    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017
    018package org.apache.commons.net.smtp;
    019
    020import java.io.BufferedWriter;
    021import java.io.IOException;
    022import java.io.InputStreamReader;
    023import java.io.OutputStreamWriter;
    024
    025import javax.net.ssl.HostnameVerifier;
    026import javax.net.ssl.KeyManager;
    027import javax.net.ssl.SSLContext;
    028import javax.net.ssl.SSLHandshakeException;
    029import javax.net.ssl.SSLSocket;
    030import javax.net.ssl.SSLSocketFactory;
    031import javax.net.ssl.TrustManager;
    032
    033import org.apache.commons.net.io.CRLFLineReader;
    034import org.apache.commons.net.util.SSLContextUtils;
    035import org.apache.commons.net.util.SSLSocketUtils;
    036
    037/**
    038 * SMTP over SSL processing. Copied from FTPSClient.java and modified to suit SMTP.
    039 * If implicit mode is selected (NOT the default), SSL/TLS negotiation starts right
    040 * after the connection has been established. In explicit mode (the default), SSL/TLS
    041 * negotiation starts when the user calls execTLS() and the server accepts the command.
    042 * Implicit usage:
    043 *               SMTPSClient c = new SMTPSClient(true);
    044 *               c.connect("127.0.0.1", 465);
    045 * Explicit usage:
    046 *               SMTPSClient c = new SMTPSClient();
    047 *               c.connect("127.0.0.1", 25);
    048 *               if (c.execTLS()) { /rest of the commands here/ }
    049 *
    050 * Warning: the hostname is not verified against the certificate by default, use
    051 * {@link #setHostnameVerifier(HostnameVerifier)} or {@link #setEndpointCheckingEnabled(boolean)}
    052 * (on Java 1.7+) to enable verification.
    053 * @since 3.0
    054 */
    055public class SMTPSClient extends SMTPClient
    056{
    057    /** Default secure socket protocol name, like TLS */
    058    private static final String DEFAULT_PROTOCOL = "TLS";
    059
    060    /** The security mode. True - Implicit Mode / False - Explicit Mode. */
    061    private final boolean isImplicit;
    062    /** The secure socket protocol to be used, like SSL/TLS. */
    063    private final String protocol;
    064    /** The context object. */
    065    private SSLContext context = null;
    066    /** The cipher suites. SSLSockets have a default set of these anyway,
    067        so no initialization required. */
    068    private String[] suites = null;
    069    /** The protocol versions. */
    070    private String[] protocols = null;
    071
    072    /** The {@link TrustManager} implementation, default null (i.e. use system managers). */
    073    private TrustManager trustManager = null;
    074
    075    /** The {@link KeyManager}, default null (i.e. use system managers). */
    076    private KeyManager keyManager = null; // seems not to be required
    077
    078    /** The {@link HostnameVerifier} to use post-TLS, default null (i.e. no verification). */
    079    private HostnameVerifier hostnameVerifier = null;
    080
    081    /** Use Java 1.7+ HTTPS Endpoint Identification Algorithim. */
    082    private boolean tlsEndpointChecking;
    083
    084    /**
    085     * Constructor for SMTPSClient, using {@link #DEFAULT_PROTOCOL} i.e. TLS
    086     * Sets security mode to explicit (isImplicit = false).
    087     */
    088    public SMTPSClient()
    089    {
    090        this(DEFAULT_PROTOCOL, false);
    091    }
    092
    093    /**
    094     * Constructor for SMTPSClient, using {@link #DEFAULT_PROTOCOL} i.e. TLS
    095     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
    096     */
    097    public SMTPSClient(boolean implicit)
    098    {
    099        this(DEFAULT_PROTOCOL, implicit);
    100    }
    101
    102    /**
    103     * Constructor for SMTPSClient, using explicit security mode.
    104     * @param proto the protocol.
    105     */
    106    public SMTPSClient(String proto)
    107    {
    108        this(proto, false);
    109    }
    110
    111    /**
    112     * Constructor for SMTPSClient.
    113     * @param proto the protocol.
    114     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
    115     */
    116    public SMTPSClient(String proto, boolean implicit)
    117    {
    118        protocol = proto;
    119        isImplicit = implicit;
    120    }
    121
    122    /**
    123     * Constructor for SMTPSClient.
    124     * @param proto the protocol.
    125     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
    126     * @param encoding the encoding
    127     * @since 3.3
    128     */
    129    public SMTPSClient(String proto, boolean implicit, String encoding)
    130    {
    131        super(encoding);
    132        protocol = proto;
    133        isImplicit = implicit;
    134    }
    135
    136    /**
    137     * Constructor for SMTPSClient, using {@link #DEFAULT_PROTOCOL} i.e. TLS
    138     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
    139     * @param ctx A pre-configured SSL Context.
    140     */
    141    public SMTPSClient(boolean implicit, SSLContext ctx)
    142    {
    143        isImplicit = implicit;
    144        context = ctx;
    145        protocol = DEFAULT_PROTOCOL;
    146    }
    147
    148    /**
    149     * Constructor for SMTPSClient.
    150     * @param context A pre-configured SSL Context.
    151     * @see #SMTPSClient(boolean, SSLContext)
    152     */
    153    public SMTPSClient(SSLContext context)
    154    {
    155        this(false, context);
    156    }
    157
    158    /**
    159     * Because there are so many connect() methods,
    160     * the _connectAction_() method is provided as a means of performing
    161     * some action immediately after establishing a connection,
    162     * rather than reimplementing all of the connect() methods.
    163     * @throws IOException If it is thrown by _connectAction_().
    164     * @see org.apache.commons.net.SocketClient#_connectAction_()
    165     */
    166    @Override
    167    protected void _connectAction_() throws IOException
    168    {
    169        // Implicit mode.
    170        if (isImplicit) {
    171            performSSLNegotiation();
    172        }
    173        super._connectAction_();
    174        // Explicit mode - don't do anything. The user calls execTLS()
    175    }
    176
    177    /**
    178     * Performs a lazy init of the SSL context.
    179     * @throws IOException When could not initialize the SSL context.
    180     */
    181    private void initSSLContext() throws IOException
    182    {
    183        if (context == null)
    184        {
    185            context = SSLContextUtils.createSSLContext(protocol, getKeyManager(), getTrustManager());
    186        }
    187    }
    188
    189    /**
    190     * SSL/TLS negotiation. Acquires an SSL socket of a
    191     * connection and carries out handshake processing.
    192     * @throws IOException If server negotiation fails.
    193     */
    194    private void performSSLNegotiation() throws IOException
    195    {
    196        initSSLContext();
    197
    198        SSLSocketFactory ssf = context.getSocketFactory();
    199        String host = (_hostname_ != null) ? _hostname_ : getRemoteAddress().getHostAddress();
    200        int port = getRemotePort();
    201        SSLSocket socket =
    202            (SSLSocket) ssf.createSocket(_socket_, host, port, true);
    203        socket.setEnableSessionCreation(true);
    204        socket.setUseClientMode(true);
    205
    206        if (tlsEndpointChecking) {
    207            SSLSocketUtils.enableEndpointNameVerification(socket);
    208        }
    209        if (protocols != null) {
    210            socket.setEnabledProtocols(protocols);
    211        }
    212        if (suites != null) {
    213            socket.setEnabledCipherSuites(suites);
    214        }
    215        socket.startHandshake();
    216
    217        // TODO the following setup appears to duplicate that in the super class methods
    218        _socket_ = socket;
    219        _input_ = socket.getInputStream();
    220        _output_ = socket.getOutputStream();
    221        _reader = new CRLFLineReader(
    222                        new InputStreamReader(_input_, encoding));
    223        _writer = new BufferedWriter(
    224                        new OutputStreamWriter(_output_, encoding));
    225
    226        if (hostnameVerifier != null && !hostnameVerifier.verify(host, socket.getSession())) {
    227            throw new SSLHandshakeException("Hostname doesn't match certificate");
    228        }
    229    }
    230
    231    /**
    232     * Get the {@link KeyManager} instance.
    233     * @return The current {@link KeyManager} instance.
    234     */
    235    public KeyManager getKeyManager()
    236    {
    237        return keyManager;
    238    }
    239
    240    /**
    241     * Set a {@link KeyManager} to use.
    242     * @param newKeyManager The KeyManager implementation to set.
    243     * @see org.apache.commons.net.util.KeyManagerUtils
    244     */
    245    public void setKeyManager(KeyManager newKeyManager)
    246    {
    247        keyManager = newKeyManager;
    248    }
    249
    250    /**
    251     * Controls which particular cipher suites are enabled for use on this
    252     * connection. Called before server negotiation.
    253     * @param cipherSuites The cipher suites.
    254     */
    255    public void setEnabledCipherSuites(String[] cipherSuites)
    256    {
    257        suites = new String[cipherSuites.length];
    258        System.arraycopy(cipherSuites, 0, suites, 0, cipherSuites.length);
    259    }
    260
    261    /**
    262     * Returns the names of the cipher suites which could be enabled
    263     * for use on this connection.
    264     * When the underlying {@link java.net.Socket Socket} is not an {@link SSLSocket} instance, returns null.
    265     * @return An array of cipher suite names, or <code>null</code>.
    266     */
    267    public String[] getEnabledCipherSuites()
    268    {
    269        if (_socket_ instanceof SSLSocket)
    270        {
    271            return ((SSLSocket)_socket_).getEnabledCipherSuites();
    272        }
    273        return null;
    274    }
    275
    276    /**
    277     * Controls which particular protocol versions are enabled for use on this
    278     * connection. I perform setting before a server negotiation.
    279     * @param protocolVersions The protocol versions.
    280     */
    281    public void setEnabledProtocols(String[] protocolVersions)
    282    {
    283        protocols = new String[protocolVersions.length];
    284        System.arraycopy(protocolVersions, 0, protocols, 0, protocolVersions.length);
    285    }
    286
    287    /**
    288     * Returns the names of the protocol versions which are currently
    289     * enabled for use on this connection.
    290     * When the underlying {@link java.net.Socket Socket} is not an {@link SSLSocket} instance, returns null.
    291     * @return An array of protocols, or <code>null</code>.
    292     */
    293    public String[] getEnabledProtocols()
    294    {
    295        if (_socket_ instanceof SSLSocket)
    296        {
    297            return ((SSLSocket)_socket_).getEnabledProtocols();
    298        }
    299        return null;
    300    }
    301
    302    /**
    303     * The TLS command execution.
    304     * @throws IOException If an I/O error occurs while sending
    305     * the command or performing the negotiation.
    306     * @return TRUE if the command and negotiation succeeded.
    307     */
    308    public boolean execTLS() throws IOException
    309    {
    310        if (!SMTPReply.isPositiveCompletion(sendCommand("STARTTLS")))
    311        {
    312            return false;
    313            //throw new SSLException(getReplyString());
    314        }
    315        performSSLNegotiation();
    316        return true;
    317    }
    318
    319    /**
    320     * Get the currently configured {@link TrustManager}.
    321     * @return A TrustManager instance.
    322     */
    323    public TrustManager getTrustManager()
    324    {
    325        return trustManager;
    326    }
    327
    328    /**
    329     * Override the default {@link TrustManager} to use.
    330     * @param newTrustManager The TrustManager implementation to set.
    331     * @see org.apache.commons.net.util.TrustManagerUtils
    332     */
    333    public void setTrustManager(TrustManager newTrustManager)
    334    {
    335        trustManager = newTrustManager;
    336    }
    337
    338    /**
    339     * Get the currently configured {@link HostnameVerifier}.
    340     * @return A HostnameVerifier instance.
    341     * @since 3.4
    342     */
    343    public HostnameVerifier getHostnameVerifier()
    344    {
    345        return hostnameVerifier;
    346    }
    347
    348    /**
    349     * Override the default {@link HostnameVerifier} to use.
    350     * @param newHostnameVerifier The HostnameVerifier implementation to set or <code>null</code> to disable.
    351     * @since 3.4
    352     */
    353    public void setHostnameVerifier(HostnameVerifier newHostnameVerifier)
    354    {
    355        hostnameVerifier = newHostnameVerifier;
    356    }
    357
    358    /**
    359     * Return whether or not endpoint identification using the HTTPS algorithm
    360     * on Java 1.7+ is enabled. The default behavior is for this to be disabled.
    361     *
    362     * @return True if enabled, false if not.
    363     * @since 3.4
    364     */
    365    public boolean isEndpointCheckingEnabled()
    366    {
    367        return tlsEndpointChecking;
    368    }
    369
    370    /**
    371     * Automatic endpoint identification checking using the HTTPS algorithm
    372     * is supported on Java 1.7+. The default behavior is for this to be disabled.
    373     *
    374     * @param enable Enable automatic endpoint identification checking using the HTTPS algorithm on Java 1.7+.
    375     * @since 3.4
    376     */
    377    public void setEndpointCheckingEnabled(boolean enable)
    378    {
    379        tlsEndpointChecking = enable;
    380    }
    381}
    382
    383/* kate: indent-width 4; replace-tabs on; */