django/docs/releases/1.6.6.txt

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==========================
Django 1.6.6 release notes
==========================
*Under development*
Django 1.6.6 fixes several security issues and bugs in 1.6.5.
:func:`~django.core.urlresolvers.reverse()` could generate URLs pointing to other hosts
=======================================================================================
In certain situations, URL reversing could generate scheme-relative URLs (URLs
starting with two slashes), which could unexpectedly redirect a user to a
different host. An attacker could exploit this, for example, by redirecting
users to a phishing site designed to ask for user's passwords.
To remedy this, URL reversing now ensures that no URL starts with two slashes
(//), replacing the second slash with its URL encoded counterpart (%2F). This
approach ensures that semantics stay the same, while making the URL relative to
the domain and not to the scheme.
File upload denial-of-service
=============================
Before this release, Django's file upload handing in its default configuration
may degrade to producing a huge number of ``os.stat()`` system calls when a
duplicate filename is uploaded. Since ``stat()`` may invoke IO, this may produce
a huge data-dependent slowdown that slowly worsens over time. The net result is
that given enough time, a user with the ability to upload files can cause poor
performance in the upload handler, eventually causing it to become very slow
simply by uploading 0-byte files. At this point, even a slow network connection
and few HTTP requests would be all that is necessary to make a site unavailable.
We've remedied the issue by changing the algorithm for generating file names
if a file with the uploaded name already exists.
:meth:`Storage.get_available_name()
<django.core.files.storage.Storage.get_available_name>` now appends an
underscore plus a random 7 character alphanumeric string (e.g. ``"_x3a1gho"``),
rather than iterating through an underscore followed by a number (e.g. ``"_1"``,
``"_2"``, etc.).
``RemoteUserMiddleware`` session hijacking
==========================================
When using the :class:`~django.contrib.auth.middleware.RemoteUserMiddleware`
and the ``RemoteUserBackend``, a change to the ``REMOTE_USER`` header between
requests without an intervening logout could result in the prior user's session
being co-opted by the subsequent user. The middleware now logs the user out on
a failed login attempt.
Bugfixes
========
* Corrected email and URL validation to reject a trailing dash
(:ticket:`22579`).
* Prevented indexes on PostgreSQL virtual fields (:ticket:`22514`).
* Prevented edge case where values of FK fields could be initialized with a
wrong value when an inline model formset is created for a relationship
defined to point to a field other than the PK (:ticket:`13794`).
* Restored ``pre_delete`` signals for ``GenericRelation`` cascade deletion
(:ticket:`22998`).
* Fixed transaction handling when specifying non-default database in
``createcachetable`` and ``flush`` (:ticket:`23089`).
* Fixed the "ORA-01843: not a valid month" errors when using Unicode
with older versions of Oracle server (:ticket:`20292`).
* Restored bug fix for sending unicode email with Python 2.6.5 and below
(:ticket:`19107`).
* Prevented ``UnicodeDecodeError`` in ``runserver`` with non-UTF-8 and
non-English locale (:ticket:`23265`).
* Fixed JavaScript errors while editing multi-geometry objects in the OpenLayers
widget (:ticket:`23137`, :ticket:`23293`).
* Prevented a crash on Python 3 with query strings containing unencoded
non-ASCII characters (:ticket:`22996`).