Merge pull request #14 from ronfrenk/read_tag_fix

Fixed a bug in read_tag

Author: russss

emv/protocol/data.py

@@ -45,10 +45,10 @@ def read_tag(data):
     if is_two_byte(data[i]):
         i += 1
         tag += [data[i]]
-        i += 1
         while len(data) > i and is_continuation(data[i]):
-            tag += [data[i]]
             i += 1
+            tag += [data[i]]
+        i += 1
     else:
         i += 1
     return tag, i

emv/protocol/structures.py

@@ -51,7 +51,7 @@ def unmarshal(cls, data):
             i += tag_len
             if len(data) <= i:
                 log.info("Invalid TLV - read beyond end of buffer at %s: %s", tag, data)
-                return data
+                return tlv
 
             length, length_len = read_length(data[i:])
             i += length_len

emv/protocol/test/test_structures.py

@@ -31,6 +31,10 @@ def test_tlv(self):
         tlv = TLV.unmarshal(data)
         self.assertEqual(tlv[(0x9F, 0x17)][0], 3)
 
+        data = unformat_bytes("DF DF 39 01 07")
+        tlv = TLV.unmarshal(data)
+        self.assertEqual(tlv[(0xDF, 0xDF, 0x39)][0], 7)
+
     def test_length_parsing(self):
         data = unformat_bytes("42 01 03")
         tlv = TLV.unmarshal(data)