267 lines
9.2 KiB
Python
267 lines
9.2 KiB
Python
import functools
|
||
import gzip
|
||
import re
|
||
from difflib import SequenceMatcher
|
||
from pathlib import Path
|
||
|
||
from django.conf import settings
|
||
from django.core.exceptions import (
|
||
FieldDoesNotExist,
|
||
ImproperlyConfigured,
|
||
ValidationError,
|
||
)
|
||
from django.utils.functional import cached_property, lazy
|
||
from django.utils.html import format_html, format_html_join
|
||
from django.utils.module_loading import import_string
|
||
from django.utils.translation import gettext as _
|
||
from django.utils.translation import ngettext
|
||
|
||
|
||
@functools.lru_cache(maxsize=None)
|
||
def get_default_password_validators():
|
||
return get_password_validators(settings.AUTH_PASSWORD_VALIDATORS)
|
||
|
||
|
||
def get_password_validators(validator_config):
|
||
validators = []
|
||
for validator in validator_config:
|
||
try:
|
||
klass = import_string(validator["NAME"])
|
||
except ImportError:
|
||
msg = (
|
||
"The module in NAME could not be imported: %s. Check your "
|
||
"AUTH_PASSWORD_VALIDATORS setting."
|
||
)
|
||
raise ImproperlyConfigured(msg % validator["NAME"])
|
||
validators.append(klass(**validator.get("OPTIONS", {})))
|
||
|
||
return validators
|
||
|
||
|
||
def validate_password(password, user=None, password_validators=None):
|
||
"""
|
||
Validate that the password meets all validator requirements.
|
||
|
||
If the password is valid, return ``None``.
|
||
If the password is invalid, raise ValidationError with all error messages.
|
||
"""
|
||
errors = []
|
||
if password_validators is None:
|
||
password_validators = get_default_password_validators()
|
||
for validator in password_validators:
|
||
try:
|
||
validator.validate(password, user)
|
||
except ValidationError as error:
|
||
errors.append(error)
|
||
if errors:
|
||
raise ValidationError(errors)
|
||
|
||
|
||
def password_changed(password, user=None, password_validators=None):
|
||
"""
|
||
Inform all validators that have implemented a password_changed() method
|
||
that the password has been changed.
|
||
"""
|
||
if password_validators is None:
|
||
password_validators = get_default_password_validators()
|
||
for validator in password_validators:
|
||
password_changed = getattr(validator, "password_changed", lambda *a: None)
|
||
password_changed(password, user)
|
||
|
||
|
||
def password_validators_help_texts(password_validators=None):
|
||
"""
|
||
Return a list of all help texts of all configured validators.
|
||
"""
|
||
help_texts = []
|
||
if password_validators is None:
|
||
password_validators = get_default_password_validators()
|
||
for validator in password_validators:
|
||
help_texts.append(validator.get_help_text())
|
||
return help_texts
|
||
|
||
|
||
def _password_validators_help_text_html(password_validators=None):
|
||
"""
|
||
Return an HTML string with all help texts of all configured validators
|
||
in an <ul>.
|
||
"""
|
||
help_texts = password_validators_help_texts(password_validators)
|
||
help_items = format_html_join(
|
||
"", "<li>{}</li>", ((help_text,) for help_text in help_texts)
|
||
)
|
||
return format_html("<ul>{}</ul>", help_items) if help_items else ""
|
||
|
||
|
||
password_validators_help_text_html = lazy(_password_validators_help_text_html, str)
|
||
|
||
|
||
class MinimumLengthValidator:
|
||
"""
|
||
Validate that the password is of a minimum length.
|
||
"""
|
||
|
||
def __init__(self, min_length=8):
|
||
self.min_length = min_length
|
||
|
||
def validate(self, password, user=None):
|
||
if len(password) < self.min_length:
|
||
raise ValidationError(
|
||
ngettext(
|
||
"This password is too short. It must contain at least "
|
||
"%(min_length)d character.",
|
||
"This password is too short. It must contain at least "
|
||
"%(min_length)d characters.",
|
||
self.min_length,
|
||
),
|
||
code="password_too_short",
|
||
params={"min_length": self.min_length},
|
||
)
|
||
|
||
def get_help_text(self):
|
||
return ngettext(
|
||
"Your password must contain at least %(min_length)d character.",
|
||
"Your password must contain at least %(min_length)d characters.",
|
||
self.min_length,
|
||
) % {"min_length": self.min_length}
|
||
|
||
|
||
def exceeds_maximum_length_ratio(password, max_similarity, value):
|
||
"""
|
||
Test that value is within a reasonable range of password.
|
||
|
||
The following ratio calculations are based on testing SequenceMatcher like
|
||
this:
|
||
|
||
for i in range(0,6):
|
||
print(10**i, SequenceMatcher(a='A', b='A'*(10**i)).quick_ratio())
|
||
|
||
which yields:
|
||
|
||
1 1.0
|
||
10 0.18181818181818182
|
||
100 0.019801980198019802
|
||
1000 0.001998001998001998
|
||
10000 0.00019998000199980003
|
||
100000 1.999980000199998e-05
|
||
|
||
This means a length_ratio of 10 should never yield a similarity higher than
|
||
0.2, for 100 this is down to 0.02 and for 1000 it is 0.002. This can be
|
||
calculated via 2 / length_ratio. As a result we avoid the potentially
|
||
expensive sequence matching.
|
||
"""
|
||
pwd_len = len(password)
|
||
length_bound_similarity = max_similarity / 2 * pwd_len
|
||
value_len = len(value)
|
||
return pwd_len >= 10 * value_len and value_len < length_bound_similarity
|
||
|
||
|
||
class UserAttributeSimilarityValidator:
|
||
"""
|
||
Validate that the password is sufficiently different from the user's
|
||
attributes.
|
||
|
||
If no specific attributes are provided, look at a sensible list of
|
||
defaults. Attributes that don't exist are ignored. Comparison is made to
|
||
not only the full attribute value, but also its components, so that, for
|
||
example, a password is validated against either part of an email address,
|
||
as well as the full address.
|
||
"""
|
||
|
||
DEFAULT_USER_ATTRIBUTES = ("username", "first_name", "last_name", "email")
|
||
|
||
def __init__(self, user_attributes=DEFAULT_USER_ATTRIBUTES, max_similarity=0.7):
|
||
self.user_attributes = user_attributes
|
||
if max_similarity < 0.1:
|
||
raise ValueError("max_similarity must be at least 0.1")
|
||
self.max_similarity = max_similarity
|
||
|
||
def validate(self, password, user=None):
|
||
if not user:
|
||
return
|
||
|
||
password = password.lower()
|
||
for attribute_name in self.user_attributes:
|
||
value = getattr(user, attribute_name, None)
|
||
if not value or not isinstance(value, str):
|
||
continue
|
||
value_lower = value.lower()
|
||
value_parts = re.split(r"\W+", value_lower) + [value_lower]
|
||
for value_part in value_parts:
|
||
if exceeds_maximum_length_ratio(
|
||
password, self.max_similarity, value_part
|
||
):
|
||
continue
|
||
if (
|
||
SequenceMatcher(a=password, b=value_part).quick_ratio()
|
||
>= self.max_similarity
|
||
):
|
||
try:
|
||
verbose_name = str(
|
||
user._meta.get_field(attribute_name).verbose_name
|
||
)
|
||
except FieldDoesNotExist:
|
||
verbose_name = attribute_name
|
||
raise ValidationError(
|
||
_("The password is too similar to the %(verbose_name)s."),
|
||
code="password_too_similar",
|
||
params={"verbose_name": verbose_name},
|
||
)
|
||
|
||
def get_help_text(self):
|
||
return _(
|
||
"Your password can’t be too similar to your other personal information."
|
||
)
|
||
|
||
|
||
class CommonPasswordValidator:
|
||
"""
|
||
Validate that the password is not a common password.
|
||
|
||
The password is rejected if it occurs in a provided list of passwords,
|
||
which may be gzipped. The list Django ships with contains 20000 common
|
||
passwords (lowercased and deduplicated), created by Royce Williams:
|
||
https://gist.github.com/roycewilliams/226886fd01572964e1431ac8afc999ce
|
||
The password list must be lowercased to match the comparison in validate().
|
||
"""
|
||
|
||
@cached_property
|
||
def DEFAULT_PASSWORD_LIST_PATH(self):
|
||
return Path(__file__).resolve().parent / "common-passwords.txt.gz"
|
||
|
||
def __init__(self, password_list_path=DEFAULT_PASSWORD_LIST_PATH):
|
||
if password_list_path is CommonPasswordValidator.DEFAULT_PASSWORD_LIST_PATH:
|
||
password_list_path = self.DEFAULT_PASSWORD_LIST_PATH
|
||
try:
|
||
with gzip.open(password_list_path, "rt", encoding="utf-8") as f:
|
||
self.passwords = {x.strip() for x in f}
|
||
except OSError:
|
||
with open(password_list_path) as f:
|
||
self.passwords = {x.strip() for x in f}
|
||
|
||
def validate(self, password, user=None):
|
||
if password.lower().strip() in self.passwords:
|
||
raise ValidationError(
|
||
_("This password is too common."),
|
||
code="password_too_common",
|
||
)
|
||
|
||
def get_help_text(self):
|
||
return _("Your password can’t be a commonly used password.")
|
||
|
||
|
||
class NumericPasswordValidator:
|
||
"""
|
||
Validate that the password is not entirely numeric.
|
||
"""
|
||
|
||
def validate(self, password, user=None):
|
||
if password.isdigit():
|
||
raise ValidationError(
|
||
_("This password is entirely numeric."),
|
||
code="password_entirely_numeric",
|
||
)
|
||
|
||
def get_help_text(self):
|
||
return _("Your password can’t be entirely numeric.")
|