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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package sun.security.ssl;

import java.net.Socket;
import java.security.*;
import java.security.cert.*;
import java.util.*;
import javax.net.ssl.*;
import sun.security.util.AnchorCertificates;
import sun.security.util.HostnameChecker;
import sun.security.validator.*;

This class implements the SunJSSE X.509 trust manager using the internal
validator API in J2SE core. The logic in this class is minimal.


This class supports both the Simple validation algorithm from previous
JSSE versions and PKIX validation. Currently, it is not possible for the
application to specify PKIX parameters other than trust anchors. This will
be fixed in a future release using new APIs. When that happens, it may also
make sense to separate the Simple and PKIX trust managers into separate
classes.
Author:
Andreas Sterbenz/**
 * This class implements the SunJSSE X.509 trust manager using the internal
 * validator API in J2SE core. The logic in this class is minimal.<p>
 * <p>
 * This class supports both the Simple validation algorithm from previous
 * JSSE versions and PKIX validation. Currently, it is not possible for the
 * application to specify PKIX parameters other than trust anchors. This will
 * be fixed in a future release using new APIs. When that happens, it may also
 * make sense to separate the Simple and PKIX trust managers into separate
 * classes.
 *
 * @author Andreas Sterbenz
 */
final class X509TrustManagerImpl extends X509ExtendedTrustManager
        implements X509TrustManager {

    private final String validatorType;

    
The Set of trusted X509Certificates.
/**
     * The Set of trusted X509Certificates.
     */
    private final Collection<X509Certificate> trustedCerts;

    private final PKIXBuilderParameters pkixParams;

    // note that we need separate validator for client and server due to
    // the different extension checks. They are initialized lazily on demand.
    private volatile Validator clientValidator, serverValidator;

    X509TrustManagerImpl(String validatorType,
            Collection<X509Certificate> trustedCerts) {

        this.validatorType = validatorType;
        this.pkixParams = null;

        if (trustedCerts == null) {
            trustedCerts = Collections.<X509Certificate>emptySet();
        }

        this.trustedCerts = trustedCerts;

        if (SSLLogger.isOn && SSLLogger.isOn("ssl,trustmanager")) {
            SSLLogger.fine("adding as trusted certificates",
                    (Object[])trustedCerts.toArray(new X509Certificate[0]));
        }
    }

    X509TrustManagerImpl(String validatorType, PKIXBuilderParameters params) {
        this.validatorType = validatorType;
        this.pkixParams = params;
        // create server validator eagerly so that we can conveniently
        // get the trusted certificates
        // clients need it anyway eventually, and servers will not mind
        // the little extra footprint
        Validator v = getValidator(Validator.VAR_TLS_SERVER);
        trustedCerts = v.getTrustedCertificates();
        serverValidator = v;

        if (SSLLogger.isOn && SSLLogger.isOn("ssl,trustmanager")) {
            SSLLogger.fine("adding as trusted certificates",
                    (Object[])trustedCerts.toArray(new X509Certificate[0]));
        }
    }

    @Override
    public void checkClientTrusted(X509Certificate[] chain, String authType)
            throws CertificateException {
        checkTrusted(chain, authType, (Socket)null, true);
    }

    @Override
    public void checkServerTrusted(X509Certificate[] chain, String authType)
            throws CertificateException {
        checkTrusted(chain, authType, (Socket)null, false);
    }

    @Override
    public X509Certificate[] getAcceptedIssuers() {
        X509Certificate[] certsArray = new X509Certificate[trustedCerts.size()];
        trustedCerts.toArray(certsArray);
        return certsArray;
    }

    @Override
    public void checkClientTrusted(X509Certificate[] chain, String authType,
                Socket socket) throws CertificateException {
        checkTrusted(chain, authType, socket, true);
    }

    @Override
    public void checkServerTrusted(X509Certificate[] chain, String authType,
            Socket socket) throws CertificateException {
        checkTrusted(chain, authType, socket, false);
    }

    @Override
    public void checkClientTrusted(X509Certificate[] chain, String authType,
            SSLEngine engine) throws CertificateException {
        checkTrusted(chain, authType, engine, true);
    }

    @Override
    public void checkServerTrusted(X509Certificate[] chain, String authType,
            SSLEngine engine) throws CertificateException {
        checkTrusted(chain, authType, engine, false);
    }

    private Validator checkTrustedInit(X509Certificate[] chain,
            String authType, boolean checkClientTrusted) {
        if (chain == null || chain.length == 0) {
            throw new IllegalArgumentException(
                "null or zero-length certificate chain");
        }

        if (authType == null || authType.isEmpty()) {
            throw new IllegalArgumentException(
                "null or zero-length authentication type");
        }

        Validator v = null;
        if (checkClientTrusted) {
            v = clientValidator;
            if (v == null) {
                synchronized (this) {
                    v = clientValidator;
                    if (v == null) {
                        v = getValidator(Validator.VAR_TLS_CLIENT);
                        clientValidator = v;
                    }
                }
            }
        } else {
            // assume double checked locking with a volatile flag works
            // (guaranteed under the new Tiger memory model)
            v = serverValidator;
            if (v == null) {
                synchronized (this) {
                    v = serverValidator;
                    if (v == null) {
                        v = getValidator(Validator.VAR_TLS_SERVER);
                        serverValidator = v;
                    }
                }
            }
        }

        return v;
    }

    private void checkTrusted(X509Certificate[] chain,
            String authType, Socket socket,
            boolean checkClientTrusted) throws CertificateException {
        Validator v = checkTrustedInit(chain, authType, checkClientTrusted);

        X509Certificate[] trustedChain = null;
        if ((socket != null) && socket.isConnected() &&
                                        (socket instanceof SSLSocket)) {

            SSLSocket sslSocket = (SSLSocket)socket;
            SSLSession session = sslSocket.getHandshakeSession();
            if (session == null) {
                throw new CertificateException("No handshake session");
            }

            // create the algorithm constraints
            boolean isExtSession = (session instanceof ExtendedSSLSession);
            AlgorithmConstraints constraints;
            if (isExtSession &&
                    ProtocolVersion.useTLS12PlusSpec(session.getProtocol())) {
                ExtendedSSLSession extSession = (ExtendedSSLSession)session;
                String[] localSupportedSignAlgs =
                        extSession.getLocalSupportedSignatureAlgorithms();

                constraints = new SSLAlgorithmConstraints(
                                sslSocket, localSupportedSignAlgs, false);
            } else {
                constraints = new SSLAlgorithmConstraints(sslSocket, false);
            }

            // Grab any stapled OCSP responses for use in validation
            List<byte[]> responseList = Collections.emptyList();
            if (!checkClientTrusted && isExtSession) {
                responseList =
                        ((ExtendedSSLSession)session).getStatusResponses();
            }
             trustedChain = validate(v, chain, responseList,
                    constraints, checkClientTrusted ? null : authType);

            // check endpoint identity
            String identityAlg = sslSocket.getSSLParameters().
                    getEndpointIdentificationAlgorithm();
            if (identityAlg != null && !identityAlg.isEmpty()) {
                checkIdentity(session,
                        trustedChain, identityAlg, checkClientTrusted);
            }
        } else {
            trustedChain = validate(v, chain, Collections.emptyList(),
                    null, checkClientTrusted ? null : authType);
        }

        if (SSLLogger.isOn && SSLLogger.isOn("ssl,trustmanager")) {
            SSLLogger.fine("Found trusted certificate",
                    trustedChain[trustedChain.length - 1]);
        }
    }

    private void checkTrusted(X509Certificate[] chain,
            String authType, SSLEngine engine,
            boolean checkClientTrusted) throws CertificateException {
        Validator v = checkTrustedInit(chain, authType, checkClientTrusted);

        X509Certificate[] trustedChain = null;
        if (engine != null) {
            SSLSession session = engine.getHandshakeSession();
            if (session == null) {
                throw new CertificateException("No handshake session");
            }

            // create the algorithm constraints
            boolean isExtSession = (session instanceof ExtendedSSLSession);
            AlgorithmConstraints constraints;
            if (isExtSession &&
                    ProtocolVersion.useTLS12PlusSpec(session.getProtocol())) {
                ExtendedSSLSession extSession = (ExtendedSSLSession)session;
                String[] localSupportedSignAlgs =
                        extSession.getLocalSupportedSignatureAlgorithms();

                constraints = new SSLAlgorithmConstraints(
                                engine, localSupportedSignAlgs, false);
            } else {
                constraints = new SSLAlgorithmConstraints(engine, false);
            }

            // Grab any stapled OCSP responses for use in validation
            List<byte[]> responseList = Collections.emptyList();
            if (!checkClientTrusted && isExtSession) {
                responseList =
                        ((ExtendedSSLSession)session).getStatusResponses();
            }
             trustedChain = validate(v, chain, responseList,
                    constraints, checkClientTrusted ? null : authType);

            // check endpoint identity
            String identityAlg = engine.getSSLParameters().
                    getEndpointIdentificationAlgorithm();
            if (identityAlg != null && !identityAlg.isEmpty()) {
                checkIdentity(session, trustedChain,
                        identityAlg, checkClientTrusted);
            }
        } else {
            trustedChain = validate(v, chain, Collections.emptyList(),
                    null, checkClientTrusted ? null : authType);
        }

        if (SSLLogger.isOn && SSLLogger.isOn("ssl,trustmanager")) {
            SSLLogger.fine("Found trusted certificate",
                    trustedChain[trustedChain.length - 1]);
        }
    }

    private Validator getValidator(String variant) {
        Validator v;
        if (pkixParams == null) {
            v = Validator.getInstance(validatorType, variant, trustedCerts);
        } else {
            v = Validator.getInstance(validatorType, variant, pkixParams);
        }
        return v;
    }

    private static X509Certificate[] validate(Validator v,
            X509Certificate[] chain, List<byte[]> responseList,
            AlgorithmConstraints constraints, String authType)
            throws CertificateException {
        Object o = JsseJce.beginFipsProvider();
        try {
            return v.validate(chain, null, responseList, constraints, authType);
        } finally {
            JsseJce.endFipsProvider(o);
        }
    }

    // Get string representation of HostName from a list of server names.
    //
    // We are only accepting host_name name type in the list.
    private static String getHostNameInSNI(List<SNIServerName> sniNames) {

        SNIHostName hostname = null;
        for (SNIServerName sniName : sniNames) {
            if (sniName.getType() != StandardConstants.SNI_HOST_NAME) {
                continue;
            }

            if (sniName instanceof SNIHostName) {
                hostname = (SNIHostName)sniName;
            } else {
                try {
                    hostname = new SNIHostName(sniName.getEncoded());
                } catch (IllegalArgumentException iae) {
                    // unlikely to happen, just in case ...
                    if (SSLLogger.isOn && SSLLogger.isOn("ssl,trustmanager")) {
                        SSLLogger.fine("Illegal server name: " + sniName);
                    }
                }
            }

            // no more than server name of the same name type
            break;
        }

        if (hostname != null) {
            return hostname.getAsciiName();
        }

        return null;
    }

    // Also used by X509KeyManagerImpl
    static List<SNIServerName> getRequestedServerNames(Socket socket) {
        if (socket != null && socket.isConnected() &&
                                        socket instanceof SSLSocket) {
            return getRequestedServerNames(
                    ((SSLSocket)socket).getHandshakeSession());
        }

        return Collections.<SNIServerName>emptyList();
    }

    // Also used by X509KeyManagerImpl
    static List<SNIServerName> getRequestedServerNames(SSLEngine engine) {
        if (engine != null) {
            return getRequestedServerNames(engine.getHandshakeSession());
        }

        return Collections.<SNIServerName>emptyList();
    }

    private static List<SNIServerName> getRequestedServerNames(
            SSLSession session) {
        if (session != null && (session instanceof ExtendedSSLSession)) {
            return ((ExtendedSSLSession)session).getRequestedServerNames();
        }

        return Collections.<SNIServerName>emptyList();
    }

    /*
     * Per RFC 6066, if an application negotiates a server name using an
     * application protocol and then upgrades to TLS, and if a server_name
     * extension is sent, then the extension SHOULD contain the same name
     * that was negotiated in the application protocol.  If the server_name
     * is established in the TLS session handshake, the client SHOULD NOT
     * attempt to request a different server name at the application layer.
     *
     * According to the above spec, we only need to check either the identity
     * in server_name extension or the peer host of the connection.  Peer host
     * is not always a reliable fully qualified domain name. The HostName in
     * server_name extension is more reliable than peer host. So we prefer
     * the identity checking aginst the server_name extension if present, and
     * may failove to peer host checking.
     */
    static void checkIdentity(SSLSession session,
            X509Certificate[] trustedChain,
            String algorithm,
            boolean checkClientTrusted) throws CertificateException {

        // check if EE certificate chains to a public root CA (as
        // pre-installed in cacerts)
        boolean chainsToPublicCA = AnchorCertificates.contains(
                trustedChain[trustedChain.length - 1]);

        boolean identifiable = false;
        String peerHost = session.getPeerHost();
        if (!checkClientTrusted) {
            List<SNIServerName> sniNames = getRequestedServerNames(session);
            String sniHostName = getHostNameInSNI(sniNames);
            if (sniHostName != null) {
                try {
                    checkIdentity(sniHostName,
                            trustedChain[0], algorithm, chainsToPublicCA);
                    identifiable = true;
                } catch (CertificateException ce) {
                    if (sniHostName.equalsIgnoreCase(peerHost)) {
                        throw ce;
                    }

                    // otherwisw, failover to check peer host
                }
            }
        }

        if (!identifiable) {
            checkIdentity(peerHost,
                    trustedChain[0], algorithm, chainsToPublicCA);
        }
    }

    /*
     * Identify the peer by its certificate and hostname.
     *
     * Lifted from sun.net.www.protocol.https.HttpsClient.
     */
    static void checkIdentity(String hostname, X509Certificate cert,
            String algorithm) throws CertificateException {
        checkIdentity(hostname, cert, algorithm, false);
    }

    private static void checkIdentity(String hostname, X509Certificate cert,
            String algorithm, boolean chainsToPublicCA)
            throws CertificateException {
        if (algorithm != null && !algorithm.isEmpty()) {
            // if IPv6 strip off the "[]"
            if ((hostname != null) && hostname.startsWith("[") &&
                    hostname.endsWith("]")) {
                hostname = hostname.substring(1, hostname.length() - 1);
            }

            if (algorithm.equalsIgnoreCase("HTTPS")) {
                HostnameChecker.getInstance(HostnameChecker.TYPE_TLS).match(
                        hostname, cert, chainsToPublicCA);
            } else if (algorithm.equalsIgnoreCase("LDAP") ||
                    algorithm.equalsIgnoreCase("LDAPS")) {
                HostnameChecker.getInstance(HostnameChecker.TYPE_LDAP).match(
                        hostname, cert, chainsToPublicCA);
            } else {
                throw new CertificateException(
                        "Unknown identification algorithm: " + algorithm);
            }
        }
    }
}