This package contains utilities that can help to protect parts of Plone or applications build on top of the Plone framework.
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 operates on HTTP requests; other types of requests are not checked.
Simply:
from plone.protect import PostOnly
...
PostOnly(self.context.REQUEST)
...
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((context, request), 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
Or just:
from plone.protect import CheckAuthenticator
...
CheckAuthenticator(self.context.REQUEST)
...
You can also pass in the token by using the header X-CSRF-TOKEN
. This can be useful for AJAX requests.
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 (case sensitive).
If you'd like use a different authentication token for different forms, you can provide an extra string to use with the token:
<tal:authenticator tal:define="authenticator context/@@authenticator">
<span tal:replace="structure python: authenticator.authenticator('a-form-related-value')"/>
</tal:authenticator>
To verify:
authenticator=getMultiAdapter((context, request), name=u"authenticator")
if not authenticator.verify('a-form-related-value'):
raise Unauthorized
With the decorator:
from plone.protect import CustomCheckAuthenticator
from plone.protect import protect
@protect(CustomCheckAuthenticator('a-form-related-value'))
def manage_doSomething(self, param, REQUEST=None):
pass
Since version 3, plone.protect provides automatic CSRF protection. It does this by automatically including the auth token to all internal forms when the user requesting the page is logged in.
Additionally, whenever a particular request attempts to write to the ZODB, it'll check for the existence of a correct auth token.
When you need to allow a known write on read, you've got several options.
If you've got a GET request that causes a known write on read, your first option should be to simply add a CSRF token to the URLs that result in that request. plone.protect
provides the addTokenToUrl
function for this purpose:
from plone.protect.utils import addTokenToUrl
url = addTokenToUrl(url)
You can use the safeWrite
helper function:
from plone.protect.auto import safeWrite
safeWrite(myobj, request)
Just add the IDisableCSRFProtection
interface to the current request object:
from plone.protect.interfaces import IDisableCSRFProtection
from zope.interface import alsoProvides
alsoProvides(request, IDisableCSRFProtection)
Warning! When you do this, the current request is susceptible to CSRF exploits so do any required CSRF protection manually.
plone.protect also provides, by default, clickjacking protection since version 3.0.
To protect against this attack, plone employs the use of the X-Frame-Options header. plone.protect will set the X-Frame-Options value to SAMEORIGIN
.
To customize this value, you can set it to a custom value for a custom view (e.g. self.request.response.setHeader('X-Frame-Options', 'ALLOWALL')
), override it at your proxy server, or you can set the environment variable of PLONE_X_FRAME_OPTIONS
to whatever value you'd like plone.protect to set this to globally.
You can opt out of this by making the environment variable empty.
To disable all automatic CSRF protection, set the environment variable PLONE_CSRF_DISABLED
value to true
.
WARNING! It is very dangerous to do this. Do not do this unless the zeo client with this setting is not public and you know what you are doing.
This package monkey patches a number of modules in order to better handle CSRF protection:
- Archetypes add forms, add csrf
- Zope2 object locking support
- pluggable auth csrf protection
If you are using a proxy cache in front of your site, be aware that you will need to clear the entry for ++resource++protect.js
every time you update this package or you will find issues with modals while editing content.
plone.protect
version 3 was made for Plone 5. You can use it on Plone 4 for better protection, but you will need the plone4.csrffixes
hotfix package as well. Otherwise you get needless warnings or errors. See the hotfix announcement and the hotfix page.