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smime.js
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smime.js
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var path = require('path');
var os = require('os');
var fs = require('fs');
var _ = require('underscore');
var async = require('async');
var nm = require('nodemailer');
var config = require('./config.js');
var utils = require('./lib/utils.js');
var urlUtils = require('./lib/urlUtils.js');
var certificateDiscovery = require('./certificateParser/certificateDiscovery.js');
var mimeParser = require('./lib/mimeParser.js');
var mdn = require('./lib/mdn.js');
var certificateParser = require('./certificateParser/certificateParser.js');
var domainUtils = require('./lib/domainUtils.js');
var smtp = nm.createTransport({
host: config.smtpTargetServer.host,
port: config.smtpTargetServer.port,
secure: false,
authOptional: true,
tls: { rejectUnauthorized: false },
ignoreTLS: true
});
/**
* Encrypt an outgoing message (from a local domain address to an external recipient)
* Note: only one recipient supported for the moment
*
* @param {String} Message
* @param {String} senderAddress Sender for the DIRECT email address: username@domain (a local address)
* @param {String} recipientAddress Recipient for the DIRECT email address: username@domain (an external address)
* @param {function(Error, String)} callback Callback function returning encrypted message
*/
var encrypt = module.exports.encrypt = function (message, senderAddress, recipientAddress, logger, callback) {
//1. get recipient public certificate -> for encryping (resolved using certificate discovery)
//2. validate recipient public certificate
//3. perform signing and encryption
var localDomain = urlUtils.getDomain(senderAddress);
var data = {
senderAddress: senderAddress,
recipientAddress: recipientAddress,
localDomain: localDomain,
message: wrapMessage(message),
log: logger
};
async.waterfall([
async.constant(data),
discoverRecipientCert,
writeRecipientCert,
signMessage,
encryptMessage,
], function(err) {
if(err) {
return callback(err);
}
callback(null, data.message);
});
};
function discoverRecipientCert(data, cb2) {
certificateDiscovery.findCertificate(data.recipientAddress, data.localDomain, data.log, function(err, recipientCertificate) {
if(err) {
return cb2(err);
}
data.recipientCertificate = recipientCertificate;
cb2(null, data);
});
}
function writeRecipientCert(data, cb2) {
data.recipientCertPath = path.join(os.tmpdir(), data.recipientAddress.replace('@','.') + '_' + Math.round(Math.random() * 1000000));
fs.writeFile(data.recipientCertPath, data.recipientCertificate, function(err) {
if(err) {
data.log.error('Error writing certificate', err.toString());
return cb2(err);
}
data.log.debug('Certificate written to', data.recipientCertPath);
cb2(null, data);
});
}
var RFC822 = "content-type: message/rfc822\r\n\r\n";
function wrapMessage(message) {
return RFC822 + message;
}
function signMessage(data, cb) {
var senderCertPath = domainUtils.getLocalCertificatePath(data.localDomain);
var senderKeyPath = domainUtils.getLocalKeyPath(data.localDomain);
data.log.debug('Signing with certificate and key:', senderCertPath, senderKeyPath);
utils.callOpenssl(['cms', '-sign', '-signer', senderCertPath, '-inkey', senderKeyPath, '-md', 'sha256'], data.message, function(err, signedMessage) {
if(err) {
return cb(err);
}
data.log.file('signed', signedMessage);
data.message = signedMessage;
return cb(null, data);
});
}
function encryptMessage(data, cb) {
data.log.debug('Encrypting with certificate:', data.recipientCertPath);
utils.callOpenssl(['cms', '-encrypt', '-recip', data.recipientCertPath, '-aes128', '-to', data.recipientAddress, '-from', data.senderAddress], data.message, function(err, encryptedMessage) {
if(err) {
return cb(err);
}
data.log.file('encrypted', encryptedMessage);
data.message = encryptedMessage;
return cb(null, data);
});
}
module.exports.decrypt = function (message, sender, rcptTo, logger, callback) {
var domain = urlUtils.getDomain(rcptTo);
var data = {
message: message,
domain: domain,
sender: sender,
rcptTo: rcptTo,
log: logger
};
async.waterfall([
async.constant(data),
decryptMessage,
verifySignature,
verifyMessage,
parseContent,
sendProcessedMdn
], function(err) {
if(err) {
return callback(err);
}
callback(null, {
parsedMessage: data.parsedMessage,
decryptedMessage: data.unwrappedMessage, // decrypted and unwrapped message
mdnData: data.mdnData,
isDispatchedMdnRequested: data.isDispatchedMdnRequested,
});
});
};
function decryptMessage(data, cb) {
var recipCertPath = domainUtils.getLocalCertificatePath(data.domain);
var recipKeyPath = domainUtils.getLocalKeyPath(data.domain);
data.log.debug('Decrypting message with recipient cert, recipient private key:', recipCertPath, recipKeyPath);
utils.callOpenssl(['cms', '-decrypt', '-recip', recipCertPath, '-inkey', recipKeyPath], data.message, function(err, decryptedMessage) {
if(err) {
return cb(err);
}
data.log.file('decryptedMessage_', decryptedMessage);
data.message = decryptedMessage;
return cb(null, data);
});
}
function wrapLongLineContent(mime) {
var signaturePartRegex = /Content\-Type:\s*application\/pkcs7\-signature/i;
var res = signaturePartRegex.exec(mime);
if(!res) {
console.log('Could not find signature!');
return mime;
}
var emptyLine = '\r\n\r\n';
var signatureStartIndex = mime.indexOf(emptyLine, res.index); //the content for a MIME-part is placed after an empty line
return mime.substring(0, signatureStartIndex + emptyLine.length) +
//match an one-line content (Base64) line with CRLFs followed by a '--' (boundary markup) beginning of line
mime.substring(signatureStartIndex + emptyLine.length).replace(/^[a-zA-Z0-9\/\+]{77,}(\=)*(?=(\r\n)+\-\-)/, function(str) {
console.log('Fixing long signature');
var parts = str.match(/.{1,76}/g);
return parts.join('\r\n');
});
}
function verifyMessage(data, cb) {
data.log.debug('Verifying message');
var normalizedMessage = wrapLongLineContent(data.message);
utils.callOpenssl(['cms', '-verify', '-no_signer_cert_verify'], normalizedMessage, function(err, result) {
if(err) {
return cb(err);
}
data.log.file('decryptedMessage_no_signer_cert_', result);
data.message = result;
return cb(null, data);
});
}
function sendProcessedMdn(data, cb) {
if(data.mdnData) {
return cb(null, data);
}
var mdnSender = data.rcptTo;
var mdnRecipient = data.sender;
var originalMesageId = data.parsedMessage.headers['message-id'] || data.parsedDecryptedMsg.headers['message-id'];
sendMdn(mdnSender, mdnRecipient, originalMesageId, data.parsedMessage.subject, mdn.MDN_DISPOSITION_PROCESSED, data.log, function(err) {
if (err) {
data.log.error('Error while preparing and sending MDN:' + err.toString());
}
return cb(null, data); //TODO review this - now hiding error occurred while building the MDN
});
}
var sendMdn = module.exports.sendMdn = function (mailFrom, dnTo, originalMessageId, subject, disposition, logger, callback) {
logger.debug('Preparing MDN: ', mailFrom, dnTo, originalMessageId, disposition);
mdn.buildMdn(mailFrom, dnTo, originalMessageId, subject, disposition, function(err, mdnMessage) {
if (err) {
return callback(err);
}
logger.file('mdn_' + disposition + '_', mdnMessage);
encrypt(mdnMessage, mailFrom, dnTo, logger, function(err2, encryptedMdn) {
if (err2) {
return callback(err2);
}
smtp.sendMail({
envelope: {
from: mailFrom,
to: dnTo
},
raw: encryptedMdn
}, function (err, info) {
if (err) {
return callback(err);
}
logger.info('Successfully sent ' + disposition + ' MDN using SMTP ' + JSON.stringify(info));
return callback(null);
});
});
});
};
function verifySignature(data, cb) {
data.log.debug('Verifying message signature');
mimeParser.parse(data.message, { shalowParse: true }, data.log, function(err, result) {
if (err) {
data.log.error('Error while parsing message before signature verify: ' + err.toString());
return cb(err);
}
var signatureAttachment = _.findWhere(result.attachments, { contentType: 'application/pkcs7-signature'});
if (!signatureAttachment) {
data.log.error('Message signature not found.');
return cb(new Error('Message signature not found.'));
}
var signature = signatureAttachment.content.toString('base64');
var parts = signature.match(/.{1,76}/g);
signature = '-----BEGIN PKCS7-----\n' + parts.join('\n') + '\n-----END PKCS7-----';
utils.loadPKCS7Bundle(signature, function(err, certs) {
if(err) {
data.log.error('Invalid message signature: ' + err.toString());
return cb(err);
}
data.log.debug(certs.length + ' certs found in attached signature');
async.detectSeries(certs, function(cert, detectCb) {
certificateParser.validateCertificate(cert, data.domain, data.sender, urlUtils.getDomain(data.sender), true, data.log, function(err2, isValid) {
if(err2) {
data.log.error('Error while verifing signature: ' + err2.toString());
return detectCb(false);
}
if(!isValid) {
data.log.error('Invalid signing certificate.');
return detectCb(false);
}
data.log.info('A valid signing certificate was found.');
return detectCb(true);
});
}, function(validSigningCert) {
if(!validSigningCert) {
return cb(new Error('No valid signing certificate found!'));
}
data.parsedDecryptedMsg = result;
return cb(null, data);
});
});
});
}
function parseContent(data, cb) {
var afterFn = function(err, parsedMessage, mdnData, isDispatchedMdnRequested, unwrappedMessage) {
if(err) {
data.log.error('Error while parsing actual message content attachment: ' + err.toString());
return cb(err);
}
data.parsedMessage = parsedMessage;
data.unwrappedMessage = unwrappedMessage;
data.mdnData = mdnData;
if(data.mdnData) {
data.log.debug('Message is a ' + data.mdnData.type + ' MDN!');
} else {
data.isDispatchedMdnRequested = isDispatchedMdnRequested;
data.log.debug('Dispatched MDN requested: ' + isDispatchedMdnRequested);
}
data.log.file('parsedMessage_', JSON.stringify(data.parsedMessage, null, 4));
return cb(null, data);
};
mimeParser.parse(data.message, { checkMdn: true }, data.log, afterFn);
}