with the same dimensions as the root image provided.
+.PP
 A filesystem requires a name, key, root image, and storage images.  To access a filesystem the correct key, filesystem name, and root image must be given.  All data is XOR'd with the key as it is read and written from the images.  The root image stores the filesystem name, consumed and total space, image and file count, image filenames, and file meta data.  All images added to the filesystem while formatting or expanding are found in the same directory as the root image.
+.PP
 Formatting a filesystem wipes each avialable least signifigant bit in the images provided, similarly removing a file wipes its imprint and shifts the filesystem if there is a hole.  All files in the filesystem have permissions of 644 and cannot be edited, but can be read, renamed, deleted, and copied.
 .TP
 .B -format

albumfs.c

@@ -63,7 +63,11 @@ int main(int argc, char *argv[]) {
     strcat(afs->name, ".afs");
     printf("Enter encryption key for %s:\n", afs->name);
     fgets(afs->key, sizeof(afs->key), stdin);
-    afs->key[strlen(afs->key) - 1] = '\0';
+    //afs->key[strlen(afs->key) - 1] = '\0';
+    MD5_CTX mdContext;
+    MD5_Init (&mdContext);
+    MD5_Update (&mdContext, afs->key, sizeof(afs->key));
+    MD5_Final ((unsigned char *)afs->key, &mdContext);
     printf("\e[1;1H\e[2J");
 
     // Check mount
@@ -108,3 +112,23 @@ int parseArgv(int argc, char *argv[], char *option) {
     }
     return 0;
 }
+
+
+/* Calculate MD5 of a file */
+int getMD5(char *filename, char *md5_sum) {
+    char path[MAX_PATH];
+    strcpy(path, afs->img_dir);
+    strcat(path, filename);
+    FILE *f = fopen(path, "rb");
+    char data[sizeof(md5_sum)];
+
+    if (f == NULL) { return 0; }
+    MD5_CTX mdContext;
+    MD5_Init (&mdContext);
+	while (fread (data, 1, sizeof(md5_sum), f) != 0) {
+            MD5_Update (&mdContext, data, sizeof(md5_sum));
+        }
+    MD5_Final ((unsigned char *)md5_sum, &mdContext);
+    pclose(f);
+    return 1;
+}

include/afspng.h

@@ -16,6 +16,7 @@ typedef enum {modified, not_modified} image_state;
 
 struct PNG_image_data {
     char filename [MAX_FILENAME];
+    char md5[64];
     int32_t width, height, channels;
     unsigned char png_sig[8];
     png_byte color_type;

include/albumfs.h

@@ -20,12 +20,11 @@
 #include <fcntl.h>
 #include <math.h>
 #include <sys/types.h>
-
+#include <openssl/md5.h>
 
 /* Preprocessor Macros */
 
 #define _GNU_SOURCE
-#define VERSION "0.1.2"
 #define MAX_FILENAME 64
 #define MAX_PATH 512
 #define MINIMUM_PNG 2
@@ -45,6 +44,7 @@ int8_t afs_dbg;
 //albumfs.c
 void afs_usage();
 int parseArgv(int argc, char *argv[], char *option);
+int getMD5(char *filename, char *mds_sum);
 //afs.c
 int wipeFile(char *path);
 int findFile(char *path);