Update TLS ciphers and protocols for JDK 11 (elastic#41385)

This commit updates the default ciphers and TLS protocols that are used after the minimum supported JDK is JDK 11. The conditionals around TLSv1.3 and 256-bit cipher support have been removed. JDK 11 no longer requires an unlimited JCE policy file for 256 bit cipher support and TLSv1.3 is supported in JDK 11+. New cipher support has been introduced in the newer JDK versions as well. The ciphers are ordered with PFS ciphers being most preferred, then AEAD ciphers, and finally those with mainstream hardware support.
jaymode · May 3, 2019 · 476c82d · 476c82d
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diff --git a/docs/reference/settings/security-settings.asciidoc b/docs/reference/settings/security-settings.asciidoc
@@ -513,8 +513,7 @@ and `full`. Defaults to `full`.
 See <<ssl-tls-settings,`ssl.verification_mode`>> for an explanation of these values.
 
 `ssl.supported_protocols`::
-Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.3,TLSv1.2,TLSv1.1` if
-the JVM supports TLSv1.3, otherwise `TLSv1.2,TLSv1.1`.
+Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.3,TLSv1.2,TLSv1.1`.
 
 `ssl.cipher_suites`:: Specifies the cipher suites that should be supported when 
 communicating with the LDAP server. 
@@ -765,8 +764,7 @@ and `full`. Defaults to `full`.
 See <<ssl-tls-settings,`ssl.verification_mode`>> for an explanation of these values.
 
 `ssl.supported_protocols`::
-Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.3,TLSv1.2,TLSv1.1` if
-the JVM supports TLSv1.3, otherwise `TLSv1.2,TLSv1.1`.
+Supported protocols for TLS/SSL (with versions). Defaults to `TLSv1.3,TLSv1.2,TLSv1.1`.
 
 `ssl.cipher_suites`:: Specifies the cipher suites that should be supported when 
 communicating with the Active Directory server. 
@@ -1173,8 +1171,7 @@ Defaults to `full`.
 See <<ssl-tls-settings,`ssl.verification_mode`>> for a more detailed explanation of these values.
 
 `ssl.supported_protocols`::
-Specifies the supported protocols for TLS/SSL. Defaults to `TLSv1.3,TLSv1.2,TLSv1.1` if
-the JVM supports TLSv1.3, otherwise `TLSv1.2,TLSv1.1`.
+Specifies the supported protocols for TLS/SSL. Defaults to `TLSv1.3,TLSv1.2,TLSv1.1`.
 
 `ssl.cipher_suites`::
 Specifies the
@@ -1489,8 +1486,7 @@ settings. For more information, see
 
 `ssl.supported_protocols`::
 Supported protocols with versions. Valid protocols: `SSLv2Hello`,
-`SSLv3`, `TLSv1`, `TLSv1.1`, `TLSv1.2`, `TLSv1.3`. Defaults to `TLSv1.3,TLSv1.2,TLSv1.1` if
-the JVM supports TLSv1.3, otherwise `TLSv1.2,TLSv1.1`.
+`SSLv3`, `TLSv1`, `TLSv1.1`, `TLSv1.2`, `TLSv1.3`. Defaults to `TLSv1.3,TLSv1.2,TLSv1.1`.
 +
 --
 NOTE: If `xpack.security.fips_mode.enabled` is `true`, you cannot use `SSLv2Hello` 
@@ -1521,13 +1517,18 @@ Controls the verification of certificates. Valid values are:
 The default value is `full`.
 
 `ssl.cipher_suites`::
-Supported cipher suites can be found in Oracle's http://docs.oracle.com/javase/8/docs/technotes/guides/security/SunProviders.html[
-Java Cryptography Architecture documentation]. Defaults to `TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256`,
-`TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256`, `TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA`, `TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA`,
-`TLS_RSA_WITH_AES_128_CBC_SHA256`, `TLS_RSA_WITH_AES_128_CBC_SHA`. If the _Java Cryptography Extension (JCE) Unlimited Strength
-Jurisdiction Policy Files_ has been installed, the default value also includes `TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384`,
-`TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384`, `TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA`, `TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA`,
-`TLS_RSA_WITH_AES_256_CBC_SHA256`, `TLS_RSA_WITH_AES_256_CBC_SHA`.
+Supported cipher suites can be found in Oracle's
+https://docs.oracle.com/en/java/javase/11/security/oracle-providers.html#GUID-7093246A-31A3-4304-AC5F-5FB6400405E2[Java Cryptography Architecture documentation].
+Defaults to `TLS_AES_256_GCM_SHA384`, `TLS_AES_128_GCM_SHA256`,
+`TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384`, `TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256`,
+`TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384`, `TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256`,
+`TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384`, `TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256`,
+`TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384`, `TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256`,
+`TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA`, `TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA`,
+`TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA`, `TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA`,
+`TLS_RSA_WITH_AES_256_GCM_SHA384`, `TLS_RSA_WITH_AES_128_GCM_SHA256`,
+`TLS_RSA_WITH_AES_256_CBC_SHA256`, `TLS_RSA_WITH_AES_128_CBC_SHA256`,
+`TLS_RSA_WITH_AES_256_CBC_SHA`, `TLS_RSA_WITH_AES_128_CBC_SHA`.
 
 [float]
 [[tls-ssl-key-settings]]

diff --git a/libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/SslConfiguration.java b/libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/SslConfiguration.java
@@ -24,7 +24,6 @@
 import javax.net.ssl.X509ExtendedTrustManager;
 import java.nio.file.Path;
 import java.security.GeneralSecurityException;
-import java.security.NoSuchAlgorithmException;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
@@ -52,12 +51,7 @@ public class SslConfiguration {
     static final Map<String, String> ORDERED_PROTOCOL_ALGORITHM_MAP;
     static {
         LinkedHashMap<String, String> protocolAlgorithmMap = new LinkedHashMap<>();
-        try {
-            SSLContext.getInstance("TLSv1.3");
-            protocolAlgorithmMap.put("TLSv1.3", "TLSv1.3");
-        } catch (NoSuchAlgorithmException e) {
-            // ignore since we support JVMs that do not support TLSv1.3
-        }
+        protocolAlgorithmMap.put("TLSv1.3", "TLSv1.3");
         protocolAlgorithmMap.put("TLSv1.2", "TLSv1.2");
         protocolAlgorithmMap.put("TLSv1.1", "TLSv1.1");
         protocolAlgorithmMap.put("TLSv1", "TLSv1");

diff --git a/libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/SslConfigurationLoader.java b/libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/SslConfigurationLoader.java
@@ -19,21 +19,15 @@
 
 package org.elasticsearch.common.ssl;
 
-import javax.crypto.Cipher;
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.TrustManagerFactory;
 import java.nio.file.Path;
-import java.security.NoSuchAlgorithmException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
 import static org.elasticsearch.common.ssl.KeyStoreUtil.inferKeyStoreType;
-import static org.elasticsearch.common.ssl.SslConfiguration.ORDERED_PROTOCOL_ALGORITHM_MAP;
 import static org.elasticsearch.common.ssl.SslConfigurationKeys.CERTIFICATE;
 import static org.elasticsearch.common.ssl.SslConfigurationKeys.CERTIFICATE_AUTHORITIES;
 import static org.elasticsearch.common.ssl.SslConfigurationKeys.CIPHERS;
@@ -70,10 +64,22 @@
  */
 public abstract class SslConfigurationLoader {
 
-    static final List<String> DEFAULT_PROTOCOLS = Collections.unmodifiableList(
-        ORDERED_PROTOCOL_ALGORITHM_MAP.containsKey("TLSv1.3") ?
-            Arrays.asList("TLSv1.3", "TLSv1.2", "TLSv1.1") : Arrays.asList("TLSv1.2", "TLSv1.1"));
-    static final List<String> DEFAULT_CIPHERS = loadDefaultCiphers();
+    static final List<String> DEFAULT_PROTOCOLS = List.of("TLSv1.3", "TLSv1.2", "TLSv1.1");
+
+    /**
+     * This list has been created with ordering
+     */
+    static final List<String> DEFAULT_CIPHERS = List.of(
+        "TLS_AES_256_GCM_SHA384", "TLS_AES_128_GCM_SHA256", // TLSv1.3 cipher has PFS, AEAD, hardware support
+        "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", // PFS, AEAD, hardware support
+        "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", // PFS, AEAD, hardware support
+        "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384",  "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", // PFS, hardware support
+        "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", // PFS, hardware support
+        "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", // PFS, hardware support
+        "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", // PFS, hardware support
+        "TLS_RSA_WITH_AES_256_GCM_SHA384", "TLS_RSA_WITH_AES_128_GCM_SHA256", // AEAD, hardware support
+        "TLS_RSA_WITH_AES_256_CBC_SHA256", "TLS_RSA_WITH_AES_128_CBC_SHA256", // hardware support
+        "TLS_RSA_WITH_AES_256_CBC_SHA", "TLS_RSA_WITH_AES_128_CBC_SHA"); // hardware support
     private static final char[] EMPTY_PASSWORD = new char[0];
 
     private final String settingPrefix;
@@ -141,9 +147,6 @@ public void setDefaultClientAuth(SslClientAuthenticationMode defaultClientAuth)
 
     /**
      * Change the default supported ciphers.
-     * The initial cipher list depends on the availability of {@link #has256BitAES() 256 bit AES}.
-     *
-     * @see #loadDefaultCiphers()
      */
     public void setDefaultCiphers(List<String> defaultCiphers) {
         this.defaultCiphers = defaultCiphers;
@@ -336,40 +339,4 @@ private <V> List<V> resolveListSetting(String key, Function<String, V> parser, L
             throw new SslConfigException("cannot retrieve setting [" + settingPrefix + key + "]", e);
         }
     }
-
-    private static List<String> loadDefaultCiphers() {
-        final List<String> ciphers128 = Arrays.asList(
-            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256",
-            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
-            "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA",
-            "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA",
-            "TLS_RSA_WITH_AES_128_CBC_SHA256",
-            "TLS_RSA_WITH_AES_128_CBC_SHA"
-        );
-        final List<String> ciphers256 = Arrays.asList(
-            "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384",
-            "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384",
-            "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",
-            "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA",
-            "TLS_RSA_WITH_AES_256_CBC_SHA256",
-            "TLS_RSA_WITH_AES_256_CBC_SHA"
-        );
-        if (has256BitAES()) {
-            List<String> ciphers = new ArrayList<>(ciphers256.size() + ciphers128.size());
-            ciphers.addAll(ciphers256);
-            ciphers.addAll(ciphers128);
-            return ciphers;
-        } else {
-            return ciphers128;
-        }
-    }
-
-    private static boolean has256BitAES() {
-        try {
-            return Cipher.getMaxAllowedKeyLength("AES") > 128;
-        } catch (NoSuchAlgorithmException e) {
-            // No AES? Things are going to be very weird, but technically that means we don't have 256 bit AES, so ...
-            return false;
-        }
-    }
 }
diff --git a/modules/reindex/src/test/java/org/elasticsearch/index/reindex/ReindexRestClientSslTests.java b/modules/reindex/src/test/java/org/elasticsearch/index/reindex/ReindexRestClientSslTests.java
@@ -120,6 +120,7 @@ public void testClientFailsWithUntrustedCertificate() throws IOException {
         final List<Thread> threads = new ArrayList<>();
         final Settings settings = Settings.builder()
             .put("path.home", createTempDir())
+            .put("reindex.ssl.supported_protocols", "TLSv1.2")
             .build();
         final Environment environment = TestEnvironment.newEnvironment(settings);
         final ReindexSslConfig ssl = new ReindexSslConfig(settings, environment, mock(ResourceWatcherService.class));
@@ -134,6 +135,7 @@ public void testClientSucceedsWithCertificateAuthorities() throws IOException {
         final Settings settings = Settings.builder()
             .put("path.home", createTempDir())
             .putList("reindex.ssl.certificate_authorities", ca.toString())
+            .put("reindex.ssl.supported_protocols", "TLSv1.2")
             .build();
         final Environment environment = TestEnvironment.newEnvironment(settings);
         final ReindexSslConfig ssl = new ReindexSslConfig(settings, environment, mock(ResourceWatcherService.class));
@@ -149,6 +151,7 @@ public void testClientSucceedsWithVerificationDisabled() throws IOException {
         final Settings settings = Settings.builder()
             .put("path.home", createTempDir())
             .put("reindex.ssl.verification_mode", "NONE")
+            .put("reindex.ssl.supported_protocols", "TLSv1.2")
             .build();
         final Environment environment = TestEnvironment.newEnvironment(settings);
         final ReindexSslConfig ssl = new ReindexSslConfig(settings, environment, mock(ResourceWatcherService.class));
@@ -169,6 +172,7 @@ public void testClientPassesClientCertificate() throws IOException {
             .put("reindex.ssl.certificate", cert)
             .put("reindex.ssl.key", key)
             .put("reindex.ssl.key_passphrase", "client-password")
+            .put("reindex.ssl.supported_protocols", "TLSv1.2")
             .build();
         AtomicReference<Certificate[]> clientCertificates = new AtomicReference<>();
         handler = https -> {

diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackSettings.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/XPackSettings.java
@@ -6,7 +6,6 @@
 
 package org.elasticsearch.xpack.core;
 
-import org.apache.logging.log4j.LogManager;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.xpack.core.security.SecurityField;
@@ -15,13 +14,10 @@
 import org.elasticsearch.xpack.core.ssl.SSLConfigurationSettings;
 import org.elasticsearch.xpack.core.ssl.VerificationMode;
 
-import javax.crypto.Cipher;
 import javax.crypto.SecretKeyFactory;
-import javax.net.ssl.SSLContext;
 
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -38,7 +34,6 @@ private XPackSettings() {
         throw new IllegalStateException("Utility class should not be instantiated");
     }
 
-
     /**
      * Setting for controlling whether or not CCR is enabled.
      */
@@ -122,28 +117,17 @@ private XPackSettings() {
      * SSL settings. These are the settings that are specifically registered for SSL. Many are private as we do not explicitly use them
      * but instead parse based on a prefix (eg *.ssl.*)
      */
-    public static final List<String> DEFAULT_CIPHERS;
-
-    static {
-        List<String> ciphers = Arrays.asList("TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256",
-                "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", "TLS_RSA_WITH_AES_128_CBC_SHA256",
-                "TLS_RSA_WITH_AES_128_CBC_SHA");
-        try {
-            final boolean use256Bit = Cipher.getMaxAllowedKeyLength("AES") > 128;
-            if (use256Bit) {
-                List<String> strongerCiphers = new ArrayList<>(ciphers.size() * 2);
-                strongerCiphers.addAll(Arrays.asList("TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384",
-                        "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384", "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA",
-                        "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_RSA_WITH_AES_256_CBC_SHA256", "TLS_RSA_WITH_AES_256_CBC_SHA"));
-                strongerCiphers.addAll(ciphers);
-                ciphers = strongerCiphers;
-            }
-        } catch (NoSuchAlgorithmException e) {
-            // ignore it here - there will be issues elsewhere and its not nice to throw in a static initializer
-        }
-
-        DEFAULT_CIPHERS = ciphers;
-    }
+    public static final List<String> DEFAULT_CIPHERS = List.of(
+        "TLS_AES_256_GCM_SHA384", "TLS_AES_128_GCM_SHA256", // TLSv1.3 cipher has PFS, AEAD, hardware support
+        "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256", // PFS, AEAD, hardware support
+        "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384", "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256", // PFS, AEAD, hardware support
+        "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384",  "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256", // PFS, hardware support
+        "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256", // PFS, hardware support
+        "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA", // PFS, hardware support
+        "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA", "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA", // PFS, hardware support
+        "TLS_RSA_WITH_AES_256_GCM_SHA384", "TLS_RSA_WITH_AES_128_GCM_SHA256", // AEAD, hardware support
+        "TLS_RSA_WITH_AES_256_CBC_SHA256", "TLS_RSA_WITH_AES_128_CBC_SHA256", // hardware support
+        "TLS_RSA_WITH_AES_256_CBC_SHA", "TLS_RSA_WITH_AES_128_CBC_SHA"); // hardware support
 
     /*
      * Do not allow insecure hashing algorithms to be used for password hashing
@@ -164,19 +148,7 @@ private XPackSettings() {
         }
     }, Setting.Property.NodeScope);
 
-    public static final List<String> DEFAULT_SUPPORTED_PROTOCOLS;
-
-    static {
-        boolean supportsTLSv13 = false;
-        try {
-            SSLContext.getInstance("TLSv1.3");
-            supportsTLSv13 = true;
-        } catch (NoSuchAlgorithmException e) {
-            LogManager.getLogger(XPackSettings.class).debug("TLSv1.3 is not supported", e);
-        }
-        DEFAULT_SUPPORTED_PROTOCOLS = supportsTLSv13 ?
-            Arrays.asList("TLSv1.3", "TLSv1.2", "TLSv1.1") : Arrays.asList("TLSv1.2", "TLSv1.1");
-    }
+    public static final List<String> DEFAULT_SUPPORTED_PROTOCOLS = List.of("TLSv1.3", "TLSv1.2", "TLSv1.1");
 
     public static final SSLClientAuth CLIENT_AUTH_DEFAULT = SSLClientAuth.REQUIRED;
     public static final SSLClientAuth HTTP_CLIENT_AUTH_DEFAULT = SSLClientAuth.NONE;

diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ssl/SSLService.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ssl/SSLService.java
@@ -57,8 +57,6 @@
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
-import static org.elasticsearch.xpack.core.XPackSettings.DEFAULT_SUPPORTED_PROTOCOLS;
-
 /**
  * Provides access to {@link SSLEngine} and {@link SSLSocketFactory} objects based on a provided configuration. All
  * configurations loaded by this service must be configured on construction.
@@ -75,9 +73,7 @@ public class SSLService {
     private static final Map<String, String> ORDERED_PROTOCOL_ALGORITHM_MAP;
     static {
         LinkedHashMap<String, String> protocolAlgorithmMap = new LinkedHashMap<>();
-        if (DEFAULT_SUPPORTED_PROTOCOLS.contains("TLSv1.3")) {
-            protocolAlgorithmMap.put("TLSv1.3", "TLSv1.3");
-        }
+        protocolAlgorithmMap.put("TLSv1.3", "TLSv1.3");
         protocolAlgorithmMap.put("TLSv1.2", "TLSv1.2");
         protocolAlgorithmMap.put("TLSv1.1", "TLSv1.1");
         protocolAlgorithmMap.put("TLSv1", "TLSv1");

diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ssl/TrustConfig.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ssl/TrustConfig.java
@@ -119,9 +119,8 @@ X509ExtendedTrustManager createTrustManager(@Nullable Environment environment) {
 
             try {
                 return CertParsingUtils.trustManager(trustConfigs.stream()
-                        .flatMap((tc) -> Arrays.stream(tc.createTrustManager(environment).getAcceptedIssuers()))
-                        .collect(Collectors.toList())
-                        .toArray(new X509Certificate[0]));
+                    .flatMap((tc) -> Arrays.stream(tc.createTrustManager(environment).getAcceptedIssuers()))
+                    .toArray(X509Certificate[]::new));
             } catch (Exception e) {
                 throw new ElasticsearchException("failed to create trust manager", e);
             }