""" The MIT License (MIT) Copyright (C) 2020-2024 Joe Testa (jtesta@positronsecurity.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. """ import copy import json import sys from typing import Dict, List, Tuple from typing import Optional, Any, Union, cast from datetime import date from ssh_audit import exitcodes from ssh_audit.banner import Banner from ssh_audit.builtin_policies import BUILTIN_POLICIES from ssh_audit.globals import SNAP_PACKAGE, SNAP_PERMISSIONS_ERROR from ssh_audit.ssh2_kex import SSH2_Kex # Validates policy files and performs policy testing class Policy: WARNING_DEPRECATED_DIRECTIVES = "\nWARNING: this policy is using deprecated features. Future versions of ssh-audit may remove support for them. Re-generating the policy file is perhaps the most straight-forward way of resolving this issue. Manually converting the 'hostkey_size_*', 'cakey_size_*', and 'dh_modulus_size_*' directives into the new format is another option.\n" def __init__(self, policy_file: Optional[str] = None, policy_data: Optional[str] = None, manual_load: bool = False, json_output: bool = False) -> None: self._name: Optional[str] = None self._version: Optional[str] = None self._banner: Optional[str] = None self._compressions: Optional[List[str]] = None self._host_keys: Optional[List[str]] = None self._optional_host_keys: Optional[List[str]] = None self._kex: Optional[List[str]] = None self._ciphers: Optional[List[str]] = None self._macs: Optional[List[str]] = None self._hostkey_sizes: Optional[Dict[str, Dict[str, Union[int, str, bytes]]]] = None self._dh_modulus_sizes: Optional[Dict[str, int]] = None self._server_policy = True self._allow_algorithm_subset_and_reordering = False self._allow_larger_keys = False self._errors: List[Any] = [] self._name_and_version: str = '' # If invoked while JSON output is expected, send warnings to stderr instead of stdout (which would corrupt the JSON output). if json_output: self._warning_target = sys.stderr else: self._warning_target = sys.stdout # Ensure that only one mode was specified. num_modes = 0 if policy_file is not None: num_modes += 1 if policy_data is not None: num_modes += 1 if manual_load is True: num_modes += 1 if num_modes != 1: raise RuntimeError('Exactly one of the following can be specified only: policy_file, policy_data, or manual_load') if manual_load: return if policy_file is not None: try: with open(policy_file, "r", encoding='utf-8') as f: policy_data = f.read() except FileNotFoundError: print("Error: policy file not found: %s" % policy_file) sys.exit(exitcodes.UNKNOWN_ERROR) except PermissionError as e: # If installed as a Snap package, print a more useful message with potential work-arounds. if SNAP_PACKAGE: print(SNAP_PERMISSIONS_ERROR) else: print("Error: insufficient permissions: %s" % str(e)) sys.exit(exitcodes.UNKNOWN_ERROR) lines = [] if policy_data is not None: lines = policy_data.split("\n") for line in lines: line = line.strip() if (len(line) == 0) or line.startswith('#'): continue key = None val = None try: key, val = line.split('=') except ValueError as ve: raise ValueError("could not parse line: %s" % line) from ve key = key.strip() val = val.strip() if key not in ['name', 'version', 'banner', 'compressions', 'host keys', 'optional host keys', 'key exchanges', 'ciphers', 'macs', 'client policy', 'host_key_sizes', 'dh_modulus_sizes', 'allow_algorithm_subset_and_reordering', 'allow_larger_keys'] and not key.startswith('hostkey_size_') and not key.startswith('cakey_size_') and not key.startswith('dh_modulus_size_'): raise ValueError("invalid field found in policy: %s" % line) if key in ['name', 'banner']: # If the banner value is blank, set it to "" so that the code below handles it. if len(val) < 2: val = "\"\"" if (val[0] != '"') or (val[-1] != '"'): raise ValueError('the value for the %s field must be enclosed in quotes: %s' % (key, val)) # Remove the surrounding quotes, and unescape quotes & newlines. val = val[1:-1]. replace("\\\"", "\"").replace("\\n", "\n") if key == 'name': self._name = val elif key == 'banner': self._banner = val elif key == 'version': self._version = val elif key in ['compressions', 'host keys', 'optional host keys', 'key exchanges', 'ciphers', 'macs']: try: algs = val.split(',') except ValueError: # If the value has no commas, then set the algorithm list to just the value. algs = [val] # Strip whitespace in each algorithm name. algs = [alg.strip() for alg in algs] if key == 'compressions': self._compressions = algs elif key == 'host keys': self._host_keys = algs elif key == 'optional host keys': self._optional_host_keys = algs elif key == 'key exchanges': self._kex = algs elif key == 'ciphers': self._ciphers = algs elif key == 'macs': self._macs = algs elif key.startswith('hostkey_size_'): # Old host key size format. print(Policy.WARNING_DEPRECATED_DIRECTIVES, file=self._warning_target) # Warn the user that the policy file is using deprecated directives. hostkey_type = key[13:] hostkey_size = int(val) if self._hostkey_sizes is None: self._hostkey_sizes = {} self._hostkey_sizes[hostkey_type] = {'hostkey_size': hostkey_size, 'ca_key_type': '', 'ca_key_size': 0} elif key.startswith('cakey_size_'): # Old host key size format. print(Policy.WARNING_DEPRECATED_DIRECTIVES, file=self._warning_target) # Warn the user that the policy file is using deprecated directives. hostkey_type = key[11:] ca_key_size = int(val) ca_key_type = 'ssh-ed25519' if hostkey_type in ['ssh-rsa-cert-v01@openssh.com', 'rsa-sha2-256-cert-v01@openssh.com', 'rsa-sha2-512-cert-v01@openssh.com']: ca_key_type = 'ssh-rsa' if self._hostkey_sizes is None: self._hostkey_sizes = {} self._hostkey_sizes[hostkey_type] = {'hostkey_size': hostkey_size, 'ca_key_type': ca_key_type, 'ca_key_size': ca_key_size} elif key == 'host_key_sizes': # New host key size format. self._hostkey_sizes = json.loads(val) # Fill in the trimmed fields that were omitted from the policy. self._normalize_hostkey_sizes() elif key.startswith('dh_modulus_size_'): # Old DH modulus format. print(Policy.WARNING_DEPRECATED_DIRECTIVES, file=self._warning_target) # Warn the user that the policy file is using deprecated directives. dh_type = key[16:] dh_size = int(val) if self._dh_modulus_sizes is None: self._dh_modulus_sizes = {} self._dh_modulus_sizes[dh_type] = dh_size elif key == 'dh_modulus_sizes': # New DH modulus format. self._dh_modulus_sizes = json.loads(val) elif key.startswith('client policy') and val.lower() == 'true': self._server_policy = False elif key == 'allow_algorithm_subset_and_reordering' and val.lower() == 'true': self._allow_algorithm_subset_and_reordering = True elif key == 'allow_larger_keys' and val.lower() == 'true': self._allow_larger_keys = True if self._name is None: raise ValueError('The policy does not have a name field.') if self._version is None: raise ValueError('The policy does not have a version field.') self._name_and_version = "%s (version %s)" % (self._name, self._version) def _append_error(self, mismatched_field: str, expected_required: Optional[List[str]], expected_optional: Optional[List[str]], actual: List[str]) -> None: if expected_required is None: expected_required = [''] if expected_optional is None: expected_optional = [''] self._errors.append({'mismatched_field': mismatched_field, 'expected_required': expected_required, 'expected_optional': expected_optional, 'actual': actual}) def _normalize_hostkey_sizes(self) -> None: '''Normalizes the self._hostkey_sizes structure to ensure all required fields are present.''' if self._hostkey_sizes is not None: for host_key_type in self._hostkey_sizes: if 'ca_key_type' not in self._hostkey_sizes[host_key_type]: self._hostkey_sizes[host_key_type]['ca_key_type'] = '' if 'ca_key_size' not in self._hostkey_sizes[host_key_type]: self._hostkey_sizes[host_key_type]['ca_key_size'] = 0 if 'raw_hostkey_bytes' not in self._hostkey_sizes[host_key_type]: self._hostkey_sizes[host_key_type]['raw_hostkey_bytes'] = b'' @staticmethod def create(source: Optional[str], banner: Optional['Banner'], kex: Optional['SSH2_Kex'], client_audit: bool) -> str: '''Creates a policy based on a server configuration. Returns a string.''' today = date.today().strftime('%Y/%m/%d') compressions = None host_keys = None kex_algs = None ciphers = None macs = None dh_modulus_sizes_str = '' client_policy_str = '' host_keys_json = '' if client_audit: client_policy_str = "\n# Set to true to signify this is a policy for clients, not servers.\nclient policy = true\n" if kex is not None: if kex.server.compression is not None: compressions = ', '.join(kex.server.compression) if kex.key_algorithms is not None: host_keys = ', '.join(kex.key_algorithms) if kex.kex_algorithms is not None: kex_algs = ', '.join(kex.kex_algorithms) if kex.server.encryption is not None: ciphers = ', '.join(kex.server.encryption) if kex.server.mac is not None: macs = ', '.join(kex.server.mac) if kex.host_keys(): # Make a deep copy of the host keys dict, then delete all the raw hostkey bytes from the copy. host_keys_trimmed = copy.deepcopy(kex.host_keys()) for hostkey_alg in host_keys_trimmed: del host_keys_trimmed[hostkey_alg]['raw_hostkey_bytes'] # Delete the CA signature if any of its fields are empty. if host_keys_trimmed[hostkey_alg]['ca_key_type'] == '' or host_keys_trimmed[hostkey_alg]['ca_key_size'] == 0: del host_keys_trimmed[hostkey_alg]['ca_key_type'] del host_keys_trimmed[hostkey_alg]['ca_key_size'] host_keys_json = "\n# Dictionary containing all host key and size information. Optionally contains the certificate authority's signature algorithm ('ca_key_type') and signature length ('ca_key_size'), if any.\nhost_key_sizes = %s\n" % json.dumps(host_keys_trimmed) if kex.dh_modulus_sizes(): dh_modulus_sizes_str = "\n# Group exchange DH modulus sizes.\ndh_modulus_sizes = %s\n" % json.dumps(kex.dh_modulus_sizes()) policy_data = '''# # Custom policy based on %s (created on %s) # %s # The name of this policy (displayed in the output during scans). Must be in quotes. name = "Custom Policy (based on %s on %s)" # The version of this policy (displayed in the output during scans). Not parsed, and may be any value, including strings. version = 1 # When false, host keys, kex, ciphers, and MAC lists must match exactly. When true, the target host may support a subset of the specified algorithms and/or algorithms may appear in a different order; this feature is useful for specifying a baseline and allowing some hosts the option to implement stricter controls. allow_algorithm_subset_and_reordering = false # When false, host keys, CA keys, and Diffie-Hellman key sizes must exactly match what's specified in this policy. When true, target systems are allowed to have larger keys; this feature is useful for specifying a baseline and allowing some hosts the option to implement stricter controls. allow_larger_keys = false # The banner that must match exactly. Commented out to ignore banners, since minor variability in the banner is sometimes normal. # banner = "%s" # The compression options that must match exactly (order matters). Commented out to ignore by default. # compressions = %s %s%s # The host key types that must match exactly (order matters). host keys = %s # Host key types that may optionally appear. #optional host keys = ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com # The key exchange algorithms that must match exactly (order matters). key exchanges = %s # The ciphers that must match exactly (order matters). ciphers = %s # The MACs that must match exactly (order matters). macs = %s ''' % (source, today, client_policy_str, source, today, banner, compressions, host_keys_json, dh_modulus_sizes_str, host_keys, kex_algs, ciphers, macs) return policy_data def evaluate(self, banner: Optional['Banner'], kex: Optional['SSH2_Kex']) -> Tuple[bool, List[Dict[str, str]], str]: '''Evaluates a server configuration against this policy. Returns a tuple of a boolean (True if server adheres to policy) and an array of strings that holds error messages.''' ret = True banner_str = str(banner) if (self._banner is not None) and (banner_str != self._banner): ret = False self._append_error('Banner', [self._banner], None, [banner_str]) # All subsequent tests require a valid kex, so end here if we don't have one. if kex is None: error_list, error_str = self._get_errors() return ret, error_list, error_str if (self._compressions is not None) and (kex.server.compression != self._compressions): ret = False self._append_error('Compression', self._compressions, None, kex.server.compression) # If a list of optional host keys was given in the policy, remove any of its entries from the list retrieved from the server. This allows us to do an exact comparison with the expected list below. pruned_host_keys = kex.key_algorithms if self._optional_host_keys is not None: pruned_host_keys = [x for x in kex.key_algorithms if x not in self._optional_host_keys] # Check host keys. if self._host_keys is not None: # If the policy allows subsets and re-ordered algorithms... if self._allow_algorithm_subset_and_reordering: for hostkey_t in kex.key_algorithms: if hostkey_t not in self._host_keys: ret = False self._append_error('Host keys', self._host_keys, self._optional_host_keys, kex.key_algorithms) break # The policy requires exact matching of algorithms. elif pruned_host_keys != self._host_keys: ret = False self._append_error('Host keys', self._host_keys, self._optional_host_keys, kex.key_algorithms) # Check host key sizes. if self._hostkey_sizes is not None: hostkey_types = list(self._hostkey_sizes.keys()) hostkey_types.sort() # Sorted to make testing output repeatable. for hostkey_type in hostkey_types: expected_hostkey_size = cast(int, self._hostkey_sizes[hostkey_type]['hostkey_size']) server_host_keys = kex.host_keys() if hostkey_type in server_host_keys: actual_hostkey_size = cast(int, server_host_keys[hostkey_type]['hostkey_size']) if (self._allow_larger_keys and actual_hostkey_size < expected_hostkey_size) or \ (not self._allow_larger_keys and actual_hostkey_size != expected_hostkey_size): ret = False self._append_error('Host key (%s) sizes' % hostkey_type, [str(expected_hostkey_size)], None, [str(actual_hostkey_size)]) # If we have expected CA signatures set, check them against what the server returned. if self._hostkey_sizes is not None and len(cast(str, self._hostkey_sizes[hostkey_type]['ca_key_type'])) > 0 and cast(int, self._hostkey_sizes[hostkey_type]['ca_key_size']) > 0: expected_ca_key_type = cast(str, self._hostkey_sizes[hostkey_type]['ca_key_type']) expected_ca_key_size = cast(int, self._hostkey_sizes[hostkey_type]['ca_key_size']) actual_ca_key_type = cast(str, server_host_keys[hostkey_type]['ca_key_type']) actual_ca_key_size = cast(int, server_host_keys[hostkey_type]['ca_key_size']) # Ensure that the CA signature type is what's expected (i.e.: the server doesn't have an RSA sig when we're expecting an ED25519 sig). if actual_ca_key_type != expected_ca_key_type: ret = False self._append_error('CA signature type', [expected_ca_key_type], None, [actual_ca_key_type]) # Ensure that the actual and expected signature sizes match. elif (self._allow_larger_keys and actual_ca_key_size < expected_ca_key_size) or \ (not self._allow_larger_keys and actual_ca_key_size != expected_ca_key_size): ret = False self._append_error('CA signature size (%s)' % actual_ca_key_type, [str(expected_ca_key_size)], None, [str(actual_ca_key_size)]) # Check key exchanges. if self._kex is not None: # If the policy allows subsets and re-ordered algorithms... if self._allow_algorithm_subset_and_reordering: for kex_t in kex.kex_algorithms: if kex_t not in self._kex: ret = False self._append_error('Key exchanges', self._kex, None, kex.kex_algorithms) break # If kex-strict-?-v00@openssh.com is in the policy (i.e. the Terrapin vulnerability countermeasure), then it must appear in the server's list, regardless of the "allow_algorithm_subset_and_reordering" flag. if ('kex-strict-s-v00@openssh.com' in self._kex and 'kex-strict-s-v00@openssh.com' not in kex.kex_algorithms) or \ ('kex-strict-c-v00@openssh.com' in self._kex and 'kex-strict-c-v00@openssh.com' not in kex.kex_algorithms): ret = False self._append_error('Key exchanges', self._kex, None, kex.kex_algorithms) # The policy requires exact matching of algorithms. elif kex.kex_algorithms != self._kex: ret = False self._append_error('Key exchanges', self._kex, None, kex.kex_algorithms) # Checking Ciphers if self._ciphers is not None: # If the policy allows subsets and re-ordered algorithms... if self._allow_algorithm_subset_and_reordering: for cipher_t in kex.server.encryption: if cipher_t not in self._ciphers: ret = False self._append_error('Ciphers', self._ciphers, None, kex.server.encryption) break # The policy requires exact matching of algorithms. elif kex.server.encryption != self._ciphers: ret = False self._append_error('Ciphers', self._ciphers, None, kex.server.encryption) # Checking MACs if self._macs is not None: # If the policy allows subsets and re-ordered algorithms... if self._allow_algorithm_subset_and_reordering: for mac_t in kex.server.mac: if mac_t not in self._macs: ret = False self._append_error('MACs', self._macs, None, kex.server.mac) break # The policy requires exact matching of algorithms. elif kex.server.mac != self._macs: ret = False self._append_error('MACs', self._macs, None, kex.server.mac) if self._dh_modulus_sizes is not None: dh_modulus_types = list(self._dh_modulus_sizes.keys()) dh_modulus_types.sort() # Sorted to make testing output repeatable. for dh_modulus_type in dh_modulus_types: expected_dh_modulus_size = self._dh_modulus_sizes[dh_modulus_type] if dh_modulus_type in kex.dh_modulus_sizes(): actual_dh_modulus_size = kex.dh_modulus_sizes()[dh_modulus_type] if (self._allow_larger_keys and actual_dh_modulus_size < expected_dh_modulus_size) or \ (not self._allow_larger_keys and actual_dh_modulus_size != expected_dh_modulus_size): ret = False self._append_error('Group exchange (%s) modulus sizes' % dh_modulus_type, [str(expected_dh_modulus_size)], None, [str(actual_dh_modulus_size)]) error_list, error_str = self._get_errors() return ret, error_list, error_str def _get_errors(self) -> Tuple[List[Any], str]: '''Returns the list of errors, along with the string representation of those errors.''' subset_and_reordering_semicolon = "; subset and/or reordering allowed" if self._allow_algorithm_subset_and_reordering else "; exact match" subset_and_reordering_parens = " (subset and/or reordering allowed)" if self._allow_algorithm_subset_and_reordering else "" error_list = [] spacer = '' for e in self._errors: e_str = " * %s did not match.\n" % e['mismatched_field'] if ('expected_optional' in e) and (e['expected_optional'] != ['']): e_str += " - Expected (required%s): %s\n - Expected (optional): %s\n" % (subset_and_reordering_semicolon, Policy._normalize_error_field(e['expected_required']), Policy._normalize_error_field(e['expected_optional'])) spacer = ' ' else: e_str += " - Expected%s: %s\n" % (subset_and_reordering_parens, Policy._normalize_error_field(e['expected_required'])) spacer = ' ' e_str += " - Actual:%s%s\n" % (spacer, Policy._normalize_error_field(e['actual'])) error_list.append(e_str) error_list.sort() # To ensure repeatable results for testing. error_str = '' if len(error_list) > 0: error_str = "\n".join(error_list) return self._errors, error_str def get_name_and_version(self) -> str: '''Returns a string of this Policy's name and version.''' return self._name_and_version def is_server_policy(self) -> bool: '''Returns True if this is a server policy, or False if this is a client policy.''' return self._server_policy @staticmethod def list_builtin_policies(verbose: bool) -> Tuple[List[str], List[str]]: '''Returns two lists: a list of names of built-in server policies, and a list of names of built-in client policies, respectively.''' server_policy_descriptions = [] client_policy_descriptions = [] for policy_name, policy in BUILTIN_POLICIES.items(): policy_description = "" if verbose: policy_description = "\"{:s}\": {:s}".format(policy_name, policy['changelog']) else: policy_description = "\"{:s}\"".format(policy_name) if policy['server_policy']: server_policy_descriptions.append(policy_description) else: client_policy_descriptions.append(policy_description) server_policy_descriptions.sort() client_policy_descriptions.sort() return server_policy_descriptions, client_policy_descriptions @staticmethod def load_builtin_policy(policy_name: str, json_output: bool = False) -> Optional['Policy']: '''Returns a Policy with the specified built-in policy name loaded, or None if no policy of that name exists.''' p = None if policy_name in BUILTIN_POLICIES: policy_struct = BUILTIN_POLICIES[policy_name] p = Policy(manual_load=True, json_output=json_output) policy_name_without_version = policy_name[0:policy_name.rfind(' (')] p._name = policy_name_without_version # pylint: disable=protected-access p._version = cast(str, policy_struct['version']) # pylint: disable=protected-access p._banner = cast(Optional[str], policy_struct['banner']) # pylint: disable=protected-access p._compressions = cast(Optional[List[str]], policy_struct['compressions']) # pylint: disable=protected-access p._host_keys = cast(Optional[List[str]], policy_struct['host_keys']) # pylint: disable=protected-access p._optional_host_keys = cast(Optional[List[str]], policy_struct['optional_host_keys']) # pylint: disable=protected-access p._kex = cast(Optional[List[str]], policy_struct['kex']) # pylint: disable=protected-access p._ciphers = cast(Optional[List[str]], policy_struct['ciphers']) # pylint: disable=protected-access p._macs = cast(Optional[List[str]], policy_struct['macs']) # pylint: disable=protected-access p._hostkey_sizes = cast(Optional[Dict[str, Dict[str, Union[int, str, bytes]]]], policy_struct['hostkey_sizes']) # pylint: disable=protected-access p._dh_modulus_sizes = cast(Optional[Dict[str, int]], policy_struct['dh_modulus_sizes']) # pylint: disable=protected-access p._server_policy = cast(bool, policy_struct['server_policy']) # pylint: disable=protected-access p._name_and_version = "%s (version %s)" % (p._name, p._version) # pylint: disable=protected-access # Ensure this struct has all the necessary fields. p._normalize_hostkey_sizes() # pylint: disable=protected-access return p @staticmethod def _normalize_error_field(field: List[str]) -> Any: '''If field is an array with a string parsable as an integer, return that integer. Otherwise, return the field joined with commas.''' if len(field) == 1: try: return int(field[0]) except ValueError: return field[0] else: return ', '.join(field) def __str__(self) -> str: undefined = '{undefined}' name = undefined version = undefined banner = undefined compressions_str = undefined host_keys_str = undefined optional_host_keys_str = undefined kex_str = undefined ciphers_str = undefined macs_str = undefined hostkey_sizes_str = undefined dh_modulus_sizes_str = undefined if self._name is not None: name = '[%s]' % self._name if self._version is not None: version = '[%s]' % self._version if self._banner is not None: banner = '[%s]' % self._banner if self._compressions is not None: compressions_str = ', '.join(self._compressions) if self._host_keys is not None: host_keys_str = ', '.join(self._host_keys) if self._optional_host_keys is not None: optional_host_keys_str = ', '.join(self._optional_host_keys) if self._kex is not None: kex_str = ', '.join(self._kex) if self._ciphers is not None: ciphers_str = ', '.join(self._ciphers) if self._macs is not None: macs_str = ', '.join(self._macs) if self._hostkey_sizes is not None: hostkey_sizes_str = str(self._hostkey_sizes) if self._dh_modulus_sizes is not None: dh_modulus_sizes_str = str(self._dh_modulus_sizes) return "Name: %s\nVersion: %s\nAllow Algorithm Subset and/or Reordering: %r\nBanner: %s\nCompressions: %s\nHost Keys: %s\nOptional Host Keys: %s\nKey Exchanges: %s\nCiphers: %s\nMACs: %s\nHost Key Sizes: %s\nDH Modulus Sizes: %s\nServer Policy: %r" % (name, version, self._allow_algorithm_subset_and_reordering, banner, compressions_str, host_keys_str, optional_host_keys_str, kex_str, ciphers_str, macs_str, hostkey_sizes_str, dh_modulus_sizes_str, self._server_policy)