Initial commit

venv/Lib/site-packages/ecdsa/test_der.py

@@ -0,0 +1,478 @@
+# compatibility with Python 2.6, for that we need unittest2 package,
+# which is not available on 3.3 or 3.4
+import warnings
+from binascii import hexlify
+
+try:
+    import unittest2 as unittest
+except ImportError:
+    import unittest
+import sys
+import hypothesis.strategies as st
+from hypothesis import given, settings
+import pytest
+from ._compat import str_idx_as_int
+from .curves import NIST256p, NIST224p
+from .der import (
+    remove_integer,
+    UnexpectedDER,
+    read_length,
+    encode_bitstring,
+    remove_bitstring,
+    remove_object,
+    encode_oid,
+    remove_constructed,
+    remove_octet_string,
+    remove_sequence,
+)
+
+
+class TestRemoveInteger(unittest.TestCase):
+    # DER requires the integers to be 0-padded only if they would be
+    # interpreted as negative, check if those errors are detected
+    def test_non_minimal_encoding(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_integer(b"\x02\x02\x00\x01")
+
+    def test_negative_with_high_bit_set(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_integer(b"\x02\x01\x80")
+
+    def test_minimal_with_high_bit_set(self):
+        val, rem = remove_integer(b"\x02\x02\x00\x80")
+
+        self.assertEqual(val, 0x80)
+        self.assertEqual(rem, b"")
+
+    def test_two_zero_bytes_with_high_bit_set(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_integer(b"\x02\x03\x00\x00\xff")
+
+    def test_zero_length_integer(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_integer(b"\x02\x00")
+
+    def test_empty_string(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_integer(b"")
+
+    def test_encoding_of_zero(self):
+        val, rem = remove_integer(b"\x02\x01\x00")
+
+        self.assertEqual(val, 0)
+        self.assertEqual(rem, b"")
+
+    def test_encoding_of_127(self):
+        val, rem = remove_integer(b"\x02\x01\x7f")
+
+        self.assertEqual(val, 127)
+        self.assertEqual(rem, b"")
+
+    def test_encoding_of_128(self):
+        val, rem = remove_integer(b"\x02\x02\x00\x80")
+
+        self.assertEqual(val, 128)
+        self.assertEqual(rem, b"")
+
+    def test_wrong_tag(self):
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_integer(b"\x01\x02\x00\x80")
+
+        self.assertIn("wanted type 'integer'", str(e.exception))
+
+    def test_wrong_length(self):
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_integer(b"\x02\x03\x00\x80")
+
+        self.assertIn("Length longer", str(e.exception))
+
+
+class TestReadLength(unittest.TestCase):
+    # DER requires the lengths between 0 and 127 to be encoded using the short
+    # form and lengths above that encoded with minimal number of bytes
+    # necessary
+    def test_zero_length(self):
+        self.assertEqual((0, 1), read_length(b"\x00"))
+
+    def test_two_byte_zero_length(self):
+        with self.assertRaises(UnexpectedDER):
+            read_length(b"\x81\x00")
+
+    def test_two_byte_small_length(self):
+        with self.assertRaises(UnexpectedDER):
+            read_length(b"\x81\x7f")
+
+    def test_long_form_with_zero_length(self):
+        with self.assertRaises(UnexpectedDER):
+            read_length(b"\x80")
+
+    def test_smallest_two_byte_length(self):
+        self.assertEqual((128, 2), read_length(b"\x81\x80"))
+
+    def test_zero_padded_length(self):
+        with self.assertRaises(UnexpectedDER):
+            read_length(b"\x82\x00\x80")
+
+    def test_two_three_byte_length(self):
+        self.assertEqual((256, 3), read_length(b"\x82\x01\x00"))
+
+    def test_empty_string(self):
+        with self.assertRaises(UnexpectedDER):
+            read_length(b"")
+
+    def test_length_overflow(self):
+        with self.assertRaises(UnexpectedDER):
+            read_length(b"\x83\x01\x00")
+
+
+class TestEncodeBitstring(unittest.TestCase):
+    # DER requires BIT STRINGS to include a number of padding bits in the
+    # encoded byte string, that padding must be between 0 and 7
+
+    def test_old_call_convention(self):
+        """This is the old way to use the function."""
+        warnings.simplefilter("always")
+        with pytest.warns(DeprecationWarning) as warns:
+            der = encode_bitstring(b"\x00\xff")
+
+        self.assertEqual(len(warns), 1)
+        self.assertIn(
+            "unused= needs to be specified", warns[0].message.args[0]
+        )
+
+        self.assertEqual(der, b"\x03\x02\x00\xff")
+
+    def test_new_call_convention(self):
+        """This is how it should be called now."""
+        # make sure no warnings are raised
+        with warnings.catch_warnings():
+            warnings.simplefilter("error")
+            der = encode_bitstring(b"\xff", 0)
+
+        self.assertEqual(der, b"\x03\x02\x00\xff")
+
+    def test_implicit_unused_bits(self):
+        """
+        Writing bit string with already included the number of unused bits.
+        """
+        # make sure no warnings are raised
+        with warnings.catch_warnings():
+            warnings.simplefilter("error")
+            der = encode_bitstring(b"\x00\xff", None)
+
+        self.assertEqual(der, b"\x03\x02\x00\xff")
+
+    def test_explicit_unused_bits(self):
+        der = encode_bitstring(b"\xff\xf0", 4)
+
+        self.assertEqual(der, b"\x03\x03\x04\xff\xf0")
+
+    def test_empty_string(self):
+        self.assertEqual(encode_bitstring(b"", 0), b"\x03\x01\x00")
+
+    def test_invalid_unused_count(self):
+        with self.assertRaises(ValueError):
+            encode_bitstring(b"\xff\x00", 8)
+
+    def test_invalid_unused_with_empty_string(self):
+        with self.assertRaises(ValueError):
+            encode_bitstring(b"", 1)
+
+    def test_non_zero_padding_bits(self):
+        with self.assertRaises(ValueError):
+            encode_bitstring(b"\xff", 2)
+
+
+class TestRemoveBitstring(unittest.TestCase):
+    def test_old_call_convention(self):
+        """This is the old way to call the function."""
+        warnings.simplefilter("always")
+        with pytest.warns(DeprecationWarning) as warns:
+            bits, rest = remove_bitstring(b"\x03\x02\x00\xff")
+
+        self.assertEqual(len(warns), 1)
+        self.assertIn(
+            "expect_unused= needs to be specified", warns[0].message.args[0]
+        )
+
+        self.assertEqual(bits, b"\x00\xff")
+        self.assertEqual(rest, b"")
+
+    def test_new_call_convention(self):
+        # make sure no warnings are raised
+        with warnings.catch_warnings():
+            warnings.simplefilter("error")
+            bits, rest = remove_bitstring(b"\x03\x02\x00\xff", 0)
+
+        self.assertEqual(bits, b"\xff")
+        self.assertEqual(rest, b"")
+
+    def test_implicit_unexpected_unused(self):
+        # make sure no warnings are raised
+        with warnings.catch_warnings():
+            warnings.simplefilter("error")
+            bits, rest = remove_bitstring(b"\x03\x02\x00\xff", None)
+
+        self.assertEqual(bits, (b"\xff", 0))
+        self.assertEqual(rest, b"")
+
+    def test_with_padding(self):
+        ret, rest = remove_bitstring(b"\x03\x02\x04\xf0", None)
+
+        self.assertEqual(ret, (b"\xf0", 4))
+        self.assertEqual(rest, b"")
+
+    def test_not_a_bitstring(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x02\x02\x00\xff", None)
+
+    def test_empty_encoding(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x03\x00", None)
+
+    def test_empty_string(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"", None)
+
+    def test_no_length(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x03", None)
+
+    def test_unexpected_number_of_unused_bits(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x03\x02\x00\xff", 1)
+
+    def test_invalid_encoding_of_unused_bits(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x03\x03\x08\xff\x00", None)
+
+    def test_invalid_encoding_of_empty_string(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x03\x01\x01", None)
+
+    def test_invalid_padding_bits(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_bitstring(b"\x03\x02\x01\xff", None)
+
+
+class TestStrIdxAsInt(unittest.TestCase):
+    def test_str(self):
+        self.assertEqual(115, str_idx_as_int("str", 0))
+
+    def test_bytes(self):
+        self.assertEqual(115, str_idx_as_int(b"str", 0))
+
+    def test_bytearray(self):
+        self.assertEqual(115, str_idx_as_int(bytearray(b"str"), 0))
+
+
+class TestEncodeOid(unittest.TestCase):
+    def test_pub_key_oid(self):
+        oid_ecPublicKey = encode_oid(1, 2, 840, 10045, 2, 1)
+        self.assertEqual(hexlify(oid_ecPublicKey), b"06072a8648ce3d0201")
+
+    def test_nist224p_oid(self):
+        self.assertEqual(hexlify(NIST224p.encoded_oid), b"06052b81040021")
+
+    def test_nist256p_oid(self):
+        self.assertEqual(
+            hexlify(NIST256p.encoded_oid), b"06082a8648ce3d030107"
+        )
+
+    def test_large_second_subid(self):
+        # from X.690, section 8.19.5
+        oid = encode_oid(2, 999, 3)
+        self.assertEqual(oid, b"\x06\x03\x88\x37\x03")
+
+    def test_with_two_subids(self):
+        oid = encode_oid(2, 999)
+        self.assertEqual(oid, b"\x06\x02\x88\x37")
+
+    def test_zero_zero(self):
+        oid = encode_oid(0, 0)
+        self.assertEqual(oid, b"\x06\x01\x00")
+
+    def test_with_wrong_types(self):
+        with self.assertRaises((TypeError, AssertionError)):
+            encode_oid(0, None)
+
+    def test_with_small_first_large_second(self):
+        with self.assertRaises(AssertionError):
+            encode_oid(1, 40)
+
+    def test_small_first_max_second(self):
+        oid = encode_oid(1, 39)
+        self.assertEqual(oid, b"\x06\x01\x4f")
+
+    def test_with_invalid_first(self):
+        with self.assertRaises(AssertionError):
+            encode_oid(3, 39)
+
+
+class TestRemoveObject(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.oid_ecPublicKey = encode_oid(1, 2, 840, 10045, 2, 1)
+
+    def test_pub_key_oid(self):
+        oid, rest = remove_object(self.oid_ecPublicKey)
+        self.assertEqual(rest, b"")
+        self.assertEqual(oid, (1, 2, 840, 10045, 2, 1))
+
+    def test_with_extra_bytes(self):
+        oid, rest = remove_object(self.oid_ecPublicKey + b"more")
+        self.assertEqual(rest, b"more")
+        self.assertEqual(oid, (1, 2, 840, 10045, 2, 1))
+
+    def test_with_large_second_subid(self):
+        # from X.690, section 8.19.5
+        oid, rest = remove_object(b"\x06\x03\x88\x37\x03")
+        self.assertEqual(rest, b"")
+        self.assertEqual(oid, (2, 999, 3))
+
+    def test_with_padded_first_subid(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06\x02\x80\x00")
+
+    def test_with_padded_second_subid(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06\x04\x88\x37\x80\x01")
+
+    def test_with_missing_last_byte_of_multi_byte(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06\x03\x88\x37\x83")
+
+    def test_with_two_subids(self):
+        oid, rest = remove_object(b"\x06\x02\x88\x37")
+        self.assertEqual(rest, b"")
+        self.assertEqual(oid, (2, 999))
+
+    def test_zero_zero(self):
+        oid, rest = remove_object(b"\x06\x01\x00")
+        self.assertEqual(rest, b"")
+        self.assertEqual(oid, (0, 0))
+
+    def test_empty_string(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"")
+
+    def test_missing_length(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06")
+
+    def test_empty_oid(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06\x00")
+
+    def test_empty_oid_overflow(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06\x01")
+
+    def test_with_wrong_type(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x04\x02\x88\x37")
+
+    def test_with_too_long_length(self):
+        with self.assertRaises(UnexpectedDER):
+            remove_object(b"\x06\x03\x88\x37")
+
+
+class TestRemoveConstructed(unittest.TestCase):
+    def test_simple(self):
+        data = b"\xa1\x02\xff\xaa"
+
+        tag, body, rest = remove_constructed(data)
+
+        self.assertEqual(tag, 0x01)
+        self.assertEqual(body, b"\xff\xaa")
+        self.assertEqual(rest, b"")
+
+    def test_with_malformed_tag(self):
+        data = b"\x01\x02\xff\xaa"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_constructed(data)
+
+        self.assertIn("constructed tag", str(e.exception))
+
+
+class TestRemoveOctetString(unittest.TestCase):
+    def test_simple(self):
+        data = b"\x04\x03\xaa\xbb\xcc"
+        body, rest = remove_octet_string(data)
+        self.assertEqual(body, b"\xaa\xbb\xcc")
+        self.assertEqual(rest, b"")
+
+    def test_with_malformed_tag(self):
+        data = b"\x03\x03\xaa\xbb\xcc"
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_octet_string(data)
+
+        self.assertIn("octetstring", str(e.exception))
+
+
+class TestRemoveSequence(unittest.TestCase):
+    def test_simple(self):
+        data = b"\x30\x02\xff\xaa"
+        body, rest = remove_sequence(data)
+        self.assertEqual(body, b"\xff\xaa")
+        self.assertEqual(rest, b"")
+
+    def test_with_empty_string(self):
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_sequence(b"")
+
+        self.assertIn("Empty string", str(e.exception))
+
+    def test_with_wrong_tag(self):
+        data = b"\x20\x02\xff\xaa"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_sequence(data)
+
+        self.assertIn("wanted type 'sequence'", str(e.exception))
+
+    def test_with_wrong_length(self):
+        data = b"\x30\x03\xff\xaa"
+
+        with self.assertRaises(UnexpectedDER) as e:
+            remove_sequence(data)
+
+        self.assertIn("Length longer", str(e.exception))
+
+
+@st.composite
+def st_oid(draw, max_value=2**512, max_size=50):
+    """
+    Hypothesis strategy that returns valid OBJECT IDENTIFIERs as tuples
+
+    :param max_value: maximum value of any single sub-identifier
+    :param max_size: maximum length of the generated OID
+    """
+    first = draw(st.integers(min_value=0, max_value=2))
+    if first < 2:
+        second = draw(st.integers(min_value=0, max_value=39))
+    else:
+        second = draw(st.integers(min_value=0, max_value=max_value))
+    rest = draw(
+        st.lists(
+            st.integers(min_value=0, max_value=max_value), max_size=max_size
+        )
+    )
+    return (first, second) + tuple(rest)
+
+
+HYP_SETTINGS = {}
+
+
+if "--fast" in sys.argv:  # pragma: no cover
+    HYP_SETTINGS["max_examples"] = 2
+
+
+@settings(**HYP_SETTINGS)
+@given(st_oid())
+def test_oids(ids):
+    encoded_oid = encode_oid(*ids)
+    decoded_oid, rest = remove_object(encoded_oid)
+    assert rest == b""
+    assert decoded_oid == ids