testing/cross_language/keyset_validation_test.py

# Copyright 2020 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Tests keyset validation.

Currently only tests if keysets without a primary key are properly handled.
"""

import datetime

from typing import List

from absl.testing import absltest
from absl.testing import parameterized

import tink
from tink import jwt

from tink.proto import tink_pb2

from util import supported_key_types
from util import testing_servers


def unset_primary(keyset: bytes) -> bytes:
  """Parses keyset and generates modified keyset without primary key."""
  keyset_proto = tink_pb2.Keyset.FromString(keyset)
  keyset_proto.ClearField('primary_key_id')
  return keyset_proto.SerializeToString()


def test_cases(key_types: List[str]):
  for key_type in key_types:
    for key_template_name in supported_key_types.KEY_TEMPLATE_NAMES[key_type]:
      for lang in supported_key_types.SUPPORTED_LANGUAGES[key_type]:
        yield (key_template_name, lang)


def setUpModule():
  testing_servers.start('key_version')


def tearDownModule():
  testing_servers.stop()


class KeysetValidationTest(parameterized.TestCase):
  """These tests verify keysets are properly validated."""

  @parameterized.parameters(test_cases(supported_key_types.AEAD_KEY_TYPES))
  def test_aead_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to use an AEAD primitive."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    keyset = testing_servers.new_keyset(lang, template)
    ciphertext = testing_servers.aead(lang, keyset).encrypt(b'foo', b'bar')

    aead_without_primary = testing_servers.aead(lang, unset_primary(keyset))
    with self.assertRaises(tink.TinkError):
      _ = aead_without_primary.encrypt(b'foo', b'bar')
    with self.assertRaises(tink.TinkError):
      _ = aead_without_primary.decrypt(ciphertext, b'bar')

  @parameterized.parameters(test_cases(supported_key_types.DAEAD_KEY_TYPES))
  def test_daead_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to use a DAEAD primitive."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    keyset = testing_servers.new_keyset(lang, template)
    p = testing_servers.deterministic_aead(lang, keyset)
    ciphertext = p.encrypt_deterministically(b'foo', b'bar')
    daead_without_primary = testing_servers.deterministic_aead(
        lang, unset_primary(keyset))
    with self.assertRaises(tink.TinkError):
      _ = daead_without_primary.encrypt_deterministically(b'foo', b'bar')
    with self.assertRaises(tink.TinkError):
      _ = daead_without_primary.decrypt_deterministically(ciphertext, b'bar')

  @parameterized.parameters(test_cases(supported_key_types.MAC_KEY_TYPES))
  def test_mac_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to use a MAC primitive."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    keyset = testing_servers.new_keyset(lang, template)
    mac_value = testing_servers.mac(lang, keyset).compute_mac(b'foo')
    mac_without_primary = testing_servers.mac(lang, unset_primary(keyset))
    with self.assertRaises(tink.TinkError):
      _ = mac_without_primary.compute_mac(b'foo')
    with self.assertRaises(tink.TinkError):
      mac_without_primary.verify_mac(mac_value, b'foo')

  @parameterized.parameters(test_cases(supported_key_types.PRF_KEY_TYPES))
  def test_prf_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to use a PRF set primitive."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    keyset = testing_servers.new_keyset(lang, template)
    _ = testing_servers.prf_set(lang, keyset).primary().compute(b'foo', 16)
    prf_set_without_primary = testing_servers.prf_set(lang,
                                                      unset_primary(keyset))
    with self.assertRaises(tink.TinkError):
      _ = prf_set_without_primary.primary().compute(b'foo', 16)

  # We skip RSA keys to make the tests run faster. It shouldn't make a
  # difference since the logic does not really depend on the key type.
  @parameterized.parameters(test_cases(['EcdsaPrivateKey']))
  def test_signature_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to sign and verify signatures."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    private_keyset = testing_servers.new_keyset(lang, template)
    public_keyset = testing_servers.public_keyset(lang, private_keyset)
    sig = testing_servers.public_key_sign(lang, private_keyset).sign(b'foo')
    testing_servers.public_key_verify(lang, public_keyset).verify(sig, b'foo')

    signer_without_primary = testing_servers.public_key_sign(
        lang, unset_primary(private_keyset))
    verifier_without_primary = testing_servers.public_key_verify(
        lang, unset_primary(public_keyset))
    with self.assertRaises(tink.TinkError):
      signer_without_primary.sign(b'foo')
    if lang in ['java', 'python']:
      # Java and Python currently allow this.
      verifier_without_primary.verify(sig, b'foo')
    else:
      with self.assertRaises(tink.TinkError):
        verifier_without_primary.verify(sig, b'foo')

  @parameterized.parameters(
      test_cases(supported_key_types.HYBRID_PRIVATE_KEY_TYPES))
  def test_hybrid_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to use hybrid encryption."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    private_keyset = testing_servers.new_keyset(lang, template)
    public_keyset = testing_servers.public_keyset(lang, private_keyset)
    ciphertext = testing_servers.hybrid_encrypt(lang, public_keyset).encrypt(
        b'foo', b'context_info')

    dec_without_primary = testing_servers.hybrid_decrypt(
        lang, unset_primary(private_keyset))
    with self.assertRaises(tink.TinkError):
      dec_without_primary.decrypt(ciphertext, b'context_info')

    enc_without_primary = testing_servers.hybrid_encrypt(
        lang, unset_primary(public_keyset))
    with self.assertRaises(tink.TinkError):
      enc_without_primary.encrypt(b'foo', b'context_info')

  # We skip RSA keys to make the tests run faster. It shouldn't make a
  # difference since the logic does not really depend on the key type.
  @parameterized.parameters(test_cases(['JwtEcdsaPrivateKey']))
  def test_jwt_signature_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to sign and verify JWT signatures."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    private_keyset = testing_servers.new_keyset(lang, template)
    public_keyset = testing_servers.public_keyset(lang, private_keyset)
    signer = testing_servers.jwt_public_key_sign(lang, private_keyset)

    now = datetime.datetime.now(tz=datetime.timezone.utc)
    raw_jwt = jwt.new_raw_jwt(
        issuer='issuer',
        expiration=now + datetime.timedelta(seconds=100))
    token = signer.sign_and_encode(raw_jwt)

    signer_without_primary = testing_servers.jwt_public_key_sign(
        lang, unset_primary(private_keyset))
    with self.assertRaises(tink.TinkError):
      signer_without_primary.sign_and_encode(raw_jwt)

    verifier_without_primary = testing_servers.jwt_public_key_verify(
        lang, unset_primary(public_keyset))
    validator = jwt.new_validator(expected_issuer='issuer', fixed_now=now)
    if lang in ['cc', 'java', 'python']:
      # C++, Java and Python currently allow this.
      verifier_without_primary.verify_and_decode(token, validator)
    else:
      with self.assertRaises(tink.TinkError):
        verifier_without_primary.verify_and_decode(token, validator)

  @parameterized.parameters(
      test_cases(supported_key_types.JWT_MAC_KEY_TYPES))
  def test_jwt_mac_without_primary(self, key_template_name, lang):
    """Unsets the primary key and tries to create and verify JWT MACs."""
    template = supported_key_types.KEY_TEMPLATE[key_template_name]
    keyset = testing_servers.new_keyset(lang, template)
    jwt_mac = testing_servers.jwt_mac(lang, keyset)

    now = datetime.datetime.now(tz=datetime.timezone.utc)
    raw_jwt = jwt.new_raw_jwt(
        issuer='issuer',
        expiration=now + datetime.timedelta(seconds=100))
    token = jwt_mac.compute_mac_and_encode(raw_jwt)

    jwt_mac_without_primary = testing_servers.jwt_mac(
        lang, unset_primary(keyset))
    with self.assertRaises(tink.TinkError):
      jwt_mac_without_primary.compute_mac_and_encode(raw_jwt)

    validator = jwt.new_validator(expected_issuer='issuer', fixed_now=now)
    with self.assertRaises(tink.TinkError):
      jwt_mac_without_primary.verify_mac_and_decode(token, validator)


if __name__ == '__main__':
  absltest.main()