From f014ca46bcf6e6fd6250f0e3e72ed0fa1b734f8d Mon Sep 17 00:00:00 2001
From: Milton Hultgren <milton.hultgren@elastic.co>
Date: Thu, 15 Sep 2022 11:36:11 +0100
Subject: [PATCH] [Stack Monitoring] Verify remote cluster client role when CCS
 is enabled (#140738)

* [Stack Monitoring] Verify remote cluster client role when CCS is enabled (#129546)

* Only show UI hint if CCS is enabled

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>
---
 .../contexts/external_config_context.tsx      |  1 +
 .../application/pages/access_denied/index.tsx | 12 ++++++-
 x-pack/plugins/monitoring/public/plugin.ts    |  1 +
 .../server/lib/errors/auth_errors.ts          | 13 ++++++--
 .../api/v1/check_access/check_access.ts       | 33 +++++++++++++++++++
 5 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/x-pack/plugins/monitoring/public/application/contexts/external_config_context.tsx b/x-pack/plugins/monitoring/public/application/contexts/external_config_context.tsx
index 805a39e2bf69e..e86262defb65e 100644
--- a/x-pack/plugins/monitoring/public/application/contexts/external_config_context.tsx
+++ b/x-pack/plugins/monitoring/public/application/contexts/external_config_context.tsx
@@ -13,6 +13,7 @@ export interface ExternalConfig {
   showCgroupMetricsLogstash: boolean;
   renderReactApp: boolean;
   staleStatusThresholdSeconds: number;
+  isCcsEnabled: boolean;
 }
 
 export const ExternalConfigContext = createContext({} as ExternalConfig);
diff --git a/x-pack/plugins/monitoring/public/application/pages/access_denied/index.tsx b/x-pack/plugins/monitoring/public/application/pages/access_denied/index.tsx
index 80c2839131047..363225cedf7dd 100644
--- a/x-pack/plugins/monitoring/public/application/pages/access_denied/index.tsx
+++ b/x-pack/plugins/monitoring/public/application/pages/access_denied/index.tsx
@@ -5,7 +5,7 @@
  * 2.0.
  */
 
-import React, { useState } from 'react';
+import React, { useContext, useState } from 'react';
 import { i18n } from '@kbn/i18n';
 import { FormattedMessage } from '@kbn/i18n-react';
 import { EuiPanel, EuiCallOut, EuiButton } from '@elastic/eui';
@@ -14,8 +14,10 @@ import { Redirect } from 'react-router-dom';
 import { useKibana } from '@kbn/kibana-react-plugin/public';
 import { ComponentProps } from '../../route_init';
 import { MonitoringStartPluginDependencies } from '../../../types';
+import { ExternalConfigContext } from '../../contexts/external_config_context';
 
 export const AccessDeniedPage: React.FC<ComponentProps> = () => {
+  const { isCcsEnabled } = useContext(ExternalConfigContext);
   const { services } = useKibana<MonitoringStartPluginDependencies>();
   const [hasAccess, setHasAccess] = useState<boolean>(false);
 
@@ -62,6 +64,14 @@ export const AccessDeniedPage: React.FC<ComponentProps> = () => {
         the monitoring cluster."
           />
         </p>
+        {isCcsEnabled && (
+          <p>
+            <FormattedMessage
+              id="xpack.monitoring.accessDenied.noRemoteClusterClientDescription"
+              defaultMessage="Since Cross Cluster Search is enabled (`monitoring.ui.ccs.enabled` is set to `true`), make sure your cluster has the `remote_cluster_client` role on at least one node."
+            />
+          </p>
+        )}
         <p>
           <EuiButton href="../app/home">
             <FormattedMessage
diff --git a/x-pack/plugins/monitoring/public/plugin.ts b/x-pack/plugins/monitoring/public/plugin.ts
index a7f017c42039c..a6b9f6549d390 100644
--- a/x-pack/plugins/monitoring/public/plugin.ts
+++ b/x-pack/plugins/monitoring/public/plugin.ts
@@ -149,6 +149,7 @@ export class MonitoringPlugin
         'staleStatusThresholdSeconds',
         monitoring.ui.kibana.reporting.stale_status_threshold_seconds,
       ],
+      ['isCcsEnabled', monitoring.ui.ccs.enabled],
     ];
   }
 
diff --git a/x-pack/plugins/monitoring/server/lib/errors/auth_errors.ts b/x-pack/plugins/monitoring/server/lib/errors/auth_errors.ts
index 55fdfee850a5e..6589b1f33249e 100644
--- a/x-pack/plugins/monitoring/server/lib/errors/auth_errors.ts
+++ b/x-pack/plugins/monitoring/server/lib/errors/auth_errors.ts
@@ -9,6 +9,7 @@ import { forbidden } from '@hapi/boom';
 import { i18n } from '@kbn/i18n';
 import { getStatusCode } from './handle_error';
 import { ErrorTypes } from '../../types';
+import { NO_REMOTE_CLIENT_ROLE_ERROR } from '../../routes/api/v1/check_access/check_access';
 
 export function isAuthError(err: ErrorTypes) {
   const statusCode = getStatusCode(err);
@@ -30,9 +31,15 @@ export function handleAuthError(err: ErrorTypes) {
       defaultMessage: 'Invalid authentication for monitoring cluster',
     });
   } else {
-    message = i18n.translate('xpack.monitoring.errors.insufficientUserErrorMessage', {
-      defaultMessage: 'Insufficient user permissions for monitoring data',
-    });
+    if (err.message === NO_REMOTE_CLIENT_ROLE_ERROR) {
+      message = i18n.translate('xpack.monitoring.errors.noRemoteClientRoleErrorMessage', {
+        defaultMessage: 'Cluster has no remote_cluster_client role',
+      });
+    } else {
+      message = i18n.translate('xpack.monitoring.errors.insufficientUserErrorMessage', {
+        defaultMessage: 'Insufficient user permissions for monitoring data',
+      });
+    }
   }
 
   return forbidden(message);
diff --git a/x-pack/plugins/monitoring/server/routes/api/v1/check_access/check_access.ts b/x-pack/plugins/monitoring/server/routes/api/v1/check_access/check_access.ts
index 2db7481882b89..d1688bfbb087a 100644
--- a/x-pack/plugins/monitoring/server/routes/api/v1/check_access/check_access.ts
+++ b/x-pack/plugins/monitoring/server/routes/api/v1/check_access/check_access.ts
@@ -5,6 +5,7 @@
  * 2.0.
  */
 
+import Boom from '@hapi/boom';
 import { verifyMonitoringAuth } from '../../../../lib/elasticsearch/verify_monitoring_auth';
 import { handleError } from '../../../../lib/errors';
 import { LegacyRequest, MonitoringCore } from '../../../../types';
@@ -24,6 +25,11 @@ export function checkAccessRoute(server: MonitoringCore) {
       const response: { has_access?: boolean } = {};
       try {
         await verifyMonitoringAuth(req);
+
+        if (server.config.ui.ccs.enabled) {
+          await verifyClusterHasRemoteClusterClientRole(req);
+        }
+
         response.has_access = true; // response data is ignored
       } catch (err) {
         throw handleError(err, req);
@@ -32,3 +38,30 @@ export function checkAccessRoute(server: MonitoringCore) {
     },
   });
 }
+
+interface NodesResponse {
+  nodes: {
+    [uuid: string]: {
+      roles: string[];
+    };
+  };
+}
+
+export const NO_REMOTE_CLIENT_ROLE_ERROR = 'Cluster has no remote_cluster_client role';
+
+async function verifyClusterHasRemoteClusterClientRole(req: LegacyRequest) {
+  const { callWithRequest } = req.server.plugins.elasticsearch.getCluster('monitoring');
+
+  const response: NodesResponse = await callWithRequest(req, 'transport.request', {
+    method: 'GET',
+    path: '/_nodes',
+  });
+
+  for (const node of Object.values(response.nodes)) {
+    if (node.roles.includes('remote_cluster_client')) {
+      return;
+    }
+  }
+
+  throw Boom.forbidden(NO_REMOTE_CLIENT_ROLE_ERROR);
+}