获取并安装SSL证书

Question

So I also came across the below java code to retrieve and import the certs published by a server and import them into truststore.

import javax.net.ssl.*;
import java.io.*;
import java.security.KeyStore;
import java.security.MessageDigest;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

/**
 * Class used to add the server's certificate to the KeyStore
 * with your trusted certificates.
 */
public class InstallCert {

    public static void main(String[] args) throws Exception {
        String host;
        int port;
        char[] passphrase;
        if ((args.length == 1) || (args.length == 2)) {
            String[] c = args[0].split(":");
            host = c[0];
            port = (c.length == 1) ? 443 : Integer.parseInt(c[1]);
            String p = (args.length == 1) ? "changeit" : args[1];
            passphrase = p.toCharArray();
        } else {
            System.out.println("Usage: java InstallCert [:port] [passphrase]");
            return;
        }

        File file = new File("jssecacerts");
        if (file.isFile() == false) {
            char SEP = File.separatorChar;
            File dir = new File(System.getProperty("java.home") + SEP
                    + "lib" + SEP + "security");
            file = new File(dir, "jssecacerts");
            if (file.isFile() == false) {
                file = new File(dir, "cacerts");
            }
        }
        System.out.println("Loading KeyStore " + file + "...");
        InputStream in = new FileInputStream(file);
        KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
        ks.load(in, passphrase);
        in.close();

        SSLContext context = SSLContext.getInstance("TLS");
        TrustManagerFactory tmf =
                TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
        tmf.init(ks);
        X509TrustManager defaultTrustManager = (X509TrustManager) tmf.getTrustManagers()[0];
        SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
        context.init(null, new TrustManager[]{tm}, null);
        SSLSocketFactory factory = context.getSocketFactory();

        System.out.println("Opening connection to " + host + ":" + port + "...");
        SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
        socket.setSoTimeout(10000);
        try {
            System.out.println("Starting SSL handshake...");
            socket.startHandshake();
            socket.close();
            System.out.println();
            System.out.println("No errors, certificate is already trusted");
        } catch (SSLException e) {
            System.out.println();
            e.printStackTrace(System.out);
        }

        X509Certificate[] chain = tm.chain;
        if (chain == null) {
            System.out.println("Could not obtain server certificate chain");
            return;
        }

        BufferedReader reader =
                new BufferedReader(new InputStreamReader(System.in));

        System.out.println();
        System.out.println("Server sent " + chain.length + " certificate(s):");
        System.out.println();
        MessageDigest sha1 = MessageDigest.getInstance("SHA1");
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        for (int i = 0; i < chain.length; i++) {
            X509Certificate cert = chain[i];
            System.out.println
                    (" " + (i + 1) + " Subject " + cert.getSubjectDN());
            System.out.println("   Issuer  " + cert.getIssuerDN());
            sha1.update(cert.getEncoded());
            System.out.println("   sha1    " + toHexString(sha1.digest()));
            md5.update(cert.getEncoded());
            System.out.println("   md5     " + toHexString(md5.digest()));
            System.out.println();
        }

        System.out.println("Enter certificate to add to trusted keystore or 'q' to quit: [1]");
        String line = reader.readLine().trim();
        int k;
        try {
            k = (line.length() == 0) ? 0 : Integer.parseInt(line) - 1;
        } catch (NumberFormatException e) {
            System.out.println("KeyStore not changed");
            return;
        }

        X509Certificate cert = chain[k];
        String alias = host + "-" + (k + 1);
        ks.setCertificateEntry(alias, cert);

        OutputStream out = new FileOutputStream("jssecacerts");
        ks.store(out, passphrase);
        out.close();

        System.out.println();
        System.out.println(cert);
        System.out.println();
        System.out.println
                ("Added certificate to keystore 'jssecacerts' using alias '"
                        + alias + "'");
    }

    private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();

    private static String toHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder(bytes.length * 3);
        for (int b : bytes) {
            b &= 0xff;
            sb.append(HEXDIGITS[b >> 4]);
            sb.append(HEXDIGITS[b & 15]);
            sb.append(' ');
        }
        return sb.toString();
    }

    private static class SavingTrustManager implements X509TrustManager {

        private final X509TrustManager tm;
        private X509Certificate[] chain;

        SavingTrustManager(X509TrustManager tm) {
            this.tm = tm;
        }

        public X509Certificate[] getAcceptedIssuers() {
            throw new UnsupportedOperationException();
        }

        public void checkClientTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            throw new UnsupportedOperationException();
        }

        public void checkServerTrusted(X509Certificate[] chain, String authType)
                throws CertificateException {
            this.chain = chain;
            tm.checkServerTrusted(chain, authType);
        }
    }
}

During the first run, I get 2 certs published by the server and I import them into my truststore without issues (I can see the certs in the truststore via keytool). However on the 2nd run, I would expect to get the "No errors, certificate is already trusted" output, however instead I get an UnsupportedOperationException as below, propagated from the getAcceptedIssuers() method of the inner class, and then prompted again to import the certs. Could someone please help me understand why?

Starting SSL handshake...

javax.net.ssl.SSLException: java.lang.UnsupportedOperationException
        at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
        at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1904)
        at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1862)
        at sun.security.ssl.SSLSocketImpl.handleException(SSLSocketImpl.java:1845)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1366)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1343)
        at LDAPCerts.start(LDAPCerts.java:41)
        at LDAPCerts.main(LDAPCerts.java:15)
Caused by: java.lang.UnsupportedOperationException
        at LDAPCerts$SavingTrustManager.getAcceptedIssuers(LDAPCerts.java:126)
        at sun.security.ssl.AbstractTrustManagerWrapper.checkAlgorithmConstraints(SSLContextImpl.java:998)
        at sun.security.ssl.AbstractTrustManagerWrapper.checkAdditionalTrust(SSLContextImpl.java:944)
        at sun.security.ssl.AbstractTrustManagerWrapper.checkServerTrusted(SSLContextImpl.java:886)
        at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1428)
        at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:209)
        at sun.security.ssl.Handshaker.processLoop(Handshaker.java:901)
        at sun.security.ssl.Handshaker.process_record(Handshaker.java:837)
        at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1023)
        at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1332)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1359)
        ... 3 more

Answer 1

It's simple, on your implementation of X509TrustManager

You just have to return an X509Certificate array. And that's all!

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

from... http://infposs.blogspot.com/2013/06/installcert-and-java-7.html

Answer 2

After the file jssecacerts has been created, copy it to $JAVA_HOME/jre/lib/security/ directory and try again.

UPDATE:

Well, it is not necessary but then you need to specify the location by a JVM system parameter:

-Djavax.net.ssl.trustStore=

Please see how the location is determined. Taken from the Oracle guide :

1. If the system property: javax.net.ssl.trustStore

is defined, then the TrustManagerFactory attempts to find a file using the filename specified by that system property, and uses that file for the KeyStore. If the javax.net.ssl.trustStorePassword system property is also defined, its value is used to check the integrity of the data in the truststore before opening it.

If javax.net.ssl.trustStore is defined but the specified file does not exist, then a default TrustManager using an empty keystore is created.

2. If the javax.net.ssl.trustStore system property was not specified, then if the file /lib/security/jssecacerts

exists, that file is used. (See The Installation Directory for information about what refers to.) Otherwise,

3. If the file /lib/security/cacerts

exists, that file is used.