from __future__ import annotations import re from configparser import ConfigParser from io import StringIO from warnings import warn from passlib import exc from passlib.exc import ExpectedStringError, ExpectedTypeError, PasslibConfigWarning from passlib.registry import _validate_handler_name, get_crypt_handler from passlib.utils import ( handlers as uh, ) from passlib.utils import ( splitcomma, to_unicode, ) from passlib.utils.compat import ( numeric_types, unicode_or_bytes, ) from passlib.utils.decor import deprecated_method, memoized_property # local __all__ = [ "CryptContext", "LazyCryptContext", ] # private object to detect unset params _UNSET = object() def _coerce_vary_rounds(value: str) -> float | int: """parse vary_rounds string to percent as [0,1) float, or integer""" if value.endswith("%"): # XXX: deprecate this in favor of raw float? return float(value.rstrip("%")) * 0.01 try: return int(value) except ValueError: return float(value) # set of options which aren't allowed to be set via policy _forbidden_scheme_options = set(["salt"]) # 'salt' - not allowed since a fixed salt would defeat the purpose. # dict containing funcs used to coerce strings to correct type for scheme option keys. # NOTE: this isn't really needed any longer, since Handler.using() handles the actual parsing. # keeping this around for now, though, since it makes context.to_dict() output cleaner. _coerce_scheme_options = dict( min_rounds=int, max_rounds=int, default_rounds=int, vary_rounds=_coerce_vary_rounds, salt_size=int, ) def _is_handler_registered(handler): """detect if handler is registered or a custom handler""" return get_crypt_handler(handler.name, None) is handler #: list of keys allowed under wildcard "all" scheme w/o a security warning. _global_settings = set(["truncate_error", "vary_rounds"]) class _CryptConfig: """parses, validates, and stores CryptContext config this is a helper used internally by CryptContext to handle parsing, validation, and serialization of its config options. split out from the main class, but not made public since that just complicates interface too much (c.f. CryptPolicy) :arg source: config as dict mapping ``(cat,scheme,option) -> value`` """ # triple-nested dict which maps scheme -> category -> key -> value, # storing all hash-specific options _scheme_options = None # double-nested dict which maps key -> category -> value # storing all CryptContext options _context_options = None # tuple of handler objects handlers = None # tuple of scheme objects in same order as handlers schemes = None # tuple of categories in alphabetical order (not including None) categories = None # set of all context keywords used by active schemes context_kwds = None # dict mapping category -> default scheme _default_schemes = None # dict mapping (scheme, category) -> custom handler _records = None # dict mapping category -> list of custom handler instances for that category, # in order of schemes(). populated on demand by _get_record_list() _record_lists = None def __init__(self, source): self._init_scheme_list(source.get((None, None, "schemes"))) self._init_options(source) self._init_default_schemes() self._init_records() def _init_scheme_list(self, data): """initialize .handlers and .schemes attributes""" handlers = [] schemes = [] if isinstance(data, str): data = splitcomma(data) for elem in data or (): # resolve elem -> handler & scheme if hasattr(elem, "name"): handler = elem scheme = handler.name _validate_handler_name(scheme) elif isinstance(elem, str): handler = get_crypt_handler(elem) scheme = handler.name else: raise TypeError( f"scheme must be name or CryptHandler, not {type(elem)!r}" ) # check scheme name isn't already in use if scheme in schemes: raise KeyError(f"multiple handlers with same name: {scheme!r}") # add to handler list handlers.append(handler) schemes.append(scheme) self.handlers = tuple(handlers) self.schemes = tuple(schemes) def _init_options(self, source): """load config dict into internal representation, and init .categories attr """ # prepare dicts & locals norm_scheme_option = self._norm_scheme_option norm_context_option = self._norm_context_option self._scheme_options = scheme_options = {} self._context_options = context_options = {} categories = set() # load source config into internal storage for (cat, scheme, key), value in source.items(): categories.add(cat) explicit_scheme = scheme if not cat and not scheme and key in _global_settings: # going forward, not using "__all__" format. instead... # whitelisting set of keys which should be passed to (all) schemes, # rather than passed to the CryptContext itself scheme = "all" if scheme: # normalize scheme option key, value = norm_scheme_option(key, value) # e.g. things like "min_rounds" should never be set cross-scheme # this will be fatal under 2.0. if scheme == "all" and key not in _global_settings: warn( f"The '{key}' option should be configured per-algorithm, and not set " "globally in the context; This will be an error in Passlib 2.0", PasslibConfigWarning, ) # this scheme is going away in 2.0; # but most keys deserve an extra warning since it impacts security. if explicit_scheme == "all": warn( "The 'all' scheme is deprecated as of Passlib 1.7, " "and will be removed in Passlib 2.0; Please configure " "options on a per-algorithm basis.", DeprecationWarning, ) # store in scheme_options # map structure: scheme_options[scheme][category][key] = value try: category_map = scheme_options[scheme] except KeyError: scheme_options[scheme] = {cat: {key: value}} else: try: option_map = category_map[cat] except KeyError: category_map[cat] = {key: value} else: option_map[key] = value else: # normalize context option if cat and key == "schemes": raise KeyError( "'schemes' context option is not allowed per category" ) key, value = norm_context_option(cat, key, value) # store in context_options # map structure: context_options[key][category] = value try: category_map = context_options[key] except KeyError: context_options[key] = {cat: value} else: category_map[cat] = value # store list of configured categories categories.discard(None) self.categories = tuple(sorted(categories)) def _norm_scheme_option(self, key, value): # check for invalid options if key in _forbidden_scheme_options: raise KeyError(f"{key!r} option not allowed in CryptContext configuration") # coerce strings for certain fields (e.g. min_rounds uses ints) if isinstance(value, str): func = _coerce_scheme_options.get(key) if func: value = func(value) return key, value def _norm_context_option(self, cat, key, value): schemes = self.schemes if key == "default": if hasattr(value, "name"): value = value.name elif not isinstance(value, str): raise ExpectedTypeError(value, "str", "default") if schemes and value not in schemes: raise KeyError("default scheme not found in policy") elif key == "deprecated": if isinstance(value, str): value = splitcomma(value) elif not isinstance(value, (list, tuple)): raise ExpectedTypeError(value, "str or seq", "deprecated") if "auto" in value: # XXX: have any statements been made about when this is default? # should do it in 1.8 at latest. if len(value) > 1: raise ValueError( "cannot list other schemes if ``deprecated=['auto']`` is used" ) elif schemes: # make sure list of deprecated schemes is subset of configured schemes for scheme in value: if not isinstance(scheme, str): raise ExpectedTypeError(value, "str", "deprecated element") if scheme not in schemes: raise KeyError( f"deprecated scheme not found in policy: {scheme!r}" ) elif key != "schemes": raise KeyError(f"unknown CryptContext keyword: {key!r}") return key, value # --------------------------------------------------------------- # reading context options # --------------------------------------------------------------- def get_context_optionmap(self, key, _default={}): """return dict mapping category->value for specific context option. .. warning:: treat return value as readonly! """ return self._context_options.get(key, _default) def get_context_option_with_flag(self, category, key): """return value of specific option, handling category inheritance. also returns flag indicating whether value is category-specific. """ try: category_map = self._context_options[key] except KeyError: return None, False value = category_map.get(None) if category: try: alt = category_map[category] except KeyError: pass else: if value is None or alt != value: return alt, True return value, False # --------------------------------------------------------------- # reading scheme options # --------------------------------------------------------------- def _get_scheme_optionmap(self, scheme, category, default={}): """return all options for (scheme,category) combination .. warning:: treat return value as readonly! """ try: return self._scheme_options[scheme][category] except KeyError: return default def get_base_handler(self, scheme): return self.handlers[self.schemes.index(scheme)] @staticmethod def expand_settings(handler): setting_kwds = handler.setting_kwds if "rounds" in handler.setting_kwds: # XXX: historically this extras won't be listed in setting_kwds setting_kwds += uh.HasRounds.using_rounds_kwds return setting_kwds # NOTE: this is only used by _get_record_options_with_flag()... def get_scheme_options_with_flag(self, scheme, category): """return composite dict of all options set for scheme. includes options inherited from 'all' and from default category. result can be modified. returns (kwds, has_cat_specific_options) """ # start out with copy of global options get_optionmap = self._get_scheme_optionmap kwds = get_optionmap("all", None).copy() has_cat_options = False # add in category-specific global options if category: defkwds = kwds.copy() # <-- used to detect category-specific options kwds.update(get_optionmap("all", category)) # filter out global settings not supported by handler allowed_settings = self.expand_settings(self.get_base_handler(scheme)) for key in set(kwds).difference(allowed_settings): kwds.pop(key) if category: for key in set(defkwds).difference(allowed_settings): defkwds.pop(key) # add in default options for scheme other = get_optionmap(scheme, None) kwds.update(other) # load category-specific options for scheme if category: defkwds.update(other) kwds.update(get_optionmap(scheme, category)) # compare default category options to see if there's anything # category-specific if kwds != defkwds: has_cat_options = True return kwds, has_cat_options def _init_default_schemes(self): """initialize maps containing default scheme for each category. have to do this after _init_options(), since the default scheme is affected by the list of deprecated schemes. """ # init maps & locals get_optionmap = self.get_context_optionmap default_map = self._default_schemes = get_optionmap("default").copy() dep_map = get_optionmap("deprecated") schemes = self.schemes if not schemes: return # figure out default scheme deps = dep_map.get(None) or () default = default_map.get(None) if not default: for scheme in schemes: if scheme not in deps: default_map[None] = scheme break else: raise ValueError("must have at least one non-deprecated scheme") elif default in deps: raise ValueError("default scheme cannot be deprecated") # figure out per-category default schemes, for cat in self.categories: cdeps = dep_map.get(cat, deps) cdefault = default_map.get(cat, default) if not cdefault: for scheme in schemes: if scheme not in cdeps: default_map[cat] = scheme break else: raise ValueError( "must have at least one non-deprecated " f"scheme for {cat!r} category" ) elif cdefault in cdeps: raise ValueError( f"default scheme for {cat!r} category cannot be deprecated" ) def default_scheme(self, category): """return default scheme for specific category""" defaults = self._default_schemes try: return defaults[category] except KeyError: pass if not self.schemes: raise KeyError("no hash schemes configured for this CryptContext instance") return defaults[None] def is_deprecated_with_flag(self, scheme, category): """is scheme deprecated under particular category?""" depmap = self.get_context_optionmap("deprecated") def test(cat): source = depmap.get(cat, depmap.get(None)) if source is None: return None if "auto" in source: return scheme != self.default_scheme(cat) return scheme in source value = test(None) or False if category: alt = test(category) if alt is not None and value != alt: return alt, True return value, False def _init_records(self): # NOTE: this step handles final validation of settings, # checking for violations against handler's internal invariants. # this is why we create all the records now, # so CryptContext throws error immediately rather than later. self._record_lists = {} records = self._records = {} all_context_kwds = self.context_kwds = set() get_options = self._get_record_options_with_flag categories = (None,) + self.categories for handler in self.handlers: scheme = handler.name all_context_kwds.update(handler.context_kwds) for cat in categories: kwds, has_cat_options = get_options(scheme, cat) if cat is None or has_cat_options: records[scheme, cat] = self._create_record(handler, cat, **kwds) # NOTE: if handler has no category-specific opts, get_record() # will automatically use the default category's record. # NOTE: default records for specific category stored under the # key (None,category); these are populated on-demand by get_record(). @staticmethod def _create_record(handler, category=None, deprecated=False, **settings): # create custom handler if needed. try: # XXX: relaxed=True is mostly here to retain backwards-compat behavior. # could make this optional flag in future. subcls = handler.using(relaxed=True, **settings) except TypeError as err: m = re.match(r".* unexpected keyword argument '(.*)'$", str(err)) if m and m.group(1) in settings: # translate into KeyError, for backwards compat. # XXX: push this down to GenericHandler.using() implementation? key = m.group(1) raise KeyError( f"keyword not supported by {handler.name} handler: {key!r}" ) raise # using private attrs to store some extra metadata in custom handler assert subcls is not handler, "expected unique variant of handler" ##subcls._Context__category = category subcls._Context__orig_handler = handler subcls.deprecated = deprecated # attr reserved for this purpose return subcls def _get_record_options_with_flag(self, scheme, category): """return composite dict of options for given scheme + category. this is currently a private method, though some variant of its output may eventually be made public. given a scheme & category, it returns two things: a set of all the keyword options to pass to :meth:`_create_record`, and a bool flag indicating whether any of these options were specific to the named category. if this flag is false, the options are identical to the options for the default category. the options dict includes all the scheme-specific settings, as well as optional *deprecated* keyword. """ # get scheme options kwds, has_cat_options = self.get_scheme_options_with_flag(scheme, category) # throw in deprecated flag value, not_inherited = self.is_deprecated_with_flag(scheme, category) if value: kwds["deprecated"] = True if not_inherited: has_cat_options = True return kwds, has_cat_options def get_record(self, scheme, category): """return record for specific scheme & category (cached)""" # NOTE: this is part of the critical path shared by # all of CryptContext's PasswordHash methods, # hence all the caching and error checking. # quick lookup in cache try: return self._records[scheme, category] except KeyError: pass # type check if category is not None and not isinstance(category, str): raise ExpectedTypeError(category, "str or None", "category") if scheme is not None and not isinstance(scheme, str): raise ExpectedTypeError(scheme, "str or None", "scheme") # if scheme=None, # use record for category's default scheme, and cache result. if not scheme: default = self.default_scheme(category) assert default record = self._records[None, category] = self.get_record(default, category) return record # if no record for (scheme, category), # use record for (scheme, None), and cache result. if category: try: cache = self._records record = cache[scheme, category] = cache[scheme, None] return record except KeyError: pass # scheme not found in configuration for default category raise KeyError(f"crypt algorithm not found in policy: {scheme!r}") def _get_record_list(self, category=None): """return list of records for category (cached) this is an internal helper used only by identify_record() """ # type check of category - handled by _get_record() # quick lookup in cache try: return self._record_lists[category] except KeyError: pass # cache miss - build list from scratch value = self._record_lists[category] = [ self.get_record(scheme, category) for scheme in self.schemes ] return value def identify_record(self, hash, category, required=True): """internal helper to identify appropriate custom handler for hash""" # NOTE: this is part of the critical path shared by # all of CryptContext's PasswordHash methods, # hence all the caching and error checking. # FIXME: if multiple hashes could match (e.g. lmhash vs nthash) # this will only return first match. might want to do something # about this in future, but for now only hashes with # unique identifiers will work properly in a CryptContext. # XXX: if all handlers have a unique prefix (e.g. all are MCF / LDAP), # could use dict-lookup to speed up this search. if not isinstance(hash, unicode_or_bytes): raise ExpectedStringError(hash, "hash") # type check of category - handled by _get_record_list() for record in self._get_record_list(category): if record.identify(hash): return record if not required: return None if not self.schemes: raise KeyError("no crypt algorithms supported") raise exc.UnknownHashError("hash could not be identified") @memoized_property def disabled_record(self): for record in self._get_record_list(None): if record.is_disabled: return record raise RuntimeError( "no disabled hasher present " "(perhaps add 'unix_disabled' to list of schemes?)" ) def iter_config(self, resolve=False): """regenerate original config. this is an iterator which yields ``(cat,scheme,option),value`` items, in the order they generally appear inside an INI file. if interpreted as a dictionary, it should match the original keywords passed to the CryptContext (aside from any canonization). it's mainly used as the internal backend for most of the public serialization methods. """ # grab various bits of data scheme_options = self._scheme_options context_options = self._context_options scheme_keys = sorted(scheme_options) context_keys = sorted(context_options) # write loaded schemes (may differ from 'schemes' local var) if "schemes" in context_keys: context_keys.remove("schemes") value = self.handlers if resolve else self.schemes if value: yield (None, None, "schemes"), list(value) # then run through config for each user category for cat in (None,) + self.categories: # write context options for key in context_keys: try: value = context_options[key][cat] except KeyError: # noqa: PERF203 pass else: if isinstance(value, list): value = list(value) yield (cat, None, key), value # write per-scheme options for all schemes. for scheme in scheme_keys: try: kwds = scheme_options[scheme][cat] except KeyError: # noqa: PERF203 pass else: for key in sorted(kwds): yield (cat, scheme, key), kwds[key] class CryptContext: """Helper for hashing & verifying passwords using multiple algorithms. Instances of this class allow applications to choose a specific set of hash algorithms which they wish to support, set limits and defaults for the rounds and salt sizes those algorithms should use, flag which algorithms should be deprecated, and automatically handle migrating users to stronger hashes when they log in. Basic usage:: >>> ctx = CryptContext(schemes=[...]) See the Passlib online documentation for details and full documentation. """ # FIXME: altering the configuration of this object isn't threadsafe, # but is generally only done during application init, so not a major # issue (just yet). # XXX: would like some way to restrict the categories that are allowed, # to restrict what the app OR the config can use. # XXX: add wrap/unwrap callback hooks so app can mutate hash format? # XXX: add method for detecting and warning user about schemes # which don't have any good distinguishing marks? # or greedy ones (unix_disabled, plaintext) which are not listed at the end? # _CryptConfig instance holding current parsed config _config = None # copy of _config methods, stored in CryptContext instance for speed. _get_record = None _identify_record = None @classmethod def _norm_source(cls, source): """internal helper - accepts string, dict, or context""" if isinstance(source, dict): return cls(**source) if isinstance(source, cls): return source self = cls() self.load(source) return self @classmethod def from_string(cls, source, section="passlib", encoding="utf-8"): """create new CryptContext instance from an INI-formatted string. :type source: str or bytes :arg source: string containing INI-formatted content. :type section: str :param section: option name of section to read from, defaults to ``"passlib"``. :type encoding: str :arg encoding: optional encoding used when source is bytes, defaults to ``"utf-8"``. :returns: new :class:`CryptContext` instance, configured based on the parameters in the *source* string. Usage example:: >>> from passlib.context import CryptContext >>> context = CryptContext.from_string(''' ... [passlib] ... schemes = sha256_crypt, des_crypt ... sha256_crypt__default_rounds = 30000 ... ''') .. versionadded:: 1.6 .. seealso:: :meth:`to_string`, the inverse of this constructor. """ if not isinstance(source, unicode_or_bytes): raise ExpectedTypeError(source, "str or bytes", "source") self = cls(_autoload=False) self.load(source, section=section, encoding=encoding) return self @classmethod def from_path(cls, path, section="passlib", encoding="utf-8"): """create new CryptContext instance from an INI-formatted file. this functions exactly the same as :meth:`from_string`, except that it loads from a local file. :type path: str :arg path: path to local file containing INI-formatted config. :type section: str :param section: option name of section to read from, defaults to ``"passlib"``. :type encoding: str :arg encoding: encoding used to load file, defaults to ``"utf-8"``. :returns: new CryptContext instance, configured based on the parameters stored in the file *path*. .. versionadded:: 1.6 .. seealso:: :meth:`from_string` for an equivalent usage example. """ self = cls(_autoload=False) self.load_path(path, section=section, encoding=encoding) return self def copy(self, **kwds): """Return copy of existing CryptContext instance. This function returns a new CryptContext instance whose configuration is exactly the same as the original, with the exception that any keywords passed in will take precedence over the original settings. As an example:: >>> from passlib.context import CryptContext >>> # given an existing context... >>> ctx1 = CryptContext(["sha256_crypt", "md5_crypt"]) >>> # copy can be used to make a clone, and update >>> # some of the settings at the same time... >>> ctx2 = custom_app_context.copy(default="md5_crypt") >>> # and the original will be unaffected by the change >>> ctx1.default_scheme() "sha256_crypt" >>> ctx2.default_scheme() "md5_crypt" .. versionadded:: 1.6 This method was previously named :meth:`!replace`. That alias was removed in Passlib 1.8. .. seealso:: :meth:`update` """ # XXX: it would be faster to store ref to self._config, # but don't want to share config objects til sure # can rely on them being immutable. other = CryptContext(_autoload=False) other.load(self) if kwds: other.load(kwds, update=True) return other def using(self, **kwds): """ alias for :meth:`copy`, to match PasswordHash.using() """ return self.copy(**kwds) def __init__( self, schemes=None, # keyword only... _autoload=True, **kwds, ): # XXX: add ability to make flag certain contexts as immutable, # e.g. the builtin passlib ones? # XXX: add a name or import path for the contexts, to help out repr? if schemes is not None: kwds["schemes"] = schemes if _autoload: self.load(kwds) else: assert not kwds, "_autoload=False and kwds are mutually exclusive" # XXX: would this be useful? ##def __str__(self): ## return self.to_string() def __repr__(self): return f"" @staticmethod def _parse_ini_stream(stream, section, filename): """helper read INI from stream, extract passlib section as dict""" # NOTE: this expects a unicode stream, # and resulting dict will always use native strings. p = ConfigParser() p.read_file(stream, filename) # XXX: could change load() to accept list of items, # and skip intermediate dict creation return dict(p.items(section)) def load_path(self, path, update=False, section="passlib", encoding="utf-8"): """Load new configuration into CryptContext from a local file. This function is a wrapper for :meth:`load` which loads a configuration string from the local file *path*, instead of an in-memory source. Its behavior and options are otherwise identical to :meth:`!load` when provided with an INI-formatted string. .. versionadded:: 1.6 """ with open(path, encoding=encoding) as stream: kwds = self._parse_ini_stream(stream, section, path) return self.load(kwds, update=update) def load(self, source, update=False, section="passlib", encoding="utf-8"): """Load new configuration into CryptContext, replacing existing config. :arg source: source of new configuration to load. this value can be a number of different types: * a :class:`!dict` object, or compatible Mapping the key/value pairs will be interpreted the same keywords for the :class:`CryptContext` class constructor. * a :class:`!str` or :class:`!bytes` string this will be interpreted as an INI-formatted file, and appropriate key/value pairs will be loaded from the specified *section*. * another :class:`!CryptContext` object. this will export a snapshot of its configuration using :meth:`to_dict`. :type update: bool :param update: By default, :meth:`load` will replace the existing configuration entirely. If ``update=True``, it will preserve any existing configuration options that are not overridden by the new source, much like the :meth:`update` method. :type section: str :param section: When parsing an INI-formatted string, :meth:`load` will look for a section named ``"passlib"``. This option allows an alternate section name to be used. Ignored when loading from a dictionary. :type encoding: str :param encoding: Encoding to use when **source** is bytes. Defaults to ``"utf-8"``. Ignored when loading from a dictionary. .. deprecated:: 1.8 This keyword, and support for bytes input, will be dropped in Passlib 2.0 :raises TypeError: * If the source cannot be identified. * If an unknown / malformed keyword is encountered. :raises ValueError: If an invalid keyword value is encountered. .. note:: If an error occurs during a :meth:`!load` call, the :class:`!CryptContext` instance will be restored to the configuration it was in before the :meth:`!load` call was made; this is to ensure it is *never* left in an inconsistent state due to a load error. .. versionadded:: 1.6 """ # ----------------------------------------------------------- # autodetect source type, convert to dict # ----------------------------------------------------------- parse_keys = True if isinstance(source, unicode_or_bytes): source = to_unicode(source, encoding, param="source") source = self._parse_ini_stream( StringIO(source), section, "" ) elif isinstance(source, CryptContext): # extract dict directly from config, so it can be merged later source = dict(source._config.iter_config(resolve=True)) parse_keys = False elif not hasattr(source, "items"): # mappings are left alone, otherwise throw an error. raise ExpectedTypeError(source, "string or dict", "source") # XXX: add support for other iterable types, e.g. sequence of pairs? # ----------------------------------------------------------- # parse dict keys into (category, scheme, option) format, # and merge with existing configuration if needed. # ----------------------------------------------------------- if parse_keys: parse = self._parse_config_key source = dict((parse(key), value) for key, value in source.items()) if update and self._config is not None: # if updating, do nothing if source is empty, if not source: return # otherwise overlay source on top of existing config tmp = source source = dict(self._config.iter_config(resolve=True)) source.update(tmp) # ----------------------------------------------------------- # compile into _CryptConfig instance, and update state # ----------------------------------------------------------- config = _CryptConfig(source) self._config = config self._reset_dummy_verify() self._get_record = config.get_record self._identify_record = config.identify_record if config.context_kwds: # (re-)enable method for this instance (in case ELSE clause below ran last load). self.__dict__.pop("_strip_unused_context_kwds", None) else: # disable method for this instance, it's not needed. self._strip_unused_context_kwds = None @staticmethod def _parse_config_key(ckey): """helper used to parse ``cat__scheme__option`` keys into a tuple""" # split string into 1-3 parts assert isinstance(ckey, str) parts = ckey.replace(".", "__").split("__") count = len(parts) if count == 1: cat, scheme, key = None, None, parts[0] elif count == 2: cat = None scheme, key = parts elif count == 3: cat, scheme, key = parts else: raise TypeError(f"keys must have less than 3 separators: {ckey!r}") # validate & normalize the parts if cat == "default": cat = None elif not cat and cat is not None: raise TypeError(f"empty category: {ckey!r}") if scheme == "context": scheme = None elif not scheme and scheme is not None: raise TypeError(f"empty scheme: {ckey!r}") if not key: raise TypeError(f"empty option: {ckey!r}") return cat, scheme, key def update(self, *args, **kwds): """Helper for quickly changing configuration. This acts much like the :meth:`!dict.update` method: it updates the context's configuration, replacing the original value(s) for the specified keys, and preserving the rest. It accepts any :ref:`keyword ` accepted by the :class:`!CryptContext` constructor. .. versionadded:: 1.6 .. seealso:: :meth:`copy` """ if args: if len(args) > 1: raise TypeError("expected at most one positional argument") if kwds: raise TypeError("positional arg and keywords mutually exclusive") self.load(args[0], update=True) elif kwds: self.load(kwds, update=True) # XXX: make this public? even just as flag to load? # FIXME: this function suffered some bitrot in 1.6.1, # will need to be updated before works again. ##def _simplify(self): ## "helper to remove redundant/unused options" ## # don't do anything if no schemes are defined ## if not self._schemes: ## return ## ## def strip_items(target, filter): ## keys = [key for key,value in target.items() if filter(key,value)] ## for key in keys: ## del target[key] ## ## # remove redundant default. ## defaults = self._default_schemes ## if defaults.get(None) == self._schemes[0]: ## del defaults[None] ## ## # remove options for unused schemes. ## scheme_options = self._scheme_options ## schemes = self._schemes + ("all",) ## strip_items(scheme_options, lambda k,v: k not in schemes) ## ## # remove rendundant cat defaults. ## cur = self.default_scheme() ## strip_items(defaults, lambda k,v: k and v==cur) ## ## # remove redundant category deprecations. ## # TODO: this should work w/ 'auto', but needs closer inspection ## deprecated = self._deprecated_schemes ## cur = self._deprecated_schemes.get(None) ## strip_items(deprecated, lambda k,v: k and v==cur) ## ## # remove redundant category options. ## for scheme, config in scheme_options.items(): ## if None in config: ## cur = config[None] ## strip_items(config, lambda k,v: k and v==cur) ## ## # XXX: anything else? def schemes(self, resolve=False, category=None, unconfigured=False): """return schemes loaded into this CryptContext instance. :type resolve: bool :arg resolve: if ``True``, will return a tuple of :class:`~passlib.ifc.PasswordHash` objects instead of their names. :returns: returns tuple of the schemes configured for this context via the *schemes* option. .. versionadded:: 1.6 This was previously available as ``CryptContext().policy.schemes()`` .. seealso:: the :ref:`schemes ` option for usage example. """ # XXX: should resolv return records rather than handlers? # or deprecate resolve keyword completely? # offering up a .hashers Mapping in v1.8 would be great. # NOTE: supporting 'category' and 'unconfigured' kwds as of 1.7 # just to pass through to .handler(), but not documenting them... # may not need to put them to use. schemes = self._config.schemes if resolve: return tuple( self.handler(scheme, category, unconfigured=unconfigured) for scheme in schemes ) return schemes def default_scheme(self, category=None, resolve=False, unconfigured=False): """return name of scheme that :meth:`hash` will use by default. :type resolve: bool :arg resolve: if ``True``, will return a :class:`~passlib.ifc.PasswordHash` object instead of the name. :type category: str or None :param category: Optional :ref:`user category `. If specified, this will return the catgory-specific default scheme instead. :returns: name of the default scheme. .. seealso:: the :ref:`default ` option for usage example. .. versionadded:: 1.6 .. versionchanged:: 1.7 This now returns a hasher configured with any CryptContext-specific options (custom rounds settings, etc). Previously this returned the base hasher from :mod:`passlib.hash`. """ # XXX: deprecate this in favor of .handler() or whatever it's replaced with? # NOTE: supporting 'unconfigured' kwds as of 1.7 # just to pass through to .handler(), but not documenting them... # may not need to put them to use. hasher = self.handler(None, category, unconfigured=unconfigured) return hasher if resolve else hasher.name # XXX: need to decide if exposing this would be useful in any way ##def categories(self): ## """return user-categories with algorithm-specific options in this CryptContext. ## ## this will always return a tuple. ## if no categories besides the default category have been configured, ## the tuple will be empty. ## """ ## return self._config.categories # XXX: need to decide if exposing this would be useful to applications # in any meaningful way that isn't already served by to_dict() ##def options(self, scheme, category=None): ## kwds, percat = self._config.get_options(scheme, category) ## return kwds def handler(self, scheme=None, category=None, unconfigured=False): """helper to resolve name of scheme -> :class:`~passlib.ifc.PasswordHash` object used by scheme. :arg scheme: This should identify the scheme to lookup. If omitted or set to ``None``, this will return the handler for the default scheme. :arg category: If a user category is specified, and no scheme is provided, it will use the default for that category. Otherwise this parameter is ignored. :param unconfigured: By default, this returns a handler object whose .hash() and .needs_update() methods will honor the configured provided by CryptContext. See ``unconfigured=True`` to get the underlying handler from before any context-specific configuration was applied. :raises KeyError: If the scheme does not exist OR is not being used within this context. :returns: :class:`~passlib.ifc.PasswordHash` object used to implement the named scheme within this context (this will usually be one of the objects from :mod:`passlib.hash`) .. versionadded:: 1.6 This was previously available as ``CryptContext().policy.get_handler()`` .. versionchanged:: 1.7 This now returns a hasher configured with any CryptContext-specific options (custom rounds settings, etc). Previously this returned the base hasher from :mod:`passlib.hash`. """ try: hasher = self._get_record(scheme, category) if unconfigured: return hasher._Context__orig_handler return hasher except KeyError: pass if self._config.handlers: raise KeyError( f"crypt algorithm not found in this CryptContext instance: {scheme!r}" ) raise KeyError("no crypt algorithms loaded in this CryptContext instance") def _get_unregistered_handlers(self): """check if any handlers in this context aren't in the global registry""" return tuple( handler for handler in self._config.handlers if not _is_handler_registered(handler) ) @property def context_kwds(self): """ return :class:`!set` containing union of all :ref:`contextual keywords ` supported by the handlers in this context. .. versionadded:: 1.6.6 """ return self._config.context_kwds @staticmethod def _render_config_key(key): """convert 3-part config key to single string""" cat, scheme, option = key if cat: return "{}__{}__{}".format(cat, scheme or "context", option) if scheme: return f"{scheme}__{option}" return option @staticmethod def _render_ini_value(key, value): """render value to string suitable for INI file""" # convert lists to comma separated lists # (mainly 'schemes' & 'deprecated') if isinstance(value, (list, tuple)): value = ", ".join(value) # convert numbers to strings elif isinstance(value, numeric_types): if isinstance(value, float) and key[2] == "vary_rounds": value = (f"{value:.2f}").rstrip("0") if value else "0" else: value = str(value) assert isinstance(value, str), f"expected string for key: {key!r} {value!r}" # escape any percent signs. return value.replace("%", "%%") def to_dict(self, resolve=False): """Return current configuration as a dictionary. :type resolve: bool :arg resolve: if ``True``, the ``schemes`` key will contain a list of a :class:`~passlib.ifc.PasswordHash` objects instead of just their names. This method dumps the current configuration of the CryptContext instance. The key/value pairs should be in the format accepted by the :class:`!CryptContext` class constructor, in fact ``CryptContext(**myctx.to_dict())`` will create an exact copy of ``myctx``. As an example:: >>> # you can dump the configuration of any crypt context... >>> from passlib.apps import ldap_nocrypt_context >>> ldap_nocrypt_context.to_dict() {'schemes': ['ldap_salted_sha1', 'ldap_salted_md5', 'ldap_sha1', 'ldap_md5', 'ldap_plaintext']} .. versionadded:: 1.6 This was previously available as ``CryptContext().policy.to_dict()`` .. seealso:: the :ref:`context-serialization-example` example in the tutorial. """ # XXX: should resolve default to conditional behavior # based on presence of unregistered handlers? render_key = self._render_config_key return dict( (render_key(key), value) for key, value in self._config.iter_config(resolve) ) def _write_to_parser(self, parser: ConfigParser, section: str) -> None: """helper to write to ConfigParser instance""" parser.add_section(section) for key, value in self._config.iter_config(): # type: ignore[attr-defined] parser.set( section=section, option=self._render_config_key(key), value=self._render_ini_value(key, value), ) def to_string(self, section="passlib") -> str: """serialize to INI format and return as unicode string. :param section: name of INI section to output, defaults to ``"passlib"``. :returns: CryptContext configuration, serialized to a INI unicode string. This function acts exactly like :meth:`to_dict`, except that it serializes all the contents into a single human-readable string, which can be hand edited, and/or stored in a file. The output of this method is accepted by :meth:`from_string`, :meth:`from_path`, and :meth:`load`. As an example:: >>> # you can dump the configuration of any crypt context... >>> from passlib.apps import ldap_nocrypt_context >>> print ldap_nocrypt_context.to_string() [passlib] schemes = ldap_salted_sha1, ldap_salted_md5, ldap_sha1, ldap_md5, ldap_plaintext .. versionadded:: 1.6 This was previously available as ``CryptContext().policy.to_string()`` .. seealso:: the :ref:`context-serialization-example` example in the tutorial. """ parser = ConfigParser() self._write_to_parser(parser, section) buf = StringIO() parser.write(buf) unregistered = self._get_unregistered_handlers() if unregistered: buf.write( ( "# NOTE: the {} handler(s) are not registered with Passlib,\n" "# this string may not correctly reproduce the current configuration.\n\n" ).format(", ".join(repr(handler.name) for handler in unregistered)) ) return buf.getvalue() # XXX: is this useful enough to enable? ##def write_to_path(self, path, section="passlib", update=False): ## "write to INI file" ## parser = ConfigParser() ## if update and os.path.exists(path): ## if not parser.read([path]): ## raise EnvironmentError("failed to read existing file") ## parser.remove_section(section) ## self._write_to_parser(parser, section) ## fh = file(path, "w") ## parser.write(fh) ## fh.close() # NOTE: all the following methods do is look up the appropriate # custom handler for a given (scheme,category) combination, # and hand off the real work to the handler itself, # which is optimized for the specific (scheme,category) configuration. # # The custom handlers are cached inside the _CryptConfig # instance stored in self._config, and are retrieved # via get_record() and identify_record(). # # _get_record() and _identify_record() are references # to _config methods of the same name, # stored in CryptContext for speed. def _get_or_identify_record(self, hash, scheme=None, category=None): """return record based on scheme, or failing that, by identifying hash""" if scheme: if not isinstance(hash, unicode_or_bytes): raise ExpectedStringError(hash, "hash") return self._get_record(scheme, category) # hash typecheck handled by identify_record() return self._identify_record(hash, category) def _strip_unused_context_kwds(self, kwds, record): """ helper which removes any context keywords from **kwds** that are known to be used by another scheme in this context, but are NOT supported by handler specified by **record**. .. note:: as optimization, load() will set this method to None on a per-instance basis if there are no context kwds. """ if not kwds: return unused_kwds = self._config.context_kwds.difference(record.context_kwds) for key in unused_kwds: kwds.pop(key, None) def needs_update(self, hash, scheme=None, category=None, secret=None): """Check if hash needs to be replaced for some reason, in which case the secret should be re-hashed. This function is the core of CryptContext's support for hash migration: This function takes in a hash string, and checks the scheme, number of rounds, and other properties against the current policy. It returns ``True`` if the hash is using a deprecated scheme, or is otherwise outside of the bounds specified by the policy (e.g. the number of rounds is lower than :ref:`min_rounds ` configuration for that algorithm). If so, the password should be re-hashed using :meth:`hash` Otherwise, it will return ``False``. :type hash: str or bytes :arg hash: The hash string to examine. :type scheme: str or None :param scheme: Optional scheme to use. Scheme must be one of the ones configured for this context (see the :ref:`schemes ` option). If no scheme is specified, it will be identified based on the value of *hash*. .. deprecated:: 1.7 Support for this keyword is deprecated, and will be removed in Passlib 2.0. :type category: str or None :param category: Optional :ref:`user category `. If specified, this will cause any category-specific defaults to be used when determining if the hash needs to be updated (e.g. is below the minimum rounds). :type secret: str, bytes, or None :param secret: Optional secret associated with the provided ``hash``. This is not required, or even currently used for anything... it's for forward-compatibility with any future update checks that might need this information. If provided, Passlib assumes the secret has already been verified successfully against the hash. .. versionadded:: 1.6 :returns: ``True`` if hash should be replaced, otherwise ``False``. :raises ValueError: If the hash did not match any of the configured :meth:`schemes`. .. versionadded:: 1.6 This method was previously named :meth:`hash_needs_update`. .. seealso:: the :ref:`context-migration-example` example in the tutorial. """ if scheme is not None: # TODO: offer replacement alternative. # ``context.handler(scheme).needs_update()`` would work, # but may deprecate .handler() in passlib 1.8. warn( "CryptContext.needs_update(): 'scheme' keyword is deprecated as of " "Passlib 1.7, and will be removed in Passlib 2.0", DeprecationWarning, ) record = self._get_or_identify_record(hash, scheme, category) return record.deprecated or record.needs_update(hash, secret=secret) @deprecated_method( deprecated="1.6", removed="2.0", replacement="CryptContext.needs_update()" ) def hash_needs_update(self, hash, scheme=None, category=None): """Legacy alias for :meth:`needs_update`. .. deprecated:: 1.6 This method was renamed to :meth:`!needs_update` in version 1.6. This alias will be removed in version 2.0, and should only be used for compatibility with Passlib 1.3 - 1.5. """ return self.needs_update(hash, scheme, category) @deprecated_method(deprecated="1.7", removed="2.0") def genconfig(self, scheme=None, category=None, **settings): """Generate a config string for specified scheme. .. deprecated:: 1.7 This method will be removed in version 2.0, and should only be used for compatibility with Passlib 1.3 - 1.6. """ record = self._get_record(scheme, category) strip_unused = self._strip_unused_context_kwds if strip_unused: strip_unused(settings, record) return record.genconfig(**settings) @deprecated_method(deprecated="1.7", removed="2.0") def genhash(self, secret, config, scheme=None, category=None, **kwds): """Generate hash for the specified secret using another hash. .. deprecated:: 1.7 This method will be removed in version 2.0, and should only be used for compatibility with Passlib 1.3 - 1.6. """ record = self._get_or_identify_record(config, scheme, category) strip_unused = self._strip_unused_context_kwds if strip_unused: strip_unused(kwds, record) return record.genhash(secret, config, **kwds) def identify( self, hash, category=None, resolve=False, required=False, unconfigured=False ): """Attempt to identify which algorithm the hash belongs to. Note that this will only consider the algorithms currently configured for this context (see the :ref:`schemes ` option). All registered algorithms will be checked, from first to last, and whichever one positively identifies the hash first will be returned. :type hash: str or bytes :arg hash: The hash string to test. :type category: str or None :param category: Optional :ref:`user category `. Ignored by this function, this parameter is provided for symmetry with the other methods. :type resolve: bool :param resolve: If ``True``, returns the hash handler itself, instead of the name of the hash. :type required: bool :param required: If ``True``, this will raise a ValueError if the hash cannot be identified, instead of returning ``None``. :returns: The handler which first identifies the hash, or ``None`` if none of the algorithms identify the hash. """ record = self._identify_record(hash, category, required) if record is None: return None if resolve: if unconfigured: return record._Context__orig_handler return record return record.name def hash(self, secret, scheme=None, category=None, **kwds): """run secret through selected algorithm, returning resulting hash. :type secret: str or bytes :arg secret: the password to hash. :type scheme: str or None :param scheme: Optional scheme to use. Scheme must be one of the ones configured for this context (see the :ref:`schemes ` option). If no scheme is specified, the configured default will be used. .. deprecated:: 1.7 Support for this keyword is deprecated, and will be removed in Passlib 2.0. :type category: str or None :param category: Optional :ref:`user category `. If specified, this will cause any category-specific defaults to be used when hashing the password (e.g. different default scheme, different default rounds values, etc). :param \\*\\*kwds: All other keyword options are passed to the selected algorithm's :meth:`PasswordHash.hash() ` method. :returns: The secret as encoded by the specified algorithm and options. The return value will always be a :class:`!str`. :raises TypeError, ValueError: * If any of the arguments have an invalid type or value. This includes any keywords passed to the underlying hash's :meth:`PasswordHash.hash() ` method. .. seealso:: the :ref:`context-basic-example` example in the tutorial """ # XXX: could insert normalization to preferred str encoding here if scheme is not None: # TODO: offer replacement alternative. # ``context.handler(scheme).hash()`` would work, # but may deprecate .handler() in passlib 1.8. warn( "CryptContext.hash(): 'scheme' keyword is deprecated as of " "Passlib 1.7, and will be removed in Passlib 2.0", DeprecationWarning, ) record = self._get_record(scheme, category) strip_unused = self._strip_unused_context_kwds if strip_unused: strip_unused(kwds, record) return record.hash(secret, **kwds) @deprecated_method( deprecated="1.7", removed="2.0", replacement="CryptContext.hash()" ) def encrypt(self, *args, **kwds): """ Legacy alias for :meth:`hash`. .. deprecated:: 1.7 This method was renamed to :meth:`!hash` in version 1.7. This alias will be removed in version 2.0, and should only be used for compatibility with Passlib 1.3 - 1.6. """ return self.hash(*args, **kwds) def verify(self, secret, hash, scheme=None, category=None, **kwds): """verify secret against an existing hash. If no scheme is specified, this will attempt to identify the scheme based on the contents of the provided hash (limited to the schemes configured for this context). It will then check whether the password verifies against the hash. :type secret: str or bytes :arg secret: the secret to verify :type hash: str or bytes :arg hash: hash string to compare to if ``None`` is passed in, this will be treated as "never verifying" :type scheme: str :param scheme: Optionally force context to use specific scheme. This is usually not needed, as most hashes can be unambiguously identified. Scheme must be one of the ones configured for this context (see the :ref:`schemes ` option). .. deprecated:: 1.7 Support for this keyword is deprecated, and will be removed in Passlib 2.0. :type category: str or None :param category: Optional :ref:`user category ` string. This is mainly used when generating new hashes, it has little effect when verifying; this keyword is mainly provided for symmetry. :param \\*\\*kwds: All additional keywords are passed to the appropriate handler, and should match its :attr:`~passlib.ifc.PasswordHash.context_kwds`. :returns: ``True`` if the password matched the hash, else ``False``. :raises ValueError: * if the hash did not match any of the configured :meth:`schemes`. * if any of the arguments have an invalid value (this includes any keywords passed to the underlying hash's :meth:`PasswordHash.verify() ` method). :raises TypeError: * if any of the arguments have an invalid type (this includes any keywords passed to the underlying hash's :meth:`PasswordHash.verify() ` method). .. seealso:: the :ref:`context-basic-example` example in the tutorial """ # XXX: could insert normalization to preferred unicode encoding here # XXX: what about supporting a setter() callback ala django 1.4 ? if scheme is not None: # TODO: offer replacement alternative. # ``context.handler(scheme).verify()`` would work, # but may deprecate .handler() in passlib 1.8. warn( "CryptContext.verify(): 'scheme' keyword is deprecated as of " "Passlib 1.7, and will be removed in Passlib 2.0", DeprecationWarning, ) if hash is None: # convenience feature -- let apps pass in hash=None when user # isn't found / has no hash; useful because it invokes dummy_verify() self.dummy_verify() return False record = self._get_or_identify_record(hash, scheme, category) strip_unused = self._strip_unused_context_kwds if strip_unused: strip_unused(kwds, record) return record.verify(secret, hash, **kwds) def verify_and_update(self, secret, hash, scheme=None, category=None, **kwds): """verify password and re-hash the password if needed, all in a single call. This is a convenience method which takes care of all the following: first it verifies the password (:meth:`~CryptContext.verify`), if this is successfull it checks if the hash needs updating (:meth:`~CryptContext.needs_update`), and if so, re-hashes the password (:meth:`~CryptContext.hash`), returning the replacement hash. This series of steps is a very common task for applications which wish to update deprecated hashes, and this call takes care of all 3 steps efficiently. :type secret: str or bytes :arg secret: the secret to verify :type secret: str or bytes :arg hash: hash string to compare to. if ``None`` is passed in, this will be treated as "never verifying" :type scheme: str :param scheme: Optionally force context to use specific scheme. This is usually not needed, as most hashes can be unambiguously identified. Scheme must be one of the ones configured for this context (see the :ref:`schemes ` option). .. deprecated:: 1.7 Support for this keyword is deprecated, and will be removed in Passlib 2.0. :type category: str or None :param category: Optional :ref:`user category `. If specified, this will cause any category-specific defaults to be used if the password has to be re-hashed. :param \\*\\*kwds: all additional keywords are passed to the appropriate handler, and should match that hash's :attr:`PasswordHash.context_kwds `. :returns: This function returns a tuple containing two elements: ``(verified, replacement_hash)``. The first is a boolean flag indicating whether the password verified, and the second an optional replacement hash. The tuple will always match one of the following 3 cases: * ``(False, None)`` indicates the secret failed to verify. * ``(True, None)`` indicates the secret verified correctly, and the hash does not need updating. * ``(True, str)`` indicates the secret verified correctly, but the current hash needs to be updated. The :class:`!str` will be the freshly generated hash, to replace the old one. :raises TypeError, ValueError: For the same reasons as :meth:`verify`. .. seealso:: the :ref:`context-migration-example` example in the tutorial. """ # XXX: could insert normalization to preferred unicode encoding here. if scheme is not None: warn( "CryptContext.verify(): 'scheme' keyword is deprecated as of " "Passlib 1.7, and will be removed in Passlib 2.0", DeprecationWarning, ) if hash is None: # convenience feature -- let apps pass in hash=None when user # isn't found / has no hash; useful because it invokes dummy_verify() self.dummy_verify() return False, None record = self._get_or_identify_record(hash, scheme, category) strip_unused = self._strip_unused_context_kwds if strip_unused and kwds: clean_kwds = kwds.copy() strip_unused(clean_kwds, record) else: clean_kwds = kwds # XXX: if record is default scheme, could extend PasswordHash # api to combine verify & needs_update to single call, # potentially saving some round-trip parsing. # but might make these codepaths more complex... if not record.verify(secret, hash, **clean_kwds): return False, None if record.deprecated or record.needs_update(hash, secret=secret): # NOTE: we re-hash with default scheme, not current one. return True, self.hash(secret, category=category, **kwds) return True, None #: secret used for dummy_verify() _dummy_secret = "too many secrets" @memoized_property def _dummy_hash(self): """ precalculated hash for dummy_verify() to use """ return self.hash(self._dummy_secret) def _reset_dummy_verify(self): """ flush memoized values used by dummy_verify() """ type(self)._dummy_hash.clear_cache(self) def dummy_verify(self): """ Helper that applications can call when user wasn't found, in order to simulate time it would take to hash a password. Runs verify() against a dummy hash, to simulate verification of a real account password. .. versionadded:: 1.7 """ self.verify(self._dummy_secret, self._dummy_hash) return False def is_enabled(self, hash): """ test if hash represents a usuable password -- i.e. does not represent an unusuable password such as ``"!"``, which is recognized by the :class:`~passlib.hash.unix_disabled` hash. :raises ValueError: if the hash is not recognized (typically solved by adding ``unix_disabled`` to the list of schemes). """ return not self._identify_record(hash, None).is_disabled def disable(self, hash=None): """ return a string to disable logins for user, usually by returning a non-verifying string such as ``"!"``. :param hash: Callers can optionally provide the account's existing hash. Some disabled handlers (such as :class:`!unix_disabled`) will encode this into the returned value, so that it can be recovered via :meth:`enable`. :raises RuntimeError: if this function is called w/o a disabled hasher (such as :class:`~passlib.hash.unix_disabled`) included in the list of schemes. :returns: hash string which will be recognized as valid by the context, but is guaranteed to not validate against *any* password. """ record = self._config.disabled_record assert record.is_disabled return record.disable(hash) def enable(self, hash): """ inverse of :meth:`disable` -- attempts to recover original hash which was converted by a :meth:`!disable` call into a disabled hash -- thus restoring the user's original password. :raises ValueError: if original hash not present, or if the disabled handler doesn't support encoding the original hash (e.g. ``django_disabled``) :returns: the original hash. """ record = self._identify_record(hash, None) if record.is_disabled: # XXX: should we throw error if result can't be identified by context? return record.enable(hash) # hash wasn't a disabled hash, so return unchanged return hash class LazyCryptContext(CryptContext): """CryptContext subclass which doesn't load handlers until needed. This is a subclass of CryptContext which takes in a set of arguments exactly like CryptContext, but won't import any handlers (or even parse its arguments) until the first time one of its methods is accessed. :arg schemes: The first positional argument can be a list of schemes, or omitted, just like CryptContext. :param onload: If a callable is passed in via this keyword, it will be invoked at lazy-load time with the following signature: ``onload(**kwds) -> kwds``; where ``kwds`` is all the additional kwds passed to LazyCryptContext. It should perform any additional deferred initialization, and return the final dict of options to be passed to CryptContext. .. versionadded:: 1.6 :param kwds: All additional keywords are passed to CryptContext; or to the *onload* function (if provided). This is mainly used internally by modules such as :mod:`passlib.apps`, which define a large number of contexts, but only a few of them will be needed at any one time. Use of this class saves the memory needed to import the specified handlers until the context instance is actually accessed. As well, it allows constructing a context at *module-init* time, but using :func:`!onload()` to provide dynamic configuration at *application-run* time. .. note:: This class is only useful if you're referencing handler objects by name, and don't want them imported until runtime. If you want to have the config validated before your application runs, or are passing in already-imported handler instances, you should use :class:`CryptContext` instead. .. versionadded:: 1.4 """ _lazy_kwds = None # NOTE: the way this class works is that whenever any of the public # attributes are accessed, _lazy_init() is invoked, the class itself is changed # to a regular CryptContext (to remove the overhead once it's unneeded) def __init__(self, schemes=None, **kwds): if schemes is not None: kwds["schemes"] = schemes self._lazy_kwds = kwds def _lazy_init(self): kwds = self._lazy_kwds if "onload" in kwds: onload = kwds.pop("onload") kwds = onload(**kwds) del self._lazy_kwds super().__init__(**kwds) self.__class__ = CryptContext def __getattribute__(self, attr): if ( not attr.startswith("_") or attr.startswith("__") ) and self._lazy_kwds is not None: self._lazy_init() return object.__getattribute__(self, attr)