"""Common code for DNS Authenticator Plugins."""
import abc
import logging
import os
import stat
from time import sleep
import configobj
import zope.interface
from acme import challenges
from certbot import errors
from certbot import interfaces
from certbot.display import ops
from certbot.display import util as display_util
from certbot.plugins import common
logger = logging.getLogger(__name__)
@zope.interface.implementer(interfaces.IAuthenticator)
@zope.interface.provider(interfaces.IPluginFactory)
[docs]class DNSAuthenticator(common.Plugin):
"""Base class for DNS Authenticators"""
def __init__(self, config, name):
super(DNSAuthenticator, self).__init__(config, name)
self._attempt_cleanup = False
@classmethod
def add_parser_arguments(cls, add, default_propagation_seconds=10): # pylint: disable=arguments-differ
add('propagation-seconds',
default=default_propagation_seconds,
type=int,
help='The number of seconds to wait for DNS to propagate before asking the ACME server '
'to verify the DNS record.')
def get_chall_pref(self, unused_domain): # pylint: disable=missing-docstring,no-self-use
return [challenges.DNS01]
def prepare(self): # pylint: disable=missing-docstring
pass
def perform(self, achalls): # pylint: disable=missing-docstring
self._setup_credentials()
self._attempt_cleanup = True
responses = []
for achall in achalls:
domain = achall.domain
validation_domain_name = achall.validation_domain_name(domain)
validation = achall.validation(achall.account_key)
self._perform(domain, validation_domain_name, validation)
responses.append(achall.response(achall.account_key))
# DNS updates take time to propagate and checking to see if the update has occurred is not
# reliable (the machine this code is running on might be able to see an update before
# the ACME server). So: we sleep for a short amount of time we believe to be long enough.
logger.info("Waiting %d seconds for DNS changes to propagate",
self.conf('propagation-seconds'))
sleep(self.conf('propagation-seconds'))
return responses
def cleanup(self, achalls): # pylint: disable=missing-docstring
if self._attempt_cleanup:
for achall in achalls:
domain = achall.domain
validation_domain_name = achall.validation_domain_name(domain)
validation = achall.validation(achall.account_key)
self._cleanup(domain, validation_domain_name, validation)
@abc.abstractmethod
[docs] def _setup_credentials(self): # pragma: no cover
"""
Establish credentials, prompting if necessary.
"""
raise NotImplementedError()
@abc.abstractmethod
@abc.abstractmethod
[docs] def _cleanup(self, domain, validation_domain_name, validation): # pragma: no cover
"""
Deletes the DNS TXT record which would have been created by `_perform_achall`.
Fails gracefully if no such record exists.
:param str domain: The domain being validated.
:param str validation_domain_name: The validation record domain name.
:param str validation: The validation record content.
"""
raise NotImplementedError()
@staticmethod
[docs] def _prompt_for_data(label):
"""
Prompt the user for a piece of information.
:param str label: The user-friendly label for this piece of information.
:returns: The user's response (guaranteed non-empty).
:rtype: str
"""
def __validator(i):
if not i:
raise errors.PluginError('Please enter your {0}.'.format(label))
code, response = ops.validated_input(
__validator,
'Input your {0}'.format(label),
force_interactive=True)
if code == display_util.OK:
return response
else:
raise errors.PluginError('{0} required to proceed.'.format(label))
@staticmethod
[docs] def _prompt_for_file(label, validator=None):
"""
Prompt the user for a path.
:param str label: The user-friendly label for the file.
:param callable validator: A method which will be called to validate the supplied input
after it has been validated to be a non-empty path to an existing file. Should throw a
`~certbot.errors.PluginError` to indicate any issue.
:returns: The user's response (guaranteed to exist).
:rtype: str
"""
def __validator(filename):
if not filename:
raise errors.PluginError('Please enter a valid path to your {0}.'.format(label))
filename = os.path.expanduser(filename)
validate_file(filename)
if validator:
validator(filename)
code, response = ops.validated_directory(
__validator,
'Input the path to your {0}'.format(label),
force_interactive=True)
if code == display_util.OK:
return response
else:
raise errors.PluginError('{0} required to proceed.'.format(label))
[docs]class CredentialsConfiguration(object):
"""Represents a user-supplied filed which stores API credentials."""
def __init__(self, filename, mapper=lambda x: x):
"""
:param str filename: A path to the configuration file.
:param callable mapper: A transformation to apply to configuration key names
:raises errors.PluginError: If the file does not exist or is not a valid format.
"""
validate_file_permissions(filename)
try:
self.confobj = configobj.ConfigObj(filename)
except configobj.ConfigObjError as e:
logger.debug("Error parsing credentials configuration: %s", e, exc_info=True)
raise errors.PluginError("Error parsing credentials configuration: {0}".format(e))
self.mapper = mapper
[docs] def require(self, required_variables):
"""Ensures that the supplied set of variables are all present in the file.
:param dict required_variables: Map of variable which must be present to error to display.
:raises errors.PluginError: If one or more are missing.
"""
messages = []
for var in required_variables:
if not self._has(var):
messages.append('Property "{0}" not found (should be {1}).'
.format(self.mapper(var), required_variables[var]))
elif not self._get(var):
messages.append('Property "{0}" not set (should be {1}).'
.format(self.mapper(var), required_variables[var]))
if messages:
raise errors.PluginError(
'Missing {0} in credentials configuration file {1}:\n * {2}'.format(
'property' if len(messages) == 1 else 'properties',
self.confobj.filename,
'\n * '.join(messages)
)
)
[docs] def conf(self, var):
"""Find a configuration value for variable `var`, as transformed by `mapper`.
:param str var: The variable to get.
:returns: The value of the variable.
:rtype: str
"""
return self._get(var)
def _has(self, var):
return self.mapper(var) in self.confobj
def _get(self, var):
return self.confobj.get(self.mapper(var))
[docs]def validate_file(filename):
"""Ensure that the specified file exists."""
if not os.path.exists(filename):
raise errors.PluginError('File not found: {0}'.format(filename))
if not os.path.isfile(filename):
raise errors.PluginError('Path is not a file: {0}'.format(filename))
[docs]def validate_file_permissions(filename):
"""Ensure that the specified file exists and warn about unsafe permissions."""
validate_file(filename)
permissions = stat.S_IMODE(os.stat(filename).st_mode)
if permissions & stat.S_IRWXO:
logger.warning('Unsafe permissions on credentials configuration file: %s', filename)
[docs]def base_domain_name_guesses(domain):
"""Return a list of progressively less-specific domain names.
One of these will probably be the domain name known to the DNS provider.
:Example:
>>> base_domain_name_guesses('foo.bar.baz.example.com')
['foo.bar.baz.example.com', 'bar.baz.example.com', 'baz.example.com', 'example.com', 'com']
:param str domain: The domain for which to return guesses.
:returns: The a list of less specific domain names.
:rtype: list
"""
fragments = domain.split('.')
return ['.'.join(fragments[i:]) for i in range(0, len(fragments))]