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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
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package com.sun.jndi.ldap.ext;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;

import java.security.Principal;
import java.security.cert.X509Certificate;
import java.security.cert.CertificateException;

import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.HostnameVerifier;
import sun.security.util.HostnameChecker;

import javax.naming.ldap.*;
import com.sun.jndi.ldap.Connection;


This class implements the LDAPv3 Extended Response for StartTLS as
defined in
Lightweight Directory
Access Protocol (v3): Extension for Transport Layer Security
The object identifier for StartTLS is 1.3.6.1.4.1.1466.20037
and no extended response value is defined.

 The Start TLS extended request and response are used to establish a TLS connection over the existing LDAP connection associated with the JNDI context on which extendedOperation() is invoked. 
Author:Vincent Ryan
See Also:
/**
 * This class implements the LDAPv3 Extended Response for StartTLS as
 * defined in
 * <a href="http://www.ietf.org/rfc/rfc2830.txt">Lightweight Directory
 * Access Protocol (v3): Extension for Transport Layer Security</a>
 *
 * The object identifier for StartTLS is 1.3.6.1.4.1.1466.20037
 * and no extended response value is defined.
 *
 * <p>
 * The Start TLS extended request and response are used to establish
 * a TLS connection over the existing LDAP connection associated with
 * the JNDI context on which {@code extendedOperation()} is invoked.
 *
 * @see StartTlsRequest
 * @author Vincent Ryan
 */
final public class StartTlsResponseImpl extends StartTlsResponse {

    private static final boolean debug = false;

    /*
     * The dNSName type in a subjectAltName extension of an X.509 certificate
     */
    private static final int DNSNAME_TYPE = 2;

    /*
     * The server's hostname.
     */
    private transient String hostname = null;

    /*
     * The LDAP socket.
     */
    private transient Connection ldapConnection = null;

    /*
     * The original input stream.
     */
    private transient InputStream originalInputStream = null;

    /*
     * The original output stream.
     */
    private transient OutputStream originalOutputStream = null;

    /*
     * The SSL socket.
     */
    private transient SSLSocket sslSocket = null;

    /*
     * The SSL socket factories.
     */
    private transient SSLSocketFactory defaultFactory = null;
    private transient SSLSocketFactory currentFactory = null;

    /*
     * The list of cipher suites to be enabled.
     */
    private transient String[] suites = null;

    /*
     * The hostname verifier callback.
     */
    private transient HostnameVerifier verifier = null;

    /*
     * The flag to indicate that the TLS connection is closed.
     */
    private transient boolean isClosed = true;

    private static final long serialVersionUID = -1126624615143411328L;

    // public no-arg constructor required by JDK's Service Provider API.

    public StartTlsResponseImpl() {}

    
Overrides the default list of cipher suites enabled for use on the TLS connection. The cipher suites must have already been listed by SSLSocketFactory.getSupportedCipherSuites() as being supported. Even if a suite has been enabled, it still might not be used because the peer does not support it, or because the requisite certificates (and private keys) are not available. 
Params:
  • suites – The non-null list of names of all the cipher suites to
enable.
See Also:
/**
     * Overrides the default list of cipher suites enabled for use on the
     * TLS connection. The cipher suites must have already been listed by
     * {@code SSLSocketFactory.getSupportedCipherSuites()} as being supported.
     * Even if a suite has been enabled, it still might not be used because
     * the peer does not support it, or because the requisite certificates
     * (and private keys) are not available.
     *
     * @param suites The non-null list of names of all the cipher suites to
     * enable.
     * @see #negotiate
     */
    public void setEnabledCipherSuites(String[] suites) {
        // The impl does accept null suites, although the spec requires
        // a non-null list.
        this.suites = suites == null ? null : suites.clone();
    }

    
Overrides the default hostname verifier used by negotiate() after the TLS handshake has completed. If setHostnameVerifier() has not been called before negotiate() is invoked, negotiate() will perform a simple case ignore match. If called after negotiate(), this method does not do anything. 
Params:
  • verifier – The non-null hostname verifier callback.
See Also:
/**
     * Overrides the default hostname verifier used by {@code negotiate()}
     * after the TLS handshake has completed. If
     * {@code setHostnameVerifier()} has not been called before
     * {@code negotiate()} is invoked, {@code negotiate()}
     * will perform a simple case ignore match. If called after
     * {@code negotiate()}, this method does not do anything.
     *
     * @param verifier The non-null hostname verifier callback.
     * @see #negotiate
     */
    public void setHostnameVerifier(HostnameVerifier verifier) {
        this.verifier = verifier;
    }

    
Negotiates a TLS session using the default SSL socket factory.

 This method is equivalent to negotiate(null). 
Throws:
  • IOException – If an IO error was encountered while establishing
the TLS session.
See Also:
Returns:The negotiated SSL session
/**
     * Negotiates a TLS session using the default SSL socket factory.
     * <p>
     * This method is equivalent to {@code negotiate(null)}.
     *
     * @return The negotiated SSL session
     * @throws IOException If an IO error was encountered while establishing
     * the TLS session.
     * @see #setEnabledCipherSuites
     * @see #setHostnameVerifier
     */
    public SSLSession negotiate() throws IOException {

        return negotiate(null);
    }

    
Negotiates a TLS session using an SSL socket factory.


Creates an SSL socket using the supplied SSL socket factory and
attaches it to the existing connection. Performs the TLS handshake
and returns the negotiated session information.

 If cipher suites have been set via setEnabledCipherSuites then they are enabled before the TLS handshake begins. 
 Hostname verification is performed after the TLS handshake completes. The default check performs a case insensitive match of the server's hostname against that in the server's certificate. The server's hostname is extracted from the subjectAltName in the server's certificate (if present). Otherwise the value of the common name attribute of the subject name is used. If a callback has been set via setHostnameVerifier then that verifier is used if the default check fails. 

If an error occurs then the SSL socket is closed and an IOException
is thrown. The underlying connection remains intact.

Params:
  • factory – The possibly null SSL socket factory to use.
If null, the default SSL socket factory is used.
Throws:
  • IOException – If an IO error was encountered while establishing
the TLS session.
See Also:
Returns:The negotiated SSL session
/**
     * Negotiates a TLS session using an SSL socket factory.
     * <p>
     * Creates an SSL socket using the supplied SSL socket factory and
     * attaches it to the existing connection. Performs the TLS handshake
     * and returns the negotiated session information.
     * <p>
     * If cipher suites have been set via {@code setEnabledCipherSuites}
     * then they are enabled before the TLS handshake begins.
     * <p>
     * Hostname verification is performed after the TLS handshake completes.
     * The default check performs a case insensitive match of the server's
     * hostname against that in the server's certificate. The server's
     * hostname is extracted from the subjectAltName in the server's
     * certificate (if present). Otherwise the value of the common name
     * attribute of the subject name is used. If a callback has
     * been set via {@code setHostnameVerifier} then that verifier is used if
     * the default check fails.
     * <p>
     * If an error occurs then the SSL socket is closed and an IOException
     * is thrown. The underlying connection remains intact.
     *
     * @param factory The possibly null SSL socket factory to use.
     * If null, the default SSL socket factory is used.
     * @return The negotiated SSL session
     * @throws IOException If an IO error was encountered while establishing
     * the TLS session.
     * @see #setEnabledCipherSuites
     * @see #setHostnameVerifier
     */
    public SSLSession negotiate(SSLSocketFactory factory) throws IOException {

        if (isClosed && sslSocket != null) {
            throw new IOException("TLS connection is closed.");
        }

        if (factory == null) {
            factory = getDefaultFactory();
        }

        if (debug) {
            System.out.println("StartTLS: About to start handshake");
        }

        SSLSession sslSession = startHandshake(factory).getSession();

        if (debug) {
            System.out.println("StartTLS: Completed handshake");
        }

        SSLPeerUnverifiedException verifExcep = null;
        try {
            if (verify(hostname, sslSession)) {
                isClosed = false;
                return sslSession;
            }
        } catch (SSLPeerUnverifiedException e) {
            // Save to return the cause
            verifExcep = e;
        }
        if ((verifier != null) &&
                verifier.verify(hostname, sslSession)) {
            isClosed = false;
            return sslSession;
        }

        // Verification failed
        close();
        sslSession.invalidate();
        if (verifExcep == null) {
            verifExcep = new SSLPeerUnverifiedException(
                        "hostname of the server '" + hostname +
                        "' does not match the hostname in the " +
                        "server's certificate.");
        }
        throw verifExcep;
    }

    
Closes the TLS connection gracefully and reverts back to the underlying
connection.

Throws:
  • IOException – If an IO error was encountered while closing the
TLS connection
/**
     * Closes the TLS connection gracefully and reverts back to the underlying
     * connection.
     *
     * @throws IOException If an IO error was encountered while closing the
     * TLS connection
     */
    public void close() throws IOException {

        if (isClosed) {
            return;
        }

        if (debug) {
            System.out.println("StartTLS: replacing SSL " +
                                "streams with originals");
        }

        // Replace SSL streams with the original streams
        ldapConnection.replaceStreams(
                        originalInputStream, originalOutputStream);

        if (debug) {
            System.out.println("StartTLS: closing SSL Socket");
        }
        sslSocket.close();

        isClosed = true;
    }

    
Sets the connection for TLS to use. The TLS connection will be attached
to this connection.

Params:
  • ldapConnection – The non-null connection to use.
  • hostname – The server's hostname. If null, the hostname used to
open the connection will be used instead.
/**
     * Sets the connection for TLS to use. The TLS connection will be attached
     * to this connection.
     *
     * @param ldapConnection The non-null connection to use.
     * @param hostname The server's hostname. If null, the hostname used to
     * open the connection will be used instead.
     */
    public void setConnection(Connection ldapConnection, String hostname) {
        this.ldapConnection = ldapConnection;
        this.hostname = (hostname != null) ? hostname : ldapConnection.host;
        originalInputStream = ldapConnection.inStream;
        originalOutputStream = ldapConnection.outStream;
    }

    /*
     * Returns the default SSL socket factory.
     *
     * @return The default SSL socket factory.
     * @throws IOException If TLS is not supported.
     */
    private SSLSocketFactory getDefaultFactory() throws IOException {

        if (defaultFactory != null) {
            return defaultFactory;
        }

        return (defaultFactory =
            (SSLSocketFactory) SSLSocketFactory.getDefault());
    }

    /*
     * Start the TLS handshake and manipulate the input and output streams.
     *
     * @param factory The SSL socket factory to use.
     * @return The SSL socket.
     * @throws IOException If an exception occurred while performing the
     * TLS handshake.
     */
    private SSLSocket startHandshake(SSLSocketFactory factory)
        throws IOException {

        if (ldapConnection == null) {
            throw new IllegalStateException("LDAP connection has not been set."
                + " TLS requires an existing LDAP connection.");
        }

        if (factory != currentFactory) {
            // Create SSL socket layered over the existing connection
            sslSocket = (SSLSocket) factory.createSocket(ldapConnection.sock,
                ldapConnection.host, ldapConnection.port, false);
            currentFactory = factory;

            if (debug) {
                System.out.println("StartTLS: Created socket : " + sslSocket);
            }
        }

        if (suites != null) {
            sslSocket.setEnabledCipherSuites(suites);
            if (debug) {
                System.out.println("StartTLS: Enabled cipher suites");
            }
        }

        // Connection must be quite for handshake to proceed

        try {
            if (debug) {
                System.out.println(
                        "StartTLS: Calling sslSocket.startHandshake");
            }
            sslSocket.startHandshake();
            if (debug) {
                System.out.println(
                        "StartTLS: + Finished sslSocket.startHandshake");
            }

            // Replace original streams with the new SSL streams
            ldapConnection.replaceStreams(sslSocket.getInputStream(),
                sslSocket.getOutputStream());
            if (debug) {
                System.out.println("StartTLS: Replaced IO Streams");
            }

        } catch (IOException e) {
            if (debug) {
                System.out.println("StartTLS: Got IO error during handshake");
                e.printStackTrace();
            }

            sslSocket.close();
            isClosed = true;
            throw e;   // pass up exception
        }

        return sslSocket;
    }

    /*
     * Verifies that the hostname in the server's certificate matches the
     * hostname of the server.
     * The server's first certificate is examined. If it has a subjectAltName
     * that contains a dNSName then that is used as the server's hostname.
     * The server's hostname may contain a wildcard for its left-most name part.
     * Otherwise, if the certificate has no subjectAltName then the value of
     * the common name attribute of the subject name is used.
     *
     * @param hostname The hostname of the server.
     * @param session the SSLSession used on the connection to host.
     * @return true if the hostname is verified, false otherwise.
     */

    private boolean verify(String hostname, SSLSession session)
        throws SSLPeerUnverifiedException {

        java.security.cert.Certificate[] certs = null;

        // if IPv6 strip off the "[]"
        if (hostname != null && hostname.startsWith("[") &&
                hostname.endsWith("]")) {
            hostname = hostname.substring(1, hostname.length() - 1);
        }
        try {
            HostnameChecker checker = HostnameChecker.getInstance(
                                                HostnameChecker.TYPE_LDAP);
            // Use ciphersuite to determine whether Kerberos is active.
            if (session.getCipherSuite().startsWith("TLS_KRB5")) {
                Principal principal = getPeerPrincipal(session);
                if (!HostnameChecker.match(hostname, principal)) {
                    throw new SSLPeerUnverifiedException(
                        "hostname of the kerberos principal:" + principal +
                        " does not match the hostname:" + hostname);
                }
            } else { // X.509

                // get the subject's certificate
                certs = session.getPeerCertificates();
                X509Certificate peerCert;
                if (certs[0] instanceof java.security.cert.X509Certificate) {
                    peerCert = (java.security.cert.X509Certificate) certs[0];
                } else {
                    throw new SSLPeerUnverifiedException(
                            "Received a non X509Certificate from the server");
                }
                checker.match(hostname, peerCert);
            }

            // no exception means verification passed
            return true;
        } catch (SSLPeerUnverifiedException e) {

            /*
             * The application may enable an anonymous SSL cipher suite, and
             * hostname verification is not done for anonymous ciphers
             */
            String cipher = session.getCipherSuite();
            if (cipher != null && (cipher.indexOf("_anon_") != -1)) {
                return true;
            }
            throw e;
        } catch (CertificateException e) {

            /*
             * Pass up the cause of the failure
             */
            throw(SSLPeerUnverifiedException)
                new SSLPeerUnverifiedException("hostname of the server '" +
                                hostname +
                                "' does not match the hostname in the " +
                                "server's certificate.").initCause(e);
        }
    }

    /*
     * Get the peer principal from the session
     */
    private static Principal getPeerPrincipal(SSLSession session)
            throws SSLPeerUnverifiedException {
        Principal principal;
        try {
            principal = session.getPeerPrincipal();
        } catch (AbstractMethodError e) {
            // if the JSSE provider does not support it, return null, since
            // we need it only for Kerberos.
            principal = null;
        }
        return principal;
    }
}