From 7e717b50370f56dd0895922196098ef6c72c347c Mon Sep 17 00:00:00 2001
From: jevans <john.g.evans.ne@gmail.com>
Date: Sat, 26 Oct 2013 18:05:44 -0400
Subject: [PATCH] Made Exif handling more resilient.  #104

---
 glymur/_uuid_io/Exif.py         |  6 +++-
 glymur/jp2box.py                | 23 +++++++++----
 glymur/test/test_jp2box_uuid.py | 57 ++++++++++++++++++++++++++++++++-
 3 files changed, 77 insertions(+), 9 deletions(-)

diff --git a/glymur/_uuid_io/Exif.py b/glymur/_uuid_io/Exif.py
index 3fb24b1..0a86c18 100644
--- a/glymur/_uuid_io/Exif.py
+++ b/glymur/_uuid_io/Exif.py
@@ -39,9 +39,13 @@ class UUIDExif(object):
         if data[0] == 73 and data[1] == 73:
             # little endian
             self.endian = '<'
-        else:
+        elif data[0] == 77 and data[1] == 77:
             # big endian
             self.endian = '>'
+        else:
+            msg = "Bad byte order indication: {0}".format(read_buffer[6:8])
+            raise RuntimeError(msg)
+
         offset = data[3]
 
         # This is the 'Exif Image' portion.
diff --git a/glymur/jp2box.py b/glymur/jp2box.py
index 681cf51..074d18e 100644
--- a/glymur/jp2box.py
+++ b/glymur/jp2box.py
@@ -19,6 +19,7 @@ import os
 import pprint
 import struct
 import sys
+import traceback
 import uuid
 import warnings
 import xml.etree.cElementTree as ET
@@ -2078,15 +2079,23 @@ class UUIDBox(Jp2kBox):
         Jp2kBox.__init__(self, box_id='uuid', longname='UUID')
         self.uuid = the_uuid
 
-        if the_uuid == uuid.UUID('be7acfcb-97a9-42e8-9c71-999491e3afac'):
-            self.data = _uuid_io.UUIDXMP(raw_data)
-            self._type = 'XMP'
-        elif the_uuid.bytes == b'JpgTiffExif->JP2':
-            self.data = _uuid_io.UUIDExif(raw_data)
-            self._type = 'Exif'
-        else:
+        try:
+            if the_uuid == uuid.UUID('be7acfcb-97a9-42e8-9c71-999491e3afac'):
+                self.data = _uuid_io.UUIDXMP(raw_data)
+                self._type = 'XMP'
+            elif the_uuid.bytes == b'JpgTiffExif->JP2':
+                self.data = _uuid_io.UUIDExif(raw_data)
+                self._type = 'Exif'
+            else:
+                self.data = _uuid_io.UUIDGeneric(raw_data)
+                self._type = 'unknown'
+        except Exception as err:
+            # In case of any exception, create the generic UUID.
             self.data = _uuid_io.UUIDGeneric(raw_data)
             self._type = 'unknown'
+            msg = "Error encountered during UUID processing, "
+            msg += "the UUID will be treated as generic.\n\n{0}"
+            warnings.warn(msg.format(traceback.format_exc()))
         
         self.raw_data = raw_data
 
diff --git a/glymur/test/test_jp2box_uuid.py b/glymur/test/test_jp2box_uuid.py
index 6278f57..a1d93a4 100644
--- a/glymur/test/test_jp2box_uuid.py
+++ b/glymur/test/test_jp2box_uuid.py
@@ -63,7 +63,7 @@ class TestUUIDExif(unittest.TestCase):
             xbuffer = struct.pack('<BBHI', 73, 73, 42, 8)
             tfile.write(xbuffer)
 
-            # We will write just a single file.
+            # We will write just a single tag.
             tfile.write(struct.pack('<H', 1))
 
             # The "Make" tag is tag no. 271.  Corrupt it to 171.
@@ -73,6 +73,61 @@ class TestUUIDExif(unittest.TestCase):
             with self.assertWarns(UserWarning):
                 j = glymur.Jp2k(tfile.name)
 
+    @unittest.skipIf(sys.hexversion < 0x03000000, "Requires assertWarns, 3.2+")
+    def test_bad_tag_datatype(self):
+        """Only certain datatypes are allowable"""
+        with tempfile.NamedTemporaryFile(suffix='.jp2', mode='wb') as tfile:
+
+            with open(self.jp2file, 'rb') as ifptr:
+                tfile.write(ifptr.read())
+
+            # Write L, T, UUID identifier.
+            tfile.write(struct.pack('>I4s', 52, b'uuid'))
+            tfile.write(b'JpgTiffExif->JP2')
+
+            tfile.write(b'Exif\x00\x00')
+            xbuffer = struct.pack('<BBHI', 73, 73, 42, 8)
+            tfile.write(xbuffer)
+
+            # We will write just a single tag.
+            tfile.write(struct.pack('<H', 1))
+
+            # 2000 is not an allowable TIFF datatype.
+            tfile.write(struct.pack('<HHI4s', 271, 2000, 3, b'HTC\x00'))
+            tfile.flush()
+
+            with self.assertWarns(UserWarning):
+                j = glymur.Jp2k(tfile.name)
+
+            self.assertEqual(j.box[-1].box_id, 'uuid')
+
+    @unittest.skipIf(sys.hexversion < 0x03000000, "Requires assertWarns, 3.2+")
+    def test_bad_tiff_header_byte_order_indication(self):
+        """Only b'II' and b'MM' are allowed."""
+        with tempfile.NamedTemporaryFile(suffix='.jp2', mode='wb') as tfile:
+
+            with open(self.jp2file, 'rb') as ifptr:
+                tfile.write(ifptr.read())
+
+            # Write L, T, UUID identifier.
+            tfile.write(struct.pack('>I4s', 52, b'uuid'))
+            tfile.write(b'JpgTiffExif->JP2')
+
+            tfile.write(b'Exif\x00\x00')
+            xbuffer = struct.pack('<BBHI', 74, 73, 42, 8)
+            tfile.write(xbuffer)
+
+            # We will write just a single tag.
+            tfile.write(struct.pack('<H', 1))
+
+            # 271 is the Make.
+            tfile.write(struct.pack('<HHI4s', 271, 2, 3, b'HTC\x00'))
+            tfile.flush()
+
+            with self.assertWarns(UserWarning):
+                j = glymur.Jp2k(tfile.name)
+
+            self.assertEqual(j.box[-1].box_id, 'uuid')
 
 if __name__ == "__main__":
     unittest.main()