[APM] Allow kibana to collect APM telemetry in background task (#52917) (#54106)

* Required for elastic/kibana#50757.
Allows the kibana user to collect APM telemetry in a background task.

* removed unnecessary priviledges on `.ml-anomalies-*` for the `kibana_system` reserved role

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/security/authz/store/ReservedRolesStore.java

@@ -126,11 +126,16 @@ public class ReservedRolesStore implements BiConsumer<Set<String>, ActionListene
                                         .indices(".monitoring-*").privileges("read", "read_cross_cluster").build(),
                                 RoleDescriptor.IndicesPrivileges.builder()
                                         .indices(".management-beats").privileges("create_index", "read", "write").build(),
-                                // .apm-* is for APM's agent configuration and custom link index creation
+                                // APM agent configuration
                                 RoleDescriptor.IndicesPrivileges.builder()
                                         .indices(".apm-agent-configuration").privileges("all").build(),
+                                // APM custom link index creation
                                 RoleDescriptor.IndicesPrivileges.builder()
                                         .indices(".apm-custom-link").privileges("all").build(),
+                                // APM telemetry queries APM indices in kibana task runner
+                                RoleDescriptor.IndicesPrivileges.builder()
+                                    .indices("apm-*")
+                                    .privileges("read", "read_cross_cluster").build(),
                         },
                         null,
                         new ConfigurableClusterPrivilege[] { new ManageApplicationPrivileges(Collections.singleton("kibana-*")) },

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/security/authz/store/ReservedRolesStoreTests.java

@@ -402,6 +402,22 @@ public class ReservedRolesStoreTests extends ESTestCase {
             assertThat(kibanaRole.indices().allowedIndicesMatcher(READ_CROSS_CLUSTER_NAME).test(index), is(true));
         });
 
+        // read-only indices for APM telemetry
+        Arrays.asList("apm-*").forEach((index) -> {
+            assertThat(kibanaRole.indices().allowedIndicesMatcher("indices:foo").test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher("indices:bar").test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(DeleteIndexAction.NAME).test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(GetIndexAction.NAME).test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(CreateIndexAction.NAME).test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(IndexAction.NAME).test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(DeleteAction.NAME).test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(UpdateSettingsAction.NAME).test(index), is(false));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(SearchAction.NAME).test(index), is(true));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(MultiSearchAction.NAME).test(index), is(true));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(GetAction.NAME).test(index), is(true));
+            assertThat(kibanaRole.indices().allowedIndicesMatcher(READ_CROSS_CLUSTER_NAME).test(index), is(true));
+        });
+
         // Beats management index
         final String index = ".management-beats";
         assertThat(kibanaRole.indices().allowedIndicesMatcher("indices:foo").test(index), is(false));