Source code for certbot.auth_handler

"""ACME AuthHandler."""
import logging
import time

import six
import zope.component

from acme import challenges
from acme import messages

from certbot import achallenges
from certbot import errors
from certbot import error_handler
from certbot import interfaces


logger = logging.getLogger(__name__)


[docs]class AuthHandler(object): """ACME Authorization Handler for a client. :ivar auth: Authenticator capable of solving :class:`~acme.challenges.Challenge` types :type auth: :class:`certbot.interfaces.IAuthenticator` :ivar acme.client.Client acme: ACME client API. :ivar account: Client's Account :type account: :class:`certbot.account.Account` :ivar dict authzr: ACME Authorization Resource dict where keys are domains and values are :class:`acme.messages.AuthorizationResource` :ivar list achalls: DV challenges in the form of :class:`certbot.achallenges.AnnotatedChallenge` :ivar list pref_challs: sorted user specified preferred challenges type strings with the most preferred challenge listed first """ def __init__(self, auth, acme, account, pref_challs): self.auth = auth self.acme = acme self.account = account self.authzr = dict() self.pref_challs = pref_challs # List must be used to keep responses straight. self.achalls = []
[docs] def get_authorizations(self, domains, best_effort=False): """Retrieve all authorizations for challenges. :param list domains: Domains for authorization :param bool best_effort: Whether or not all authorizations are required (this is useful in renewal) :returns: List of authorization resources :rtype: list :raises .AuthorizationError: If unable to retrieve all authorizations """ for domain in domains: self.authzr[domain] = self.acme.request_domain_challenges(domain) self._choose_challenges(domains) config = zope.component.getUtility(interfaces.IConfig) notify = zope.component.getUtility(interfaces.IDisplay).notification # While there are still challenges remaining... while self.achalls: resp = self._solve_challenges() logger.info("Waiting for verification...") if config.debug_challenges: notify('Challenges loaded. Press continue to submit to CA. ' 'Pass "-v" for more info about challenges.', pause=True) # Send all Responses - this modifies achalls self._respond(resp, best_effort) # Just make sure all decisions are complete. self.verify_authzr_complete() # Only return valid authorizations retVal = [authzr for authzr in self.authzr.values() if authzr.body.status == messages.STATUS_VALID] if not retVal: raise errors.AuthorizationError( "Challenges failed for all domains") return retVal
[docs] def _choose_challenges(self, domains): """Retrieve necessary challenges to satisfy server.""" logger.info("Performing the following challenges:") for dom in domains: path = gen_challenge_path( self.authzr[dom].body.challenges, self._get_chall_pref(dom), self.authzr[dom].body.combinations) dom_achalls = self._challenge_factory( dom, path) self.achalls.extend(dom_achalls)
[docs] def _solve_challenges(self): """Get Responses for challenges from authenticators.""" resp = [] with error_handler.ErrorHandler(self._cleanup_challenges): try: if self.achalls: resp = self.auth.perform(self.achalls) except errors.AuthorizationError: logger.critical("Failure in setting up challenges.") logger.info("Attempting to clean up outstanding challenges...") raise assert len(resp) == len(self.achalls) return resp
[docs] def _respond(self, resp, best_effort): """Send/Receive confirmation of all challenges. .. note:: This method also cleans up the auth_handler state. """ # TODO: chall_update is a dirty hack to get around acme-spec #105 chall_update = dict() active_achalls = self._send_responses(self.achalls, resp, chall_update) # Check for updated status... try: self._poll_challenges(chall_update, best_effort) finally: # This removes challenges from self.achalls self._cleanup_challenges(active_achalls)
[docs] def _send_responses(self, achalls, resps, chall_update): """Send responses and make sure errors are handled. :param dict chall_update: parameter that is updated to hold authzr -> list of outstanding solved annotated challenges """ active_achalls = [] for achall, resp in six.moves.zip(achalls, resps): # This line needs to be outside of the if block below to # ensure failed challenges are cleaned up correctly active_achalls.append(achall) # Don't send challenges for None and False authenticator responses if resp is not None and resp: self.acme.answer_challenge(achall.challb, resp) # TODO: answer_challenge returns challr, with URI, # that can be used in _find_updated_challr # comparisons... if achall.domain in chall_update: chall_update[achall.domain].append(achall) else: chall_update[achall.domain] = [achall] return active_achalls
[docs] def _poll_challenges( self, chall_update, best_effort, min_sleep=3, max_rounds=15): """Wait for all challenge results to be determined.""" dom_to_check = set(chall_update.keys()) comp_domains = set() rounds = 0 while dom_to_check and rounds < max_rounds: # TODO: Use retry-after... time.sleep(min_sleep) all_failed_achalls = set() for domain in dom_to_check: comp_achalls, failed_achalls = self._handle_check( domain, chall_update[domain]) if len(comp_achalls) == len(chall_update[domain]): comp_domains.add(domain) elif not failed_achalls: for achall, _ in comp_achalls: chall_update[domain].remove(achall) # We failed some challenges... damage control else: if best_effort: comp_domains.add(domain) logger.warning( "Challenge failed for domain %s", domain) else: all_failed_achalls.update( updated for _, updated in failed_achalls) if all_failed_achalls: _report_failed_challs(all_failed_achalls) raise errors.FailedChallenges(all_failed_achalls) dom_to_check -= comp_domains comp_domains.clear() rounds += 1
[docs] def _handle_check(self, domain, achalls): """Returns tuple of ('completed', 'failed').""" completed = [] failed = [] self.authzr[domain], _ = self.acme.poll(self.authzr[domain]) if self.authzr[domain].body.status == messages.STATUS_VALID: return achalls, [] # Note: if the whole authorization is invalid, the individual failed # challenges will be determined here... for achall in achalls: updated_achall = achall.update(challb=self._find_updated_challb( self.authzr[domain], achall)) # This does nothing for challenges that have yet to be decided yet. if updated_achall.status == messages.STATUS_VALID: completed.append((achall, updated_achall)) elif updated_achall.status == messages.STATUS_INVALID: failed.append((achall, updated_achall)) return completed, failed
[docs] def _find_updated_challb(self, authzr, achall): # pylint: disable=no-self-use """Find updated challenge body within Authorization Resource. .. warning:: This assumes only one instance of type of challenge in each challenge resource. :param .AuthorizationResource authzr: Authorization Resource :param .AnnotatedChallenge achall: Annotated challenge for which to get status """ for authzr_challb in authzr.body.challenges: if type(authzr_challb.chall) is type(achall.challb.chall): # noqa return authzr_challb raise errors.AuthorizationError( "Target challenge not found in authorization resource")
[docs] def _get_chall_pref(self, domain): """Return list of challenge preferences. :param str domain: domain for which you are requesting preferences """ chall_prefs = [] # Make sure to make a copy... plugin_pref = self.auth.get_chall_pref(domain) if self.pref_challs: plugin_pref_types = set(chall.typ for chall in plugin_pref) for typ in self.pref_challs: if typ in plugin_pref_types: chall_prefs.append(challenges.Challenge.TYPES[typ]) if chall_prefs: return chall_prefs raise errors.AuthorizationError( "None of the preferred challenges " "are supported by the selected plugin") chall_prefs.extend(plugin_pref) return chall_prefs
[docs] def _cleanup_challenges(self, achall_list=None): """Cleanup challenges. If achall_list is not provided, cleanup all achallenges. """ logger.info("Cleaning up challenges") if achall_list is None: achalls = self.achalls else: achalls = achall_list if achalls: self.auth.cleanup(achalls) for achall in achalls: self.achalls.remove(achall)
[docs] def verify_authzr_complete(self): """Verifies that all authorizations have been decided. :returns: Whether all authzr are complete :rtype: bool """ for authzr in self.authzr.values(): if (authzr.body.status != messages.STATUS_VALID and authzr.body.status != messages.STATUS_INVALID): raise errors.AuthorizationError("Incomplete authorizations")
[docs] def _challenge_factory(self, domain, path): """Construct Namedtuple Challenges :param str domain: domain of the enrollee :param list path: List of indices from `challenges`. :returns: achalls, list of challenge type :class:`certbot.achallenges.Indexed` :rtype: list :raises .errors.Error: if challenge type is not recognized """ achalls = [] for index in path: challb = self.authzr[domain].body.challenges[index] achalls.append(challb_to_achall(challb, self.account.key, domain)) return achalls
[docs]def challb_to_achall(challb, account_key, domain): """Converts a ChallengeBody object to an AnnotatedChallenge. :param .ChallengeBody challb: ChallengeBody :param .JWK account_key: Authorized Account Key :param str domain: Domain of the challb :returns: Appropriate AnnotatedChallenge :rtype: :class:`certbot.achallenges.AnnotatedChallenge` """ chall = challb.chall logger.info("%s challenge for %s", chall.typ, domain) if isinstance(chall, challenges.KeyAuthorizationChallenge): return achallenges.KeyAuthorizationAnnotatedChallenge( challb=challb, domain=domain, account_key=account_key) elif isinstance(chall, challenges.DNS): return achallenges.DNS(challb=challb, domain=domain) else: raise errors.Error( "Received unsupported challenge of type: %s", chall.typ)
[docs]def gen_challenge_path(challbs, preferences, combinations): """Generate a plan to get authority over the identity. .. todo:: This can be possibly be rewritten to use resolved_combinations. :param tuple challbs: A tuple of challenges (:class:`acme.messages.Challenge`) from :class:`acme.messages.AuthorizationResource` to be fulfilled by the client in order to prove possession of the identifier. :param list preferences: List of challenge preferences for domain (:class:`acme.challenges.Challenge` subclasses) :param tuple combinations: A collection of sets of challenges from :class:`acme.messages.Challenge`, each of which would be sufficient to prove possession of the identifier. :returns: tuple of indices from ``challenges``. :rtype: tuple :raises certbot.errors.AuthorizationError: If a path cannot be created that satisfies the CA given the preferences and combinations. """ if combinations: return _find_smart_path(challbs, preferences, combinations) else: return _find_dumb_path(challbs, preferences)
[docs]def _find_smart_path(challbs, preferences, combinations): """Find challenge path with server hints. Can be called if combinations is included. Function uses a simple ranking system to choose the combo with the lowest cost. """ chall_cost = {} max_cost = 1 for i, chall_cls in enumerate(preferences): chall_cost[chall_cls] = i max_cost += i # max_cost is now equal to sum(indices) + 1 best_combo = [] # Set above completing all of the available challenges best_combo_cost = max_cost combo_total = 0 for combo in combinations: for challenge_index in combo: combo_total += chall_cost.get(challbs[ challenge_index].chall.__class__, max_cost) if combo_total < best_combo_cost: best_combo = combo best_combo_cost = combo_total combo_total = 0 if not best_combo: _report_no_chall_path() return best_combo
[docs]def _find_dumb_path(challbs, preferences): """Find challenge path without server hints. Should be called if the combinations hint is not included by the server. This function either returns a path containing all challenges provided by the CA or raises an exception. """ path = [] for i, challb in enumerate(challbs): # supported is set to True if the challenge type is supported supported = next((True for pref_c in preferences if isinstance(challb.chall, pref_c)), False) if supported: path.append(i) else: _report_no_chall_path() return path
[docs]def _report_no_chall_path(): """Logs and raises an error that no satisfiable chall path exists.""" msg = ("Client with the currently selected authenticator does not support " "any combination of challenges that will satisfy the CA.") logger.fatal(msg) raise errors.AuthorizationError(msg)
_ERROR_HELP_COMMON = ( "To fix these errors, please make sure that your domain name was entered " "correctly and the DNS A/AAAA record(s) for that domain contain(s) the " "right IP address.") _ERROR_HELP = { "connection": _ERROR_HELP_COMMON + " Additionally, please check that your computer " "has a publicly routable IP address and that no firewalls are preventing " "the server from communicating with the client. If you're using the " "webroot plugin, you should also verify that you are serving files " "from the webroot path you provided.", "dnssec": _ERROR_HELP_COMMON + " Additionally, if you have DNSSEC enabled for " "your domain, please ensure that the signature is valid.", "malformed": "To fix these errors, please make sure that you did not provide any " "invalid information to the client, and try running Certbot " "again.", "serverInternal": "Unfortunately, an error on the ACME server prevented you from completing " "authorization. Please try again later.", "tls": _ERROR_HELP_COMMON + " Additionally, please check that you have an " "up-to-date TLS configuration that allows the server to communicate " "with the Certbot client.", "unauthorized": _ERROR_HELP_COMMON, "unknownHost": _ERROR_HELP_COMMON, }
[docs]def _report_failed_challs(failed_achalls): """Notifies the user about failed challenges. :param set failed_achalls: A set of failed :class:`certbot.achallenges.AnnotatedChallenge`. """ problems = dict() for achall in failed_achalls: if achall.error: problems.setdefault(achall.error.typ, []).append(achall) reporter = zope.component.getUtility(interfaces.IReporter) for achalls in six.itervalues(problems): reporter.add_message( _generate_failed_chall_msg(achalls), reporter.MEDIUM_PRIORITY)
[docs]def _generate_failed_chall_msg(failed_achalls): """Creates a user friendly error message about failed challenges. :param list failed_achalls: A list of failed :class:`certbot.achallenges.AnnotatedChallenge` with the same error type. :returns: A formatted error message for the client. :rtype: str """ error = failed_achalls[0].error typ = error.typ if messages.is_acme_error(error): typ = error.code msg = ["The following errors were reported by the server:"] for achall in failed_achalls: msg.append("\n\nDomain: %s\nType: %s\nDetail: %s" % ( achall.domain, typ, achall.error.detail)) if typ in _ERROR_HELP: msg.append("\n\n") msg.append(_ERROR_HELP[typ]) return "".join(msg)