Full content extraction is working!

src/libWiiPy/content.py

@@ -34,8 +34,12 @@ class ContentRegion:
             self.content_region_size = sys.getsizeof(content_region_data)
             self.num_contents = len(self.content_records)
             # Calculate the offsets of each content in the content region.
+            # Content is aligned to 16 bytes, however a new content won't start until the next multiple of 64 bytes.
+            # Because of this, we need to add bytes to the next 64 byte offset if the previous content wasn't that long.
             for content in self.content_records[:-1]:
-                start_offset = int(64 * round(content.content_size / 64)) + self.content_start_offsets[-1]
+                start_offset = content.content_size + self.content_start_offsets[-1]
+                if (content.content_size % 64) != 0:
+                    start_offset += 64 - (content.content_size % 64)
                 self.content_start_offsets.append(start_offset)
 
     def get_enc_content(self, index: int) -> bytes:
@@ -54,8 +58,10 @@ class ContentRegion:
         with io.BytesIO(self.content_region) as content_region_data:
             # Seek to the start of the requested content based on the list of offsets.
             content_region_data.seek(self.content_start_offsets[index])
-            # Calculate the number of bytes we need to read by rounding the size to the nearest 16 bytes.
+            # Calculate the number of bytes we need to read by adding bytes up the nearest multiple of 16 if needed.
-            bytes_to_read = int(64 * round(self.content_records[index].content_size / 64))
+            bytes_to_read = self.content_records[index].content_size
+            if (bytes_to_read % 16) != 0:
+                bytes_to_read += 16 - (bytes_to_read % 16)
             # Read the file based on the size of the content in the associated record.
             content_enc = content_region_data.read(bytes_to_read)
             return content_enc
@@ -77,18 +83,16 @@ class ContentRegion:
         """
         # Load the encrypted content at the specified index and then decrypt it with the Title Key.
         content_enc = self.get_enc_content(index)
-        content_dec = decrypt_content(content_enc, title_key, self.content_records[index].index, self.content_records[index].content_size)
+        content_dec = decrypt_content(content_enc, title_key, self.content_records[index].index,
+                                      self.content_records[index].content_size)
         # Hash the decrypted content and ensure that the hash matches the one in its Content Record.
         # If it does not, then something has gone wrong in the decryption, and an error will be thrown.
         content_dec_hash = hashlib.sha1(content_dec)
         content_record_hash = str(self.content_records[index].content_hash.decode())
+        # Compare the hash and throw a ValueError if the hash doesn't match.
         if content_dec_hash.hexdigest() != content_record_hash:
-            #raise ValueError("Content hash did not match the expected hash in its record! This most likely means that "
+            raise ValueError("Content hash did not match the expected hash in its record! The incorrect Title Key may"
-                             #"the incorrect Title Key was used for this content.\n"
+                             "have been used!.\n"
-                             #"Expected hash is: {}\n".format(content_record_hash) +
-                             #"Actual hash is: {}".format(content_dec_hash.hexdigest()))
-            print("Content hash did not match the expected hash in its record! This most likely means that "
-                             "the incorrect Title Key was used for this content.\n"
                              "Expected hash is: {}\n".format(content_record_hash) +
                              "Actual hash is: {}".format(content_dec_hash.hexdigest()))
         return content_dec

src/libWiiPy/crypto.py

@@ -1,7 +1,5 @@
 # "crypto.py" from libWiiPy by NinjaCheetah & Contributors
 # https://github.com/NinjaCheetah/libWiiPy
-#
-# See https://wiibrew.org/wiki/Ticket for details about the TMD format
 
 import struct
 from .commonkeys import get_common_key
@@ -9,7 +7,7 @@ from Crypto.Cipher import AES
 from Crypto.Util.Padding import pad, unpad
 
 
-def decrypt_title_key(title_key_enc, common_key_index, title_id):
+def decrypt_title_key(title_key_enc, common_key_index, title_id) -> bytes:
     """Gets the decrypted version of the encrypted Title Key provided.
 
     Requires the index of the common key to use, and the Title ID of the title that the Title Key is for.
@@ -21,7 +19,7 @@ def decrypt_title_key(title_key_enc, common_key_index, title_id):
     common_key_index : int
         The index of the common key to be returned.
     title_id : bytes
-        The title ID of the tite that the key is for.
+        The title ID of the title that the key is for.
 
     Returns
     -------
@@ -39,7 +37,7 @@ def decrypt_title_key(title_key_enc, common_key_index, title_id):
     return title_key
 
 
-def decrypt_content(content_enc, title_key, content_index, content_length):
+def decrypt_content(content_enc, title_key, content_index, content_length) -> bytes:
     """Gets the decrypted version of the encrypted content.
 
     Requires the index of the common key to use, and the Title ID of the title that the Title Key is for.
@@ -50,6 +48,10 @@ def decrypt_content(content_enc, title_key, content_index, content_length):
         The encrypted content.
     title_key : bytes
         The Title Key for the title the content is from.
+    content_index : int
+        The index in the TMD's content record of the content being decrypted.
+    content_length : int
+        The length in the TMD's content record of the content being decrypted.
 
     Returns
     -------
@@ -60,18 +62,15 @@ def decrypt_content(content_enc, title_key, content_index, content_length):
     content_index_bin = struct.pack('>H', content_index)
     while len(content_index_bin) < 16:
         content_index_bin += b'\x00'
-    # In CBC mode, content must be padded out to a 16-byte boundary, so do that here, and then remove bytes added after.
+    # Align content to 64 bytes to ensure that all the data is being decrypted, and so it works with AES encryption.
-    padded = False
+    if (len(content_enc) % 64) != 0:
-    if (len(content_enc) % 128) != 0:
+        print("needs padding to 64 bytes")
-        print("needs padding to 16 bytes")
+        content_enc = content_enc + (b'\x00' * (64 - (len(content_enc) % 64)))
-        content_enc = pad(content_enc, 128, "pkcs7")
-        padded = True
     # Create a new AES object with the values provided, with the content's unique ID as the IV.
     aes = AES.new(title_key, AES.MODE_CBC, content_index_bin)
     # Decrypt the content using the AES object.
     content_dec = aes.decrypt(content_enc)
-    # Remove padding bytes, if any were added.
+    # Trim additional bytes that may have been added so the content is the correct size.
-    if padded:
+    while len(content_dec) > content_length:
-        while len(content_dec) > content_length:
+        content_dec = content_dec[:-1]
-            content_dec = content_dec[:-1]
     return content_dec

src/libWiiPy/ticket.py

@@ -1,7 +1,7 @@
 # "ticket.py" from libWiiPy by NinjaCheetah & Contributors
 # https://github.com/NinjaCheetah/libWiiPy
 #
-# See https://wiibrew.org/wiki/Ticket for details about the TMD format
+# See https://wiibrew.org/wiki/Ticket for details about the ticket format
 
 import io
 from .crypto import decrypt_title_key

src/libWiiPy/types.py

@@ -22,8 +22,8 @@ class ContentRecord:
     content_hash
         The SHA-1 hash of the decrypted content.
     """
-    content_id: int  # Unique ID for the current content
+    content_id: int  # The unique ID of the content.
-    index: int  # Index in the list of contents
+    index: int  # The index of this content in the content record.
-    content_type: int  # Type of content, possible values of: 0x0001: Normal, 0x4001: DLC, 0x8001: Shared
+    content_type: int  # Type of content, possible values of: 0x0001: Normal, 0x4001: DLC, 0x8001: Shared.
-    content_size: int  # Size of the current content
+    content_size: int  # Size of the content when decrypted.
-    content_hash: bytes  # SHA1 hash of the current content
+    content_hash: bytes  # SHA-1 hash of the content when decrypted.