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Diffstat (limited to 'test/test_policy.py')
| -rw-r--r-- | test/test_policy.py | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/test/test_policy.py b/test/test_policy.py new file mode 100644 index 0000000..3e4b5f2 --- /dev/null +++ b/test/test_policy.py @@ -0,0 +1,436 @@ +import hashlib +import pytest +from datetime import date + +from ssh_audit.outputbuffer import OutputBuffer +from ssh_audit.policy import Policy +from ssh_audit.ssh2_kex import SSH2_Kex +from ssh_audit.writebuf import WriteBuf + + +class TestPolicy: + @pytest.fixture(autouse=True) + def init(self, ssh_audit): + self.OutputBuffer = OutputBuffer + self.Policy = Policy + self.wbuf = WriteBuf + self.ssh2_kex = SSH2_Kex + + + def _get_kex(self): + '''Returns an SSH2.Kex object to simulate a server connection.''' + + w = self.wbuf() + w.write(b'\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xaa\xbb\xcc\xdd\xee\xff') + w.write_list(['kex_alg1', 'kex_alg2']) + w.write_list(['key_alg1', 'key_alg2']) + w.write_list(['cipher_alg1', 'cipher_alg2', 'cipher_alg3']) + w.write_list(['cipher_alg1', 'cipher_alg2', 'cipher_alg3']) + w.write_list(['mac_alg1', 'mac_alg2', 'mac_alg3']) + w.write_list(['mac_alg1', 'mac_alg2', 'mac_alg3']) + w.write_list(['comp_alg1', 'comp_alg2']) + w.write_list(['comp_alg1', 'comp_alg2']) + w.write_list(['']) + w.write_list(['']) + w.write_byte(False) + w.write_int(0) + return self.ssh2_kex.parse(self.OutputBuffer, w.write_flush()) + + + def test_builtin_policy_consistency(self): + '''Ensure that the BUILTIN_POLICIES struct is consistent.''' + + for policy_name in Policy.BUILTIN_POLICIES: + # Ensure that the policy name ends with " (version X)", where X is the 'version' field. + version_str = " (version %s)" % Policy.BUILTIN_POLICIES[policy_name]['version'] + assert policy_name.endswith(version_str) + + # Ensure that all required fields are present. + required_fields = ['version', 'banner', 'compressions', 'host_keys', 'optional_host_keys', 'kex', 'ciphers', 'macs', 'hostkey_sizes', 'dh_modulus_sizes', 'server_policy'] + for field in required_fields: + assert field in Policy.BUILTIN_POLICIES[policy_name] + + # Ensure no extra fields are present. + assert len(required_fields) == len(Policy.BUILTIN_POLICIES[policy_name]) + + # Ensure that at least one host key is defined. + assert type(Policy.BUILTIN_POLICIES[policy_name]['host_keys']) is list + assert len(Policy.BUILTIN_POLICIES[policy_name]['host_keys']) > 0 + + # Ensure that at least one key exchange is defined. + assert type(Policy.BUILTIN_POLICIES[policy_name]['kex']) is list + assert len(Policy.BUILTIN_POLICIES[policy_name]['kex']) > 0 + + # Ensure that at least one cipher is defined. + assert type(Policy.BUILTIN_POLICIES[policy_name]['ciphers']) is list + assert len(Policy.BUILTIN_POLICIES[policy_name]['ciphers']) > 0 + + # Ensure that at least one MAC is defined + assert type(Policy.BUILTIN_POLICIES[policy_name]['macs']) is list + assert len(Policy.BUILTIN_POLICIES[policy_name]['macs']) > 0 + + # These tests apply to server policies only. + if Policy.BUILTIN_POLICIES[policy_name]['server_policy']: + assert type(Policy.BUILTIN_POLICIES[policy_name]['hostkey_sizes']) is dict + assert len(Policy.BUILTIN_POLICIES[policy_name]['hostkey_sizes']) > 0 + + # Examine all the hostkey_sizes entries... + for hostkey_type in Policy.BUILTIN_POLICIES[policy_name]['hostkey_sizes']: + hostkey_data = Policy.BUILTIN_POLICIES[policy_name]['hostkey_sizes'][hostkey_type] + + # Ensure that 'hostkey_size' is always included and that it is an integer. + assert 'hostkey_size' in hostkey_data + assert type(hostkey_data['hostkey_size']) is int + + # If this is an ed25519 host key, ensure its size is fixed at 256. If its an RSA host key, ensure the size is 4096. + if hostkey_type.find('ed25519') != -1: + assert int(hostkey_data['hostkey_size']) == 256 + elif hostkey_type.startswith('rsa-'): + assert int(hostkey_data['hostkey_size']) == 4096 + else: # Catch unexpected host key types. + assert False + + # Ensure either that 'ca_key_type' and 'ca_key_size' are both present, or neither are. Fail cases when only one of the fields are present. + assert (('ca_key_type' in hostkey_data) and ('ca_key_size' in hostkey_data)) or (('ca_key_type' not in hostkey_data) and ('ca_key_size' not in hostkey_data)) + + # Ensure that the ca_key_type is either ssh-rsa or ssh-ed25519. + if 'ca_key_type' in hostkey_data: + assert hostkey_data['ca_key_type'] in ['ssh-rsa', 'ssh-ed25519'] + + # Ensure RSA CA key sizes are fixed at 4096. Ensure ED25519 CA keys are 256. + if 'ca_key_size' in hostkey_data: + if 'ca_key_type' == 'ssh-rsa': + assert hostkey_data['ca_key_size'] == 4096 + elif 'ca_key_type' == 'ssh-ed25519': + assert hostkey_data['ca_key_size'] == 256 + + # Ensure that the 'dh_modulus_size' field is a dict. + assert type(Policy.BUILTIN_POLICIES[policy_name]['dh_modulus_sizes']) is dict + + # The 'dh_modulus_size' field should have either one entry, or be empty. + assert len(Policy.BUILTIN_POLICIES[policy_name]['dh_modulus_sizes']) in range(0, 2) # The endpoint in range() is not inclusive + + # If 'diffie-hellman-group-exchange-sha256' is in the kex list, ensure that it exists in the 'dh_modulus_sizes' entry. That entry must be defined for 2048 bits or larger. + if 'diffie-hellman-group-exchange-sha256' in Policy.BUILTIN_POLICIES[policy_name]['kex']: + assert 'diffie-hellman-group-exchange-sha256' in Policy.BUILTIN_POLICIES[policy_name]['dh_modulus_sizes'] + assert int(Policy.BUILTIN_POLICIES[policy_name]['dh_modulus_sizes']['diffie-hellman-group-exchange-sha256']) >= 2048 + + else: # Client-specific tests. + + # These must be set to None for client policies, since they have no meaning otherwise. + assert Policy.BUILTIN_POLICIES[policy_name]['hostkey_sizes'] is None + assert Policy.BUILTIN_POLICIES[policy_name]['dh_modulus_sizes'] is None + + # Ensure that each built-in policy can be loaded with Policy.load_builtin_policy(). + assert Policy.load_builtin_policy(policy_name) is not None + + # Ensure that both server and client policy names are returned. + server_policy_names, client_policy_names = Policy.list_builtin_policies() + assert len(server_policy_names) > 0 + assert len(client_policy_names) > 0 + + + def test_policy_basic(self): + '''Ensure that a basic policy can be parsed correctly.''' + + policy_data = '''# This is a comment +name = "Test Policy" +version = 1 + +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + assert str(policy) == "Name: [Test Policy]\nVersion: [1]\nBanner: {undefined}\nCompressions: comp_alg1\nHost Keys: key_alg1\nOptional Host Keys: {undefined}\nKey Exchanges: kex_alg1, kex_alg2\nCiphers: cipher_alg1, cipher_alg2, cipher_alg3\nMACs: mac_alg1, mac_alg2, mac_alg3\nHost Key Sizes: {undefined}\nDH Modulus Sizes: {undefined}\nServer Policy: True" + + + def test_policy_invalid_1(self): + '''Basic policy, but with 'ciphersx' instead of 'ciphers'.''' + + policy_data = '''# This is a comment +name = "Test Policy" +version = 1 + +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphersx = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + failed = False + try: + self.Policy(policy_data=policy_data) + except ValueError: + failed = True + + assert failed, "Invalid policy did not cause Policy object to throw exception" + + + def test_policy_invalid_2(self): + '''Basic policy, but is missing the required name field.''' + + policy_data = '''# This is a comment +#name = "Test Policy" +version = 1 + +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + failed = False + try: + self.Policy(policy_data=policy_data) + except ValueError: + failed = True + + assert failed, "Invalid policy did not cause Policy object to throw exception" + + + def test_policy_invalid_3(self): + '''Basic policy, but is missing the required version field.''' + + policy_data = '''# This is a comment +name = "Test Policy" +#version = 1 + +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + failed = False + try: + self.Policy(policy_data=policy_data) + except ValueError: + failed = True + + assert failed, "Invalid policy did not cause Policy object to throw exception" + + + def test_policy_invalid_4(self): + '''Basic policy, but is missing quotes in the name field.''' + + policy_data = '''# This is a comment +name = Test Policy +version = 1 + +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + failed = False + try: + self.Policy(policy_data=policy_data) + except ValueError: + failed = True + + assert failed, "Invalid policy did not cause Policy object to throw exception" + + + def test_policy_invalid_5(self): + '''Basic policy, but is missing quotes in the banner field.''' + + policy_data = '''# This is a comment +name = "Test Policy" +version = 1 + +banner = 0mg +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + failed = False + try: + self.Policy(policy_data=policy_data) + except ValueError: + failed = True + + assert failed, "Invalid policy did not cause Policy object to throw exception" + + + def test_policy_invalid_6(self): + '''Basic policy, but is missing quotes in the header field.''' + + policy_data = '''# This is a comment +name = "Test Policy" +version = 1 + +header = 0mg +compressions = comp_alg1 +host keys = key_alg1 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + failed = False + try: + self.Policy(policy_data=policy_data) + except ValueError: + failed = True + + assert failed, "Invalid policy did not cause Policy object to throw exception" + + + def test_policy_create_1(self): + '''Creates a policy from a kex and ensures it is generated exactly as expected.''' + + kex = self._get_kex() + pol_data = self.Policy.create('www.l0l.com', 'bannerX', kex, False) + + # Today's date is embedded in the policy, so filter it out to get repeatable results. + pol_data = pol_data.replace(date.today().strftime('%Y/%m/%d'), '[todays date]') + + # Instead of writing out the entire expected policy--line by line--just check that it has the expected hash. + assert hashlib.sha256(pol_data.encode('ascii')).hexdigest() == '4af7777fb57a1dad0cf438c899a11d4f625fd9276ea3bb5ef5c9fe8806cb47dc' + + + def test_policy_evaluate_passing_1(self): + '''Creates a policy and evaluates it against the same server''' + + kex = self._get_kex() + policy_data = self.Policy.create('www.l0l.com', None, kex, False) + policy = self.Policy(policy_data=policy_data) + + ret, errors, error_str = policy.evaluate('SSH Server 1.0', kex) + assert ret is True + assert len(errors) == 0 + print(error_str) + assert len(error_str) == 0 + + + def test_policy_evaluate_failing_1(self): + '''Ensure that a policy with a specified banner fails against a server with a different banner''' + + policy_data = '''name = "Test Policy" +version = 1 +banner = "XXX mismatched banner XXX" +compressions = comp_alg1, comp_alg2 +host keys = key_alg1, key_alg2 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 1 + assert error_str.find('Banner did not match.') != -1 + + + def test_policy_evaluate_failing_2(self): + '''Ensure that a mismatched compressions list results in a failure''' + + policy_data = '''name = "Test Policy" +version = 1 +compressions = XXXmismatchedXXX, comp_alg1, comp_alg2 +host keys = key_alg1, key_alg2 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 1 + assert error_str.find('Compression did not match.') != -1 + + + def test_policy_evaluate_failing_3(self): + '''Ensure that a mismatched host keys results in a failure''' + + policy_data = '''name = "Test Policy" +version = 1 +compressions = comp_alg1, comp_alg2 +host keys = XXXmismatchedXXX, key_alg1, key_alg2 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 1 + assert error_str.find('Host keys did not match.') != -1 + + + def test_policy_evaluate_failing_4(self): + '''Ensure that a mismatched key exchange list results in a failure''' + + policy_data = '''name = "Test Policy" +version = 1 +compressions = comp_alg1, comp_alg2 +host keys = key_alg1, key_alg2 +key exchanges = XXXmismatchedXXX, kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 1 + assert error_str.find('Key exchanges did not match.') != -1 + + + def test_policy_evaluate_failing_5(self): + '''Ensure that a mismatched cipher list results in a failure''' + + policy_data = '''name = "Test Policy" +version = 1 +compressions = comp_alg1, comp_alg2 +host keys = key_alg1, key_alg2 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, XXXmismatched, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 1 + assert error_str.find('Ciphers did not match.') != -1 + + + def test_policy_evaluate_failing_6(self): + '''Ensure that a mismatched MAC list results in a failure''' + + policy_data = '''name = "Test Policy" +version = 1 +compressions = comp_alg1, comp_alg2 +host keys = key_alg1, key_alg2 +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, XXXmismatched, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 1 + assert error_str.find('MACs did not match.') != -1 + + + def test_policy_evaluate_failing_7(self): + '''Ensure that a mismatched host keys and MACs results in a failure''' + + policy_data = '''name = "Test Policy" +version = 1 +compressions = comp_alg1, comp_alg2 +host keys = key_alg1, key_alg2, XXXmismatchedXXX +key exchanges = kex_alg1, kex_alg2 +ciphers = cipher_alg1, cipher_alg2, cipher_alg3 +macs = mac_alg1, mac_alg2, XXXmismatchedXXX, mac_alg3''' + + policy = self.Policy(policy_data=policy_data) + ret, errors, error_str = policy.evaluate('SSH Server 1.0', self._get_kex()) + assert ret is False + assert len(errors) == 2 + assert error_str.find('Host keys did not match.') != -1 + assert error_str.find('MACs did not match.') != -1 |