From 454f2fb93437f98917283336201b4048293f7582 Mon Sep 17 00:00:00 2001 From: Mariusz Felisiak Date: Wed, 14 Jun 2023 12:23:06 +0200 Subject: [PATCH] [3.2.x] Fixed CVE-2023-36053 -- Prevented potential ReDoS in EmailValidator and URLValidator. Thanks Seokchan Yoon for reports. --- django/core/validators.py | 7 ++++-- django/forms/fields.py | 3 +++ docs/ref/forms/fields.txt | 7 +++++- docs/ref/validators.txt | 25 ++++++++++++++++++- docs/releases/3.2.20.txt | 7 +++++- .../field_tests/test_emailfield.py | 5 +++- tests/forms_tests/tests/test_forms.py | 19 +++++++++----- tests/validators/tests.py | 11 ++++++++ 8 files changed, 72 insertions(+), 12 deletions(-) diff --git a/django/core/validators.py b/django/core/validators.py index 731ccf2d46..b9b58dfa61 100644 --- a/django/core/validators.py +++ b/django/core/validators.py @@ -93,6 +93,7 @@ class URLValidator(RegexValidator): message = _('Enter a valid URL.') schemes = ['http', 'https', 'ftp', 'ftps'] unsafe_chars = frozenset('\t\r\n') + max_length = 2048 def __init__(self, schemes=None, **kwargs): super().__init__(**kwargs) @@ -100,7 +101,7 @@ class URLValidator(RegexValidator): self.schemes = schemes def __call__(self, value): - if not isinstance(value, str): + if not isinstance(value, str) or len(value) > self.max_length: raise ValidationError(self.message, code=self.code, params={'value': value}) if self.unsafe_chars.intersection(value): raise ValidationError(self.message, code=self.code, params={'value': value}) @@ -210,7 +211,9 @@ class EmailValidator: self.domain_allowlist = allowlist def __call__(self, value): - if not value or '@' not in value: + # The maximum length of an email is 320 characters per RFC 3696 + # section 3. + if not value or '@' not in value or len(value) > 320: raise ValidationError(self.message, code=self.code, params={'value': value}) user_part, domain_part = value.rsplit('@', 1) diff --git a/django/forms/fields.py b/django/forms/fields.py index 0214d60c1c..8adb09e382 100644 --- a/django/forms/fields.py +++ b/django/forms/fields.py @@ -540,6 +540,9 @@ class EmailField(CharField): default_validators = [validators.validate_email] def __init__(self, **kwargs): + # The default maximum length of an email is 320 characters per RFC 3696 + # section 3. + kwargs.setdefault("max_length", 320) super().__init__(strip=True, **kwargs) diff --git a/docs/ref/forms/fields.txt b/docs/ref/forms/fields.txt index 9438214a28..5b485f2153 100644 --- a/docs/ref/forms/fields.txt +++ b/docs/ref/forms/fields.txt @@ -592,7 +592,12 @@ For each field, we describe the default widget used if you don't specify * Error message keys: ``required``, ``invalid`` Has three optional arguments ``max_length``, ``min_length``, and - ``empty_value`` which work just as they do for :class:`CharField`. + ``empty_value`` which work just as they do for :class:`CharField`. The + ``max_length`` argument defaults to 320 (see :rfc:`3696#section-3`). + + .. versionchanged:: 3.2.20 + + The default value for ``max_length`` was changed to 320 characters. ``FileField`` ------------- diff --git a/docs/ref/validators.txt b/docs/ref/validators.txt index 50761e5a42..b22762b17b 100644 --- a/docs/ref/validators.txt +++ b/docs/ref/validators.txt @@ -130,6 +130,11 @@ to, or in lieu of custom ``field.clean()`` methods. :param code: If not ``None``, overrides :attr:`code`. :param allowlist: If not ``None``, overrides :attr:`allowlist`. + An :class:`EmailValidator` ensures that a value looks like an email, and + raises a :exc:`~django.core.exceptions.ValidationError` with + :attr:`message` and :attr:`code` if it doesn't. Values longer than 320 + characters are always considered invalid. + .. attribute:: message The error message used by @@ -158,13 +163,19 @@ to, or in lieu of custom ``field.clean()`` methods. The undocumented ``domain_whitelist`` attribute is deprecated. Use ``domain_allowlist`` instead. + .. versionchanged:: 3.2.20 + + In older versions, values longer than 320 characters could be + considered valid. + ``URLValidator`` ---------------- .. class:: URLValidator(schemes=None, regex=None, message=None, code=None) A :class:`RegexValidator` subclass that ensures a value looks like a URL, - and raises an error code of ``'invalid'`` if it doesn't. + and raises an error code of ``'invalid'`` if it doesn't. Values longer than + :attr:`max_length` characters are always considered invalid. Loopback addresses and reserved IP spaces are considered valid. Literal IPv6 addresses (:rfc:`3986#section-3.2.2`) and Unicode domains are both @@ -181,6 +192,18 @@ to, or in lieu of custom ``field.clean()`` methods. .. _valid URI schemes: https://www.iana.org/assignments/uri-schemes/uri-schemes.xhtml + .. attribute:: max_length + + .. versionadded:: 3.2.20 + + The maximum length of values that could be considered valid. Defaults + to 2048 characters. + + .. versionchanged:: 3.2.20 + + In older versions, values longer than 2048 characters could be + considered valid. + ``validate_email`` ------------------ diff --git a/docs/releases/3.2.20.txt b/docs/releases/3.2.20.txt index e4ef914394..c8f60a70e2 100644 --- a/docs/releases/3.2.20.txt +++ b/docs/releases/3.2.20.txt @@ -6,4 +6,9 @@ Django 3.2.20 release notes Django 3.2.20 fixes a security issue with severity "moderate" in 3.2.19. -... +CVE-2023-36053: Potential regular expression denial of service vulnerability in ``EmailValidator``/``URLValidator`` +=================================================================================================================== + +``EmailValidator`` and ``URLValidator`` were subject to potential regular +expression denial of service attack via a very large number of domain name +labels of emails and URLs. diff --git a/tests/forms_tests/field_tests/test_emailfield.py b/tests/forms_tests/field_tests/test_emailfield.py index 8b85e4dcc1..19d315205d 100644 --- a/tests/forms_tests/field_tests/test_emailfield.py +++ b/tests/forms_tests/field_tests/test_emailfield.py @@ -9,7 +9,10 @@ class EmailFieldTest(FormFieldAssertionsMixin, SimpleTestCase): def test_emailfield_1(self): f = EmailField() - self.assertWidgetRendersTo(f, '') + self.assertEqual(f.max_length, 320) + self.assertWidgetRendersTo( + f, '' + ) with self.assertRaisesMessage(ValidationError, "'This field is required.'"): f.clean('') with self.assertRaisesMessage(ValidationError, "'This field is required.'"): diff --git a/tests/forms_tests/tests/test_forms.py b/tests/forms_tests/tests/test_forms.py index 26f8ecafea..82a32af403 100644 --- a/tests/forms_tests/tests/test_forms.py +++ b/tests/forms_tests/tests/test_forms.py @@ -422,11 +422,18 @@ class FormsTestCase(SimpleTestCase): get_spam = BooleanField() f = SignupForm(auto_id=False) - self.assertHTMLEqual(str(f['email']), '') + self.assertHTMLEqual( + str(f["email"]), + '', + ) self.assertHTMLEqual(str(f['get_spam']), '') f = SignupForm({'email': 'test@example.com', 'get_spam': True}, auto_id=False) - self.assertHTMLEqual(str(f['email']), '') + self.assertHTMLEqual( + str(f["email"]), + '", + ) self.assertHTMLEqual( str(f['get_spam']), '', @@ -2824,7 +2831,7 @@ Good luck picking a username that doesn't already exist.

-
    • +
    • """ ) @@ -2840,7 +2847,7 @@ Good luck picking a username that doesn't already exist.

    -

    +

    """ @@ -2859,7 +2866,7 @@ Good luck picking a username that doesn't already exist.

    - + """ @@ -3489,7 +3496,7 @@ Good luck picking a username that doesn't already exist.

    f = CommentForm(data, auto_id=False, error_class=DivErrorList) self.assertHTMLEqual(f.as_p(), """

    Name:

    Enter a valid email address.
    -

    Email:

    +

    Email:

    This field is required.

    Comment:

    """) diff --git a/tests/validators/tests.py b/tests/validators/tests.py index e39d0e3a1c..1065727a97 100644 --- a/tests/validators/tests.py +++ b/tests/validators/tests.py @@ -59,6 +59,7 @@ TEST_DATA = [ (validate_email, 'example@atm.%s' % ('a' * 64), ValidationError), (validate_email, 'example@%s.atm.%s' % ('b' * 64, 'a' * 63), ValidationError), + (validate_email, "example@%scom" % (("a" * 63 + ".") * 100), ValidationError), (validate_email, None, ValidationError), (validate_email, '', ValidationError), (validate_email, 'abc', ValidationError), @@ -246,6 +247,16 @@ TEST_DATA = [ (URLValidator(), None, ValidationError), (URLValidator(), 56, ValidationError), (URLValidator(), 'no_scheme', ValidationError), + ( + URLValidator(), + "http://example." + ("a" * 63 + ".") * 1000 + "com", + ValidationError, + ), + ( + URLValidator(), + "http://userid:password" + "d" * 2000 + "@example.aaaaaaaaaaaaa.com", + None, + ), # Newlines and tabs are not accepted. (URLValidator(), 'http://www.djangoproject.com/\n', ValidationError), (URLValidator(), 'http://[::ffff:192.9.5.5]\n', ValidationError),