smimeabstractsign.java

java mail,java mailjava mailjava mailjava mail

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package org.apache.james.transport.mailets.smime;

import org.apache.james.security.KeyHolder;
import org.apache.james.security.SMIMEAttributeNames;
import org.apache.mailet.GenericMailet;
import org.apache.mailet.Mail;
import org.apache.mailet.MailAddress;
import org.apache.mailet.RFC2822Headers;

import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;
import javax.mail.internet.ParseException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;

/**
 * <P>Abstract mailet providing common SMIME signature services.<BR>
 * It can be subclassed to make authoring signing mailets simple.<BR>
 * By extending it and overriding one or more of the following methods a new behaviour can
 * be quickly created without the author having to address any issue other than
 * the relevant one:</P>
 * <ul>
 * <li>{@link #initDebug}, {@link #setDebug} and {@link #isDebug} manage the debugging mode.</li>
 * <li>{@link #initExplanationText}, {@link #setExplanationText} and {@link #getExplanationText} manage the text of
 * an attachment that will be added to explain the meaning of this server-side signature.</li>
 * <li>{@link #initKeyHolder}, {@link #setKeyHolder} and {@link #getKeyHolder} manage the {@link KeyHolder} object that will
 * contain the keys and certificates and will do the crypto work.</li>
 * <li>{@link #initPostmasterSigns}, {@link #setPostmasterSigns} and {@link #isPostmasterSigns}
 * determines whether messages originated by the Postmaster will be signed or not.</li>
 * <li>{@link #initRebuildFrom}, {@link #setRebuildFrom} and {@link #isRebuildFrom}
 * determines whether the "From:" header will be rebuilt to neutralize the wrong behaviour of
 * some MUAs like Microsoft Outlook Express.</li>
 * <li>{@link #initSignerName}, {@link #setSignerName} and {@link #getSignerName} manage the name
 * of the signer to be shown in the explanation text.</li>
 * <li>{@link #isOkToSign} controls whether the mail can be signed or not.</li>
 * <li>The abstract method {@link #getWrapperBodyPart} returns the massaged {@link javax.mail.internet.MimeBodyPart}
 * that will be signed, or null if the message has to be signed "as is".</li>
 * </ul>
 *
 * <P>Handles the following init parameters:</P>
 * <ul>
 * <li>&lt;debug&gt;: if <CODE>true</CODE> some useful information is logged.
 * The default is <CODE>false</CODE>.</li>
 * <li>&lt;keyStoreFileName&gt;: the {@link java.security.KeyStore} full file name.</li>
 * <li>&lt;keyStorePassword&gt;: the <CODE>KeyStore</CODE> password.
 *      If given, it is used to check the integrity of the keystore data,
 *      otherwise, if null, the integrity of the keystore is not checked.</li>
 * <li>&lt;keyAlias&gt;: the alias name to use to search the Key using {@link java.security.KeyStore#getKey}.
 * The default is to look for the first and only alias in the keystore;
 * if zero or more than one is found a {@link java.security.KeyStoreException} is thrown.</li>
 * <li>&lt;keyAliasPassword&gt;: the alias password. The default is to use the <CODE>KeyStore</CODE> password.
 *      At least one of the passwords must be provided.</li>
 * <li>&lt;keyStoreType&gt;: the type of the keystore. The default will use {@link java.security.KeyStore#getDefaultType}.</li>
 * <li>&lt;postmasterSigns&gt;: if <CODE>true</CODE> the message will be signed even if the sender is the Postmaster.
 * The default is <CODE>false</CODE>.</li></li>
 * <li>&lt;rebuildFrom&gt;: If <CODE>true</CODE> will modify the "From:" header.
 * For more info see {@link #isRebuildFrom}.
 * The default is <CODE>false</CODE>.</li>
 * <li>&lt;signerName&gt;: the name of the signer to be shown in the explanation text.
 * The default is to use the "CN=" property of the signing certificate.</li>
 * <li>&lt;explanationText&gt;: the text of an explanation of the meaning of this server-side signature.
 * May contain the following substitution patterns (see also {@link #getReplacedExplanationText}):
 * <CODE>[signerName]</CODE>, <CODE>[signerAddress]</CODE>, <CODE>[reversePath]</CODE>, <CODE>[headers]</CODE>.
 * It should be included in the signature.
 * The actual presentation of the text depends on the specific concrete mailet subclass:
 * see for example {@link SMIMESign}.
 * The default is to not have any explanation text.</li>
 * </ul>
 * @version CVS $Revision: 494012 $ $Date: 2007-01-08 11:23:58 +0100 (Mo, 08 Jan 2007) $
 * @since 2.2.1
 */
public abstract class SMIMEAbstractSign extends GenericMailet {
    
    private static final String HEADERS_PATTERN = "[headers]";
    
    private static final String SIGNER_NAME_PATTERN = "[signerName]";
    
    private static final String SIGNER_ADDRESS_PATTERN = "[signerAddress]";
    
    private static final String REVERSE_PATH_PATTERN = "[reversePath]";
    
    /**
     * Holds value of property debug.
     */
    private boolean debug;
    
    /**
     * Holds value of property explanationText.
     */
    private String explanationText;
    
    /**
     * Holds value of property keyHolder.
     */
    private KeyHolder keyHolder;
    
    /**
     * Holds value of property postmasterSigns.
     */
    private boolean postmasterSigns;
    
    /**
     * Holds value of property rebuildFrom.
     */
    private boolean rebuildFrom;
    
    /**
     * Holds value of property signerName.
     */
    private String signerName;
    
    /**
     * Gets the expected init parameters.
     * @return An array containing the parameter names allowed for this mailet.
     */
    protected abstract String[] getAllowedInitParameters();
    
    /* ******************************************************************** */
    /* ****************** Begin of setters and getters ******************** */
    /* ******************************************************************** */
    
    /**
     * Initializer for property debug.
     */
    protected void initDebug() {
        setDebug((getInitParameter("debug") == null) ? false : new Boolean(getInitParameter("debug")).booleanValue());
    }
    
    /**
     * Getter for property debug.
     * @return Value of property debug.
     */
    public boolean isDebug() {
        return this.debug;
    }
    
    /**
     * Setter for property debug.
     * @param debug New value of property debug.
     */
    public void setDebug(boolean debug) {
        this.debug = debug;
    }
    
    /**
     * Initializer for property explanationText.
     */
    protected void initExplanationText() {
        setExplanationText(getInitParameter("explanationText"));
        if (isDebug()) {
            log("Explanation text:\r\n" + getExplanationText());
        }
    }
    
    /**
     * Getter for property explanationText.
     * Text to be used in the SignatureExplanation.txt file.
     * @return Value of property explanationText.
     */
    public String getExplanationText() {
        return this.explanationText;
    }
    
    /**
     * Setter for property explanationText.
     * @param explanationText New value of property explanationText.
     */
    public void setExplanationText(String explanationText) {
        this.explanationText = explanationText;
    }
    
    /**
     * Initializer for property keyHolder.
     */
    protected void initKeyHolder() throws Exception {
        String keyStoreFileName = getInitParameter("keyStoreFileName");
        if (keyStoreFileName == null) {
            throw new MessagingException("<keyStoreFileName> parameter missing.");
        }
        
        String keyStorePassword = getInitParameter("keyStorePassword");
        if (keyStorePassword == null) {
            throw new MessagingException("<keyStorePassword> parameter missing.");
        }
        String keyAliasPassword = getInitParameter("keyAliasPassword");
        if (keyAliasPassword == null) {
            keyAliasPassword = keyStorePassword;
            if (isDebug()) {
                log("<keyAliasPassword> parameter not specified: will default to the <keyStorePassword> parameter.");
            }
        }
        
        String keyStoreType = getInitParameter("keyStoreType");
        if (keyStoreType == null) {
            if (isDebug()) {
                log("<type> parameter not specified: will default to \"" + KeyHolder.getDefaultType() + "\".");
            }
        }
        
        String keyAlias = getInitParameter("keyAlias");
        if (keyAlias == null) {
            if (isDebug()) {
                log("<keyAlias> parameter not specified: will look for the first one in the keystore.");
            }
        }
        
        if (isDebug()) {
            StringBuffer logBuffer =
            new StringBuffer(1024)
            .append("KeyStore related parameters:")
            .append("  keyStoreFileName=").append(keyStoreFileName)
            .append(", keyStoreType=").append(keyStoreType)
            .append(", keyAlias=").append(keyAlias)
            .append(" ");
            log(logBuffer.toString());
        }
            
        // Certificate preparation
        setKeyHolder(new KeyHolder(keyStoreFileName, keyStorePassword, keyAlias, keyAliasPassword, keyStoreType));
        
        if (isDebug()) {
            log("Subject Distinguished Name: " + getKeyHolder().getSignerDistinguishedName());
        }
        
        if (getKeyHolder().getSignerAddress() == null) {
            throw new MessagingException("Signer address missing in the certificate.");
        }
    }
    
    /**
     * Getter for property keyHolder.
     * It is <CODE>protected</CODE> instead of <CODE>public</CODE> for security reasons.
     * @return Value of property keyHolder.
     */
    protected KeyHolder getKeyHolder() {
        return this.keyHolder;
    }
    
    /**
     * Setter for property keyHolder.
     * It is <CODE>protected</CODE> instead of <CODE>public</CODE> for security reasons.
     * @param keyHolder New value of property keyHolder.
     */
    protected void setKeyHolder(KeyHolder keyHolder) {
        this.keyHolder = keyHolder;
    }
    
    /**
     * Initializer for property postmasterSigns.
     */
    protected void initPostmasterSigns() {
        setPostmasterSigns((getInitParameter("postmasterSigns") == null) ? false : new Boolean(getInitParameter("postmasterSigns")).booleanValue());
    }
    
    /**
     * Getter for property postmasterSigns.
     * If true will sign messages signed by the postmaster.
     * @return Value of property postmasterSigns.
     */
    public boolean isPostmasterSigns() {
        return this.postmasterSigns;
    }
    
    /**
     * Setter for property postmasterSigns.
     * @param postmasterSigns New value of property postmasterSigns.
     */
    public void setPostmasterSigns(boolean postmasterSigns) {
        this.postmasterSigns = postmasterSigns;
    }
    
    /**
     * Initializer for property rebuildFrom.
     */
    protected void initRebuildFrom() throws MessagingException {
        setRebuildFrom((getInitParameter("rebuildFrom") == null) ? false : new Boolean(getInitParameter("rebuildFrom")).booleanValue());
        if (isDebug()) {
            if (isRebuildFrom()) {
                log("Will modify the \"From:\" header.");
            } else {
                log("Will leave the \"From:\" header unchanged.");
            }
        }
    }
    
    /**
     * Getter for property rebuildFrom.
     * If true will modify the "From:" header.
     * <P>The modification is as follows:
     * assuming that the signer mail address in the signer certificate is <I>[e-mail]&gt;</I>
     * and that <I>From: "John Smith" <[e-mail]></I>
     * we will get <I>From: "John Smith" <[e-mail]>" &lt;[e-mail]&gt;</I>.</P>
     * <P>If the "ReplyTo:" header is missing or empty it will be set to the original "From:" header.</P>
     * <P>Such modification is necessary to achieve a correct behaviour
     * with some mail clients (e.g. Microsoft Outlook Express).</P>
     * @return Value of property rebuildFrom.
     */
    public boolean isRebuildFrom() {
        return this.rebuildFrom;
    }
    
    /**
     * Setter for property rebuildFrom.
     * @param rebuildFrom New value of property rebuildFrom.
     */
    public void setRebuildFrom(boolean rebuildFrom) {
        this.rebuildFrom = rebuildFrom;
    }
    
    /**
     * Initializer for property signerName.
     */
    protected void initSignerName() {
        setSignerName(getInitParameter("signerName"));
        if (getSignerName() == null) {
            if (getKeyHolder() == null) {
                throw new RuntimeException("initKeyHolder() must be invoked before initSignerName()");
            }
            setSignerName(getKeyHolder().getSignerCN());
            if (isDebug()) {
                log("<signerName> parameter not specified: will use the certificate signer \"CN=\" attribute.");
            }
        }
    }
    
    /**
     * Getter for property signerName.
     * @return Value of property signerName.
     */
    public String getSignerName() {