[policy in code] Part 1 Base framework

This adds the basic framework for registering and using default policy
rules. Rules should be defined and returned from a module in
heat/policies/, and then added to the list in heat/policies/__init__.py.

new policy wrapers `registered_identified_stack` and
`registered_policy_enforce` has been added for policy enforcement of
registered rules with same parameter as `identified_stack` and
`policy_enforce` besides set `is_registered_policy` flag to true.
This flag will decide to use new policy framework or not.

Now we can use `tox -e genpolicy` to check and generate policy file.

Change-Id: I7a232b3ea7ce0f69a5b7ffa278ceace7a76b666f
Partially-Implements: bp policy-in-code

.gitignore

@@ -25,5 +25,8 @@ etc/heat/heat.conf.sample
 # integration tests requirements are auto-generated from stub file
 heat_integrationtests/requirements.txt
 
+# generated policy file
+etc/heat/policy.json.sample
+
 # Files created by releasenotes build
 releasenotes/build

etc/heat/heat-policy-generator.conf

@@ -0,0 +1,4 @@
+[DEFAULT]
+format = json
+namespace = heat
+output_file = etc/heat/policy.json.sample

etc/heat/policy.json

@@ -1,9 +1,4 @@
 {
-    "context_is_admin": "role:admin and is_admin_project:True",
-    "project_admin": "role:admin",
-    "deny_stack_user": "not role:heat_stack_user",
-    "deny_everybody": "!",
-
     "cloudformation:ListStacks": "rule:deny_stack_user",
     "cloudformation:CreateStack": "rule:deny_stack_user",
     "cloudformation:DescribeStacks": "rule:deny_stack_user",

heat/api/openstack/v1/util.py

@@ -22,17 +22,34 @@ def policy_enforce(handler):
     """Decorator that enforces policies.
 
     Checks the path matches the request context and enforce policy defined in
-    policy.json.
+    policy.json or in policies.
 
     This is a handler method decorator.
     """
+    return _policy_enforce(handler)
+
+
+def registered_policy_enforce(handler):
+    """Decorator that enforces policies.
+
+    Checks the path matches the request context and enforce policy defined in
+    policies.
+
+    This is a handler method decorator.
+    """
+    return _policy_enforce(handler, is_registered_policy=True)
+
+
+def _policy_enforce(handler, is_registered_policy=False):
     @six.wraps(handler)
     def handle_stack_method(controller, req, tenant_id, **kwargs):
         if req.context.tenant_id != tenant_id and not req.context.is_admin:
             raise exc.HTTPForbidden()
-        allowed = req.context.policy.enforce(context=req.context,
-                                             action=handler.__name__,
-                                             scope=controller.REQUEST_SCOPE)
+        allowed = req.context.policy.enforce(
+            context=req.context,
+            action=handler.__name__,
+            scope=controller.REQUEST_SCOPE,
+            is_registered_policy=is_registered_policy)
         if not allowed:
             raise exc.HTTPForbidden()
         return handler(controller, req, **kwargs)
@@ -45,7 +62,21 @@ def identified_stack(handler):
 
     This is a handler method decorator.
     """
-    @policy_enforce
+
+    return _identified_stack(handler)
+
+
+def registered_identified_stack(handler):
+    """Decorator that passes a stack identifier instead of path components.
+
+    This is a handler method decorator.
+    """
+
+    return _identified_stack(handler, is_registered_policy=True)
+
+
+def _identified_stack(handler, is_registered_policy=False):
+
     @six.wraps(handler)
     def handle_stack_method(controller, req, stack_name, stack_id, **kwargs):
         stack_identity = identifier.HeatIdentifier(req.context.tenant_id,
@@ -53,7 +84,8 @@ def identified_stack(handler):
                                                    stack_id)
         return handler(controller, req, dict(stack_identity), **kwargs)
 
-    return handle_stack_method
+    return _policy_enforce(handle_stack_method,
+                           is_registered_policy=is_registered_policy)
 
 
 def make_url(req, identity):

heat/common/policy.py

@@ -20,9 +20,12 @@
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_policy import policy
+from oslo_utils import excutils
 import six
 
 from heat.common import exception
+from heat.common.i18n import _
+from heat import policies
 
 
 CONF = cfg.CONF
@@ -45,6 +48,9 @@ class Enforcer(object):
         self.enforcer = policy.Enforcer(
             CONF, default_rule=default_rule, policy_file=policy_file)
 
+        # register rules
+        self.enforcer.register_defaults(policies.list_rules())
+
     def set_rules(self, rules, overwrite=True):
         """Create a new Rules object based on the provided dict of rules."""
         rules_obj = policy.Rules(rules, self.default_rule)
@@ -54,7 +60,8 @@ class Enforcer(object):
         """Set the rules found in the json file on disk."""
         self.enforcer.load_rules(force_reload)
 
-    def _check(self, context, rule, target, exc, *args, **kwargs):
+    def _check(self, context, rule, target, exc,
+               is_registered_policy=False, *args, **kwargs):
         """Verifies that the action is valid on the target in this context.
 
            :param context: Heat request context
@@ -65,10 +72,20 @@ class Enforcer(object):
         """
         do_raise = False if not exc else True
         credentials = context.to_policy_values()
-        return self.enforcer.enforce(rule, target, credentials,
-                                     do_raise, exc=exc, *args, **kwargs)
-
-    def enforce(self, context, action, scope=None, target=None):
+        if is_registered_policy:
+            try:
+                return self.enforcer.authorize(rule, target, credentials,
+                                               do_raise=do_raise,
+                                               exc=exc, action=rule)
+            except policy.PolicyNotRegistered:
+                with excutils.save_and_reraise_exception():
+                    LOG.exception(_('Policy not registered.'))
+        else:
+            return self.enforcer.enforce(rule, target, credentials,
+                                         do_raise, exc=exc, *args, **kwargs)
+
+    def enforce(self, context, action, scope=None, target=None,
+                is_registered_policy=False):
         """Verifies that the action is valid on the target in this context.
 
            :param context: Heat request context
@@ -79,10 +96,11 @@ class Enforcer(object):
         """
         _action = '%s:%s' % (scope or self.scope, action)
         _target = target or {}
-        return self._check(context, _action, _target, self.exc, action=action)
+        return self._check(context, _action, _target, self.exc, action=action,
+                           is_registered_policy=is_registered_policy)
 
     def check_is_admin(self, context):
-        """Whether or not is admin according to policy.json.
+        """Whether or not is admin according to policy.
 
         By default the rule will check whether or not roles contains
         'admin' role and is admin project.

heat/policies/__init__.py

@@ -0,0 +1,22 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+import itertools
+
+from heat.policies import base
+
+
+def list_rules():
+    return itertools.chain(
+        base.list_rules(),
+    )

heat/policies/base.py

@@ -0,0 +1,48 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_policy import policy
+
+RULE_CONTEXT_IS_ADMIN = 'rule:context_is_admin'
+RULE_PROJECT_ADMIN = 'rule:project_admin'
+RULE_DENY_STACK_USER = 'rule:deny_stack_user'
+RULE_DENY_EVERYBODY = 'rule:deny_everybody'
+RULE_ALLOW_EVERYBODY = 'rule:allow_everybody'
+
+
+rules = [
+    policy.RuleDefault(
+        name="context_is_admin",
+        check_str="role:admin and is_admin_project:True",
+        description="Decides what is required for the 'is_admin:True' check "
+        "to succeed."),
+    policy.RuleDefault(
+        name="project_admin",
+        check_str="role:admin",
+        description="Default rule for project admin."),
+    policy.RuleDefault(
+        name="deny_stack_user",
+        check_str="not role:heat_stack_user",
+        description="Default rule for deny stack user."),
+    policy.RuleDefault(
+        name="deny_everybody",
+        check_str="!",
+        description="Default rule for deny everybody."),
+    policy.RuleDefault(
+        name="allow_everybody",
+        check_str="",
+        description="Default rule for allow everybody.")
+]
+
+
+def list_rules():
+    return rules

heat/tests/api/openstack_v1/test_stacks.py

@@ -473,6 +473,7 @@ class StackControllerTest(tools.ControllerTest, common.HeatTestCase):
         self.controller.index(req, tenant_id=self.tenant)
         mock_enforce.assert_called_with(action='global_index',
                                         scope=self.controller.REQUEST_SCOPE,
+                                        is_registered_policy=False,
                                         context=self.context)
 
     def test_global_index_uses_admin_context(self, mock_enforce):

heat/tests/api/openstack_v1/tools.py

@@ -11,6 +11,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import mock
 from oslo_config import cfg
 from oslo_log import log
 from oslo_messaging._drivers import common as rpc_common
@@ -117,7 +118,9 @@ class ControllerTest(object):
             self.mock_enforce.assert_called_with(
                 action=self.action,
                 context=self.context,
-                scope=self.controller.REQUEST_SCOPE)
+                scope=self.controller.REQUEST_SCOPE,
+                is_registered_policy=mock.ANY
+            )
             self.assertEqual(self.expected_request_count,
                              len(self.mock_enforce.call_args_list))
         super(ControllerTest, self).tearDown()

setup.cfg

@@ -63,6 +63,9 @@ oslo.config.opts =
 oslo.config.opts.defaults =
     heat.common.config = heat.common.config:set_config_defaults
 
+oslo.policy.policies =
+    heat = heat.policies:list_rules
+
 heat.clients =
     aodh = heat.engine.clients.os.aodh:AodhClientPlugin
     barbican = heat.engine.clients.os.barbican:BarbicanClientPlugin

tox.ini

@@ -72,6 +72,10 @@ commands =
 commands =
     oslo-config-generator --config-file=config-generator.conf
 
+[testenv:genpolicy]
+commands =
+    oslopolicy-sample-generator --config-file etc/heat/heat-policy-generator.conf
+
 [testenv:bandit]
 deps = -r{toxinidir}/test-requirements.txt
 # The following bandit tests are being skipped: