zope.securitypolicy 3.6.1

Global grants

Grants 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 prinroleG

And 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)
True

Local versus global grants

We, of course, acquire global grants by default:

>>> interaction.checkPermission('P1G', ob)
False
>>> interaction.checkPermission('P2G', ob)
True
>>> interaction.checkPermission('P3G', ob)
True

Local role-based grants do not override global principal-specific denials:

>>> roleper.grantPermissionToRole('P1G', 'R1G')
>>> prinrole.assignRoleToPrincipal('R1G', 'bob')
>>> interaction.checkPermission('P1G', ob)
False

And local role-based denials don’t override global principal-grants:

>>> roleper.denyPermissionToRole('P2G', 'R1G')
>>> interaction.checkPermission('P2G', ob)
True

A local role-based deny can cancel a global role-based grant:

>>> roleper.denyPermissionToRole('P3G', 'R1G')
>>> interaction.checkPermission('P3G', ob)
False

and 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)
True

Of 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)
False

Sublocations

We can have sub-locations. A sublocation of a location is an object whose __parent__ attribute is the location:

>>> ob2 = Ob()
>>> ob2.__parent__ = ob

By 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)
True

Sublocation 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)
False

And local role-based denials don’t override their parents principal-grant:

>>> roleper2.denyPermissionToRole('P2', 'R1')
>>> interaction.checkPermission('P2', ob2)
True

A local role-based deny can cancel a parent role-based grant:

>>> roleper2.denyPermissionToRole('P3', 'R1')
>>> interaction.checkPermission('P3', ob2)
False

and 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)
True

Of 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)
False

If 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)
True

The 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)
True

and 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)
True

We’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)
False

The Anonymous role

The 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)
True

Proxies

Objects 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)
True

as 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)
True

Groups

Principals 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’s groups attribute. 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 the getPrincipal method 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
>>> class FauxPrincipals(object):
...     zope.interface.implements(IAuthentication)
...     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)
False

Now, if we grant a permission to the group:

>>> prinper.grantPermissionToPrincipal('gP1', 'g1')

We see that our principal has the permission:

>>> interaction.checkPermission('gP1', ob)
True

This works even if the group grant is global:

>>> interaction.checkPermission('gP1G', ob)
False

>>> prinperG.grantPermissionToPrincipal('gP1G', 'g1', True)

>>> interaction.checkPermission('gP1G', ob)
True

Grants are, of course, acquired:

>>> interaction.checkPermission('gP1', ob2)
True

>>> interaction.checkPermission('gP1G', ob2)
True

Inner grants can override outer grants:

>>> prinper2.denyPermissionToPrincipal('gP1', 'g1')
>>> interaction.checkPermission('gP1', ob2)
False

But principal grants always trump group grants:

>>> prinper2.grantPermissionToPrincipal('gP1', 'bob')
>>> interaction.checkPermission('gP1', ob2)
True

Groups 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)
True

Just as principal grants override group grants, group grants can override other group grants:

>>> prinper.denyPermissionToPrincipal('gP2', 'g1')
>>> interaction.checkPermission('gP2', ob2)
False

Principals 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)
True

In 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)
False

Let’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)
True

We can assign roles to groups:

>>> prinrole.assignRoleToPrincipal('gR1', 'g2')

and get permissions through the roles:

>>> roleper.grantPermissionToRole('gP4', 'gR1')
>>> interaction.checkPermission('gP4', ob2)
True

we can override role assignments to groups through subgroups:

>>> prinrole.removeRoleFromPrincipal('gR1', 'g1')
>>> prinrole.removeRoleFromPrincipal('gR1', 'g3')
>>> interaction.checkPermission('gP4', ob2)
False

and through principals:

>>> prinrole.assignRoleToPrincipal('gR1', 'bob')
>>> interaction.checkPermission('gP4', ob2)
True

We clean up the changes we made in these examples:

>>> zope.security.management.endInteraction()
>>> ignore = zope.security.management.setSecurityPolicy(oldpolicy)

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)

• Change zope.app.security dependency to the new zope.authentication package, dropping a big number of unused dependencies.

• Get rid of zope.app.testing and other testing dependencices.

• Add ZODB3 to install dependencies, because we use Persistent class. We didn’t fail before, because it was installed implicitly.

3.5.1 (2009-03-10)

• Don’t depend on the hook extra of zope.component, as we don’t need it explicitly.

• Import security settings (Allow, Deny, Unset) in the interfaces module from the zope.securitypolicy.settings, added in previous release instead of old zope.app.security.settings. The zope.app.security will be adapted to import them from zope.securitypolicy.interfaces.

• Use _z_instances instead of __instances__ for storing instances for zope.securitypolicy.settings.PermissionSetting singleton implementation, because __*__ name pattern is reserved for special names in python.

• Add security protections for the PermissionSetting.

• 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)

• Changed 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 from setup.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