Fixed #19758 -- Avoided leaking email existence through the password reset form.

django/contrib/admin/templates/registration/password_reset_done.html

@@ -14,6 +14,8 @@
 
 <h1>{% trans 'Password reset successful' %}</h1>
 
-<p>{% trans "We've emailed you instructions for setting your password to the email address you submitted. You should be receiving it shortly." %}</p>
+<p>{% trans "We've emailed you instructions for setting your password. You should be receiving them shortly." %}</p>
+
+<p>{% trans "If you don't receive an email, please make sure you've entered the address you registered with, and check your spam folder." %}</p>
 
 {% endblock %}

django/contrib/auth/forms.py

@@ -206,31 +206,8 @@ class AuthenticationForm(forms.Form):
 
 
 class PasswordResetForm(forms.Form):
-    error_messages = {
-        'unknown': _("That email address doesn't have an associated "
-                     "user account. Are you sure you've registered?"),
-        'unusable': _("The user account associated with this email "
-                      "address cannot reset the password."),
-    }
     email = forms.EmailField(label=_("Email"), max_length=254)
 
-    def clean_email(self):
-        """
-        Validates that an active user exists with the given email address.
-        """
-        UserModel = get_user_model()
-        email = self.cleaned_data["email"]
-        self.users_cache = UserModel._default_manager.filter(email__iexact=email)
-        if not len(self.users_cache):
-            raise forms.ValidationError(self.error_messages['unknown'])
-        if not any(user.is_active for user in self.users_cache):
-            # none of the filtered users are active
-            raise forms.ValidationError(self.error_messages['unknown'])
-        if any((user.password == UNUSABLE_PASSWORD)
-               for user in self.users_cache):
-            raise forms.ValidationError(self.error_messages['unusable'])
-        return email
-
     def save(self, domain_override=None,
              subject_template_name='registration/password_reset_subject.txt',
              email_template_name='registration/password_reset_email.html',
@@ -241,7 +218,14 @@ class PasswordResetForm(forms.Form):
         user.
         """
         from django.core.mail import send_mail
-        for user in self.users_cache:
+        UserModel = get_user_model()
+        email = self.cleaned_data["email"]
+        users = UserModel._default_manager.filter(email__iexact=email)
+        for user in users:
+            # Make sure that no email is sent to a user that actually has
+            # a password marked as unusable
+            if user.password == UNUSABLE_PASSWORD:
+                continue
             if not domain_override:
                 current_site = get_current_site(request)
                 site_name = current_site.name

django/contrib/auth/tests/forms.py

@@ -326,20 +326,28 @@ class PasswordResetFormTest(TestCase):
                          [force_text(EmailField.default_error_messages['invalid'])])
 
     def test_nonexistant_email(self):
-        # Test nonexistant email address
+        # Test nonexistant email address. This should not fail because it would
+        # expose information about registered users.
         data = {'email': 'foo@bar.com'}
         form = PasswordResetForm(data)
-        self.assertFalse(form.is_valid())
+        self.assertTrue(form.is_valid())
-        self.assertEqual(form.errors,
+        self.assertEquals(len(mail.outbox), 0)
-                         {'email': [force_text(form.error_messages['unknown'])]})
 
+    @override_settings(
+        TEMPLATE_LOADERS=('django.template.loaders.filesystem.Loader',),
+        TEMPLATE_DIRS=(
+            os.path.join(os.path.dirname(upath(__file__)), 'templates'),
+        ),
+    )
     def test_cleaned_data(self):
         # Regression test
         (user, username, email) = self.create_dummy_user()
         data = {'email': email}
         form = PasswordResetForm(data)
         self.assertTrue(form.is_valid())
+        form.save(domain_override='example.com')
         self.assertEqual(form.cleaned_data['email'], email)
+        self.assertEqual(len(mail.outbox), 1)
 
     @override_settings(
         TEMPLATE_LOADERS=('django.template.loaders.filesystem.Loader',),
@@ -373,7 +381,8 @@ class PasswordResetFormTest(TestCase):
         user.is_active = False
         user.save()
         form = PasswordResetForm({'email': email})
-        self.assertFalse(form.is_valid())
+        self.assertTrue(form.is_valid())
+        self.assertEqual(len(mail.outbox), 0)
 
     def test_unusable_password(self):
         user = User.objects.create_user('testuser', 'test@example.com', 'test')
@@ -383,9 +392,10 @@ class PasswordResetFormTest(TestCase):
         user.set_unusable_password()
         user.save()
         form = PasswordResetForm(data)
-        self.assertFalse(form.is_valid())
+        # The form itself is valid, but no email is sent
-        self.assertEqual(form["email"].errors,
+        self.assertTrue(form.is_valid())
-                         [_("The user account associated with this email address cannot reset the password.")])
+        form.save()
+        self.assertEquals(len(mail.outbox), 0)
 
 
 class ReadOnlyPasswordHashTest(TestCase):

django/contrib/auth/tests/views.py

@@ -86,11 +86,12 @@ class AuthViewNamedURLTests(AuthViewsTestCase):
 class PasswordResetTest(AuthViewsTestCase):
 
     def test_email_not_found(self):
-        "Error is raised if the provided email address isn't currently registered"
+        """If the provided email is not registered, don't raise any error but
+        also don't send any email."""
         response = self.client.get('/password_reset/')
         self.assertEqual(response.status_code, 200)
         response = self.client.post('/password_reset/', {'email': 'not_a_real_email@email.com'})
-        self.assertFormError(response, PasswordResetForm.error_messages['unknown'])
+        self.assertEqual(response.status_code, 302)
         self.assertEqual(len(mail.outbox), 0)
 
     def test_email_found(self):

docs/topics/auth/default.txt

@@ -743,10 +743,24 @@ patterns.
     that can be used to reset the password, and sending that link to the
     user's registered email address.
 
+    If the email address provided does not exist in the system, this view
+    won't send an email, but the user won't receive any error message either.
+    This prevents information leaking to potential attackers. If you want to
+    provide an error message in this case, you can subclass
+    :class:`~django.contrib.auth.forms.PasswordResetForm` and use the
+    ``password_reset_form`` argument.
+
+
     Users flagged with an unusable password (see
     :meth:`~django.contrib.auth.models.User.set_unusable_password()` aren't
     allowed to request a password reset to prevent misuse when using an
-    external authentication source like LDAP.
+    external authentication source like LDAP. Note that they won't receive any
+    error message since this would expose their account's existence but no
+    mail will be sent either.
+
+    .. versionchanged:: 1.6
+        Previously, error messages indicated whether a given email was
+        registered.
 
     **URL name:** ``password_reset``