[ZDP] BackTalk to Document Zope Developer's Guide (2.4 edition)/Security

[nobody@nowhere.com]

A comment to the paragraph below was recently added via http://www.zope.org/Documentation/Books/ZDG/current/Security.stx#2-53

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    Zope security is based upon roles and permissions. Users have
    roles. Security policies map permissions to roles. Classes
    protect methods with permissions. As a developer you main job is
    to protect your classes by associating methods with
    permissions. Of course there are many other details such as
    protecting modules and functions, creating security user
    interfaces, and initializing security settings.

      % Anonymous User - Jan. 4, 2002 4:14 pm - This from Dieter Maurer --    The basic security mechanism uses the attribute "m__roles__" in order  to protect "m". If this attribute it "None", then "m" is public.  Otherwise, it is expected to be a sequence of roles that are allowed  to use "m".    But, "ExtensionsClass" brings with it computed attributes. This allows  "m__roles__" to be not a sequence but a method returning a sequence.  When you protect "m" with a permission "p", then  "m__roles__" is set to "PermissionRole(p)". This instance dynamically  evaluates into a sequence of roles by crawling up the "aq_container"  (which is correctly "aq_parent" after "aq_inner") chain and translating  "p" into roles by interpreting the "permission-to-role" mapping  it finds on its way to the application object.    Therefore, "declarePublic" works for non-wrapped instances while  "declareProtected" requires the wrapping.

      % Anonymous User - May 3, 2002 4:47 am:
       From Julian Munoz -- I don't find any reference to security and object properties.

      % d.maurer - Aug. 22, 2002 4:04 am:
       I would like to learn details about __guarded_getattr__,
       __guarded_setattr__ and friends.

       What is their semantics?

       Are they expected to do their own security checks (I
       expect a "yes" to this question)?

       Is it usually safe to implement "__guarded_getattr__"
       by:

         result= getattr(self,key)
         if not getSecurityManager().validate(accessed=self,
                                              name=key,
                                              value= result)
           raise 'Unauthorized', attr
         return result

      % d.maurer - Aug. 22, 2002 4:29 am:
       I would like to learn about the details of
       "validate", at least for the ZopeSecurityPolicy.

       What precisely are "accessed" and "container".

       "ZopeSecurityPolicy.validate" contains several
       mysterious instances of

               if accessedbase is containerbase:
                  raise Unauthorized

       What is the purpose for this. I cannot understand
       the accompanying comment.

       Why does it not "return 0" but raises "Unauthorizred"?

       What about a succint semantics for
       "ZopeSecurityPolicy.validate". It should describe
       when the function returns "1", "0" and raises an
       exception.