django/django

==========================
Django 1.1.4 release notes
==========================

Welcome to Django 1.1.4!

This is the fourth "bugfix" release in the Django 1.1 series,
improving the stability and performance of the Django 1.1 codebase.

With one exception, Django 1.1.4 maintains backwards compatibility
with Django 1.1.3. It also contains a number of fixes and other
improvements. Django 1.1.4 is a recommended upgrade for any
development or deployment currently using or targeting Django 1.1.

For full details on the new features, backwards incompatibilities, and
deprecated features in the 1.1 branch, see the :doc:`/releases/1.1`.

Backwards incompatible changes
==============================

CSRF exception for AJAX requests
--------------------------------

Django includes a CSRF-protection mechanism, which makes use of a
token inserted into outgoing forms. Middleware then checks for the
token's presence on form submission, and validates it.

Prior to Django 1.2.5, our CSRF protection made an exception for AJAX
requests, on the following basis:

* Many AJAX toolkits add an X-Requested-With header when using
  XMLHttpRequest.

* Browsers have strict same-origin policies regarding
  XMLHttpRequest.

* In the context of a browser, the only way that a custom header
  of this nature can be added is with XMLHttpRequest.

Therefore, for ease of use, we did not apply CSRF checks to requests
that appeared to be AJAX on the basis of the X-Requested-With header.
The Ruby on Rails web framework had a similar exemption.

Recently, engineers at Google made members of the Ruby on Rails
development team aware of a combination of browser plugins and
redirects which can allow an attacker to provide custom HTTP headers
on a request to any website. This can allow a forged request to appear
to be an AJAX request, thereby defeating CSRF protection which trusts
the same-origin nature of AJAX requests.

Michael Koziarski of the Rails team brought this to our attention, and
we were able to produce a proof-of-concept demonstrating the same
vulnerability in Django's CSRF handling.

To remedy this, Django will now apply full CSRF validation to all
requests, regardless of apparent AJAX origin. This is technically
backwards-incompatible, but the security risks have been judged to
outweigh the compatibility concerns in this case.

Additionally, Django will now accept the CSRF token in the custom HTTP
header X-CSRFTOKEN, as well as in the form submission itself, for ease
of use with popular JavaScript toolkits which allow insertion of
custom headers into all AJAX requests.

Please see the :ref:`CSRF docs for example jQuery code <csrf-ajax>`
that demonstrates this technique, ensuring that you are looking at the
documentation for your version of Django, as the exact code necessary
is different for some older versions of Django.