/***********************************************************************
* Copyright (c) 2000-2006 The Apache Software Foundation. *
* All rights reserved. *
* ------------------------------------------------------------------- *
* Licensed under the Apache License, Version 2.0 (the "License"); you *
* may not use this file except in compliance with the License. You *
* may obtain a copy of the License at: *
* *
* http://www.apache.org/licenses/LICENSE-2.0 *
* *
* Unless required by applicable law or agreed to in writing, software *
* distributed under the License is distributed on an "AS IS" BASIS, *
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or *
* implied. See the License for the specific language governing *
* permissions and limitations under the License. *
***********************************************************************/
package org.apache.james.transport.mailets.smime;
import java.io.IOException;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.Part;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import org.apache.james.security.KeyHolder;
import org.apache.mailet.GenericMailet;
import org.apache.mailet.Mail;
import org.apache.mailet.MailetConfig;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.RecipientId;
import org.bouncycastle.cms.RecipientInformation;
import org.bouncycastle.mail.smime.SMIMEEnveloped;
import org.bouncycastle.mail.smime.SMIMEUtil;
/**
* This mailet decrypts a s/mime encrypted message. It takes as input an
* encrypted message and it tries to dechiper it using the key specified in its
* configuration. If the decryption is successful the mail will be changed and
* it will contain the decrypted message. The mail attribute
* <code>org.apache.james.SMIMEDecrypt</code> will contain the public
* certificate of the key used in the process.
*
* The configuration parameters of this mailet are summarized below. The firsts
* define the keystore where the key that will be used to decrypt messages is
* saved.
* <ul>
* <li>keyStoreType (default: system dependent): defines the type of the store.
* Usually jks, pkcs12 or pkcs7</li>
* <li>keyStoreFileName (mandatory): private key store path.</li>
* <li>keyStorePassword (default: ""): private key store password</li>
* </ul>
* The other parameters define which private key have to be used. (if the store
* contains more than one key).
* <ul>
* <li>keyAlias: private key alias.</li>
* <li>keyPass: private key password</li>
* </ul>
*
*/
public class SMIMEDecrypt extends GenericMailet {
private KeyHolder keyHolder;
protected String mailAttribute = "org.apache.james.SMIMEDecrypt";
public void init() throws MessagingException {
super.init();
MailetConfig config = getMailetConfig();
String privateStoreType = config.getInitParameter("keyStoreType");
String privateStoreFile = config.getInitParameter("keyStoreFileName");
if (privateStoreFile == null) throw new MessagingException("No keyStoreFileName specified");
String privateStorePass = config.getInitParameter("keyStorePassword");
String keyAlias= config.getInitParameter("keyAlias");
String keyPass = config.getInitParameter("keyAliasPassword");
String mailAttributeConf = config.getInitParameter("mailAttribute");
if (mailAttributeConf != null) mailAttribute = mailAttributeConf;
try {
keyHolder = new KeyHolder(privateStoreFile, privateStorePass, keyAlias, keyPass, privateStoreType);
} catch (IOException e) {
throw new MessagingException("Error loading keystore", e);
} catch (GeneralSecurityException e) {
throw new MessagingException("Error loading keystore", e);
}
}
/* (non-Javadoc)
* @see org.apache.mailet.Mailet#service(org.apache.mailet.Mail)
*/
public void service(Mail mail) throws MessagingException {
MimeMessage message = mail.getMessage();
Part strippedMessage = null;
log("Starting message decryption..");
if (message.isMimeType("application/x-pkcs7-mime") || message.isMimeType("application/pkcs7-mime")) {
try {
SMIMEEnveloped env = new SMIMEEnveloped(message);
Collection recipients = env.getRecipientInfos().getRecipients();
for (Iterator iter = recipients.iterator();iter.hasNext();) {
RecipientInformation info = (RecipientInformation) iter.next();
RecipientId id = info.getRID();
if (id.match(keyHolder.getCertificate())) {
try {
MimeBodyPart part = SMIMEUtil.toMimeBodyPart(info.getContent(keyHolder.getPrivateKey(), "BC"));
// strippedMessage contains the decrypted message.
strippedMessage = part;
log("Encrypted message decrypted");
} catch (Exception e) {
throw new MessagingException("Error during the decryption of the message", e); }
} else {
log("Found an encrypted message but it isn't encrypted for the supplied key");
}
}
} catch (CMSException e) { throw new MessagingException("Error during the decryption of the message",e); }
}
// if the decryption has been successful..
if (strippedMessage != null) {
// I put the private key's public certificate as a mailattribute.
// I create a list of certificate because I want to minic the
// behavior of the SMIMEVerifySignature mailet. In that way
// it is possible to reuse the same matchers to analyze
// the result of the operation.
ArrayList list = new ArrayList(1);
list.add(keyHolder.getCertificate());
mail.setAttribute(mailAttribute, list);
// I start the message stripping.
try {
MimeMessage newmex = new MimeMessage(message);
Object obj = strippedMessage.getContent();
if (obj instanceof Multipart) {
log("The message is multipart, content type "+((Multipart)obj).getContentType());
newmex.setContent((Multipart)obj);
} else {
newmex.setContent(obj, strippedMessage.getContentType());
newmex.setDisposition(null);
}
newmex.saveChanges();
mail.setMessage(newmex);
} catch (IOException e) {
log("Error during the strip of the encrypted message");
throw new MessagingException("Error during the stripping of the encrypted message",e);
}
}
}
}