Le 10/05/10 15:54, Tom Boutell a écrit :
It says hidden fields are not removed. The id is a hidden field.
The patch of Thomas removes the hidden fields. Btw the actual
implementation of useFields does not.
To avoid this kind of problem, I'm now using swFormHelper::useOnly from
Thomas's swFormExtraPlugin.
You should give it a try.
On Mon, May 10, 2010 at 9:43 AM, Thomas Rabaix<[email protected]> wrote:
You should read this : http://trac.symfony-project.org/ticket/6100
On Mon, May 10, 2010 at 3:35 PM, Tom Boutell<[email protected]> wrote:
Actually, you don't set $this->Blog in the code you showed either, so
I really have no idea whether your code is secure. (:
2010/5/10 Michał Piotrowski<[email protected]>:
2010/5/10 Tom Boutell<[email protected]>:
This is a dangerous behavior of the standard Symfony Doctrine and
Propel CRUD module generators (and the admin generator as well).
The Doctrine admin generator and CRUD generator (presumably Propel
too) generate redundant code in which the object is fetched based on
an ID in the route, but the form still contains an ID.
Sure, the generated code gets away with this because it has no per-row
validation anyway, but it still does not make sense and it is
dangerous because the conspicuous IDs in the generated CRUD code mask
the presence of the "sneaky," redundant ID field in the form. The
minute you try to add any validation of who's supposed to be doing
what at the controller level, you've got a big security hole and you
don't know it.
Hmmm... I'm doing things like
public function editCommon($request)
{
[..]
$this->logged_user_id = $this->UserData['logged_user_id'];
[..]
$this->forward404Unless($this->logged_user_id ==
$this->Blog->getUserId());
[..]
}
public function executeEdit(sfWebRequest $request)
{
$this->editCommon($request);
$this->form = new BlogForm($this->Blog);
}
public function executeUpdate(sfWebRequest $request)
{
$this->forward404Unless($request->isMethod(sfRequest::POST) ||
$request->isMethod(sfRequest::PUT));
$this->editCommon($request);
$this->form = new BlogForm($this->Blog);
$this->processForm($request, $this->form);
$this->setTemplate('edit');
}
I'm always checking logged user_id against user_id of record creator.
I don't see vulnerability here.
The CRUD generator and admin generator should generate form subclasses
that unset the ID field, unset it directly at the action level, or
verify that it's the same as the ID coming from the route and ignore
it entirely in the create action, IMHO. Otherwise it's misleading and
a danger in exactly the way you suggest.
In our own projects we unset($this['id']) in the configure method of
our Doctrine forms.
2010/5/10 Michał Piotrowski<[email protected]>:
Hi,
2010/5/10 Stephen Melrose<[email protected]>:
Hi,
We have discovered what could be a potential flaw in the form
framework. The reason I'm discussing this here is because I'm in
mixed
feelings as to whether this is actually bug or not, or rather poor
implementation on our part. Either way, I'm also saying this flaw
should be safe guarded against.
We discovered that a malicious user can use the forms generated by
the
form framework to edit content they shouldn't be able to.
They do this by replacing the primary ID in the hidden form field
with
that of the record they want to edit. When they hit save, the
validation is run, and the Object is updated with the new ID, so when
the save() is called, the other row is updated.
Now, if we (as in developers) want to restrict editing of content for
certain users, then it is our responsibility to make sure we put safe
guards in place. I'm not arguing this fact.
The reason I believe this to be a problem is how users will actually
guard their code. Most people (including myself) run all the safe
guard checks before the Object is passed into the Form on
construction. I don't then expect the POST data to override the
primary key of the Object on save. Infact, I can't think of an
instance I would ever want this to happen.
I therefore propose that some sort of restriction/block is put in
place by default that stops the PK of an Object being altered on
bind().
Thoughts?
I create a methods like newCommon() or editCommon() with all safe
checks and call them from new/create, edit/update.
The main reason for this is that you _always_ _need_ to perform the
same checks in new and create as well in edit and update. Why?
For example - user want to create a comment to blog post
- new method is called - all safe checks pass well
- form is rendered
- user write his comment
- other user delete his blog post
- user tries to write his comment
If you wont do the same check in create method you failed :)
IMHO it's a security vulnerability, but it's not symfony fault.
And BTW. CSRF protection should do the trick for form protection
Stephen Melrose
Regards,
Michal
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