204 lines
7.4 KiB
Python
204 lines
7.4 KiB
Python
import functools
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import gzip
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import re
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from difflib import SequenceMatcher
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from pathlib import Path
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from django.conf import settings
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from django.core.exceptions import (
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FieldDoesNotExist, ImproperlyConfigured, ValidationError,
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)
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from django.utils.functional import lazy
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from django.utils.html import format_html, format_html_join
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from django.utils.module_loading import import_string
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from django.utils.translation import gettext as _, ngettext
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@functools.lru_cache(maxsize=None)
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def get_default_password_validators():
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return get_password_validators(settings.AUTH_PASSWORD_VALIDATORS)
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def get_password_validators(validator_config):
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validators = []
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for validator in validator_config:
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try:
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klass = import_string(validator['NAME'])
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except ImportError:
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msg = "The module in NAME could not be imported: %s. Check your AUTH_PASSWORD_VALIDATORS setting."
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raise ImproperlyConfigured(msg % validator['NAME'])
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validators.append(klass(**validator.get('OPTIONS', {})))
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return validators
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def validate_password(password, user=None, password_validators=None):
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"""
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Validate whether the password meets all validator requirements.
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If the password is valid, return ``None``.
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If the password is invalid, raise ValidationError with all error messages.
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"""
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errors = []
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if password_validators is None:
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password_validators = get_default_password_validators()
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for validator in password_validators:
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try:
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validator.validate(password, user)
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except ValidationError as error:
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errors.append(error)
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if errors:
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raise ValidationError(errors)
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def password_changed(password, user=None, password_validators=None):
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"""
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Inform all validators that have implemented a password_changed() method
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that the password has been changed.
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"""
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if password_validators is None:
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password_validators = get_default_password_validators()
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for validator in password_validators:
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password_changed = getattr(validator, 'password_changed', lambda *a: None)
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password_changed(password, user)
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def password_validators_help_texts(password_validators=None):
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"""
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Return a list of all help texts of all configured validators.
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"""
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help_texts = []
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if password_validators is None:
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password_validators = get_default_password_validators()
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for validator in password_validators:
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help_texts.append(validator.get_help_text())
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return help_texts
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def _password_validators_help_text_html(password_validators=None):
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"""
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Return an HTML string with all help texts of all configured validators
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in an <ul>.
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"""
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help_texts = password_validators_help_texts(password_validators)
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help_items = format_html_join('', '<li>{}</li>', ((help_text,) for help_text in help_texts))
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return format_html('<ul>{}</ul>', help_items) if help_items else ''
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password_validators_help_text_html = lazy(_password_validators_help_text_html, str)
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class MinimumLengthValidator:
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"""
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Validate whether the password is of a minimum length.
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"""
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def __init__(self, min_length=8):
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self.min_length = min_length
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def validate(self, password, user=None):
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if len(password) < self.min_length:
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raise ValidationError(
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ngettext(
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"This password is too short. It must contain at least %(min_length)d character.",
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"This password is too short. It must contain at least %(min_length)d characters.",
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self.min_length
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),
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code='password_too_short',
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params={'min_length': self.min_length},
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)
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def get_help_text(self):
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return ngettext(
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"Your password must contain at least %(min_length)d character.",
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"Your password must contain at least %(min_length)d characters.",
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self.min_length
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) % {'min_length': self.min_length}
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class UserAttributeSimilarityValidator:
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"""
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Validate whether the password is sufficiently different from the user's
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attributes.
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If no specific attributes are provided, look at a sensible list of
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defaults. Attributes that don't exist are ignored. Comparison is made to
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not only the full attribute value, but also its components, so that, for
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example, a password is validated against either part of an email address,
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as well as the full address.
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"""
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DEFAULT_USER_ATTRIBUTES = ('username', 'first_name', 'last_name', 'email')
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def __init__(self, user_attributes=DEFAULT_USER_ATTRIBUTES, max_similarity=0.7):
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self.user_attributes = user_attributes
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self.max_similarity = max_similarity
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def validate(self, password, user=None):
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if not user:
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return
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for attribute_name in self.user_attributes:
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value = getattr(user, attribute_name, None)
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if not value or not isinstance(value, str):
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continue
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value_parts = re.split(r'\W+', value) + [value]
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for value_part in value_parts:
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if SequenceMatcher(a=password.lower(), b=value_part.lower()).quick_ratio() >= self.max_similarity:
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try:
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verbose_name = str(user._meta.get_field(attribute_name).verbose_name)
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except FieldDoesNotExist:
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verbose_name = attribute_name
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raise ValidationError(
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_("The password is too similar to the %(verbose_name)s."),
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code='password_too_similar',
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params={'verbose_name': verbose_name},
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)
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def get_help_text(self):
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return _('Your password can’t be too similar to your other personal information.')
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class CommonPasswordValidator:
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"""
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Validate whether the password is a common password.
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The password is rejected if it occurs in a provided list of passwords,
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which may be gzipped. The list Django ships with contains 20000 common
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passwords (lowercased and deduplicated), created by Royce Williams:
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https://gist.github.com/roycewilliams/281ce539915a947a23db17137d91aeb7
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The password list must be lowercased to match the comparison in validate().
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"""
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DEFAULT_PASSWORD_LIST_PATH = Path(__file__).resolve().parent / 'common-passwords.txt.gz'
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def __init__(self, password_list_path=DEFAULT_PASSWORD_LIST_PATH):
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try:
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with gzip.open(password_list_path, 'rt', encoding='utf-8') as f:
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self.passwords = {x.strip() for x in f}
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except OSError:
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with open(password_list_path) as f:
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self.passwords = {x.strip() for x in f}
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def validate(self, password, user=None):
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if password.lower().strip() in self.passwords:
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raise ValidationError(
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_("This password is too common."),
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code='password_too_common',
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)
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def get_help_text(self):
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return _('Your password can’t be a commonly used password.')
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class NumericPasswordValidator:
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"""
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Validate whether the password is alphanumeric.
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"""
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def validate(self, password, user=None):
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if password.isdigit():
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raise ValidationError(
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_("This password is entirely numeric."),
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code='password_entirely_numeric',
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)
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def get_help_text(self):
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return _('Your password can’t be entirely numeric.')
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