#28699: Document middleware ordering requirements following CSRF change in 
Django
1.11.6
-------------------------------+------------------------------------
     Reporter:  stephanm       |                    Owner:  Rodrigo
         Type:  Bug            |                   Status:  assigned
    Component:  Documentation  |                  Version:  1.11
     Severity:  Normal         |               Resolution:
     Keywords:                 |             Triage Stage:  Accepted
    Has patch:  1              |      Needs documentation:  0
  Needs tests:  0              |  Patch needs improvement:  0
Easy pickings:  0              |                    UI/UX:  0
-------------------------------+------------------------------------

Comment (by Carlton Gibson):

 The PR here looks fine, re the discussion, but I'm missing a crucial part
 in my understanding here: I can't see how you're meant to make a
 successful CSRF check in the **same request** as a `REMOTE_USER` login...

 As I read it, if `RemoteUserMiddleware` is first then:

 * `RemoteUserMiddleware.process_request()` calls `auth.login()` which
 calls `rotate_token()`:

 {{{
 def rotate_token(request):
     """
     Change the CSRF token in use for a request - should be done on login
     for security purposes.
     """
     request.META.update({
         "CSRF_COOKIE_USED": True,
         "CSRF_COOKIE": _get_new_csrf_token(),
     })
     request.csrf_cookie_needs_reset = True
 }}}

 * But then `CsrfViewMiddleware.process_request()` calls `_get_token()`
 which fetches the **old** `CSRF_COOKIE`, from either the session or the
 cookie, and
 
[https://github.com/django/django/blob/4d60261b2a77460b4c127c3d832518b95e11a0ac/django/middleware/csrf.py#L201
 resets it on `request.META`].

 Unless I missed something, this is **negating the `rotate_token()` call**.
 Is that correct, or have I misread it? Given the docstring in
 `rotate_token()` isn't this a no-no?

 On the other hand, if `CsrfViewMiddleware` is first then the
 `rotate_token()` call will replace whatever `CSRF_COOKIE` was previously
 set, and so the actual CSRF check in `process_view()` will necessarily
 fail. (As we must be seeing here.)

-- 
Ticket URL: <https://code.djangoproject.com/ticket/28699#comment:16>
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