Fixed #31291 -- Renamed salt to mask for CSRF tokens.

django/middleware/csrf.py

@@ -42,33 +42,33 @@ def _get_new_csrf_string():
     return get_random_string(CSRF_SECRET_LENGTH, allowed_chars=CSRF_ALLOWED_CHARS)
 
 
-def _salt_cipher_secret(secret):
+def _mask_cipher_secret(secret):
     """
     Given a secret (assumed to be a string of CSRF_ALLOWED_CHARS), generate a
-    token by adding a salt and using it to encrypt the secret.
+    token by adding a mask and applying it to the secret.
     """
-    salt = _get_new_csrf_string()
+    mask = _get_new_csrf_string()
     chars = CSRF_ALLOWED_CHARS
-    pairs = zip((chars.index(x) for x in secret), (chars.index(x) for x in salt))
+    pairs = zip((chars.index(x) for x in secret), (chars.index(x) for x in mask))
     cipher = ''.join(chars[(x + y) % len(chars)] for x, y in pairs)
-    return salt + cipher
+    return mask + cipher
 
 
-def _unsalt_cipher_token(token):
+def _unmask_cipher_token(token):
     """
     Given a token (assumed to be a string of CSRF_ALLOWED_CHARS, of length
-    CSRF_TOKEN_LENGTH, and that its first half is a salt), use it to decrypt
+    CSRF_TOKEN_LENGTH, and that its first half is a mask), use it to decrypt
     the second half to produce the original secret.
     """
-    salt = token[:CSRF_SECRET_LENGTH]
+    mask = token[:CSRF_SECRET_LENGTH]
     token = token[CSRF_SECRET_LENGTH:]
     chars = CSRF_ALLOWED_CHARS
-    pairs = zip((chars.index(x) for x in token), (chars.index(x) for x in salt))
+    pairs = zip((chars.index(x) for x in token), (chars.index(x) for x in mask))
     return ''.join(chars[x - y] for x, y in pairs)  # Note negative values are ok
 
 
 def _get_new_csrf_token():
-    return _salt_cipher_secret(_get_new_csrf_string())
+    return _mask_cipher_secret(_get_new_csrf_string())
 
 
 def get_token(request):
@@ -83,11 +83,11 @@ def get_token(request):
     """
     if "CSRF_COOKIE" not in request.META:
         csrf_secret = _get_new_csrf_string()
-        request.META["CSRF_COOKIE"] = _salt_cipher_secret(csrf_secret)
+        request.META["CSRF_COOKIE"] = _mask_cipher_secret(csrf_secret)
     else:
-        csrf_secret = _unsalt_cipher_token(request.META["CSRF_COOKIE"])
+        csrf_secret = _unmask_cipher_token(request.META["CSRF_COOKIE"])
     request.META["CSRF_COOKIE_USED"] = True
-    return _salt_cipher_secret(csrf_secret)
+    return _mask_cipher_secret(csrf_secret)
 
 
 def rotate_token(request):
@@ -111,20 +111,20 @@ def _sanitize_token(token):
     elif len(token) == CSRF_SECRET_LENGTH:
         # Older Django versions set cookies to values of CSRF_SECRET_LENGTH
         # alphanumeric characters. For backwards compatibility, accept
-        # such values as unsalted secrets.
+        # such values as unmasked secrets.
-        # It's easier to salt here and be consistent later, rather than add
+        # It's easier to mask here and be consistent later, rather than add
         # different code paths in the checks, although that might be a tad more
         # efficient.
-        return _salt_cipher_secret(token)
+        return _mask_cipher_secret(token)
     return _get_new_csrf_token()
 
 
-def _compare_salted_tokens(request_csrf_token, csrf_token):
+def _compare_masked_tokens(request_csrf_token, csrf_token):
     # Assume both arguments are sanitized -- that is, strings of
     # length CSRF_TOKEN_LENGTH, all CSRF_ALLOWED_CHARS.
     return constant_time_compare(
-        _unsalt_cipher_token(request_csrf_token),
+        _unmask_cipher_token(request_csrf_token),
-        _unsalt_cipher_token(csrf_token),
+        _unmask_cipher_token(csrf_token),
     )
 
 
@@ -306,7 +306,7 @@ class CsrfViewMiddleware(MiddlewareMixin):
                 request_csrf_token = request.META.get(settings.CSRF_HEADER_NAME, '')
 
             request_csrf_token = _sanitize_token(request_csrf_token)
-            if not _compare_salted_tokens(request_csrf_token, csrf_token):
+            if not _compare_masked_tokens(request_csrf_token, csrf_token):
                 return self._reject(request, REASON_BAD_TOKEN)
 
         return self._accept(request)

docs/ref/csrf.txt

@@ -239,15 +239,15 @@ The CSRF protection is based on the following things:
    set on the request.
 
    In order to protect against `BREACH`_ attacks, the token is not simply the
-   secret; a random salt is prepended to the secret and used to scramble it.
+   secret; a random mask is prepended to the secret and used to scramble it.
 
    For security reasons, the value of the secret is changed each time a
    user logs in.
 
 #. A hidden form field with the name 'csrfmiddlewaretoken' present in all
    outgoing POST forms. The value of this field is, again, the value of the
-   secret, with a salt which is both added to it and used to scramble it. The
+   secret, with a mask which is both added to it and used to scramble it. The
-   salt is regenerated on every call to ``get_token()`` so that the form field
+   mask is regenerated on every call to ``get_token()`` so that the form field
    value is changed in every such response.
 
    This part is done by the template tag.

tests/csrf_tests/test_context_processor.py

@@ -1,5 +1,5 @@
 from django.http import HttpRequest
-from django.middleware.csrf import _compare_salted_tokens as equivalent_tokens
+from django.middleware.csrf import _compare_masked_tokens as equivalent_tokens
 from django.template.context_processors import csrf
 from django.test import SimpleTestCase
 

tests/csrf_tests/tests.py

@@ -7,7 +7,7 @@ from django.http import HttpRequest, HttpResponse
 from django.middleware.csrf import (
     CSRF_SESSION_KEY, CSRF_TOKEN_LENGTH, REASON_BAD_TOKEN,
     REASON_NO_CSRF_COOKIE, CsrfViewMiddleware,
-    _compare_salted_tokens as equivalent_tokens, get_token,
+    _compare_masked_tokens as equivalent_tokens, get_token,
 )
 from django.test import SimpleTestCase, override_settings
 from django.views.decorators.csrf import csrf_exempt, requires_csrf_token

tests/template_backends/test_dummy.py

@@ -3,7 +3,7 @@ import re
 from django.forms import CharField, Form, Media
 from django.http import HttpRequest, HttpResponse
 from django.middleware.csrf import (
-    CsrfViewMiddleware, _compare_salted_tokens as equivalent_tokens, get_token,
+    CsrfViewMiddleware, _compare_masked_tokens as equivalent_tokens, get_token,
 )
 from django.template import TemplateDoesNotExist, TemplateSyntaxError
 from django.template.backends.dummy import TemplateStrings