Package: zope.securitypolicy
zope.securitypolicyThis package provides an useful security policy for Zope3. It’s the
default security policy used in “zope3 the application” and many other
zope-based projects.Classic Zope Security PolicyThis package implements a role-based security policy similar to the
policy found in Zope 2.  The security policy is responsible for
deciding whether an interaction has a permission on an object.  This
security policy does this using grant and denial information.  Managers
can grant or deny:roles to principals,permissions to principals, andpermissions to rolesGrants and denials are stored as annotations on objects.  To store
grants and denials, objects must be annotatable:>>> import zope.interface
>>> from zope.annotation.interfaces import IAttributeAnnotatable
>>> @zope.interface.implementer(IAttributeAnnotatable)
... class Ob:
...     pass>>> ob = Ob()We use objects to represent principals.  These objects implement an
interface namedIPrincipal, but the security policy only uses theidandgroupsattributes:>>> class Principal:
...     def __init__(self, id):
...         self.id = id
...         self.groups = []>>> principal = Principal('bob')Roles and permissions are also represented by objects, however, for
the purposes of the security policy, only stringidsare used.The security policy provides a factory for creating interactions:>>> import zope.securitypolicy.zopepolicy
>>> interaction = zope.securitypolicy.zopepolicy.ZopeSecurityPolicy()An interaction represents a specific interaction between some
principals (normally users) and the system.  Normally, we are only
concerned with the interaction of one principal with the system, although
we can have interactions of multiple principals.  Multiple-principal
interactions normally occur when untrusted users store code on a
system for later execution.  When untrusted code is executing, the
authors of the code participate in the interaction.  An
interaction has a permission on an object only if all of the
principals participating in the interaction have access to the object.ThecheckPermissionmethod on interactions is used to test whether
an interaction has a permission for an object.  An interaction without
participants always has every permission:>>> interaction.checkPermission('P1', ob)
TrueIn this example, ‘P1’ is a permission id.Normally, interactions have participants:>>> class Participation:
...     interaction = None
>>> participation = Participation()
>>> participation.principal = principal
>>> interaction.add(participation)If we have participants, then we don’t have a permission unless there
are grants:>>> interaction.checkPermission('P1', ob)
FalseNote, however, that we always have the CheckerPublic permission:>>> from zope.security.checker import CheckerPublic
>>> interaction.checkPermission(CheckerPublic, ob)
TrueWe make grants and denials on objects by adapting them to various
granting interfaces.  The objects returned from the adaptation are
object-specific manager objects:>>> from zope.securitypolicy import interfaces
>>> roleper  = interfaces.IRolePermissionManager(ob)
>>> prinrole = interfaces.IPrincipalRoleManager(ob)
>>> prinper  = interfaces.IPrincipalPermissionManager(ob)The computations involved in checking permissions can be
significant. To reduce the computational cost, caching is used
extensively. We could invalidate the cache as we make grants, but the
adapters for making grants will automatically invalidate the cache of
the current interaction.  They use the security-management apis to do
this. To take advantage of the cache invalidation, we’ll need to let
the security-management system manage our interactions.  First, we’ll
set our security policy as the default:>>> import zope.security.management
>>> oldpolicy = zope.security.management.setSecurityPolicy(
...      zope.securitypolicy.zopepolicy.ZopeSecurityPolicy)and then we’ll create a new interaction:>>> participation = Participation()
>>> participation.principal = principal
>>> zope.security.management.newInteraction(participation)
>>> interaction = zope.security.management.getInteraction()We normally provide access by granting permissions to roles for an object:>>> roleper.grantPermissionToRole('P1', 'R1')and then granting roles to principals for an object (local roles):>>> prinrole.assignRoleToPrincipal('R1', 'bob')The combination of these grants, which we call a role-based grant,
provides the permission:>>> interaction.checkPermission('P1', ob)
TrueWe can also provide a permission directly:>>> prinper.grantPermissionToPrincipal('P2', 'bob')
>>> interaction.checkPermission('P2', ob)
TruePermission grants or denials override role-based grant or denials.  So
if we deny P1:>>> prinper.denyPermissionToPrincipal('P1', 'bob')we cause the interaction to lack the permission, despite the role
grants:>>> interaction.checkPermission('P1', ob)
FalseSimilarly, even if we have a role-based denial of P2:>>> roleper.denyPermissionToRole('P2', 'R1')we still have access, because of the permission-based grant:>>> interaction.checkPermission('P2', ob)
TrueA role-based denial doesn’t actually deny a permission; rather it
prevents the granting of a permission. So, if we have both grants and
denials based on roles, we have access:>>> roleper.grantPermissionToRole('P3', 'R1')
>>> roleper.grantPermissionToRole('P3', 'R2')
>>> roleper.denyPermissionToRole('P3', 'R3')
>>> prinrole.removeRoleFromPrincipal('R2', 'bob')
>>> prinrole.assignRoleToPrincipal('R3', 'bob')>>> interaction.checkPermission('P3', ob)
TrueGlobal grantsGrants made to an object are said to be “local”.  We can also make
global grants:>>> from zope.securitypolicy.rolepermission import \
...     rolePermissionManager as roleperG
>>> from zope.securitypolicy.principalpermission import \
...     principalPermissionManager as prinperG
>>> from zope.securitypolicy.principalrole import \
...     principalRoleManager as prinroleGAnd the same rules apply to global grants and denials.>>> roleperG.grantPermissionToRole('P1G', 'R1G', False)In these tests, we aren’t bothering to define any roles, permissions,
or principals, so we pass an extra argument that tells the granting
routines not to check the validity of the values.>>> prinroleG.assignRoleToPrincipal('R1G', 'bob', False)
>>> interaction.checkPermission('P1G', ob)
True>>> prinperG.grantPermissionToPrincipal('P2G', 'bob', False)
>>> interaction.checkPermission('P2G', ob)
True>>> prinperG.denyPermissionToPrincipal('P1G', 'bob', False)
>>> interaction.checkPermission('P1G', ob)
False>>> roleperG.denyPermissionToRole('P2G', 'R1G', False)
>>> interaction.checkPermission('P2G', ob)
True>>> roleperG.grantPermissionToRole('P3G', 'R1G', False)
>>> roleperG.grantPermissionToRole('P3G', 'R2G', False)
>>> roleperG.denyPermissionToRole('P3G', 'R3G', False)
>>> prinroleG.removeRoleFromPrincipal('R2G', 'bob', False)
>>> prinroleG.assignRoleToPrincipal('R3G', 'bob', False)
>>> interaction.checkPermission('P3G', ob)
TrueLocal versus global grantsWe, of course, acquire global grants by default:>>> interaction.checkPermission('P1G', ob)
False
>>> interaction.checkPermission('P2G', ob)
True
>>> interaction.checkPermission('P3G', ob)
TrueLocal role-based grants do not override global principal-specific denials:>>> roleper.grantPermissionToRole('P1G', 'R1G')
>>> prinrole.assignRoleToPrincipal('R1G', 'bob')
>>> interaction.checkPermission('P1G', ob)
FalseAnd local role-based denials don’t override global
principal-grants:>>> roleper.denyPermissionToRole('P2G', 'R1G')
>>> interaction.checkPermission('P2G', ob)
TrueA local role-based deny can cancel a global role-based grant:>>> roleper.denyPermissionToRole('P3G', 'R1G')
>>> interaction.checkPermission('P3G', ob)
Falseand a local role-based grant can override a global role-based denial:>>> roleperG.denyPermissionToRole('P4G', 'R1G', False)
>>> prinroleG.assignRoleToPrincipal('R1G', "bob", False)
>>> interaction.checkPermission('P4G', ob)
False
>>> roleper.grantPermissionToRole('P4G', 'R1G')
>>> interaction.checkPermission('P4G', ob)
True
>>> prinroleG.removeRoleFromPrincipal('R1G', "bob", False)
>>> interaction.checkPermission('P4G', ob)
TrueOf course, a local permission-based grant or denial overrides any
global setting and overrides local role-based grants or denials:>>> prinper.grantPermissionToPrincipal('P3G', 'bob')
>>> interaction.checkPermission('P3G', ob)
True>>> prinper.denyPermissionToPrincipal('P2G', 'bob')
>>> interaction.checkPermission('P2G', ob)
FalseSublocationsWe can have sub-locations. A sublocation of a location is an object
whose__parent__attribute is the location:>>> ob2 = Ob()
>>> ob2.__parent__ = obBy default, sublocations acquire grants from higher locations:>>> interaction.checkPermission('P1', ob2)
False
>>> interaction.checkPermission('P2', ob2)
True
>>> interaction.checkPermission('P3', ob2)
True
>>> interaction.checkPermission('P1G', ob2)
False
>>> interaction.checkPermission('P2G', ob2)
False
>>> interaction.checkPermission('P3G', ob2)
True
>>> interaction.checkPermission('P4G', ob2)
TrueSublocation role-based grants do not override their parent
principal-specific denials:>>> roleper2  = interfaces.IRolePermissionManager(ob2)
>>> prinrole2 = interfaces.IPrincipalRoleManager(ob2)
>>> prinper2  = interfaces.IPrincipalPermissionManager(ob2)>>> roleper2.grantPermissionToRole('P1', 'R1')
>>> prinrole2.assignRoleToPrincipal('R1', 'bob')
>>> interaction.checkPermission('P1', ob2)
FalseAnd local role-based denials don’t override their parents
principal-grant:>>> roleper2.denyPermissionToRole('P2', 'R1')
>>> interaction.checkPermission('P2', ob2)
TrueA local role-based deny can cancel a parent role-based grant:>>> roleper2.denyPermissionToRole('P3', 'R1')
>>> interaction.checkPermission('P3', ob2)
Falseand a local role-based grant can override a parent role-based denial:>>> roleper.denyPermissionToRole('P4', 'R1')
>>> prinrole.assignRoleToPrincipal('R1', 'bob')
>>> interaction.checkPermission('P4', ob2)
False
>>> roleper2.grantPermissionToRole('P4', 'R1')
>>> interaction.checkPermission('P4', ob2)
True
>>> prinrole.removeRoleFromPrincipal('R1', 'bob')
>>> interaction.checkPermission('P4', ob2)
TrueOf course, a local permission-based grant or denial overrides any
global setting and overrides local role-based grants or denials:>>> prinper.grantPermissionToPrincipal('P3', 'bob')
>>> interaction.checkPermission('P3', ob2)
True>>> prinper.denyPermissionToPrincipal('P2', 'bob')
>>> interaction.checkPermission('P2', ob2)
FalseIf an object is not annotatable, but does have a parent, it will get
its grants from its parent:>>> class C:
...     pass>>> ob3 = C()
>>> ob3.__parent__ = ob>>> interaction.checkPermission('P1', ob3)
False
>>> interaction.checkPermission('P2', ob3)
False
>>> interaction.checkPermission('P3', ob3)
True
>>> interaction.checkPermission('P1G', ob3)
False
>>> interaction.checkPermission('P2G', ob3)
False
>>> interaction.checkPermission('P3G', ob3)
True
>>> interaction.checkPermission('P4G', ob3)
TrueThe same results will be had if there are multiple non-annotatable
objects:>>> ob3.__parent__ = C()
>>> ob3.__parent__.__parent__ = ob>>> interaction.checkPermission('P1', ob3)
False
>>> interaction.checkPermission('P2', ob3)
False
>>> interaction.checkPermission('P3', ob3)
True
>>> interaction.checkPermission('P1G', ob3)
False
>>> interaction.checkPermission('P2G', ob3)
False
>>> interaction.checkPermission('P3G', ob3)
True
>>> interaction.checkPermission('P4G', ob3)
Trueand if an object doesn’t have a parent:>>> ob4 = C()it will have whatever grants were made globally:>>> interaction.checkPermission('P1', ob4)
False
>>> interaction.checkPermission('P2', ob4)
False
>>> interaction.checkPermission('P3', ob4)
False
>>> interaction.checkPermission('P1G', ob4)
False
>>> interaction.checkPermission('P2G', ob4)
True
>>> interaction.checkPermission('P3G', ob4)
False
>>> interaction.checkPermission('P4G', ob4)
False>>> prinroleG.assignRoleToPrincipal('R1G', "bob", False)
>>> interaction.checkPermission('P3G', ob4)
TrueWe’ll get the same result if we have a non-annotatable parent without a
parent:>>> ob3.__parent__ = C()>>> interaction.checkPermission('P1', ob3)
False
>>> interaction.checkPermission('P2', ob3)
False
>>> interaction.checkPermission('P3', ob3)
False
>>> interaction.checkPermission('P1G', ob3)
False
>>> interaction.checkPermission('P2G', ob3)
True
>>> interaction.checkPermission('P3G', ob3)
True
>>> interaction.checkPermission('P4G', ob3)
FalseThe Anonymous roleThe security policy defines a special role named “zope.Anonymous”.  All
principals have this role and the role cannot be taken away.>>> roleperG.grantPermissionToRole('P5', 'zope.Anonymous', False)
>>> interaction.checkPermission('P5', ob2)
TrueProxiesObjects may be proxied:>>> from zope.security.checker import ProxyFactory
>>> ob = ProxyFactory(ob)
>>> interaction.checkPermission('P1', ob)
False
>>> interaction.checkPermission('P2', ob)
False
>>> interaction.checkPermission('P3', ob)
True
>>> interaction.checkPermission('P1G', ob)
False
>>> interaction.checkPermission('P2G', ob)
False
>>> interaction.checkPermission('P3G', ob)
True
>>> interaction.checkPermission('P4G', ob)
Trueas may their parents:>>> ob3 = C()
>>> ob3.__parent__ = ob>>> interaction.checkPermission('P1', ob3)
False
>>> interaction.checkPermission('P2', ob3)
False
>>> interaction.checkPermission('P3', ob3)
True
>>> interaction.checkPermission('P1G', ob3)
False
>>> interaction.checkPermission('P2G', ob3)
False
>>> interaction.checkPermission('P3G', ob3)
True
>>> interaction.checkPermission('P4G', ob3)
TrueGroupsPrincipals may have groups.  Groups are also principals (and, thus,
may have groups).If a principal has groups, the groups are available as group ids in
the principal’sgroupsattribute.  The interaction has to convert
these group ids to group objects, so that it can tell whether the
groups have groups.  It does this by calling thegetPrincipalmethod
on the principal authentication service, which is responsible for,
among other things, converting a principal id to a principal.
For our examples here, we’ll create and register a stub principal
authentication service:>>> from zope.authentication.interfaces import IAuthentication
>>> @zope.interface.implementer(IAuthentication)
... class FauxPrincipals(object):
...     def __init__(self):
...         self.data = {}
...     def __setitem__(self, key, value):
...         self.data[key] = value
...     def __getitem__(self, key):
...         return self.data[key]
...     def getPrincipal(self, id):
...         return self.data[id]>>> auth = FauxPrincipals()>>> from zope.component import provideUtility
>>> provideUtility(auth, IAuthentication)Let’s define a group:>>> auth['g1'] = Principal('g1')Let’s put the principal in our group.  We do that by adding the group id
to the new principals groups:>>> principal.groups.append('g1')Of course, the principal doesn’t have permissions not granted:>>> interaction.checkPermission('gP1', ob)
FalseNow, if we grant a permission to the group:>>> prinper.grantPermissionToPrincipal('gP1', 'g1')We see that our principal has the permission:>>> interaction.checkPermission('gP1', ob)
TrueThis works even if the group grant is global:>>> interaction.checkPermission('gP1G', ob)
False>>> prinperG.grantPermissionToPrincipal('gP1G', 'g1', True)>>> interaction.checkPermission('gP1G', ob)
TrueGrants are, of course, acquired:>>> interaction.checkPermission('gP1', ob2)
True>>> interaction.checkPermission('gP1G', ob2)
TrueInner grants can override outer grants:>>> prinper2.denyPermissionToPrincipal('gP1', 'g1')
>>> interaction.checkPermission('gP1', ob2)
FalseBut principal grants always trump group grants:>>> prinper2.grantPermissionToPrincipal('gP1', 'bob')
>>> interaction.checkPermission('gP1', ob2)
TrueGroups can have groups too:>>> auth['g2'] = Principal('g2')
>>> auth['g1'].groups.append('g2')If we grant to the new group:>>> prinper.grantPermissionToPrincipal('gP2', 'g2')Then we, of course have that permission too:>>> interaction.checkPermission('gP2', ob2)
TrueJust as principal grants override group grants, group grants can
override other group grants:>>> prinper.denyPermissionToPrincipal('gP2', 'g1')
>>> interaction.checkPermission('gP2', ob2)
FalsePrincipals can be in more than one group. Let’s define a new group:>>> auth['g3'] = Principal('g3')
>>> principal.groups.append('g3')
>>> prinper.grantPermissionToPrincipal('gP2', 'g3')Now, the principal has two groups. In one group, the permission ‘gP2’
is denied, but in the other, it is allowed.  In a case like this, the
permission is allowed:>>> interaction.checkPermission('gP2', ob2)
TrueIn a case where a principal has two or more groups, the group denies
prevent allows from their parents. They don’t prevent the principal
from getting an allow from another principal.Grants can be inherited from ancestor groups through multiple paths.
Let’s grant a permission to g2 and deny it to g1:>>> prinper.grantPermissionToPrincipal('gP3', 'g2')
>>> prinper.denyPermissionToPrincipal('gP3', 'g1')Now, as before, the deny in g1 blocks the grant in g2:>>> interaction.checkPermission('gP3', ob2)
FalseLet’s make g2 a group of g3:>>> auth['g3'].groups.append('g2')Now, we get g2’s grant through g3, and access is allowed:>>> interaction.invalidate_cache()
>>> interaction.checkPermission('gP3', ob2)
TrueWe can assign roles to groups:>>> prinrole.assignRoleToPrincipal('gR1', 'g2')and get permissions through the roles:>>> roleper.grantPermissionToRole('gP4', 'gR1')
>>> interaction.checkPermission('gP4', ob2)
Truewe can override role assignments to groups through subgroups:>>> prinrole.removeRoleFromPrincipal('gR1', 'g1')
>>> prinrole.removeRoleFromPrincipal('gR1', 'g3')
>>> interaction.checkPermission('gP4', ob2)
Falseand through principals:>>> prinrole.assignRoleToPrincipal('gR1', 'bob')
>>> interaction.checkPermission('gP4', ob2)
TrueWe clean up the changes we made in these examples:>>> zope.security.management.endInteraction()
>>> ignore = zope.security.management.setSecurityPolicy(oldpolicy)Changes5.0 (2023-02-24)Add support for Python 3.9, 3.10, 3.11.Drop support for Python 2.7, 3.5, 3.6.4.3.2 (2021-03-19)Add support for Python 3.8.Drop support for Python 3.4.Fix some test imports to use the proper imports fromzope.interfaceinstead ofzope.component.4.3.1 (2018-10-11)Use current location forIRegisteredandIUnregisteredinterface.4.3.0 (2018-08-27)Add support for Python 3.7.Drop support for Python 3.3.Drop support forpython setup.py test.MakeSecurityMapandAnnotationGrantInfohave proper truth
behaviour on Python 3; previously they were always true.MakeAnnotationGrantInfoconsistently return lists instead of
dict views on Python 3.MakeAnnotationSecurityMap(and objects derived from it, such asAnnotationPrincipalPermissionManagerand the role managers) more
efficient when adding or removing cells before they have been
persisted. They now avoid some unnecessary object copying.4.2.0 (2017-08-24)Add<zope:deny>directive, which is a mirror of the<zope:grant>directive.Add support for Python 3.6.4.1.0 (2016-11-05)Add support for Python 3.5.Drop support for Python 2.6.Add support to grant multiple permissions with one ZCML statement. Example:<grant
  role="my-role"
  permissions="zope.foo
               zope.bar" />4.0.0 (2014-12-24)Add support for PyPy.  (PyPy3 is pending release of a fix for:https://bitbucket.org/pypy/pypy/issue/1946)Add support for Python 3.4.Add support for testing on Travis.4.0.0a1 (2013-02-22)Add support for Python 3.3.Replace deprecatedzope.interface.classProvidesusage with equivalentzope.interface.providerdecorator.Replace deprecatedzope.interface.implementsusage with equivalentzope.interface.implementerdecorator.Drop support for Python 2.4 and 2.5.3.7.0 (2010-09-25)LP #131115: Clean up inconsistency ingetSettinginterface definitions
and actual usage for the various security maps.LP #564525:  fix permission moved fromzope.app.dublincorenamespace
tozope.dublincore.Remove unused imports and pep8 cleanup.Use doctest module instead of the deprecated zope.testing.doctest.AnnotationGrantInfo implements IGrantInfo.Add test extra to declare test dependency onzope.component [test].Add an extra nameddublincoreto express optional dependency onzope.dublincore >= 3.7.Add tests for ZCML files making sure they include everything they need.3.6.1 (2009-07-24)Make tests work when the default and Zope vocabulary registry compete in the
cleanup.3.6.0 (2009-03-14)Changezope.app.securitydependency to the newzope.authenticationpackage, dropping a big number of unused dependencies.Get rid ofzope.app.testingand other testing dependencices.AddZODB3to install dependencies, because we usePersistentclass. We didn’t fail before, because it was installed implicitly.3.5.1 (2009-03-10)Don’t depend on thehookextra of zope.component, as we don’t need
it explicitly.Import security settings (Allow, Deny, Unset) in theinterfacesmodule from thezope.securitypolicy.settings, added in previous
release instead of oldzope.app.security.settings.
Thezope.app.securitywill be adapted to import them fromzope.securitypolicy.interfaces.Use_z_instancesinstead of__instances__for storing instances
forzope.securitypolicy.settings.PermissionSettingsingleton
implementation, because __*__ name pattern is reserved for special
names in python.Add security protections for thePermissionSetting.Improve documentation formatting, add it to the package’s long
description.Remove unneeded dependencies.Remove old zpkg-related files and zcml slugs.3.5.0 (2009-01-31)Include settings that were previously imported from zope.app.security.3.4.2 (2009-01-28)Change mailing list address to zope-dev at zope.org. Fix package
homepage to the pypi page.Fix test in buildout which still depended on zope.app.securitypolicy
by mistake.Remove explicit dependency on zope.app.form fromsetup.py; nothing
in the code directly depends on this.3.4.1 (2008-06-02)Fix reference to deprecated security policy from ZCML.3.4.0 (2007-09-25)Initial documented release