Fixed #27611 -- Doc'd that CSRF_COOKIE_HTTPONLY setting offers no security.

4 files changed, 15 insertions, 65 deletions

diff --git a/django/core/checks/security/csrf.py b/django/core/checks/security/csrf.py
index 1cd0ace56d..d9dd47b3ea 100644
--- a/django/core/checks/security/csrf.py
+++ b/django/core/checks/security/csrf.py
@@ -20,14 +20,6 @@ W016 = Warning(
     id='security.W016',
 )
 
-W017 = Warning(
-    "You have 'django.middleware.csrf.CsrfViewMiddleware' in your "
-    "MIDDLEWARE, but you have not set CSRF_COOKIE_HTTPONLY to True. "
-    "Using an HttpOnly CSRF cookie makes it more difficult for cross-site "
-    "scripting attacks to steal the CSRF token.",
-    id='security.W017',
-)
-
 
 def _csrf_middleware():
     return ("django.middleware.csrf.CsrfViewMiddleware" in settings.MIDDLEWARE_CLASSES or
@@ -48,13 +40,3 @@ def check_csrf_cookie_secure(app_configs, **kwargs):
         settings.CSRF_COOKIE_SECURE
     )
     return [] if passed_check else [patch_middleware_message(W016)]
-
-
-@register(Tags.security, deploy=True)
-def check_csrf_cookie_httponly(app_configs, **kwargs):
-    passed_check = (
-        settings.CSRF_USE_SESSIONS or
-        not _csrf_middleware() or
-        settings.CSRF_COOKIE_HTTPONLY
-    )
-    return [] if passed_check else [patch_middleware_message(W017)]
diff --git a/docs/ref/checks.txt b/docs/ref/checks.txt
index 3b16921e52..c6f7e518ef 100644
--- a/docs/ref/checks.txt
+++ b/docs/ref/checks.txt
@@ -593,7 +593,9 @@ The following checks are run if you use the :option:`check --deploy` option:
   sniffers to steal the CSRF token.
 * **security.W017**: :setting:`CSRF_COOKIE_HTTPONLY` is not set to ``True``.
   Using an ``HttpOnly`` CSRF cookie makes it more difficult for cross-site
-  scripting attacks to steal the CSRF token.
+  scripting attacks to steal the CSRF token. *This check is removed in Django
+  1.11 as the* :setting:`CSRF_COOKIE_HTTPONLY` *setting offers no pratical
+  benefit.*
 * **security.W018**: You should not have :setting:`DEBUG` set to ``True`` in
   deployment.
 * **security.W019**: You have
diff --git a/docs/ref/settings.txt b/docs/ref/settings.txt
index 87dbc89584..1d28c96137 100644
--- a/docs/ref/settings.txt
+++ b/docs/ref/settings.txt
@@ -334,10 +334,18 @@ Default: ``False``
 Whether to use ``HttpOnly`` flag on the CSRF cookie. If this is set to
 ``True``, client-side JavaScript will not to be able to access the CSRF cookie.
 
-This can help prevent malicious JavaScript from bypassing CSRF protection. If
-you enable this and need to send the value of the CSRF token with Ajax requests,
-your JavaScript will need to pull the value from a hidden CSRF token form input
-on the page instead of from the cookie.
+Designating the CSRF cookie as ``HttpOnly`` doesn't offer any practical
+protection because CSRF is only to protect against cross-domain attacks. If an
+attacker can read the cookie via JavaScript, they're already on the same domain
+as far as the browser knows, so they can do anything they like anyway. (XSS is
+a much bigger hole than CSRF.)
+
+Although the setting offers little practical benefit, it's sometimes required
+by security auditors.
+
+If you enable this and need to send the value of the CSRF token with an AJAX
+request, your JavaScript must pull the value from a hidden CSRF token form
+input on the page instead of from the cookie.
 
 See :setting:`SESSION_COOKIE_HTTPONLY` for details on ``HttpOnly``.
 
diff --git a/tests/check_framework/test_security.py b/tests/check_framework/test_security.py
index 1e6d2fac8b..8c3b73d8bb 100644
--- a/tests/check_framework/test_security.py
+++ b/tests/check_framework/test_security.py
@@ -192,48 +192,6 @@ class CheckCSRFCookieSecureTest(SimpleTestCase):
         self.assertEqual(self.func(None), [])
 
 
-class CheckCSRFCookieHttpOnlyTest(SimpleTestCase):
-    @property
-    def func(self):
-        from django.core.checks.security.csrf import check_csrf_cookie_httponly
-        return check_csrf_cookie_httponly
-
-    @override_settings(
-        MIDDLEWARE=["django.middleware.csrf.CsrfViewMiddleware"],
-        CSRF_COOKIE_HTTPONLY=False)
-    def test_with_csrf_cookie_httponly_false(self):
-        """
-        Warn if CsrfViewMiddleware is in MIDDLEWARE but
-        CSRF_COOKIE_HTTPONLY isn't True.
-        """
-        self.assertEqual(self.func(None), [csrf.W017])
-
-    @override_settings(
-        MIDDLEWARE=["django.middleware.csrf.CsrfViewMiddleware"],
-        CSRF_USE_SESSIONS=True,
-        CSRF_COOKIE_HTTPONLY=False)
-    def test_use_sessions_with_csrf_cookie_httponly_false(self):
-        """
-        No warning if CSRF_COOKIE_HTTPONLY isn't True while CSRF_USE_SESSIONS
-        is True.
-        """
-        self.assertEqual(self.func(None), [])
-
-    @override_settings(MIDDLEWARE=[], MIDDLEWARE_CLASSES=[], CSRF_COOKIE_HTTPONLY=False)
-    def test_with_csrf_cookie_httponly_false_no_middleware(self):
-        """
-        No warning if CsrfViewMiddleware isn't in MIDDLEWARE, even if
-        CSRF_COOKIE_HTTPONLY is False.
-        """
-        self.assertEqual(self.func(None), [])
-
-    @override_settings(
-        MIDDLEWARE=["django.middleware.csrf.CsrfViewMiddleware"],
-        CSRF_COOKIE_HTTPONLY=True)
-    def test_with_csrf_cookie_httponly_true(self):
-        self.assertEqual(self.func(None), [])
-
-
 class CheckSecurityMiddlewareTest(SimpleTestCase):
     @property
     def func(self):