co.elastic.clients.transport.TransportUtils Maven / Gradle / Ivy

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/*
 * Licensed to Elasticsearch B.V. under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch B.V. licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package co.elastic.clients.transport;

import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.Arrays;

public class TransportUtils {

    /**
     * Creates an SSLContext from the self-signed http_ca.crt certificate created by Elasticsearch during
     * its first start.
     *
     * @see Elasticsearch
     *      documentation
     */
    public static SSLContext sslContextFromHttpCaCrt(File file) throws IOException {
        try(InputStream in = new FileInputStream(file)) {
            return sslContextFromHttpCaCrt(in);
        }
    }

    /**
     * Creates an SSLContext from the self-signed http_ca.crt certificate created by Elasticsearch during
     * its first start.
     *
     * @see Elasticsearch
     *      documentation
     */
    public static SSLContext sslContextFromHttpCaCrt(InputStream in) {
        try {
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            Certificate certificate = cf.generateCertificate(in);

            final KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
            keyStore.load(null, null);
            keyStore.setCertificateEntry("elasticsearch-ca", certificate);

            TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
            tmf.init(keyStore);

            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, tmf.getTrustManagers(), null);
            return sslContext;

        } catch (CertificateException | NoSuchAlgorithmException | KeyManagementException | KeyStoreException | IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Creates an SSLContext from the SHA-256 fingerprint of self-signed http_ca.crt certificate output by
     * Elasticsearch at startup time.
     *
     * @param fingerPrint the SHA-256 fingerprint. Can be uppercase or lowercase, with or without colons separating bytes
     * @see Elasticsearch
     *      documentation
     */
    public static SSLContext sslContextFromCaFingerprint(String fingerPrint) {

        fingerPrint = fingerPrint.replace(":", "");
        int len = fingerPrint.length();
        byte[] fpBytes = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            fpBytes[i / 2] = (byte) (
                (Character.digit(fingerPrint.charAt(i), 16) << 4) +
                Character.digit(fingerPrint.charAt(i+1), 16)
            );
        }

        try {
            X509TrustManager tm = new X509TrustManager() {
                @Override
                public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
                    throw new CertificateException("This is a client-side only trust manager");
                }

                @Override
                public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {

                    // The CA root is the last element of the chain
                    X509Certificate anchor = chain[chain.length - 1];

                    byte[] bytes;
                    try {
                        MessageDigest md = MessageDigest.getInstance("SHA-256");
                        md.update(anchor.getEncoded());
                        bytes = md.digest();
                    } catch (NoSuchAlgorithmException e) {
                        throw new RuntimeException(e);
                    }

                    if (Arrays.equals(fpBytes, bytes)) {
                        return;
                    }

                    throw new CertificateException("Untrusted certificate: " + anchor.getSubjectX500Principal());
                }

                @Override
                public X509Certificate[] getAcceptedIssuers() {
                    return new X509Certificate[0];
                }
            };

            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, new X509TrustManager[] { tm }, null);
            return sslContext;

        } catch (NoSuchAlgorithmException | KeyManagementException e) {
            // Exceptions that should normally not occur
            throw new RuntimeException(e);
        }
    }
}