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__doc__='''Define Zope\'s default security policy


$Id: pZopeSecurityPolicy.py,v 1.1 2001/08/08 15:57:49 matt Exp $'''
__version__='$Revision: 1.1 $'[11:-2]

from types import StringType

import SimpleObjectPolicies
from AccessControl import Unauthorized
_noroles=SimpleObjectPolicies._noroles
from zLOG import LOG, PROBLEM
from Acquisition import aq_base

from PermissionRole import _what_not_even_god_should_do, rolesForPermissionOn


class ZopeSecurityPolicy:
    
    def validate(self, accessed, container, name, value, context,
                 roles=_noroles, None=None, type=type, IntType=type(0),
                 DictType=type({}), getattr=getattr, _noroles=_noroles,
                 StringType=type(''),
                 Containers=SimpleObjectPolicies.Containers,
                 valid_aq_=('aq_parent','aq_explicit')):


        ############################################################
        # Provide special rules for the acquisition attributes
        if type(name) is StringType:
            if name[:3]=='aq_' and name not in valid_aq_:
                return 0

        containerbase = aq_base(container)
        accessedbase=getattr(accessed, 'aq_base', container)

        ############################################################
        # If roles weren't passed in, we'll try to get them from the object

        if roles is _noroles:
            roles=getattr(value, '__roles__', _noroles)

        ############################################################
        # We still might not have any roles

        if roles is _noroles:

            ############################################################
            # We have an object without roles and we didn't get a list
            # of roles passed in. Presumably, the value is some simple
            # object like a string or a list.  We'll try to get roles
            # from its container.
            if container is None: return 0 # Bail if no container

            roles=getattr(container, '__roles__', _noroles)
            if roles is _noroles:
                aq=getattr(container, 'aq_acquire', None)
                if aq is None:
                    roles=_noroles
                    if containerbase is not accessedbase: return 0
                else:
                    # Try to acquire roles
                    try: roles=aq('__roles__')
                    except AttributeError:
                        roles=_noroles
                        if containerbase is not accessedbase: return 0

            # We need to make sure that we are allowed to
            # get unprotected attributes from the container. We are
            # allowed for certain simple containers and if the
            # container says we can. Simple containers
            # may also impose name restrictions.
            p=Containers(type(container), None)
            if p is None:
                p=getattr(container,
                          '__allow_access_to_unprotected_subobjects__', None)

            if p is not None:
                tp=type(p)
                if tp is not IntType:
                    if tp is DictType:
                        p=p.get(name, None)
                    else:
                        p=p(name, value)

            if not p:
                if (containerbase is accessedbase):
                    raise Unauthorized, cleanupName(name, value)
                else:
                    return 0
                        
            if roles is _noroles: return 1

            # We are going to need a security-aware object to pass
            # to allowed(). We'll use the container.
            value=container

        # Short-circuit tests if we can:
        try:
            if roles is None or 'Anonymous' in roles: return 1
        except TypeError:
            # 'roles' isn't a sequence
            LOG('Zope Security Policy', PROBLEM, "'%s' passed as roles"
                " during validation of '%s' is not a sequence." % (
                `roles`, name))
            raise

        # Check executable security
        stack=context.stack
        if stack:
            eo=stack[-1]

            # If the executable had an owner, can it execute?
            owner=eo.getOwner()
            if (owner is not None) and not owner.allowed(value, roles):
                # We don't want someone to acquire if they can't
                # get an unacquired!
                if accessedbase is containerbase:
                    raise Unauthorized, (
                        'You are not authorized to access <em>%s</em>.' \
                        % cleanupName(name, value))
                return 0

            # Proxy roles, which are a lot safer now.
            proxy_roles=getattr(eo, '_proxy_roles', None)
            if proxy_roles:
                for r in proxy_roles:
                    if r in roles: return 1
                    
                # Proxy roles actually limit access!
                if accessedbase is containerbase:
                    raise Unauthorized, (
                        'You are not authorized to access <em>%s</em>.' \
                        % cleanupName(name, value))
                
                return 0
                

        try:
            if context.user.allowed(value, roles): return 1
        except AttributeError: pass

        # We don't want someone to acquire if they can't get an unacquired!
        if accessedbase is containerbase:
            raise Unauthorized, (
                'You are not authorized to access <em>%s</em>.' \
                % cleanupName(name, value))

        return 0

    def checkPermission(self, permission, object, context):
        roles=rolesForPermissionOn(permission, object)
        if type(roles) is StringType:
            roles=[roles]
        return context.user.allowed(object, roles)
    

def cleanupName(name, value):
    # If name is not available, tries to get it from the value.
    _name = name
    if _name is None and value is not None:
        try: _name = value.id
        except:
            try: _name = value.__name__
            except: pass
        if callable(_name):
            try: _name = _name()
            except: pass
    return _name
