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package panda.net.smtp;
import java.io.IOException;
import java.net.InetAddress;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.net.ssl.SSLContext;
import panda.codec.binary.Base64;
/**
* An SMTP Client class with authentication support (RFC4954).
*
* @see SMTPClient
*/
public class AuthenticatingSMTPClient extends SMTPSClient {
/**
* The default AuthenticatingSMTPClient constructor. Creates a new Authenticating SMTP Client.
*/
public AuthenticatingSMTPClient() {
super();
}
/**
* Constructor for AuthenticatingSMTPClient, using {@link #DEFAULT_PROTOCOL} i.e. TLS
*
* @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
*/
public AuthenticatingSMTPClient(boolean implicit) {
super(implicit);
}
/**
* Overloaded constructor that takes a protocol specification
*
* @param protocol The protocol to use
*/
public AuthenticatingSMTPClient(String protocol) {
super(protocol);
}
/**
* Overloaded constructor that takes a protocol specification and the implicit argument
*
* @param proto the protocol.
* @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
*/
public AuthenticatingSMTPClient(String proto, boolean implicit) {
super(proto, implicit);
}
/**
* Overloaded constructor that takes the protocol specification, the implicit argument and
* encoding
*
* @param proto the protocol.
* @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
* @param encoding the encoding
*/
public AuthenticatingSMTPClient(String proto, boolean implicit, String encoding) {
super(proto, implicit, encoding);
}
/**
* Overloaded constructor that takes the implicit argument, and using {@link #DEFAULT_PROTOCOL}
* i.e. TLS
*
* @param implicit The security mode, {@code true} for implicit, {@code false} for explicit
* @param ctx A pre-configured SSL Context.
*/
public AuthenticatingSMTPClient(boolean implicit, SSLContext ctx) {
super(implicit, ctx);
}
/**
* Overloaded constructor that takes a protocol specification and encoding
*
* @param protocol The protocol to use
* @param encoding The encoding to use
*/
public AuthenticatingSMTPClient(String protocol, String encoding) {
super(protocol, false, encoding);
}
/***
* A convenience method to send the ESMTP EHLO command to the server, receive the reply, and
* return the reply code.
*
*
* @param hostname The hostname of the sender.
* @return The reply code received from the server.
* @exception SMTPConnectionClosedException If the SMTP server prematurely closes the connection
* as a result of the client being idle or some other reason causing the server
* to send SMTP reply code 421. This exception may be caught either as an
* IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending the command or receiving
* the server reply.
***/
public int ehlo(String hostname) throws IOException {
return sendCommand(SMTPCommand.EHLO, hostname);
}
/***
* 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.
*
*
* @param hostname The hostname with which to greet the SMTP server.
* @return True if successfully completed, false if not.
* @exception SMTPConnectionClosedException If the SMTP server prematurely closes the connection
* as a result of the client being idle or some other reason causing the server
* to send SMTP reply code 421. This exception may be caught either as an
* IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a command to the server or
* receiving a reply from the server.
***/
public boolean elogin(String hostname) throws IOException {
return SMTPReply.isPositiveCompletion(ehlo(hostname));
}
/***
* 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.
*
*
* @return True if successfully completed, false if not.
* @exception SMTPConnectionClosedException If the SMTP server prematurely closes the connection
* as a result of the client being idle or some other reason causing the server
* to send SMTP reply code 421. This exception may be caught either as an
* IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a command to the server or
* receiving a reply from the server.
***/
public boolean elogin() throws IOException {
String name;
InetAddress host;
host = getLocalAddress();
name = host.getHostName();
if (name == null) {
return false;
}
return SMTPReply.isPositiveCompletion(ehlo(name));
}
/***
* Returns the integer values of the enhanced reply code of the last SMTP reply.
*
* @return The integer values of the enhanced reply code of the last SMTP reply. First digit is
* in the first array element.
***/
public int[] getEnhancedReplyCode() {
String reply = getReplyString().substring(4);
String[] parts = reply.substring(0, reply.indexOf(' ')).split("\\.");
int[] res = new int[parts.length];
for (int i = 0; i < parts.length; i++) {
res[i] = Integer.parseInt(parts[i]);
}
return res;
}
/***
* Authenticate to the SMTP server by sending the AUTH command with the selected mechanism,
* using the given username and the given password.
*
* @param method the method to use, one of the {@link AuthenticatingSMTPClient.AUTH_METHOD} enum
* values
* @param username the user name. If the method is XOAUTH, then this is used as the plain text
* oauth protocol parameter string which is Base64-encoded for transmission.
* @param password the password for the username. Ignored for XOAUTH.
* @return True if successfully completed, false if not.
* @exception SMTPConnectionClosedException If the SMTP server prematurely closes the connection
* as a result of the client being idle or some other reason causing the server
* to send SMTP reply code 421. This exception may be caught either as an
* IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a command to the server or
* receiving a reply from the server.
* @exception NoSuchAlgorithmException If the CRAM hash algorithm cannot be instantiated by the
* Java runtime system.
* @exception InvalidKeyException If the CRAM hash algorithm failed to use the given password.
* @exception InvalidKeySpecException If the CRAM hash algorithm failed to use the given
* password.
***/
public boolean auth(AuthenticatingSMTPClient.AUTH_METHOD method, String username, String password)
throws IOException, NoSuchAlgorithmException, InvalidKeyException, InvalidKeySpecException {
if (!SMTPReply.isPositiveIntermediate(sendCommand(SMTPCommand.AUTH, AUTH_METHOD.getAuthName(method)))) {
return false;
}
if (method.equals(AUTH_METHOD.PLAIN)) {
// the server sends an empty response ("334 "), so we don't have to read it.
return SMTPReply.isPositiveCompletion(sendCommand(
// Java 1.6 can use getCharset()
Base64.encodeBase64String(("\000" + username + "\000" + password).getBytes(getCharsetName()))));
}
else if (method.equals(AUTH_METHOD.CRAM_MD5)) {
// get the CRAM challenge
byte[] serverChallenge = Base64.decodeBase64(getReplyString().substring(4).trim());
// get the Mac instance
Mac hmac_md5 = Mac.getInstance("HmacMD5");
hmac_md5.init(new SecretKeySpec(password.getBytes(getCharsetName()), "HmacMD5")); // Java
// 1.6
// can
// use
// getCharset()
// compute the result:
// Java 1.6 can use getCharset()
byte[] hmacResult = _convertToHexString(hmac_md5.doFinal(serverChallenge)).getBytes(getCharsetName());
// join the byte arrays to form the reply
byte[] usernameBytes = username.getBytes(getCharsetName()); // Java 1.6 can use
// getCharset()
byte[] toEncode = new byte[usernameBytes.length + 1 /* the space */+ hmacResult.length];
System.arraycopy(usernameBytes, 0, toEncode, 0, usernameBytes.length);
toEncode[usernameBytes.length] = ' ';
System.arraycopy(hmacResult, 0, toEncode, usernameBytes.length + 1, hmacResult.length);
// send the reply and read the server code:
return SMTPReply.isPositiveCompletion(sendCommand(Base64.encodeBase64String(toEncode)));
}
else if (method.equals(AUTH_METHOD.LOGIN)) {
// the server sends fixed responses (base64("Username") and
// base64("Password")), so we don't have to read them.
if (!SMTPReply.isPositiveIntermediate(sendCommand(Base64.encodeBase64String(username
.getBytes(getCharsetName()))))) { // Java 1.6 can use getCharset()
return false;
}
return SMTPReply.isPositiveCompletion(sendCommand(Base64.encodeBase64String(password
.getBytes(getCharsetName())))); // Java 1.6 can use getCharset()
}
else if (method.equals(AUTH_METHOD.XOAUTH)) {
return SMTPReply.isPositiveIntermediate(sendCommand(Base64.encodeBase64String(username
.getBytes(getCharsetName())) // Java 1.6 can use getCharset()
));
}
else {
return false; // safety check
}
}
/**
* Converts the given byte array to a String containing the hex values of the bytes. For
* example, the byte 'A' will be converted to '41', because this is the ASCII code (and the byte
* value) of the capital letter 'A'.
*
* @param a The byte array to convert.
* @return The resulting String of hex codes.
*/
private String _convertToHexString(byte[] a) {
StringBuilder result = new StringBuilder(a.length * 2);
for (byte element : a) {
if ((element & 0x0FF) <= 15) {
result.append("0");
}
result.append(Integer.toHexString(element & 0x0FF));
}
return result.toString();
}
/**
* The enumeration of currently-supported authentication methods.
*/
public static enum AUTH_METHOD {
/** The standarised (RFC4616) PLAIN method, which sends the password unencrypted (insecure). */
PLAIN,
/** The standarised (RFC2195) CRAM-MD5 method, which doesn't send the password (secure). */
CRAM_MD5,
/**
* The unstandarised Microsoft LOGIN method, which sends the password unencrypted
* (insecure).
*/
LOGIN,
/** XOAuth method which accepts a signed and base64ed OAuth URL. */
XOAUTH;
/**
* Gets the name of the given authentication method suitable for the server.
*
* @param method The authentication method to get the name for.
* @return The name of the given authentication method suitable for the server.
*/
public static final String getAuthName(AUTH_METHOD method) {
if (method.equals(AUTH_METHOD.PLAIN)) {
return "PLAIN";
}
else if (method.equals(AUTH_METHOD.CRAM_MD5)) {
return "CRAM-MD5";
}
else if (method.equals(AUTH_METHOD.LOGIN)) {
return "LOGIN";
}
else if (method.equals(AUTH_METHOD.XOAUTH)) {
return "XOAUTH";
}
else {
return null;
}
}
}
}
/* kate: indent-width 4; replace-tabs on; */