Refs #21379 -- Normalized unicode username inputs

3 files changed, 18 insertions, 2 deletions

diff --git a/django/contrib/auth/base_user.py b/django/contrib/auth/base_user.py
index c8f748cf02..d168262bb0 100644
--- a/django/contrib/auth/base_user.py
+++ b/django/contrib/auth/base_user.py
@@ -4,6 +4,8 @@ not in INSTALLED_APPS.
 """
 from __future__ import unicode_literals
 
+import unicodedata
+
 from django.contrib.auth import password_validation
 from django.contrib.auth.hashers import (
     check_password, is_password_usable, make_password,
@@ -11,7 +13,7 @@ from django.contrib.auth.hashers import (
 from django.db import models
 from django.utils.crypto import get_random_string, salted_hmac
 from django.utils.deprecation import CallableFalse, CallableTrue
-from django.utils.encoding import python_2_unicode_compatible
+from django.utils.encoding import force_text, python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 
 
@@ -31,6 +33,10 @@ class BaseUserManager(models.Manager):
             email = '@'.join([email_name, domain_part.lower()])
         return email
 
+    @classmethod
+    def normalize_username(cls, username):
+        return unicodedata.normalize('NFKC', force_text(username))
+
     def make_random_password(self, length=10,
                              allowed_chars='abcdefghjkmnpqrstuvwxyz'
                                            'ABCDEFGHJKLMNPQRSTUVWXYZ'
diff --git a/django/contrib/auth/forms.py b/django/contrib/auth/forms.py
index 692cdb5dab..f279f5e893 100644
--- a/django/contrib/auth/forms.py
+++ b/django/contrib/auth/forms.py
@@ -1,5 +1,7 @@
 from __future__ import unicode_literals
 
+import unicodedata
+
 from django import forms
 from django.contrib.auth import (
     authenticate, get_user_model, password_validation,
@@ -60,6 +62,11 @@ class ReadOnlyPasswordHashField(forms.Field):
         return False
 
 
+class UsernameField(forms.CharField):
+    def to_python(self, value):
+        return unicodedata.normalize('NFKC', super(UsernameField, self).to_python(value))
+
+
 class UserCreationForm(forms.ModelForm):
     """
     A form that creates a user, with no privileges, from the given username and
@@ -83,6 +90,7 @@ class UserCreationForm(forms.ModelForm):
     class Meta:
         model = User
         fields = ("username",)
+        field_classes = {'username': UsernameField}
 
     def __init__(self, *args, **kwargs):
         super(UserCreationForm, self).__init__(*args, **kwargs)
@@ -121,6 +129,7 @@ class UserChangeForm(forms.ModelForm):
     class Meta:
         model = User
         fields = '__all__'
+        field_classes = {'username': UsernameField}
 
     def __init__(self, *args, **kwargs):
         super(UserChangeForm, self).__init__(*args, **kwargs)
@@ -140,7 +149,7 @@ class AuthenticationForm(forms.Form):
     Base class for authenticating users. Extend this to get a form that accepts
     username/password logins.
     """
-    username = forms.CharField(
+    username = UsernameField(
         max_length=254,
         widget=forms.TextInput(attrs={'autofocus': ''}),
     )
diff --git a/django/contrib/auth/models.py b/django/contrib/auth/models.py
index 8fcdf9108c..87c3adf36b 100644
--- a/django/contrib/auth/models.py
+++ b/django/contrib/auth/models.py
@@ -145,6 +145,7 @@ class UserManager(BaseUserManager):
         if not username:
             raise ValueError('The given username must be set')
         email = self.normalize_email(email)
+        username = self.normalize_username(username)
         user = self.model(username=username, email=email, **extra_fields)
         user.set_password(password)
         user.save(using=self._db)