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 */ 017 018 package org.apache.commons.net.pop3; 019 020 import java.io.IOException; 021 import java.security.InvalidKeyException; 022 import java.security.NoSuchAlgorithmException; 023 import java.security.spec.InvalidKeySpecException; 024 import javax.crypto.Mac; 025 import javax.crypto.spec.SecretKeySpec; 026 027 import org.apache.commons.net.util.Base64; 028 029 030 /** 031 * A POP3 Cilent class with protocol and authentication extensions support 032 * (RFC2449 and RFC2195). 033 * @see POP3Client 034 * @since 3.0 035 */ 036 public class ExtendedPOP3Client extends POP3SClient 037 { 038 /** 039 * The default ExtendedPOP3Client constructor. 040 * Creates a new Extended POP3 Client. 041 * @throws NoSuchAlgorithmException 042 */ 043 public ExtendedPOP3Client() throws NoSuchAlgorithmException 044 { 045 super(); 046 } 047 048 /*** 049 * Authenticate to the POP3 server by sending the AUTH command with the 050 * selected mechanism, using the given username and the given password. 051 * <p> 052 * @param method the {@link AUTH_METHOD} to use 053 * @param username the user name 054 * @param password the password 055 * @return True if successfully completed, false if not. 056 * @exception IOException If an I/O error occurs while either sending a 057 * command to the server or receiving a reply from the server. 058 * @exception NoSuchAlgorithmException If the CRAM hash algorithm 059 * cannot be instantiated by the Java runtime system. 060 * @exception InvalidKeyException If the CRAM hash algorithm 061 * failed to use the given password. 062 * @exception InvalidKeySpecException If the CRAM hash algorithm 063 * failed to use the given password. 064 ***/ 065 public boolean auth(AUTH_METHOD method, 066 String username, String password) 067 throws IOException, NoSuchAlgorithmException, 068 InvalidKeyException, InvalidKeySpecException 069 { 070 if (sendCommand(POP3Command.AUTH, method.getAuthName()) 071 != POP3Reply.OK_INT) { 072 return false; 073 } 074 075 switch(method) { 076 case PLAIN: 077 // the server sends an empty response ("+ "), so we don't have to read it. 078 return sendCommand( 079 new String( 080 Base64.encodeBase64(("\000" + username + "\000" + password).getBytes()) 081 ) 082 ) == POP3Reply.OK; 083 case CRAM_MD5: 084 // get the CRAM challenge 085 byte[] serverChallenge = Base64.decodeBase64(getReplyString().substring(2).trim()); 086 // get the Mac instance 087 Mac hmac_md5 = Mac.getInstance("HmacMD5"); 088 hmac_md5.init(new SecretKeySpec(password.getBytes(), "HmacMD5")); 089 // compute the result: 090 byte[] hmacResult = _convertToHexString(hmac_md5.doFinal(serverChallenge)).getBytes(); 091 // join the byte arrays to form the reply 092 byte[] usernameBytes = username.getBytes(); 093 byte[] toEncode = new byte[usernameBytes.length + 1 /* the space */ + hmacResult.length]; 094 System.arraycopy(usernameBytes, 0, toEncode, 0, usernameBytes.length); 095 toEncode[usernameBytes.length] = ' '; 096 System.arraycopy(hmacResult, 0, toEncode, usernameBytes.length + 1, hmacResult.length); 097 // send the reply and read the server code: 098 return sendCommand(Base64.encodeBase64StringUnChunked(toEncode)) == POP3Reply.OK; 099 default: 100 return false; 101 } 102 } 103 104 /** 105 * Converts the given byte array to a String containing the hex values of the bytes. 106 * For example, the byte 'A' will be converted to '41', because this is the ASCII code 107 * (and the byte value) of the capital letter 'A'. 108 * @param a The byte array to convert. 109 * @return The resulting String of hex codes. 110 */ 111 private String _convertToHexString(byte[] a) 112 { 113 StringBuilder result = new StringBuilder(a.length*2); 114 for (byte element : a) 115 { 116 if ( (element & 0x0FF) <= 15 ) { 117 result.append("0"); 118 } 119 result.append(Integer.toHexString(element & 0x0FF)); 120 } 121 return result.toString(); 122 } 123 124 /** 125 * The enumeration of currently-supported authentication methods. 126 */ 127 public static enum AUTH_METHOD 128 { 129 /** The standarised (RFC4616) PLAIN method, which sends the password unencrypted (insecure). */ 130 PLAIN("PLAIN"), 131 132 /** The standarised (RFC2195) CRAM-MD5 method, which doesn't send the password (secure). */ 133 CRAM_MD5("CRAM-MD5"); 134 135 private final String methodName; 136 137 AUTH_METHOD(String methodName){ 138 this.methodName = methodName; 139 } 140 /** 141 * Gets the name of the given authentication method suitable for the server. 142 * @return The name of the given authentication method suitable for the server. 143 */ 144 public final String getAuthName() 145 { 146 return this.methodName; 147 } 148 } 149 }