Deliver cleartext if Unicode encoding or message serialisation fail

lacre/core.py

@@ -40,7 +40,7 @@ import lacre.keyring as kcache
 import lacre.recipients as recpt
 import lacre.smime as smime
 from lacre.transport import send_msg, register_sender, SendFrom
-from lacre.mailop import KeepIntact, InlineOpenPGPEncrypt, MimeOpenPGPEncrypt
+from lacre.mailop import KeepIntact, InlineOpenPGPEncrypt, MimeOpenPGPEncrypt, MailSerialisationException
 
 
 LOG = logging.getLogger(__name__)
@@ -127,7 +127,10 @@ def _gpg_encrypt_copy(message: EmailMessage, keys, recipients, encrypt_f):
 
 def _gpg_encrypt_to_bytes(message: EmailMessage, keys, recipients, encrypt_f) -> bytes:
     msg_copy = _gpg_encrypt_copy(message, keys, recipients, encrypt_f)
-    return msg_copy.as_bytes(policy=SMTPUTF8)
+    try:
+        return msg_copy.as_bytes(policy=SMTPUTF8)
+    except IndexError:
+        raise MailSerialisationException()
 
 
 def _gpg_encrypt_to_str(message: EmailMessage, keys, recipients, encrypt_f) -> str:

lacre/daemon.py

@@ -22,7 +22,7 @@ from GnuPG import EncryptionException
 import lacre.core as gate
 import lacre.keyring as kcache
 import lacre.transport as xport
-from lacre.mailop import KeepIntact
+from lacre.mailop import KeepIntact, MailSerialisationException
 
 
 class MailEncryptionProxy:
@@ -48,7 +48,7 @@ class MailEncryptionProxy:
                     try:
                         new_message = operation.perform(message)
                         send(new_message, operation.recipients())
-                    except EncryptionException as e:
+                    except (EncryptionException, MailSerialisationException, UnicodeEncodeError) as e:
                         # If the message can't be encrypted, deliver cleartext.
                         LOG.error('Unable to encrypt message, delivering in cleartext: %s', e)
                         if not isinstance(operation, KeepIntact):

lacre/mailop.py

@@ -22,6 +22,11 @@ from email.policy import SMTP, SMTPUTF8
 LOG = logging.getLogger(__name__)
 
 
+class MailSerialisationException(BaseException):
+    """We can't turn an EmailMessage into sequence of bytes."""
+    pass
+
+
 class MailOperation:
     """Contract for an operation to be performed on a message."""
 
@@ -124,7 +129,10 @@ class KeepIntact(MailOperation):
 
     def perform(self, message: Message) -> bytes:
         """Return MESSAGE unmodified."""
-        return message.as_bytes(policy=SMTPUTF8)
+        try:
+            return message.as_bytes(policy=SMTPUTF8)
+        except IndexError as e:
+            raise MailSerialisationException(e)
 
     def __repr__(self):
         """Return representation with just method and email."""

test/modules/test_stats.py

@@ -33,6 +33,6 @@ class ExecutionTimeLoggerTest(unittest.TestCase):
         self.assertEqual(handler.logged_records[1], 'Doing something')
 
         # Exception record should include the timing result and the traceback...
-        self.assertRegex(handler.logged_records[2], '^Just a test took 0 ms, raised exception\nTraceback.*')
+        self.assertRegex(handler.logged_records[2], '^Just a test took \\d ms, raised exception\nTraceback.*')
         # ...as well as the original exception
         self.assertRegex(handler.logged_records[2], 'Exception: this is a test$')