Update "ssl-config" to support X-Pack features

libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/CompositeTrustConfig.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.common.ssl;
+
+import javax.net.ssl.TrustManagerFactory;
+import javax.net.ssl.X509ExtendedTrustManager;
+import java.nio.file.Path;
+import java.security.GeneralSecurityException;
+import java.security.KeyStore;
+import java.security.cert.Certificate;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
+
+/**
+ * A TrustConfiguration that merges trust anchors from a number of other trust configs to produce a single {@link X509ExtendedTrustManager}.
+ */
+public class CompositeTrustConfig implements SslTrustConfig {
+    private final List<SslTrustConfig> configs;
+
+    CompositeTrustConfig(List<SslTrustConfig> configs) {
+        this.configs = List.copyOf(configs);
+    }
+
+    @Override
+    public Collection<Path> getDependentFiles() {
+        return configs.stream().map(SslTrustConfig::getDependentFiles).flatMap(Collection::stream).collect(Collectors.toUnmodifiableSet());
+    }
+
+    @Override
+    public boolean isSystemDefault() {
+        return configs.stream().allMatch(SslTrustConfig::isSystemDefault);
+    }
+
+    @Override
+    public X509ExtendedTrustManager createTrustManager() {
+        try {
+            Collection<Certificate> trustedIssuers = configs.stream()
+                .map(c -> c.createTrustManager())
+                .map(tm -> tm.getAcceptedIssuers())
+                .flatMap(Arrays::stream)
+                .collect(Collectors.toSet());
+            final KeyStore store = KeyStoreUtil.buildTrustStore(trustedIssuers);
+            return KeyStoreUtil.createTrustManager(store, TrustManagerFactory.getDefaultAlgorithm());
+        } catch (GeneralSecurityException e) {
+            throw new SslConfigException("Cannot combine trust configurations ["
+                + configs.stream().map(SslTrustConfig::toString).collect(Collectors.joining(","))
+                + "]",
+                e);
+        }
+    }
+
+    @Override
+    public Collection<? extends StoredCertificate> getConfiguredCertificates() {
+        return configs.stream().map(SslTrustConfig::getConfiguredCertificates)
+            .flatMap(Collection::stream)
+            .collect(Collectors.toUnmodifiableList());
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        CompositeTrustConfig that = (CompositeTrustConfig) o;
+        return configs.equals(that.configs);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(configs);
+    }
+
+    @Override
+    public String toString() {
+        return "Composite-Trust{" + configs.stream().map(SslTrustConfig::toString).collect(Collectors.joining(",")) + '}';
+    }
+}

libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/DefaultJdkTrustConfig.java

@@ -18,13 +18,15 @@
 import java.security.KeyStore;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
+import java.util.List;
 import java.util.function.BiFunction;
 
 /**
  * This class represents a trust configuration that corresponds to the default trusted CAs of the JDK
  */
-final class DefaultJdkTrustConfig implements SslTrustConfig {
+public final class DefaultJdkTrustConfig implements SslTrustConfig {
+
+    public static final DefaultJdkTrustConfig DEFAULT_INSTANCE = new DefaultJdkTrustConfig();
 
     private final BiFunction<String, String, String> systemProperties;
     private final char[] trustStorePassword;
@@ -51,6 +53,11 @@ final class DefaultJdkTrustConfig implements SslTrustConfig {
         this.trustStorePassword = trustStorePassword;
     }
 
+    @Override
+    public boolean isSystemDefault() {
+        return true;
+    }
+
     @Override
     public X509ExtendedTrustManager createTrustManager() {
         try {
@@ -90,7 +97,12 @@ private static char[] getSystemTrustStorePassword(BiFunction<String, String, Str
 
     @Override
     public Collection<Path> getDependentFiles() {
-        return Collections.emptyList();
+        return List.of();
+    }
+
+    @Override
+    public Collection<? extends StoredCertificate> getConfiguredCertificates() {
+        return List.of();
     }
 
     @Override

libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/DerParser.java

@@ -31,7 +31,7 @@
  * Based on https://github.com/groovenauts/jmeter_oauth_plugin/blob/master/jmeter/src/
  * main/java/org/apache/jmeter/protocol/oauth/sampler/PrivateKeyReader.java
  */
-final class DerParser {
+public final class DerParser {
     // Constructed Flag
     private static final int CONSTRUCTED = 0x20;
 
@@ -55,12 +55,12 @@ final class DerParser {
     private InputStream derInputStream;
     private int maxAsnObjectLength;
 
-    DerParser(byte[] bytes) {
+    public DerParser(byte[] bytes) {
         this.derInputStream = new ByteArrayInputStream(bytes);
         this.maxAsnObjectLength = bytes.length;
     }
 
-    Asn1Object readAsn1Object() throws IOException {
+    public Asn1Object readAsn1Object() throws IOException {
         int tag = derInputStream.read();
         if (tag == -1) {
             throw new IOException("Invalid DER: stream too short, missing tag");
@@ -133,7 +133,7 @@ private int getLength() throws IOException {
      *
      * @author zhang
      */
-    static class Asn1Object {
+    public static class Asn1Object {
 
         protected final int type;
         protected final int length;

libs/ssl-config/src/main/java/org/elasticsearch/common/ssl/EmptyKeyConfig.java

@@ -8,25 +8,45 @@
 
 package org.elasticsearch.common.ssl;
 
-import javax.net.ssl.X509ExtendedKeyManager;
+import org.elasticsearch.core.Tuple;
+
 import java.nio.file.Path;
+import java.security.PrivateKey;
+import java.security.cert.X509Certificate;
 import java.util.Collection;
-import java.util.Collections;
+import java.util.List;
+
+import javax.net.ssl.X509ExtendedKeyManager;
 
 /**
  * A {@link SslKeyConfig} that does nothing (provides a null key manager)
  */
-final class EmptyKeyConfig implements SslKeyConfig {
+public final class EmptyKeyConfig implements SslKeyConfig {
 
-    static final EmptyKeyConfig INSTANCE = new EmptyKeyConfig();
+    public static final EmptyKeyConfig INSTANCE = new EmptyKeyConfig();
 
     private EmptyKeyConfig() {
         // Enforce a single instance
     }
 
     @Override
     public Collection<Path> getDependentFiles() {
-        return Collections.emptyList();
+        return List.of();
+    }
+
+    @Override
+    public List<Tuple<PrivateKey, X509Certificate>> getKeys() {
+        return List.of();
+    }
+
+    @Override
+    public Collection<? extends StoredCertificate> getConfiguredCertificates() {
+        return List.of();
+    }
+
+    @Override
+    public boolean hasKeyMaterial() {
+        return false;
     }
 
     @Override