Source code

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.IOException;
021import java.net.InetAddress;
022import java.security.InvalidKeyException;
023import java.security.NoSuchAlgorithmException;
024import java.security.spec.InvalidKeySpecException;
025import java.util.Arrays;
026import java.util.Base64;
027
028import javax.crypto.Mac;
029import javax.crypto.spec.SecretKeySpec;
030import javax.net.ssl.SSLContext;
031
032/**
033 * An SMTP Client class with authentication support (RFC4954).
034 *
035 * @see SMTPClient
036 * @since 3.0
037 */
038public class AuthenticatingSMTPClient extends SMTPSClient {
039
040    /**
041     * The enumeration of currently-supported authentication methods.
042     */
043    public enum AUTH_METHOD {
044
045        /** The standardized (RFC4616) PLAIN method, which sends the password unencrypted (insecure). */
046        PLAIN,
047
048        /** The standardized (RFC2195) CRAM-MD5 method, which doesn't send the password (secure). */
049        CRAM_MD5,
050
051        /** The non-standarized Microsoft LOGIN method, which sends the password unencrypted (insecure). */
052        LOGIN,
053
054        /** XOAuth method which accepts a signed and base64ed OAuth URL. */
055        XOAUTH,
056
057        /** XOAuth 2 method which accepts a signed and base64ed OAuth JSON. */
058        XOAUTH2;
059
060        /**
061         * Gets the name of the given authentication method suitable for the server.
062         *
063         * @param method The authentication method to get the name for.
064         * @return The name of the given authentication method suitable for the server.
065         */
066        public static final String getAuthName(final AUTH_METHOD method) {
067            if (method.equals(AUTH_METHOD.PLAIN)) {
068                return "PLAIN";
069            }
070            if (method.equals(AUTH_METHOD.CRAM_MD5)) {
071                return "CRAM-MD5";
072            }
073            if (method.equals(AUTH_METHOD.LOGIN)) {
074                return "LOGIN";
075            }
076            if (method.equals(AUTH_METHOD.XOAUTH)) {
077                return "XOAUTH";
078            }
079            if (method.equals(AUTH_METHOD.XOAUTH2)) {
080                return "XOAUTH2";
081            }
082            return null;
083        }
084    }
085
086    /** {@link Mac} algorithm. */
087    private static final String MAC_ALGORITHM = "HmacMD5";
088
089    /**
090     * The default AuthenticatingSMTPClient constructor. Creates a new Authenticating SMTP Client.
091     */
092    public AuthenticatingSMTPClient() {
093    }
094
095    /**
096     * Overloaded constructor that takes the implicit argument, and using {@link #DEFAULT_PROTOCOL} i.e. TLS
097     *
098     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
099     * @param ctx      A pre-configured SSL Context.
100     * @since 3.3
101     */
102    public AuthenticatingSMTPClient(final boolean implicit, final SSLContext ctx) {
103        super(implicit, ctx);
104    }
105
106    /**
107     * Overloaded constructor that takes a protocol specification
108     *
109     * @param protocol The protocol to use
110     */
111    public AuthenticatingSMTPClient(final String protocol) {
112        super(protocol);
113    }
114
115    /**
116     * Overloaded constructor that takes a protocol specification and the implicit argument
117     *
118     * @param proto    the protocol.
119     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
120     * @since 3.3
121     */
122    public AuthenticatingSMTPClient(final String proto, final boolean implicit) {
123        super(proto, implicit);
124    }
125
126    /**
127     * Overloaded constructor that takes the protocol specification, the implicit argument and encoding
128     *
129     * @param proto    the protocol.
130     * @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
131     * @param encoding the encoding
132     * @since 3.3
133     */
134    public AuthenticatingSMTPClient(final String proto, final boolean implicit, final String encoding) {
135        super(proto, implicit, encoding);
136    }
137
138    /**
139     * Overloaded constructor that takes a protocol specification and encoding
140     *
141     * @param protocol The protocol to use
142     * @param encoding The encoding to use
143     * @since 3.3
144     */
145    public AuthenticatingSMTPClient(final String protocol, final String encoding) {
146        super(protocol, false, encoding);
147    }
148
149    /**
150     * Authenticate to the SMTP server by sending the AUTH command with the selected mechanism, using the given user and the given password.
151     *
152     * @param method   the method to use, one of the {@link AuthenticatingSMTPClient.AUTH_METHOD} enum values
153     * @param user the user name. If the method is XOAUTH/XOAUTH2, then this is used as the plain text oauth protocol parameter string which is
154     *                 Base64-encoded for transmission.
155     * @param password the password for the username. Ignored for XOAUTH/XOAUTH2.
156     *
157     * @return True if successfully completed, false if not.
158     * @throws SMTPConnectionClosedException If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
159     *                                       causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
160     *                                       independently as itself.
161     * @throws IOException                   If an I/O error occurs while either sending a command to the server or receiving a reply from the server.
162     * @throws NoSuchAlgorithmException      If the CRAM hash algorithm cannot be instantiated by the Java runtime system.
163     * @throws InvalidKeyException           If the CRAM hash algorithm failed to use the given password.
164     * @throws InvalidKeySpecException       If the CRAM hash algorithm failed to use the given password.
165     */
166    public boolean auth(final AuthenticatingSMTPClient.AUTH_METHOD method, final String user, final String password)
167            throws IOException, NoSuchAlgorithmException, InvalidKeyException, InvalidKeySpecException {
168        if (!SMTPReply.isPositiveIntermediate(sendCommand(SMTPCommand.AUTH, AUTH_METHOD.getAuthName(method)))) {
169            return false;
170        }
171
172        if (method.equals(AUTH_METHOD.PLAIN)) {
173            // the server sends an empty response ("334 "), so we don't have to read it.
174            return SMTPReply
175                    .isPositiveCompletion(sendCommand(Base64.getEncoder().encodeToString(("\000" + user + "\000" + password).getBytes(getCharset()))));
176        }
177        if (method.equals(AUTH_METHOD.CRAM_MD5)) {
178            // get the CRAM challenge
179            final byte[] serverChallenge = Base64.getDecoder().decode(getReplyString().substring(4).trim());
180            // get the Mac instance
181            final Mac hmacMd5 = Mac.getInstance(MAC_ALGORITHM);
182            hmacMd5.init(new SecretKeySpec(password.getBytes(getCharset()), MAC_ALGORITHM));
183            // compute the result:
184            final byte[] hmacResult = convertToHexString(hmacMd5.doFinal(serverChallenge)).getBytes(getCharset());
185            // join the byte arrays to form the reply
186            final byte[] userNameBytes = user.getBytes(getCharset());
187            final byte[] toEncode = new byte[userNameBytes.length + 1 /* the space */ + hmacResult.length];
188            System.arraycopy(userNameBytes, 0, toEncode, 0, userNameBytes.length);
189            toEncode[userNameBytes.length] = ' ';
190            System.arraycopy(hmacResult, 0, toEncode, userNameBytes.length + 1, hmacResult.length);
191            // send the reply and read the server code:
192            return SMTPReply.isPositiveCompletion(sendCommand(Base64.getEncoder().encodeToString(toEncode)));
193        }
194        if (method.equals(AUTH_METHOD.LOGIN)) {
195            // the server sends fixed responses (base64("UserName") and
196            // base64("Password")), so we don't have to read them.
197            if (!SMTPReply.isPositiveIntermediate(sendCommand(Base64.getEncoder().encodeToString(user.getBytes(getCharset()))))) {
198                return false;
199            }
200            return SMTPReply.isPositiveCompletion(sendCommand(Base64.getEncoder().encodeToString(password.getBytes(getCharset()))));
201        }
202        if (method.equals(AUTH_METHOD.XOAUTH) || method.equals(AUTH_METHOD.XOAUTH2)) {
203            return SMTPReply.isPositiveIntermediate(sendCommand(Base64.getEncoder().encodeToString(user.getBytes(getCharset()))));
204        }
205        return false; // safety check
206    }
207
208    /**
209     * Converts the given byte array to a String containing the hexadecimal values of the bytes. For example, the byte 'A' will be converted to '41', because
210     * this is the ASCII code (and the byte value) of the capital letter 'A'.
211     *
212     * @param a The byte array to convert.
213     * @return The resulting String of hexadecimal codes.
214     */
215    private String convertToHexString(final byte[] a) {
216        final StringBuilder result = new StringBuilder(a.length * 2);
217        for (final byte element : a) {
218            if ((element & 0x0FF) <= 15) {
219                result.append("0");
220            }
221            result.append(Integer.toHexString(element & 0x0FF));
222        }
223        return result.toString();
224    }
225
226    /**
227     * A convenience method to send the ESMTP EHLO command to the server, receive the reply, and return the reply code.
228     *
229     * @param hostname The hostname of the sender.
230     * @return The reply code received from the server.
231     * @throws SMTPConnectionClosedException If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
232     *                                       causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
233     *                                       independently as itself.
234     * @throws IOException                   If an I/O error occurs while either sending the command or receiving the server reply.
235     */
236    public int ehlo(final String hostname) throws IOException {
237        return sendCommand(SMTPCommand.EHLO, hostname);
238    }
239
240    /**
241     * Login to the ESMTP server by sending the EHLO command with the client hostname as an argument. Before performing any mail commands, you must first login.
242     *
243     * @return True if successfully completed, false if not.
244     * @throws SMTPConnectionClosedException If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
245     *                                       causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
246     *                                       independently as itself.
247     * @throws IOException                   If an I/O error occurs while either sending a command to the server or receiving a reply from the server.
248     */
249    public boolean elogin() throws IOException {
250        final String name;
251        final InetAddress host;
252
253        host = getLocalAddress();
254        name = host.getHostName();
255
256        if (name == null) {
257            return false;
258        }
259
260        return SMTPReply.isPositiveCompletion(ehlo(name));
261    }
262
263    /**
264     * Login to the ESMTP server by sending the EHLO command with the given hostname as an argument. Before performing any mail commands, you must first login.
265     *
266     * @param hostname The hostname with which to greet the SMTP server.
267     * @return True if successfully completed, false if not.
268     * @throws SMTPConnectionClosedException If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
269     *                                       causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
270     *                                       independently as itself.
271     * @throws IOException                   If an I/O error occurs while either sending a command to the server or receiving a reply from the server.
272     */
273    public boolean elogin(final String hostname) throws IOException {
274        return SMTPReply.isPositiveCompletion(ehlo(hostname));
275    }
276
277    /**
278     * Returns the integer values of the enhanced reply code of the last SMTP reply.
279     *
280     * @return The integer values of the enhanced reply code of the last SMTP reply. First digit is in the first array element.
281     */
282    public int[] getEnhancedReplyCode() {
283        final String reply = getReplyString().substring(4);
284        final String[] parts = reply.substring(0, reply.indexOf(' ')).split("\\.");
285        final int[] res = new int[parts.length];
286        Arrays.setAll(res, i -> Integer.parseInt(parts[i]));
287        return res;
288    }
289}