From 67be9077ab61f31eecaa02f6cf2946b1cec328cd Mon Sep 17 00:00:00 2001
From: Kevin Froman <beardog@mailbox.org>
Date: Thu, 24 Dec 2020 05:00:36 +0000
Subject: [PATCH] raise exception when kasten loads invalid packed bytes

---
 kasten/exceptions/__init__.py |  4 ++++
 kasten/main.py                | 22 ++++++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/kasten/exceptions/__init__.py b/kasten/exceptions/__init__.py
index 128821b..cbc09aa 100644
--- a/kasten/exceptions/__init__.py
+++ b/kasten/exceptions/__init__.py
@@ -14,3 +14,7 @@ class InvalidID(KastenException):
     """Occurs when a Kasten generator fails validation, which means data does not match KastenChecksum"""
     pass
 
+class InvalidPackedBytes(KastenException):
+    """Occurs when packed bytes cannot be deserialized"""
+    pass
+
diff --git a/kasten/main.py b/kasten/main.py
index 450da10..683fd42 100644
--- a/kasten/main.py
+++ b/kasten/main.py
@@ -1,9 +1,13 @@
 """Main Kasten object, does nothing but provide access to packed Kasten bytes and call a specified generator function"""
+import traceback
+
 from msgpack import unpackb
+import msgpack
 
 from .types import KastenChecksum
 from .types import KastenPacked
 from .generator import pack
+from .exceptions import InvalidPackedBytes
 """
 Copyright (C) <2020>  Kevin Froman
 
@@ -31,10 +35,20 @@ class Kasten:
                  **additional_generator_kwargs):  # noqa
         self.id = id
         self.generator = generator
-        header, data = packed_bytes.split(b'\n', 1)
-        header = unpackb(
-            header,
-            strict_map_key=True)
+        try:
+            header, data = packed_bytes.split(b'\n', 1)
+        except ValueError:
+            raise InvalidPackedBytes("Could not extract data section")
+        try:
+            header = unpackb(
+                header,
+                strict_map_key=True)
+        except(  # noqa
+                msgpack.exceptions.ExtraData,
+                msgpack.FormatError,
+                UnicodeEncodeError,
+                ValueError) as _:
+            raise InvalidPackedBytes("Could not decode packed bytes")
         self.header = header
         self.data = data
         self.additional_generator_args = list(additional_generator_args)