Merge pull request #43 from bnnm/decryption-keyfiles

Decryption keyfiles

src/meta/adx_header.c

@@ -470,9 +470,15 @@ static struct {
     /* Phantasy Star Online 2
      * guessed with degod */
     {0x07d2,0x1ec5,0x0c7f},
+
     /* Dragon Ball Z: Dokkan Battle
      * guessed with degod */
     {0x0003,0x0d19,0x043b},
+
+    /* Kisou Ryouhei Gunhound EX (2013-01-31)(Dracue)[PSP]
+     * guessed with degod */
+    {0x0005,0x0bcd,0x1add},
+
 };
 
 static const int keys_8_count = sizeof(keys_8)/sizeof(keys_8[0]);
@@ -487,6 +493,21 @@ static int find_key(STREAMFILE *file, uint8_t type, uint16_t *xor_start, uint16_
     int startoff, endoff;
     int rc = 0;
 
+
+    /* try to find key in external file first */
+    {
+        uint8_t keybuf[6];
+
+        if ( read_key_file(keybuf, 6, file) ) {
+            *xor_start = get_16bitBE(keybuf+0);
+            *xor_mult = get_16bitBE(keybuf+2);
+            *xor_add = get_16bitBE(keybuf+4);
+            return 1;
+        }
+    }
+
+
+    /* guess key from the tables above */
     startoff=read_16bitBE(2, file)+4;
     endoff=(read_32bitBE(12, file)+31)/32*18*read_8bit(7, file)+startoff;
 

src/streamfile.c

@@ -271,3 +271,82 @@ size_t get_streamfile_dos_line(int dst_length, char * dst, off_t offset,
 
     return i+extra_bytes;
 }
+
+
+/**
+ * open file containing decryption keys and copy to buffer
+ * tries combinations of keynames based on the original filename
+ *
+ * returns true if found and copied
+ */
+int read_key_file(uint8_t * buf, size_t bufsize, STREAMFILE *streamFile) {
+    char keyname[PATH_LIMIT];
+    char filename[PATH_LIMIT];
+    const char *path, *ext;
+    STREAMFILE * streamFileKey = NULL;
+
+    streamFile->get_name(streamFile,filename,sizeof(filename));
+
+    if (strlen(filename)+4 > sizeof(keyname)) goto fail;
+
+    /* try to open a keyfile using variations:
+     *  "(name.ext)key" (per song), "(.ext)key" (per folder) */
+    {
+        ext = strrchr(filename,'.');
+        if (ext!=NULL) ext = ext+1;
+
+        path = strrchr(filename,DIR_SEPARATOR);
+        if (path!=NULL) path = path+1;
+
+        /* "(name.ext)key" */
+        strcpy(keyname, filename);
+        strcat(keyname, "key");
+        streamFileKey = streamFile->open(streamFile,keyname,STREAMFILE_DEFAULT_BUFFER_SIZE);
+        if (streamFileKey) goto found;
+
+        /* "(name.ext)KEY" */
+        /*
+        strcpy(keyname+strlen(keyname)-3,"KEY");
+        streamFileKey = streamFile->open(streamFile,keyname,STREAMFILE_DEFAULT_BUFFER_SIZE);
+        if (streamFileKey) goto found;
+        */
+
+
+        /* "(.ext)key" */
+        if (path) {
+            strcpy(keyname, filename);
+            keyname[path-filename] = '\0';
+            strcat(keyname, ".");
+        } else {
+            strcpy(keyname, ".");
+        }
+        if (ext) strcat(keyname, ext);
+        strcat(keyname, "key");
+        streamFileKey = streamFile->open(streamFile,keyname,STREAMFILE_DEFAULT_BUFFER_SIZE);
+        if (streamFileKey) goto found;
+
+        /* "(.ext)KEY" */
+        /*
+        strcpy(keyname+strlen(keyname)-3,"KEY");
+        streamFileKey = streamFile->open(streamFile,keyname,STREAMFILE_DEFAULT_BUFFER_SIZE);
+        if (streamFileKey) goto found;
+        */
+
+        goto fail;
+    }
+
+found:
+    if (get_streamfile_size(streamFileKey) != bufsize) goto fail;
+
+    if (read_streamfile(buf, 0, bufsize, streamFileKey)!=bufsize) goto fail;
+
+    close_streamfile(streamFileKey);
+
+    return 1;
+
+fail:
+    if (streamFileKey) close_streamfile(streamFileKey);
+
+    return 0;
+}
+

src/streamfile.h

@@ -34,6 +34,14 @@
 
 #define STREAMFILE_DEFAULT_BUFFER_SIZE 0x400
 
+#ifndef DIR_SEPARATOR
+#if defined (_WIN32) || defined (WIN32)
+#define DIR_SEPARATOR '\\'
+#else
+#define DIR_SEPARATOR '/'
+#endif
+#endif
+
 typedef struct _STREAMFILE {
     size_t (*read)(struct _STREAMFILE *,uint8_t * dest, off_t offset, size_t length);
     size_t (*get_size)(struct _STREAMFILE *);
@@ -141,4 +149,7 @@ static inline STREAMFILE * open_stdio_streamfile(const char * const filename) {
 size_t get_streamfile_dos_line(int dst_length, char * dst, off_t offset,
                 STREAMFILE * infile, int *line_done_ptr);
 
+int read_key_file(uint8_t * buf, size_t bufsize, STREAMFILE *streamFile);
+
+
 #endif