Update system grant policies for system admin

This commit updates the policies for adding and removing system
assignments from users to be consistent with other system-scoped
policies.

 - domain user test coverage
 - project user test coverage

Change-Id: Ia24a81669477ca5c737d0dedefac0c8fb0edc51a
Related-Bug: 1805368
Related-Bug: 1750669
Related-Bug: 1806762
(cherry picked from commit 8f4e179c69)

keystone/common/policies/grant.py

@@ -23,6 +23,14 @@ deprecated_list_system_grants_for_user = policy.DeprecatedRule(
     name=base.IDENTITY % 'list_system_grants_for_user',
     check_str=base.RULE_ADMIN_REQUIRED
 )
+deprecated_create_system_grant_for_user = policy.DeprecatedRule(
+    name=base.IDENTITY % 'create_system_grant_for_user',
+    check_str=base.RULE_ADMIN_REQUIRED
+)
+deprecated_revoke_system_grant_for_user = policy.DeprecatedRule(
+    name=base.IDENTITY % 'revoke_system_grant_for_user',
+    check_str=base.RULE_ADMIN_REQUIRED
+)
 
 DEPRECATED_REASON = """
 As of the Stein release, the system assignment API now understands default
@@ -163,7 +171,7 @@ grant_policies = [
     ),
     policy.DocumentedRuleDefault(
         name=base.IDENTITY % 'create_system_grant_for_user',
-        check_str=base.RULE_ADMIN_REQUIRED,
+        check_str=base.SYSTEM_ADMIN,
         scope_types=['system'],
         description='Grant a user a role on the system.',
         operations=[
@@ -171,11 +179,14 @@ grant_policies = [
                 'path': '/v3/system/users/{user_id}/roles/{role_id}',
                 'method': ['PUT']
             }
-        ]
+        ],
+        deprecated_rule=deprecated_create_system_grant_for_user,
+        deprecated_reason=DEPRECATED_REASON,
+        deprecated_since=versionutils.deprecated.STEIN
     ),
     policy.DocumentedRuleDefault(
         name=base.IDENTITY % 'revoke_system_grant_for_user',
-        check_str=base.RULE_ADMIN_REQUIRED,
+        check_str=base.SYSTEM_ADMIN,
         scope_types=['system'],
         description='Remove a role from a user on the system.',
         operations=[
@@ -183,7 +194,10 @@ grant_policies = [
                 'path': '/v3/system/users/{user_id}/roles/{role_id}',
                 'method': ['DELETE']
             }
-        ]
+        ],
+        deprecated_rule=deprecated_revoke_system_grant_for_user,
+        deprecated_reason=DEPRECATED_REASON,
+        deprecated_since=versionutils.deprecated.STEIN
     ),
     policy.DocumentedRuleDefault(
         name=base.IDENTITY % 'list_system_grants_for_group',

keystone/tests/unit/protection/v3/test_system_assignments.py

@@ -168,3 +168,57 @@ class SystemMemberTests(base_classes.TestCaseWithBootstrap,
             r = c.post('/v3/auth/tokens', json=auth)
             self.token_id = r.headers['X-Subject-Token']
             self.headers = {'X-Auth-Token': self.token_id}
+
+
+class SystemAdminTests(base_classes.TestCaseWithBootstrap,
+                       common_auth.AuthTestMixin,
+                       _SystemUserSystemAssignmentTests):
+
+    def setUp(self):
+        super(SystemAdminTests, self).setUp()
+        self.loadapp()
+        self.useFixture(ksfixtures.Policy(self.config_fixture))
+        self.config_fixture.config(group='oslo_policy', enforce_scope=True)
+
+        self.user_id = self.bootstrapper.admin_user_id
+        self.expected = []
+
+        auth = self.build_authentication_request(
+            user_id=self.user_id, password=self.bootstrapper.admin_password,
+            system=True
+        )
+
+        # Grab a token using the persona we're testing and prepare headers
+        # for requests we'll be making in the tests.
+        with self.test_client() as c:
+            r = c.post('/v3/auth/tokens', json=auth)
+            self.token_id = r.headers['X-Subject-Token']
+            self.headers = {'X-Auth-Token': self.token_id}
+
+    def test_user_can_grant_system_assignments(self):
+        user = PROVIDERS.identity_api.create_user(
+            unit.new_user_ref(CONF.identity.default_domain_id)
+        )
+
+        with self.test_client() as c:
+            c.put(
+                '/v3/system/users/%s/roles/%s' % (
+                    user['id'], self.bootstrapper.member_role_id
+                ), headers=self.headers,
+            )
+
+    def test_user_can_revoke_system_assignments(self):
+        user = PROVIDERS.identity_api.create_user(
+            unit.new_user_ref(CONF.identity.default_domain_id)
+        )
+
+        PROVIDERS.assignment_api.create_system_grant_for_user(
+            user['id'], self.bootstrapper.member_role_id
+        )
+
+        with self.test_client() as c:
+            c.delete(
+                '/v3/system/users/%s/roles/%s' % (
+                    user['id'], self.bootstrapper.member_role_id
+                ), headers=self.headers
+            )