admin list_filter security fix doesn't allow 'pk' lookups in query string

[3point2]

Let's say I have a Payment model containing a received_by field that is a ForeignKey to a Customer model.

Now I add this to my Payment ModelAdmin:

list_filter = ["received_by"]

If I use a query string like "?received_by__id__exact=2" on the payment changelist view, there is no problem. This is the form that the admin itself uses for the filter. Using something more implicit like "?received_by__id=2" works fine too.

However, using "?received_by__pk=2" raises SuspiciousOperation. This was introduced by the security fix in r15031.

The lookup_allowed method in admin/options.py explicitly makes an exception for "__id" (or whatever the primary key attribute of the model is explicitly called), but it doesn't allow direct use of the 'pk' shortcut.

The point of the security fix was to only allow lookups specified by list_filter. However, in its current form it also causes the query string syntax to diverge from the documented lookup syntax ​https://docs.djangoproject.com/en/1.4/topics/db/queries/#the-pk-lookup-shortcut . I suggest allowing use of the pk shortcut in the query string.

I would be happy to write a patch for this if the developers agree it should be fixed.

[Aymeric Augustin]

The querystring in the admin URLs isn't a public API, and it isn't meant to provide access to the model lookup API -- it just happens to similar.

You can override lookup_allowed if you need to. See also #17985.