From a0b2eeeb7350d0c3a9b9be191783ff15daeffec5 Mon Sep 17 00:00:00 2001 From: Mariusz Felisiak Date: Thu, 27 Jul 2023 14:51:48 +0000 Subject: [PATCH] Fixed CVE-2023-36053 -- Prevented potential ReDoS in EmailValidator and URLValidator. Thanks Seokchan Yoon for reports. CVE: CVE-2023-36053 Upstream-Status: Backport [https://github.com/django/django/commit/454f2fb93437f98917283336201b4048293f7582] Signed-off-by: Narpat Mali --- django/core/validators.py | 9 +++++++-- django/forms/fields.py | 3 +++ docs/ref/forms/fields.txt | 4 ++++ docs/ref/validators.txt | 19 ++++++++++++++++++- docs/releases/2.2.28.txt | 9 +++++++++ .../field_tests/test_emailfield.py | 5 ++++- tests/forms_tests/tests/test_forms.py | 19 +++++++++++++------ tests/validators/tests.py | 11 +++++++++++ 8 files changed, 69 insertions(+), 10 deletions(-) diff --git a/django/core/validators.py b/django/core/validators.py index 2da0688..2dbd3bf 100644 --- a/django/core/validators.py +++ b/django/core/validators.py @@ -102,6 +102,7 @@ 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) @@ -109,7 +110,9 @@ class URLValidator(RegexValidator): self.schemes = schemes def __call__(self, value): - if isinstance(value, str) and self.unsafe_chars.intersection(value): + if not isinstance(value, str) or len(value) > self.max_length: + raise ValidationError(self.message, code=self.code) + if self.unsafe_chars.intersection(value): raise ValidationError(self.message, code=self.code) # Check if the scheme is valid. scheme = value.split('://')[0].lower() @@ -190,7 +193,9 @@ class EmailValidator: self.domain_whitelist = whitelist 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) user_part, domain_part = value.rsplit('@', 1) diff --git a/django/forms/fields.py b/django/forms/fields.py index a977256..f939338 100644 --- a/django/forms/fields.py +++ b/django/forms/fields.py @@ -542,6 +542,9 @@ class FileField(Field): def __init__(self, *, max_length=None, allow_empty_file=False, **kwargs): self.max_length = max_length self.allow_empty_file = allow_empty_file + # The default maximum length of an email is 320 characters per RFC 3696 + # section 3. + kwargs.setdefault("max_length", 320) super().__init__(**kwargs) def to_python(self, data): diff --git a/docs/ref/forms/fields.txt b/docs/ref/forms/fields.txt index 6f76d0d..3a888ef 100644 --- a/docs/ref/forms/fields.txt +++ b/docs/ref/forms/fields.txt @@ -592,6 +592,10 @@ For each field, we describe the default widget used if you don't specify Has two optional arguments for validation, ``max_length`` and ``min_length``. If provided, these arguments ensure that the string is at most or at least the given length. + ``empty_value`` which work just as they do for :class:`CharField`. The + ``max_length`` argument defaults to 320 (see :rfc:`3696#section-3`). + + 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 75d1394..4178a1f 100644 --- a/docs/ref/validators.txt +++ b/docs/ref/validators.txt @@ -125,6 +125,11 @@ to, or in lieu of custom ``field.clean()`` methods. :param code: If not ``None``, overrides :attr:`code`. :param whitelist: If not ``None``, overrides :attr:`whitelist`. + 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 @@ -145,13 +150,17 @@ to, or in lieu of custom ``field.clean()`` methods. ``['localhost']``. Other domains that don't contain a dot won't pass validation, so you'd need to whitelist them as necessary. + 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` that ensures a value looks like a URL, and raises - an error code of ``'invalid'`` if it doesn't. + 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 @@ -168,6 +177,14 @@ 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 + + The maximum length of values that could be considered valid. Defaults + to 2048 characters. + + In older versions, values longer than 2048 characters could be + considered valid. + ``validate_email`` ------------------ diff --git a/docs/releases/2.2.28.txt b/docs/releases/2.2.28.txt index 854c6b0..ab4884b 100644 --- a/docs/releases/2.2.28.txt +++ b/docs/releases/2.2.28.txt @@ -38,3 +38,12 @@ keep the old behavior, set ``allow_multiple_selected`` to ``True``. For more details on using the new attribute and handling of multiple files through a single field, see :ref:`uploading_multiple_files`. + +Backporting the CVE-2023-36053 fix on Django 2.2.28. + +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 826524a..fe5b644 100644 --- a/tests/forms_tests/field_tests/test_emailfield.py +++ b/tests/forms_tests/field_tests/test_emailfield.py @@ -8,7 +8,10 @@ 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 d4e421d..8893f89 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']), '', @@ -2780,7 +2787,7 @@ Good luck picking a username that doesn't already exist.

-
    • +
    • This field is required.
    • """ ) @@ -2796,7 +2803,7 @@ Good luck picking a username that doesn't already exist.

    -

    +

    """ @@ -2815,7 +2822,7 @@ Good luck picking a username that doesn't already exist.

    - + """ @@ -3428,7 +3435,7 @@ 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 1f09fb5..8204f00 100644 --- a/tests/validators/tests.py +++ b/tests/validators/tests.py @@ -58,6 +58,7 @@ 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), @@ -242,6 +243,16 @@ TEST_DATA = [ (URLValidator(EXTENDED_SCHEMES), 'git+ssh://git@github.com/example/hg-git.git', None), (URLValidator(EXTENDED_SCHEMES), 'git://-invalid.com', 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), -- 2.40.0