plone.protect 1.0

Security for browser forms

Introduction

This package contains utilities that can help to protect parts of Plone or applications build on top of the Plone framework.

protect decorator

The most common way to use plone.protect is through the protect decorator. This decorator takes a list of checkers as parameters: each checker will check a specific security aspect of the request. For example:

from plone.protect import protect
from plone.protect import PostOnly

@protect(PostOnly)
def SensitiveMethod(self, REQUEST=None):
    # This is only allowed with HTTP POST requests.

This relies on the protected method having a parameter called REQUEST.

HTTP POST

If you only need to allow HTTP POST requests you can use the PostOnly checker:

from plone.protect import PostOnly
from plone.protect import protect

@protect(PostOnly)
def manage_doSomething(self, param, REQUEST=None):
    pass

This checker only operators on HTTP requests; other types of requests are not checked.

Form authentication

A common problem in web applications is Cross Site Request Forgery or CSRF. This is an attack method in which an attacker tricks a browser to do a HTTP form submit to another site. To do this the attacker needs to know the exact form parameters. Form authentication is a method to make it impossible for an attacker to predict those parameters by adding an extra authenticator which can be verified.

To use the form authenticator you first need to insert it into your form. This can be done using a simple TAL statement inside your form:

<span tal:replace="structure context/@@authenticator/authenticator"/>

this will produce a HTML input element with the authentication information. Next you need to add logic somewhere to verify the authenticator. This can be done using a call to the authenticator view. For example:

authenticator=getMultiAdapter((request, context), name=u"authenticator")
if not authenticator.verify():
    raise Unauthorized

You can do the same thing more conveniently using the protect decorator:

from plone.protect import CheckAuthenticator
from plone.protect import protect

@protect(CheckAuthenticator)
def manage_doSomething(self, param, REQUEST=None):
    pass

Changelog

1.0 - April 19, 2008

• The protect decorator had a serious design flaw which broke it. Added proper tests for it and fixed the problems. [wichert]

1.0rc1 - March 28, 2008

• Rename plone.app.protect to plone.protect: there is nothing Plone-specific about the functionality in this package and it really should be used outside of Plone as well. [wichert]

• Made utils.protect work with Zope >= 2.11. [stefan]

1.0b1 - March 7, 2008

• Refactor the code to offer a generic protect decorator for methods which takes a list of checkers as options. Add checkers for both the authenticator verification and HTTP POST-only. [wichert]

1.0a1 - January 27, 2008

• Initial release [wichert]