"""ACME AuthHandler."""
import collections
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__)
AnnotatedAuthzr = collections.namedtuple("AnnotatedAuthzr", ["authzr", "achalls"])
"""Stores an authorization resource and its active annotated challenges."""
[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.BackwardsCompatibleClientV2 acme: ACME client API.
:ivar account: Client's Account
:type account: :class:`certbot.account.Account`
:ivar aauthzrs: ACME Authorization Resources and their active challenges
:type aauthzrs: `list` of `AnnotatedAuthzr`
: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.aauthzrs = []
self.pref_challs = pref_challs
[docs] def handle_authorizations(self, orderr, best_effort=False):
"""Retrieve all authorizations for challenges.
:param acme.messages.OrderResource orderr: must have
authorizations filled in
: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 authzr in orderr.authorizations:
self.aauthzrs.append(AnnotatedAuthzr(authzr, []))
self._choose_challenges()
config = zope.component.getUtility(interfaces.IConfig)
notify = zope.component.getUtility(interfaces.IDisplay).notification
# While there are still challenges remaining...
while self._has_challenges():
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 = [aauthzr.authzr for aauthzr in self.aauthzrs
if aauthzr.authzr.body.status == messages.STATUS_VALID]
if not retVal:
raise errors.AuthorizationError(
"Challenges failed for all domains")
return retVal
[docs] def _choose_challenges(self):
"""Retrieve necessary challenges to satisfy server."""
logger.info("Performing the following challenges:")
for aauthzr in self.aauthzrs:
aauthzr_challenges = aauthzr.authzr.body.challenges
if self.acme.acme_version == 1:
combinations = aauthzr.authzr.body.combinations
else:
combinations = tuple((i,) for i in range(len(aauthzr_challenges)))
path = gen_challenge_path(
aauthzr_challenges,
self._get_chall_pref(aauthzr.authzr.body.identifier.value),
combinations)
aauthzr_achalls = self._challenge_factory(
aauthzr.authzr, path)
aauthzr.achalls.extend(aauthzr_achalls)
[docs] def _has_challenges(self):
"""Do we have any challenges to perform?"""
return any(aauthzr.achalls for aauthzr in self.aauthzrs)
[docs] def _solve_challenges(self):
"""Get Responses for challenges from authenticators."""
resp = []
all_achalls = self._get_all_achalls()
with error_handler.ErrorHandler(self._cleanup_challenges):
try:
if all_achalls:
resp = self.auth.perform(all_achalls)
except errors.AuthorizationError:
logger.critical("Failure in setting up challenges.")
logger.info("Attempting to clean up outstanding challenges...")
raise
assert len(resp) == len(all_achalls)
return resp
[docs] def _get_all_achalls(self):
"""Return all active challenges."""
all_achalls = []
for aauthzr in self.aauthzrs:
all_achalls.extend(aauthzr.achalls)
return all_achalls
[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(resp, chall_update)
# Check for updated status...
try:
self._poll_challenges(chall_update, best_effort)
finally:
self._cleanup_challenges(active_achalls)
[docs] def _send_responses(self, resps, chall_update):
"""Send responses and make sure errors are handled.
:param dict chall_update: parameter that is updated to hold
aauthzr index to list of outstanding solved annotated challenges
"""
active_achalls = []
resps_iter = iter(resps)
for i, aauthzr in enumerate(self.aauthzrs):
for achall in aauthzr.achalls:
# This line needs to be outside of the if block below to
# ensure failed challenges are cleaned up correctly
active_achalls.append(achall)
resp = next(resps_iter)
# Don't send challenges for None and False authenticator responses
if resp:
self.acme.answer_challenge(achall.challb, resp)
# TODO: answer_challenge returns challr, with URI,
# that can be used in _find_updated_challr
# comparisons...
chall_update.setdefault(i, []).append(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."""
indices_to_check = set(chall_update.keys())
comp_indices = set()
rounds = 0
while indices_to_check and rounds < max_rounds:
# TODO: Use retry-after...
time.sleep(min_sleep)
all_failed_achalls = set()
for index in indices_to_check:
comp_achalls, failed_achalls = self._handle_check(
index, chall_update[index])
if len(comp_achalls) == len(chall_update[index]):
comp_indices.add(index)
elif not failed_achalls:
for achall, _ in comp_achalls:
chall_update[index].remove(achall)
# We failed some challenges... damage control
else:
if best_effort:
comp_indices.add(index)
logger.warning(
"Challenge failed for domain %s",
self.aauthzrs[index].authzr.body.identifier.value)
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)
indices_to_check -= comp_indices
comp_indices.clear()
rounds += 1
[docs] def _handle_check(self, index, achalls):
"""Returns tuple of ('completed', 'failed')."""
completed = []
failed = []
original_aauthzr = self.aauthzrs[index]
updated_authzr, _ = self.acme.poll(original_aauthzr.authzr)
self.aauthzrs[index] = AnnotatedAuthzr(updated_authzr, original_aauthzr.achalls)
if updated_authzr.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(
updated_authzr, 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._get_all_achalls()
else:
achalls = achall_list
if achalls:
self.auth.cleanup(achalls)
for achall in achalls:
for aauthzr in self.aauthzrs:
if achall in aauthzr.achalls:
aauthzr.achalls.remove(achall)
break
[docs] def verify_authzr_complete(self):
"""Verifies that all authorizations have been decided.
:returns: Whether all authzr are complete
:rtype: bool
"""
for aauthzr in self.aauthzrs:
authzr = aauthzr.authzr
if (authzr.body.status != messages.STATUS_VALID and
authzr.body.status != messages.STATUS_INVALID):
raise errors.AuthorizationError("Incomplete authorizations")
[docs] def _challenge_factory(self, authzr, path):
"""Construct Namedtuple Challenges
:param messages.AuthorizationResource authzr: authorization
: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 = authzr.body.challenges[index]
achalls.append(challb_to_achall(
challb, self.account.key, authzr.body.identifier.value))
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(challbs)
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(challbs)
return path
[docs]def _report_no_chall_path(challbs):
"""Logs and raises an error that no satisfiable chall path exists.
:param challbs: challenges from the authorization that can't be satisfied
"""
msg = ("Client with the currently selected authenticator does not support "
"any combination of challenges that will satisfy the CA.")
if len(challbs) == 1 and isinstance(challbs[0].chall, challenges.DNS01):
msg += (
" You may need to use an authenticator "
"plugin that can do challenges over DNS.")
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)