Display OIDs in dotted form

This commit causes `repr` for OIDs to display the OID in dotted
form instead of as the raw ASN.1 BER-encoded bytes.

Also-Authored-By: Simo Sorce <simo@redhat.com>

Author: sigmaris

gssapi/raw/oids.pyx

@@ -70,8 +70,33 @@ cdef class OID:
     def __bytes__(self):
         return (<char*>self.raw_oid.elements)[:self.raw_oid.length]
 
+    def _decode_asn1ber(self):
+        ber_encoding = self.__bytes__()
+        # NB(directxman12): indexing a byte string yields an int in Python 3,
+        #                   but yields a substring in Python 2
+        if six.PY2:
+            ber_encoding = [ord(c) for c in ber_encoding]
+
+        decoded = [ber_encoding[0] // 40, ber_encoding[0] % 40]
+        pos = 1
+        value = 0
+        while pos < len(ber_encoding):
+            byte = ber_encoding[pos]
+            if byte & 0x80:
+                # This is one of the leading bytes
+                value <<= 7
+                value += ((byte & 0x7f) * 128)
+            else:
+                # This is the last byte of this value
+                value += (byte & 0x7f)
+                decoded.append(value)
+                value = 0
+            pos += 1
+        return decoded
+
     def __repr__(self):
-        return "<OID {0}>".format([ord(c) for c in self.__bytes__()])
+        dotted_oid = '.'.join(str(x) for x in self._decode_asn1ber())
+        return "<OID {0}>".format(dotted_oid)
 
     def __hash__(self):
         return hash(self.__bytes__())

gssapi/tests/test_raw.py

@@ -780,3 +780,23 @@ def test_basic_wrap_unwrap(self):
         unwrapped_message.should_be_a(bytes)
         unwrapped_message.shouldnt_be_empty()
         unwrapped_message.should_be(b'test message')
+
+
+TEST_OIDS = {'SPNEGO': {'bytes': b'\053\006\001\005\005\002',
+                        'string': '1.3.6.1.5.5.2'},
+             'KRB5': {'bytes': b'\052\206\110\206\367\022\001\002\002',
+                      'string': '1.2.840.113554.1.2.2'},
+             'KRB5_OLD': {'bytes': b'\053\005\001\005\002',
+                          'string': '1.3.5.1.5.2'},
+             'KRB5_WRONG': {'bytes': b'\052\206\110\202\367\022\001\002\002',
+                            'string': '1.2.840.48018.1.2.2'},
+             'IAKERB': {'bytes': b'\053\006\001\005\002\005',
+                        'string': '1.3.6.1.5.2.5'}}
+
+
+class TestOIDTransforms(unittest.TestCase):
+    def test_decode_from_bytes(self):
+        for oid in TEST_OIDS.values():
+            o = gb.OID(elements=oid['bytes'])
+            text = repr(o)
+            text.should_be("<OID {0}>".format(oid['string']))