[1.7.x] Prevented newlines from being accepted in some validators.

timgraham · timgraham · commit ae49b4d99465 · 2015-07-08T07:35:43.000-04:00
This is a security fix; disclosure to follow shortly.

Thanks to Sjoerd Job Postmus for the report and draft patch.
diff --git a/django/core/validators.py b/django/core/validators.py
@@ -73,7 +73,7 @@ class URLValidator(RegexValidator):
         r'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}|'  # ...or ipv4
         r'\[?[A-F0-9]*:[A-F0-9:]+\]?)'  # ...or ipv6
         r'(?::\d+)?'  # optional port
-        r'(?:/?|[/?]\S+)$', re.IGNORECASE)
+        r'(?:/?|[/?]\S+)\Z', re.IGNORECASE)
     message = _('Enter a valid URL.')
     schemes = ['http', 'https', 'ftp', 'ftps']
 
@@ -107,28 +107,31 @@ def __call__(self, value):
         else:
             url = value
 
+integer_validator = RegexValidator(
+    re.compile('^-?\d+\Z'),
+    message=_('Enter a valid integer.'),
+    code='invalid',
+)
+
 
 def validate_integer(value):
-    try:
-        int(value)
-    except (ValueError, TypeError):
-        raise ValidationError(_('Enter a valid integer.'), code='invalid')
+    return integer_validator(value)
 
 
 @deconstructible
 class EmailValidator(object):
     message = _('Enter a valid email address.')
     code = 'invalid'
     user_regex = re.compile(
-        r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*$"  # dot-atom
-        r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"$)',  # quoted-string
+        r"(^[-!#$%&'*+/=?^_`{}|~0-9A-Z]+(\.[-!#$%&'*+/=?^_`{}|~0-9A-Z]+)*\Z"  # dot-atom
+        r'|^"([\001-\010\013\014\016-\037!#-\[\]-\177]|\\[\001-\011\013\014\016-\177])*"\Z)',  # quoted-string
         re.IGNORECASE)
     domain_regex = re.compile(
-        r'(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}|[A-Z0-9-]{2,}(?<!-))$',
+        r'(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}|[A-Z0-9-]{2,}(?<!-))\Z',
         re.IGNORECASE)
     literal_regex = re.compile(
         # literal form, ipv4 or ipv6 address (SMTP 4.1.3)
-        r'\[([A-f0-9:\.]+)\]$',
+        r'\[([A-f0-9:\.]+)\]\Z',
         re.IGNORECASE)
     domain_whitelist = ['localhost']
 
@@ -181,10 +184,10 @@ def __eq__(self, other):
 
 validate_email = EmailValidator()
 
-slug_re = re.compile(r'^[-a-zA-Z0-9_]+$')
+slug_re = re.compile(r'^[-a-zA-Z0-9_]+\Z')
 validate_slug = RegexValidator(slug_re, _("Enter a valid 'slug' consisting of letters, numbers, underscores or hyphens."), 'invalid')
 
-ipv4_re = re.compile(r'^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$')
+ipv4_re = re.compile(r'^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}\Z')
 validate_ipv4_address = RegexValidator(ipv4_re, _('Enter a valid IPv4 address.'), 'invalid')
 
 
@@ -225,7 +228,7 @@ def ip_address_validators(protocol, unpack_ipv4):
         raise ValueError("The protocol '%s' is unknown. Supported: %s"
                          % (protocol, list(ip_address_validator_map)))
 
-comma_separated_int_list_re = re.compile('^[\d,]+$')
+comma_separated_int_list_re = re.compile('^[\d,]+\Z')
 validate_comma_separated_integer_list = RegexValidator(comma_separated_int_list_re, _('Enter only digits separated by commas.'), 'invalid')
 
 
diff --git a/docs/releases/1.4.21.txt b/docs/releases/1.4.21.txt
@@ -26,3 +26,29 @@ As each built-in session backend was fixed separately (rather than a fix in the
 core sessions framework), maintainers of third-party session backends should
 check whether the same vulnerability is present in their backend and correct
 it if so.
+
+Header injection possibility since validators accept newlines in input
+======================================================================
+
+Some of Django's built-in validators
+(``django.core.validators.EmailValidator``, most seriously) didn't
+prohibit newline characters (due to the usage of ``$`` instead of ``\Z`` in the
+regular expressions). If you use values with newlines in HTTP response or email
+headers, you can suffer from header injection attacks. Django itself isn't
+vulnerable because :class:`~django.http.HttpResponse` and the mail sending
+utilities in :mod:`django.core.mail` prohibit newlines in HTTP and SMTP
+headers, respectively. While the validators have been fixed in Django, if
+you're creating HTTP responses or email messages in other ways, it's a good
+idea to ensure that those methods prohibit newlines as well. You might also
+want to validate that any existing data in your application doesn't contain
+unexpected newlines.
+
+:func:`~django.core.validators.validate_ipv4_address`,
+:func:`~django.core.validators.validate_slug`, and
+:class:`~django.core.validators.URLValidator` and their usage in the
+corresponding form fields ``GenericIPAddresseField``, ``IPAddressField``,
+``SlugField``, and ``URLField`` are also affected.
+
+The undocumented, internally unused ``validate_integer()`` function is now
+stricter as it validates using a regular expression instead of simply casting
+the value using ``int()`` and checking if an exception was raised.
diff --git a/docs/releases/1.7.9.txt b/docs/releases/1.7.9.txt
@@ -27,6 +27,34 @@ core sessions framework), maintainers of third-party session backends should
 check whether the same vulnerability is present in their backend and correct
 it if so.
 
+Header injection possibility since validators accept newlines in input
+======================================================================
+
+Some of Django's built-in validators
+(``django.core.validators.EmailValidator``, most seriously) didn't
+prohibit newline characters (due to the usage of ``$`` instead of ``\Z`` in the
+regular expressions). If you use values with newlines in HTTP response or email
+headers, you can suffer from header injection attacks. Django itself isn't
+vulnerable because :class:`~django.http.HttpResponse` and the mail sending
+utilities in :mod:`django.core.mail` prohibit newlines in HTTP and SMTP
+headers, respectively. While the validators have been fixed in Django, if
+you're creating HTTP responses or email messages in other ways, it's a good
+idea to ensure that those methods prohibit newlines as well. You might also
+want to validate that any existing data in your application doesn't contain
+unexpected newlines.
+
+:func:`~django.core.validators.validate_ipv4_address`,
+:func:`~django.core.validators.validate_slug`, and
+:class:`~django.core.validators.URLValidator` are also affected, however, as
+of Django 1.6 the ``GenericIPAddresseField``, ``IPAddressField``, ``SlugField``,
+and ``URLField`` form fields which use these validators all strip the input, so
+the possibility of newlines entering your data only exists if you are using
+these validators outside of the form fields.
+
+The undocumented, internally unused ``validate_integer()`` function is now
+stricter as it validates using a regular expression instead of simply casting
+the value using ``int()`` and checking if an exception was raised.
+
 Bugfixes
 ========
 
diff --git a/tests/validators/tests.py b/tests/validators/tests.py
@@ -25,10 +25,12 @@
     (validate_integer, '42', None),
     (validate_integer, '-42', None),
     (validate_integer, -42, None),
-    (validate_integer, -42.5, None),
 
+    (validate_integer, -42.5, ValidationError),
     (validate_integer, None, ValidationError),
     (validate_integer, 'a', ValidationError),
+    (validate_integer, '\n42', ValidationError),
+    (validate_integer, '42\n', ValidationError),
 
     (validate_email, 'email@here.com', None),
     (validate_email, 'weirder-email@here.and.there.com', None),
@@ -66,6 +68,11 @@
     (validate_email, '"\\\011"@here.com', None),
     (validate_email, '"\\\012"@here.com', ValidationError),
     (validate_email, 'trailingdot@shouldfail.com.', ValidationError),
+    # Trailing newlines in username or domain not allowed
+    (validate_email, 'a@b.com\n', ValidationError),
+    (validate_email, 'a\n@b.com', ValidationError),
+    (validate_email, '"test@test"\n@example.com', ValidationError),
+    (validate_email, 'a@[127.0.0.1]\n', ValidationError),
 
     (validate_slug, 'slug-ok', None),
     (validate_slug, 'longer-slug-still-ok', None),
@@ -78,6 +85,7 @@
     (validate_slug, 'some@mail.com', ValidationError),
     (validate_slug, '你好', ValidationError),
     (validate_slug, '\n', ValidationError),
+    (validate_slug, 'trailing-newline\n', ValidationError),
 
     (validate_ipv4_address, '1.1.1.1', None),
     (validate_ipv4_address, '255.0.0.0', None),
@@ -87,6 +95,7 @@
     (validate_ipv4_address, '25.1.1.', ValidationError),
     (validate_ipv4_address, '25,1,1,1', ValidationError),
     (validate_ipv4_address, '25.1 .1.1', ValidationError),
+    (validate_ipv4_address, '1.1.1.1\n', ValidationError),
 
     # validate_ipv6_address uses django.utils.ipv6, which
     # is tested in much greater detail in its own testcase
@@ -120,6 +129,7 @@
     (validate_comma_separated_integer_list, '', ValidationError),
     (validate_comma_separated_integer_list, 'a,b,c', ValidationError),
     (validate_comma_separated_integer_list, '1, 2, 3', ValidationError),
+    (validate_comma_separated_integer_list, '1,2,3\n', ValidationError),
 
     (MaxValueValidator(10), 10, None),
     (MaxValueValidator(10), -10, None),
@@ -181,6 +191,9 @@
     (URLValidator(), 'file://localhost/path', ValidationError),
     (URLValidator(), 'git://example.com/', ValidationError),
     (URLValidator(EXTENDED_SCHEMES), 'git://-invalid.com', ValidationError),
+    # Trailing newlines not accepted
+    (URLValidator(), 'http://www.djangoproject.com/\n', ValidationError),
+    (URLValidator(), 'http://[::ffff:192.9.5.5]\n', ValidationError),
 
     (BaseValidator(True), True, None),
     (BaseValidator(True), False, ValidationError),
