diff options
Diffstat (limited to 'src/leap/mx/mail_receiver.py')
| -rw-r--r-- | src/leap/mx/mail_receiver.py | 143 |
1 files changed, 139 insertions, 4 deletions
diff --git a/src/leap/mx/mail_receiver.py b/src/leap/mx/mail_receiver.py index 3561d33..dd76f08 100644 --- a/src/leap/mx/mail_receiver.py +++ b/src/leap/mx/mail_receiver.py @@ -18,6 +18,16 @@ """ MailReceiver service definition + +If there's a user facing problem when processing an email, it will be +bounced back to the sender. + +User facing problems could be: +- Unknown user (missing uuid) +- Public key not found + +Any other problem is a bug, which will be logged. Until the bug is +fixed, the email will stay in there waiting. """ import os @@ -28,9 +38,13 @@ import email.utils import socket from email import message_from_string +from email.MIMEMultipart import MIMEMultipart +from email.MIMEText import MIMEText +from email.Utils import formatdate +from email.header import decode_header from twisted.application.service import Service -from twisted.internet import inotify, defer, task +from twisted.internet import inotify, defer, task, reactor from twisted.python import filepath, log from leap.soledad.common.crypto import ( @@ -41,6 +55,77 @@ from leap.soledad.common.crypto import ( from leap.soledad.common.couch import CouchDatabase, CouchDocument from leap.keymanager import openpgp +BOUNCE_TEMPLATE = """ +Delivery to the following recipient failed: + {0} + +Reasons: + {1} + +Original message: + {2} +""".strip() + + +from twisted.internet import protocol +from twisted.internet.error import ProcessDone + + +class BouncerSubprocessProtocol(protocol.ProcessProtocol): + """ + Bouncer subprocess protocol that will feed the msg contents to be + bounced through stdin + """ + + def __init__(self, msg): + """ + Constructor for the BouncerSubprocessProtocol + + :param msg: Message to send to stdin when the process has + launched + :type msg: str + """ + self._msg = msg + self._outBuffer = "" + self._errBuffer = "" + self._d = None + + def connectionMade(self): + self._d = defer.Deferred() + + self.transport.write(self._msg) + self.transport.closeStdin() + + def outReceived(self, data): + self._outBuffer += data + + def errReceived(self, data): + self._errBuffer += data + + def processEnded(self, reason): + if reason.check(ProcessDone): + self._d.callback(self._outBuffer) + else: + self._d.errback(reason) + + +def async_check_output(args, msg): + """ + Async spawn a process and return a defer to be able to check the + output with a callback/errback + + :param args: the command to execute along with the params for it + :type args: list of str + :param msg: string that will be send to stdin of the process once + it's spawned + :type msg: str + + :rtype: defer.Deferred + """ + pprotocol = BouncerSubprocessProtocol(msg) + reactor.spawnProcess(pprotocol, args[0], args) + return pprotocol.d + class MailReceiver(Service): """ @@ -48,8 +133,10 @@ class MailReceiver(Service): """ INCOMING_KEY = 'incoming' + ERROR_DECRYPTING_KEY = "errdecr" - def __init__(self, mail_couch_url, users_cdb, directories): + def __init__(self, mail_couch_url, users_cdb, directories, bounce_from, + bounce_subject): """ Constructor @@ -61,6 +148,10 @@ class MailReceiver(Service): :type users_cdb: ConnectedCouchDB :param directories: list of directories to monitor :type directories: list of tuples (path: str, recursive: bool) + :param bounce_from: Email address of the bouncer + :type bounce_from: str + :param bounce_subject: Subject line used in the bounced mail + :type bounce_subject: str """ # Service doesn't define an __init__ self._mail_couch_url = mail_couch_url @@ -69,6 +160,9 @@ class MailReceiver(Service): self._domain = socket.gethostbyaddr(socket.gethostname())[0] self._processing_skipped = False + self._bounce_from = bounce_from + self._bounce_subject = bounce_subject + def startService(self): """ Starts the MailReceiver service @@ -119,6 +213,7 @@ class MailReceiver(Service): if pubkey is None or len(pubkey) == 0: doc.content = { self.INCOMING_KEY: True, + self.ERROR_DECRYPTING_KEY: False, ENC_SCHEME_KEY: EncryptionSchemes.NONE, ENC_JSON_KEY: json.dumps(data, ensure_ascii=False) @@ -145,6 +240,7 @@ class MailReceiver(Service): data = {'incoming': True, 'content': message.as_string()} doc.content = { self.INCOMING_KEY: True, + self.ERROR_DECRYPTING_KEY: False, ENC_SCHEME_KEY: EncryptionSchemes.PUBKEY, ENC_JSON_KEY: str(gpg.encrypt( json.dumps(data, ensure_ascii=False), @@ -228,6 +324,37 @@ class MailReceiver(Service): return uuid + @defer.inlineCallbacks + def _bounce_mail(self, orig_msg, filepath, reason): + """ + Bounces the email contained in orig_msg to it's sender and + removes it from the queue. + + :param orig_msg: Message that is going to be bounced + :type orig_msg: email.message.Message + :param filepath: Path for that message + :type filepath: twisted.python.filepath.FilePath + :param reason: Brief explanation about why it's being bounced + :type reason: str + """ + to = orig_msg.get("From") + + msg = MIMEMultipart() + msg['From'] = self._bounce_from + msg['To'] = to + msg['Date'] = formatdate(localtime=True) + msg['Subject'] = self._bounce_subject + + decoded_to = " ".join([x[0] for x in decode_header(to)]) + text = BOUNCE_TEMPLATE.format(decoded_to, + reason, + orig_msg.as_string()) + + msg.attach(MIMEText(text)) + + yield async_check_output(["/usr/sbin/sendmail", "-t"], msg.as_string()) + yield self._conditional_remove(True, filepath) + def sleep(self, secs): """ Async sleep for a defer. Use this when you want to wait for @@ -266,13 +393,13 @@ class MailReceiver(Service): fullpath = os.path.join(root, fname) fpath = filepath.FilePath(fullpath) yield self._step_process_mail_backend(fpath) - except Exception as e: + except Exception: log.msg("Error processing skipped mail: %r" % \ (fullpath,)) log.err() if not recursive: break - except Exception as e: + except Exception: log.msg("Error processing skipped mail") log.err() finally: @@ -299,6 +426,9 @@ class MailReceiver(Service): if uuid is None: log.msg("Don't know how to deliver mail %r, skipping..." % (filepath.path,)) + bounce_reason = "Missing UUID: There was a problem " \ + "locating the user in our database." + yield self._bounce_mail(msg, filepath, bounce_reason) defer.returnValue(None) log.msg("Mail owner: %s" % (uuid,)) @@ -309,6 +439,10 @@ class MailReceiver(Service): pubkey = yield self._users_cdb.getPubKey(uuid) if pubkey is None or len(pubkey) == 0: log.msg("No public key, stopping the processing chain") + bounce_reason = "Missing PubKey: There was a problem " \ + "locating the user's public key in our " \ + "database." + yield self._bounce_mail(msg, filepath, bounce_reason) defer.returnValue(None) log.msg("Encrypting message to %s's pubkey" % (uuid,)) @@ -340,3 +474,4 @@ class MailReceiver(Service): except Exception as e: log.msg("Something went wrong while processing {0!r}: {1!r}" .format(filepath, e)) + log.err() |