diff options
Diffstat (limited to 'src/leap/mail/smtp/gateway.py')
| -rw-r--r-- | src/leap/mail/smtp/gateway.py | 458 |
1 files changed, 33 insertions, 425 deletions
diff --git a/src/leap/mail/smtp/gateway.py b/src/leap/mail/smtp/gateway.py index 13d3bbf..b022091 100644 --- a/src/leap/mail/smtp/gateway.py +++ b/src/leap/mail/smtp/gateway.py @@ -31,39 +31,27 @@ The following classes comprise the SMTP gateway service: """ -import re -from StringIO import StringIO -from email.Header import Header -from email.utils import parseaddr -from email.parser import Parser -from email.mime.application import MIMEApplication from zope.interface import implements -from OpenSSL import SSL from twisted.mail import smtp from twisted.internet.protocol import ServerFactory -from twisted.internet import reactor, ssl -from twisted.internet import defer -from twisted.internet.threads import deferToThread from twisted.python import log -from leap.common.check import leap_assert, leap_assert_type +from email.Header import Header +from leap.common.check import leap_assert_type from leap.common.events import proto, signal -from leap.keymanager import KeyManager from leap.keymanager.openpgp import OpenPGPKey from leap.keymanager.errors import KeyNotFound -from leap.mail import __version__ +from leap.mail.utils import validate_address + from leap.mail.smtp.rfc3156 import ( - MultipartSigned, - MultipartEncrypted, - PGPEncrypted, - PGPSignature, RFC3156CompliantGenerator, - encode_base64_rec, ) +from leap.mail.service import OutgoingMail # replace email generator with a RFC 3156 compliant one. from email import generator + generator.Generator = RFC3156CompliantGenerator @@ -74,31 +62,6 @@ generator.Generator = RFC3156CompliantGenerator LOCAL_FQDN = "bitmask.local" -def validate_address(address): - """ - Validate C{address} as defined in RFC 2822. - - :param address: The address to be validated. - :type address: str - - @return: A valid address. - @rtype: str - - @raise smtp.SMTPBadRcpt: Raised if C{address} is invalid. - """ - leap_assert_type(address, str) - # in the following, the address is parsed as described in RFC 2822 and - # ('', '') is returned if the parse fails. - _, address = parseaddr(address) - if address == '': - raise smtp.SMTPBadRcpt(address) - return address - - -# -# SMTPFactory -# - class SMTPHeloLocalhost(smtp.SMTP): """ An SMTP class that ensures a proper FQDN @@ -119,45 +82,26 @@ class SMTPFactory(ServerFactory): """ domain = LOCAL_FQDN - def __init__(self, userid, keymanager, host, port, cert, key, - encrypted_only): + def __init__(self, userid, keymanager, encrypted_only, outgoing_mail): """ Initialize the SMTP factory. :param userid: The user currently logged in :type userid: unicode - :param keymanager: A KeyManager for retrieving recipient's keys. - :type keymanager: leap.common.keymanager.KeyManager - :param host: The hostname of the remote SMTP server. - :type host: str - :param port: The port of the remote SMTP server. - :type port: int - :param cert: The client certificate for authentication. - :type cert: str - :param key: The client key for authentication. - :type key: str + :param keymanager: A Key Manager from where to get recipients' public + keys. :param encrypted_only: Whether the SMTP gateway should send unencrypted mail or not. :type encrypted_only: bool + :param outgoing_mail: The outgoing mail to send the message + :type outgoing_mail: leap.mail.service.OutgoingMail """ - # assert params - leap_assert_type(keymanager, KeyManager) - leap_assert_type(host, str) - leap_assert(host != '') - leap_assert_type(port, int) - leap_assert(port is not 0) - leap_assert_type(cert, unicode) - leap_assert(cert != '') - leap_assert_type(key, unicode) - leap_assert(key != '') + leap_assert_type(encrypted_only, bool) # and store them self._userid = userid self._km = keymanager - self._host = host - self._port = port - self._cert = cert - self._key = key + self._outgoing_mail = outgoing_mail self._encrypted_only = encrypted_only def buildProtocol(self, addr): @@ -170,9 +114,7 @@ class SMTPFactory(ServerFactory): @return: The protocol. @rtype: SMTPDelivery """ - smtpProtocol = SMTPHeloLocalhost(SMTPDelivery( - self._userid, self._km, self._host, self._port, self._cert, - self._key, self._encrypted_only)) + smtpProtocol = SMTPHeloLocalhost(SMTPDelivery(self._userid, self._km, self._encrypted_only, self._outgoing_mail)) smtpProtocol.factory = self return smtpProtocol @@ -188,33 +130,23 @@ class SMTPDelivery(object): implements(smtp.IMessageDelivery) - def __init__(self, userid, keymanager, host, port, cert, key, - encrypted_only): + def __init__(self, userid, keymanager, encrypted_only, outgoing_mail): """ Initialize the SMTP delivery object. :param userid: The user currently logged in :type userid: unicode - :param keymanager: A KeyManager for retrieving recipient's keys. - :type keymanager: leap.common.keymanager.KeyManager - :param host: The hostname of the remote SMTP server. - :type host: str - :param port: The port of the remote SMTP server. - :type port: int - :param cert: The client certificate for authentication. - :type cert: str - :param key: The client key for authentication. - :type key: str + :param keymanager: A Key Manager from where to get recipients' public + keys. :param encrypted_only: Whether the SMTP gateway should send unencrypted mail or not. :type encrypted_only: bool + :param outgoing_mail: The outgoing mail to send the message + :type outgoing_mail: leap.mail.service.OutgoingMail """ self._userid = userid + self._outgoing_mail = outgoing_mail self._km = keymanager - self._host = host - self._port = port - self._cert = cert - self._key = key self._encrypted_only = encrypted_only self._origin = None @@ -280,9 +212,7 @@ class SMTPDelivery(object): "encrypted_only' is set to False).") signal( proto.SMTP_RECIPIENT_ACCEPTED_UNENCRYPTED, user.dest.addrstr) - return lambda: EncryptedMessage( - self._origin, user, self._km, self._host, self._port, self._cert, - self._key) + return lambda: EncryptedMessage(user, self._outgoing_mail) def validateFrom(self, helo, origin): """ @@ -314,19 +244,6 @@ class SMTPDelivery(object): # EncryptedMessage # -class SSLContextFactory(ssl.ClientContextFactory): - def __init__(self, cert, key): - self.cert = cert - self.key = key - - def getContext(self): - self.method = SSL.TLSv1_METHOD # SSLv23_METHOD - ctx = ssl.ClientContextFactory.getContext(self) - ctx.use_certificate_file(self.cert) - ctx.use_privatekey_file(self.key) - return ctx - - class EncryptedMessage(object): """ Receive plaintext from client, encrypt it and send message to a @@ -334,44 +251,21 @@ class EncryptedMessage(object): """ implements(smtp.IMessage) - FOOTER_STRING = "I prefer encrypted email" - - def __init__(self, fromAddress, user, keymanager, host, port, cert, key): + def __init__(self, user, outgoing_mail): """ Initialize the encrypted message. - :param fromAddress: The address of the sender. - :type fromAddress: twisted.mail.smtp.Address :param user: The recipient of this message. :type user: twisted.mail.smtp.User - :param keymanager: A KeyManager for retrieving recipient's keys. - :type keymanager: leap.common.keymanager.KeyManager - :param host: The hostname of the remote SMTP server. - :type host: str - :param port: The port of the remote SMTP server. - :type port: int - :param cert: The client certificate for authentication. - :type cert: str - :param key: The client key for authentication. - :type key: str + :param outgoing_mail: The outgoing mail to send the message + :type outgoing_mail: leap.mail.service.OutgoingMail """ # assert params leap_assert_type(user, smtp.User) - leap_assert_type(keymanager, KeyManager) - # and store them - self._fromAddress = fromAddress - self._user = user - self._km = keymanager - self._host = host - self._port = port - self._cert = cert - self._key = key - # initialize list for message's lines - self.lines = [] - # - # methods from smtp.IMessage - # + self._user = user + self._lines = [] + self._outgoing_mail = outgoing_mail def lineReceived(self, line): """ @@ -380,7 +274,7 @@ class EncryptedMessage(object): :param line: The received line. :type line: str """ - self.lines.append(line) + self._lines.append(line) def eomReceived(self): """ @@ -391,10 +285,10 @@ class EncryptedMessage(object): :returns: a deferred """ log.msg("Message data complete.") - self.lines.append('') # add a trailing newline - d = deferToThread(self._maybe_encrypt_and_sign) - d.addCallbacks(self.sendMessage, self.skipNoKeyErrBack) - return d + self._lines.append('') # add a trailing newline + raw_mail = '\r\n'.join(self._lines) + + return self._outgoing_mail.send_message(raw_mail, self._user) def connectionLost(self): """ @@ -404,290 +298,4 @@ class EncryptedMessage(object): log.err() signal(proto.SMTP_CONNECTION_LOST, self._user.dest.addrstr) # unexpected loss of connection; don't save - self.lines = [] - - # ends IMessage implementation - - def skipNoKeyErrBack(self, failure): - """ - Errback that ignores a KeyNotFound - - :param failure: the failure - :type Failure: Failure - """ - err = failure.value - if failure.check(KeyNotFound): - pass - else: - raise err - - def parseMessage(self): - """ - Separate message headers from body. - """ - parser = Parser() - return parser.parsestr('\r\n'.join(self.lines)) - - def sendQueued(self, r): - """ - Callback for the queued message. - - :param r: The result from the last previous callback in the chain. - :type r: anything - """ - log.msg(r) - - def sendSuccess(self, r): - """ - Callback for a successful send. - - :param r: The result from the last previous callback in the chain. - :type r: anything - """ - log.msg(r) - signal(proto.SMTP_SEND_MESSAGE_SUCCESS, self._user.dest.addrstr) - - def sendError(self, failure): - """ - Callback for an unsuccessfull send. - - :param e: The result from the last errback. - :type e: anything - """ - signal(proto.SMTP_SEND_MESSAGE_ERROR, self._user.dest.addrstr) - err = failure.value - log.err(err) - raise err - - def sendMessage(self, *args): - """ - Sends the message. - - :return: A deferred with callback and errback for - this #message send. - :rtype: twisted.internet.defer.Deferred - """ - d = deferToThread(self._route_msg) - d.addCallbacks(self.sendQueued, self.sendError) - return d - - def _route_msg(self): - """ - Sends the msg using the ESMTPSenderFactory. - """ - log.msg("Connecting to SMTP server %s:%s" % (self._host, self._port)) - msg = self._msg.as_string(False) - - # we construct a defer to pass to the ESMTPSenderFactory - d = defer.Deferred() - d.addCallbacks(self.sendSuccess, self.sendError) - # we don't pass an ssl context factory to the ESMTPSenderFactory - # because ssl will be handled by reactor.connectSSL() below. - factory = smtp.ESMTPSenderFactory( - "", # username is blank because server does not use auth. - "", # password is blank because server does not use auth. - self._fromAddress.addrstr, - self._user.dest.addrstr, - StringIO(msg), - d, - heloFallback=True, - requireAuthentication=False, - requireTransportSecurity=True) - factory.domain = __version__ - signal(proto.SMTP_SEND_MESSAGE_START, self._user.dest.addrstr) - reactor.connectSSL( - self._host, self._port, factory, - contextFactory=SSLContextFactory(self._cert, self._key)) - - # - # encryption methods - # - - def _encrypt_and_sign(self, pubkey, signkey): - """ - Create an RFC 3156 compliang PGP encrypted and signed message using - C{pubkey} to encrypt and C{signkey} to sign. - - :param pubkey: The public key used to encrypt the message. - :type pubkey: OpenPGPKey - :param signkey: The private key used to sign the message. - :type signkey: OpenPGPKey - """ - # create new multipart/encrypted message with 'pgp-encrypted' protocol - newmsg = MultipartEncrypted('application/pgp-encrypted') - # move (almost) all headers from original message to the new message - self._fix_headers(self._origmsg, newmsg, signkey) - # create 'application/octet-stream' encrypted message - encmsg = MIMEApplication( - self._km.encrypt(self._origmsg.as_string(unixfrom=False), pubkey, - sign=signkey), - _subtype='octet-stream', _encoder=lambda x: x) - encmsg.add_header('content-disposition', 'attachment', - filename='msg.asc') - # create meta message - metamsg = PGPEncrypted() - metamsg.add_header('Content-Disposition', 'attachment') - # attach pgp message parts to new message - newmsg.attach(metamsg) - newmsg.attach(encmsg) - self._msg = newmsg - - def _sign(self, signkey): - """ - Create an RFC 3156 compliant PGP signed MIME message using C{signkey}. - - :param signkey: The private key used to sign the message. - :type signkey: leap.common.keymanager.openpgp.OpenPGPKey - """ - # create new multipart/signed message - newmsg = MultipartSigned('application/pgp-signature', 'pgp-sha512') - # move (almost) all headers from original message to the new message - self._fix_headers(self._origmsg, newmsg, signkey) - # apply base64 content-transfer-encoding - encode_base64_rec(self._origmsg) - # get message text with headers and replace \n for \r\n - fp = StringIO() - g = RFC3156CompliantGenerator( - fp, mangle_from_=False, maxheaderlen=76) - g.flatten(self._origmsg) - msgtext = re.sub('\r?\n', '\r\n', fp.getvalue()) - # make sure signed message ends with \r\n as per OpenPGP stantard. - if self._origmsg.is_multipart(): - if not msgtext.endswith("\r\n"): - msgtext += "\r\n" - # calculate signature - signature = self._km.sign(msgtext, signkey, digest_algo='SHA512', - clearsign=False, detach=True, binary=False) - sigmsg = PGPSignature(signature) - # attach original message and signature to new message - newmsg.attach(self._origmsg) - newmsg.attach(sigmsg) - self._msg = newmsg - - def _maybe_encrypt_and_sign(self): - """ - Attempt to encrypt and sign the outgoing message. - - The behaviour of this method depends on: - - 1. the original message's content-type, and - 2. the availability of the recipient's public key. - - If the original message's content-type is "multipart/encrypted", then - the original message is not altered. For any other content-type, the - method attempts to fetch the recipient's public key. If the - recipient's public key is available, the message is encrypted and - signed; otherwise it is only signed. - - Note that, if the C{encrypted_only} configuration is set to True and - the recipient's public key is not available, then the recipient - address would have been rejected in SMTPDelivery.validateTo(). - - The following table summarizes the overall behaviour of the gateway: - - +---------------------------------------------------+----------------+ - | content-type | rcpt pubkey | enforce encr. | action | - +---------------------+-------------+---------------+----------------+ - | multipart/encrypted | any | any | pass | - | other | available | any | encrypt + sign | - | other | unavailable | yes | reject | - | other | unavailable | no | sign | - +---------------------+-------------+---------------+----------------+ - """ - # pass if the original message's content-type is "multipart/encrypted" - self._origmsg = self.parseMessage() - if self._origmsg.get_content_type() == 'multipart/encrypted': - self._msg = self._origmsg - return - - from_address = validate_address(self._fromAddress.addrstr) - username, domain = from_address.split('@') - - # add a nice footer to the outgoing message - if self._origmsg.get_content_type() == 'text/plain': - self.lines.append('--') - self.lines.append('%s - https://%s/key/%s' % - (self.FOOTER_STRING, domain, username)) - self.lines.append('') - - self._origmsg = self.parseMessage() - - # get sender and recipient data - signkey = self._km.get_key(from_address, OpenPGPKey, private=True) - log.msg("Will sign the message with %s." % signkey.fingerprint) - to_address = validate_address(self._user.dest.addrstr) - try: - # try to get the recipient pubkey - pubkey = self._km.get_key(to_address, OpenPGPKey) - log.msg("Will encrypt the message to %s." % pubkey.fingerprint) - signal(proto.SMTP_START_ENCRYPT_AND_SIGN, - "%s,%s" % (self._fromAddress.addrstr, to_address)) - self._encrypt_and_sign(pubkey, signkey) - signal(proto.SMTP_END_ENCRYPT_AND_SIGN, - "%s,%s" % (self._fromAddress.addrstr, to_address)) - except KeyNotFound: - # at this point we _can_ send unencrypted mail, because if the - # configuration said the opposite the address would have been - # rejected in SMTPDelivery.validateTo(). - log.msg('Will send unencrypted message to %s.' % to_address) - signal(proto.SMTP_START_SIGN, self._fromAddress.addrstr) - self._sign(signkey) - signal(proto.SMTP_END_SIGN, self._fromAddress.addrstr) - - def _fix_headers(self, origmsg, newmsg, signkey): - """ - Move some headers from C{origmsg} to C{newmsg}, delete unwanted - headers from C{origmsg} and add new headers to C{newms}. - - Outgoing messages are either encrypted and signed or just signed - before being sent. Because of that, they are packed inside new - messages and some manipulation has to be made on their headers. - - Allowed headers for passing through: - - - From - - Date - - To - - Subject - - Reply-To - - References - - In-Reply-To - - Cc - - Headers to be added: - - - Message-ID (i.e. should not use origmsg's Message-Id) - - Received (this is added automatically by twisted smtp API) - - OpenPGP (see #4447) - - Headers to be deleted: - - - User-Agent - - :param origmsg: The original message. - :type origmsg: email.message.Message - :param newmsg: The new message being created. - :type newmsg: email.message.Message - :param signkey: The key used to sign C{newmsg} - :type signkey: OpenPGPKey - """ - # move headers from origmsg to newmsg - headers = origmsg.items() - passthrough = [ - 'from', 'date', 'to', 'subject', 'reply-to', 'references', - 'in-reply-to', 'cc' - ] - headers = filter(lambda x: x[0].lower() in passthrough, headers) - for hkey, hval in headers: - newmsg.add_header(hkey, hval) - del(origmsg[hkey]) - # add a new message-id to newmsg - newmsg.add_header('Message-Id', smtp.messageid()) - # add openpgp header to newmsg - username, domain = signkey.address.split('@') - newmsg.add_header( - 'OpenPGP', 'id=%s' % signkey.key_id, - url='https://%s/key/%s' % (domain, username), - preference='signencrypt') - # delete user-agent from origmsg - del(origmsg['user-agent']) + self._lines = [] |