Add exception metadata for disabled features

This change adds a new exception with consistent metadata for when
security features are not enabled. This allows clients to be able to
tell that an API failed due to a configuration option, and respond
accordingly.

Relates: kibana#55255
Resolves: elastic#52311, elastic#47759

Backport of: elastic#52811

Author: tvernum

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/ApiKeyService.java

@@ -70,6 +70,8 @@
 import org.elasticsearch.xpack.core.security.authc.support.Hasher;
 import org.elasticsearch.xpack.core.security.authz.RoleDescriptor;
 import org.elasticsearch.xpack.core.security.user.User;
+import org.elasticsearch.xpack.security.support.FeatureNotEnabledException;
+import org.elasticsearch.xpack.security.support.FeatureNotEnabledException.Feature;
 import org.elasticsearch.xpack.security.support.SecurityIndexManager;
 
 import java.io.Closeable;
@@ -586,7 +588,7 @@ private void ensureEnabled() {
             throw LicenseUtils.newComplianceException("api keys");
         }
         if (enabled == false) {
-            throw new IllegalStateException("api keys are not enabled");
+            throw new FeatureNotEnabledException(Feature.API_KEY_SERVICE, "api keys are not enabled");
         }
     }
 

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/authc/TokenService.java

@@ -89,6 +89,8 @@
 import org.elasticsearch.xpack.core.security.authc.TokenMetaData;
 import org.elasticsearch.xpack.core.security.authc.support.Hasher;
 import org.elasticsearch.xpack.core.security.authc.support.TokensInvalidationResult;
+import org.elasticsearch.xpack.security.support.FeatureNotEnabledException;
+import org.elasticsearch.xpack.security.support.FeatureNotEnabledException.Feature;
 import org.elasticsearch.xpack.security.support.SecurityIndexManager;
 
 import javax.crypto.Cipher;
@@ -1459,7 +1461,7 @@ private void ensureEnabled() {
             throw LicenseUtils.newComplianceException("security tokens");
         }
         if (enabled == false) {
-            throw new IllegalStateException("security tokens are not enabled");
+            throw new FeatureNotEnabledException(Feature.TOKEN_SERVICE, "security tokens are not enabled");
         }
     }
 

x-pack/plugin/security/src/main/java/org/elasticsearch/xpack/security/support/FeatureNotEnabledException.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+package org.elasticsearch.xpack.security.support;
+
+import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.rest.RestStatus;
+
+public class FeatureNotEnabledException extends ElasticsearchException {
+
+    public static final String DISABLED_FEATURE_METADATA = "es.disabled.feature";
+
+    /**
+     * The features names here are constants that form part of our API contract.
+     * Callers (e.g. Kibana) may be dependent on these strings. Do not change them without consideration of BWC.
+     */
+    public enum Feature {
+        TOKEN_SERVICE("security_tokens"),
+        API_KEY_SERVICE("api_keys");
+
+        private final String featureName;
+
+        Feature(String featureName) {
+            this.featureName = featureName;
+        }
+    }
+
+    public FeatureNotEnabledException(Feature feature, String message, Object... args) {
+        super(message, args);
+        addMetadata(DISABLED_FEATURE_METADATA, feature.featureName);
+    }
+
+    @Override
+    public RestStatus status() {
+        return RestStatus.BAD_REQUEST;
+    }
+}

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authc/ApiKeyServiceTests.java

@@ -6,6 +6,7 @@
 
 package org.elasticsearch.xpack.security.authc;
 
+import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.support.PlainActionFuture;
@@ -38,6 +39,7 @@
 import org.elasticsearch.xpack.security.authc.ApiKeyService.ApiKeyRoleDescriptors;
 import org.elasticsearch.xpack.security.authc.ApiKeyService.CachedApiKeyHashResult;
 import org.elasticsearch.xpack.security.authz.store.NativePrivilegeStore;
+import org.elasticsearch.xpack.security.support.FeatureNotEnabledException;
 import org.elasticsearch.xpack.security.support.SecurityIndexManager;
 import org.elasticsearch.xpack.security.test.SecurityMocks;
 import org.junit.After;
@@ -59,8 +61,10 @@
 import java.util.concurrent.Semaphore;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import static org.elasticsearch.test.TestMatchers.throwableWithMessage;
 import static org.elasticsearch.xpack.core.security.authz.store.ReservedRolesStore.SUPERUSER_ROLE_DESCRIPTOR;
 import static org.hamcrest.Matchers.arrayContaining;
+import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
@@ -435,6 +439,20 @@ public void testGetRolesForApiKey() throws Exception {
         }
     }
 
+    public void testApiKeyServiceDisabled() throws Exception {
+        final Settings settings = Settings.builder().put(XPackSettings.API_KEY_SERVICE_ENABLED_SETTING.getKey(), false).build();
+        final ApiKeyService service = createApiKeyService(settings);
+
+        ElasticsearchException e = expectThrows(ElasticsearchException.class,
+            () -> service.getApiKeys(randomAlphaOfLength(6), randomAlphaOfLength(8), null, null, new PlainActionFuture<>()));
+
+        assertThat(e, instanceOf(FeatureNotEnabledException.class));
+        // Older Kibana version looked for this exact text:
+        assertThat(e, throwableWithMessage("api keys are not enabled"));
+        // Newer Kibana versions will check the metadata for this string literal:
+        assertThat(e.getMetadata(FeatureNotEnabledException.DISABLED_FEATURE_METADATA), contains("api_keys"));
+    }
+
     public void testApiKeyCache() {
         final String apiKey = randomAlphaOfLength(16);
         Hasher hasher = randomFrom(Hasher.PBKDF2, Hasher.BCRYPT4, Hasher.BCRYPT);

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authc/TokenServiceTests.java

@@ -5,6 +5,7 @@
  */
 package org.elasticsearch.xpack.security.authc;
 
+import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ElasticsearchSecurityException;
 import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionListener;
@@ -54,6 +55,7 @@
 import org.elasticsearch.xpack.core.security.authc.support.TokensInvalidationResult;
 import org.elasticsearch.xpack.core.security.user.User;
 import org.elasticsearch.xpack.core.watcher.watch.ClockMock;
+import org.elasticsearch.xpack.security.support.FeatureNotEnabledException;
 import org.elasticsearch.xpack.security.support.SecurityIndexManager;
 import org.elasticsearch.xpack.security.test.SecurityMocks;
 import org.hamcrest.Matchers;
@@ -63,7 +65,6 @@
 import org.junit.BeforeClass;
 
 import javax.crypto.SecretKey;
-
 import java.io.IOException;
 import java.net.URLEncoder;
 import java.nio.charset.StandardCharsets;
@@ -79,8 +80,11 @@
 import static java.time.Clock.systemUTC;
 import static org.elasticsearch.repositories.blobstore.ESBlobStoreRepositoryIntegTestCase.randomBytes;
 import static org.elasticsearch.test.ClusterServiceUtils.setState;
+import static org.elasticsearch.test.TestMatchers.throwableWithMessage;
+import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.notNullValue;
 import static org.hamcrest.Matchers.nullValue;
 import static org.mockito.Matchers.any;
@@ -561,20 +565,23 @@ public void testTokenServiceDisabled() throws Exception {
                 .put(XPackSettings.TOKEN_SERVICE_ENABLED_SETTING.getKey(), false)
                 .build(),
             Clock.systemUTC(), client, licenseState, securityContext, securityMainIndex, securityTokensIndex, clusterService);
-        IllegalStateException e = expectThrows(IllegalStateException.class,
+        ElasticsearchException e = expectThrows(ElasticsearchException.class,
             () -> tokenService.createOAuth2Tokens(null, null, null, true, null));
-        assertEquals("security tokens are not enabled", e.getMessage());
+        assertThat(e, throwableWithMessage("security tokens are not enabled"));
+        assertThat(e, instanceOf(FeatureNotEnabledException.class));
+        // Client can check the metadata for this value, and depend on an exact string match:
+        assertThat(e.getMetadata(FeatureNotEnabledException.DISABLED_FEATURE_METADATA), contains("security_tokens"));
 
         PlainActionFuture<UserToken> future = new PlainActionFuture<>();
         tokenService.getAndValidateToken(null, future);
         assertNull(future.get());
 
-        e = expectThrows(IllegalStateException.class, () -> {
-            PlainActionFuture<TokensInvalidationResult> invalidateFuture = new PlainActionFuture<>();
-            tokenService.invalidateAccessToken((String) null, invalidateFuture);
-            invalidateFuture.actionGet();
-        });
-        assertEquals("security tokens are not enabled", e.getMessage());
+        PlainActionFuture<TokensInvalidationResult> invalidateFuture = new PlainActionFuture<>();
+        e = expectThrows(ElasticsearchException.class, () -> tokenService.invalidateAccessToken((String) null, invalidateFuture));
+        assertThat(e, throwableWithMessage("security tokens are not enabled"));
+        assertThat(e, instanceOf(FeatureNotEnabledException.class));
+        // Client can check the metadata for this value, and depend on an exact string match:
+        assertThat(e.getMetadata(FeatureNotEnabledException.DISABLED_FEATURE_METADATA), contains("security_tokens"));
     }
 
     public void testBytesKeyEqualsHashCode() {