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Fixed queries that may return unexpected results on MySQL due to typecasting. 

This is a security fix; disclosure to follow shortly.
This commit is contained in:
Erik Romijn 2014-04-20 16:13:41 -04:00 committed by Tim Graham
parent c083e3815a
commit 75c0d4ea3a
6 changed files with 95 additions and 2 deletions
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16
django/db/models/fields/__init__.py
View File

@ -1509,6 +1509,12 @@ class FilePathField(Field):
del kwargs["max_length"]
return name, path, args, kwargs
def get_prep_value(self, value):
value = super(FilePathField, self).get_prep_value(value)
if value is None:
return None
return six.text_type(value)
def formfield(self, **kwargs):
defaults = {
'path': self.path,
@ -1642,6 +1648,12 @@ class IPAddressField(Field):
del kwargs['max_length']
return name, path, args, kwargs
def get_prep_value(self, value):
value = super(IPAddressField, self).get_prep_value(value)
if value is None:
return None
return six.text_type(value)
def get_internal_type(self):
return "IPAddressField"
@ -1711,12 +1723,14 @@ class GenericIPAddressField(Field):
def get_prep_value(self, value):
value = super(GenericIPAddressField, self).get_prep_value(value)
if value is None:
return None
if value and ':' in value:
try:
return clean_ipv6_address(value, self.unpack_ipv4)
except exceptions.ValidationError:
pass
return value
return six.text_type(value)
def formfield(self, **kwargs):
defaults = {

11
docs/howto/custom-model-fields.txt
View File

@ -593,6 +593,17 @@ For example::
return ''.join([''.join(l) for l in (value.north,
value.east, value.south, value.west)])
.. warning::
If your custom field uses the ``CHAR``, ``VARCHAR`` or ``TEXT``
types for MySQL, you must make sure that :meth:`.get_prep_value`
always returns a string type. MySQL performs flexible and unexpected
matching when a query is performed on these types and the provided
value is an integer, which can cause queries to include unexpected
objects in their results. This problem cannot occur if you always
return a string type from :meth:`.get_prep_value`.
Converting query values to database values
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

16
docs/ref/databases.txt
View File

@ -507,6 +507,22 @@ MySQL does not support the ``NOWAIT`` option to the ``SELECT ... FOR UPDATE``
statement. If ``select_for_update()`` is used with ``nowait=True`` then a
``DatabaseError`` will be raised.
Automatic typecasting can cause unexpected results
--------------------------------------------------
When performing a query on a string type, but with an integer value, MySQL will
coerce the types of all values in the table to an integer before performing the
comparison. If your table contains the values ``'abc'``, ``'def'`` and you
query for ``WHERE mycolumn=0``, both rows will match. Similarly, ``WHERE mycolumn=1``
will match the value ``'abc1'``. Therefore, string type fields included in Django
will always cast the value to a string before using it in a query.
If you implement custom model fields that inherit from :class:`~django.db.models.Field`
directly, are overriding :meth:`~django.db.models.Field.get_prep_value`, or use
:meth:`extra() <django.db.models.query.QuerySet.extra>` or
:meth:`raw() <django.db.models.Manager.raw>`, you should ensure that you
perform the appropriate typecasting.
.. _sqlite-notes:
SQLite notes

10
docs/ref/models/querysets.txt
View File

@ -1189,6 +1189,16 @@ of the arguments is required, but you should use at least one of them.
Entry.objects.extra(where=['headline=%s'], params=['Lennon'])
.. warning::
If you are performing queries on MySQL, note that MySQL's silent type coercion
may cause unexpected results when mixing types. If you query on a string
type column, but with an integer value, MySQL will coerce the types of all values
in the table to an integer before performing the comparison. For example, if your
table contains the values ``'abc'``, ``'def'`` and you query for ``WHERE mycolumn=0``,
both rows will match. To prevent this, perform the correct typecasting
before using the value in a query.
defer
~~~~~

10
docs/topics/db/sql.txt
View File

@ -66,6 +66,16 @@ options that make it very powerful.
database, but does nothing to enforce that. If the query does not
return rows, a (possibly cryptic) error will result.
.. warning::
If you are performing queries on MySQL, note that MySQL's silent type coercion
may cause unexpected results when mixing types. If you query on a string
type column, but with an integer value, MySQL will coerce the types of all values
in the table to an integer before performing the comparison. For example, if your
table contains the values ``'abc'``, ``'def'`` and you query for ``WHERE mycolumn=0``,
both rows will match. To prevent this, perform the correct typecasting
before using the value in a query.
Mapping query fields to model fields
------------------------------------

34
tests/model_fields/tests.py
View File

@ -673,12 +673,20 @@ class PromiseTest(test.TestCase):
self.assertIsInstance(
CharField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
CharField().get_prep_value(lazy_func()),
six.text_type)
def test_CommaSeparatedIntegerField(self):
lazy_func = lazy(lambda: '1,2', six.text_type)
self.assertIsInstance(
CommaSeparatedIntegerField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
CommaSeparatedIntegerField().get_prep_value(lazy_func()),
six.text_type)
def test_DateField(self):
lazy_func = lazy(lambda: datetime.date.today(), datetime.date)
@ -709,12 +717,20 @@ class PromiseTest(test.TestCase):
self.assertIsInstance(
FileField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
FileField().get_prep_value(lazy_func()),
six.text_type)
def test_FilePathField(self):
lazy_func = lazy(lambda: 'tests.py', six.text_type)
self.assertIsInstance(
FilePathField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
FilePathField().get_prep_value(lazy_func()),
six.text_type)
def test_FloatField(self):
lazy_func = lazy(lambda: 1.2, float)
@ -735,9 +751,13 @@ class PromiseTest(test.TestCase):
int)
def test_IPAddressField(self):
lazy_func = lazy(lambda: '127.0.0.1', six.text_type)
with warnings.catch_warnings(record=True):
warnings.simplefilter("always")
lazy_func = lazy(lambda: '127.0.0.1', six.text_type)
self.assertIsInstance(
IPAddressField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
IPAddressField().get_prep_value(lazy_func()),
six.text_type)
@ -747,6 +767,10 @@ class PromiseTest(test.TestCase):
self.assertIsInstance(
GenericIPAddressField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
GenericIPAddressField().get_prep_value(lazy_func()),
six.text_type)
def test_NullBooleanField(self):
lazy_func = lazy(lambda: True, bool)
@ -771,6 +795,10 @@ class PromiseTest(test.TestCase):
self.assertIsInstance(
SlugField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
SlugField().get_prep_value(lazy_func()),
six.text_type)
def test_SmallIntegerField(self):
lazy_func = lazy(lambda: 1, int)
@ -783,6 +811,10 @@ class PromiseTest(test.TestCase):
self.assertIsInstance(
TextField().get_prep_value(lazy_func()),
six.text_type)
lazy_func = lazy(lambda: 0, int)
self.assertIsInstance(
TextField().get_prep_value(lazy_func()),
six.text_type)
def test_TimeField(self):
lazy_func = lazy(lambda: datetime.datetime.now().time(), datetime.time)