imaplib authenticate raises TypeError if authenticator tries to abort

[craigh]

BPO	23779
Nosy	@warsaw, @ericvsmith, @rbtcollins, @bitdancer, @berkerpeksag
Files	imap_auth.patch: imaplib.py patch imap_auth2.patch imap_auth3.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2015-07-30.21:04:24.572>
created_at = <Date 2015-03-25.22:21:23.664>
labels = ['type-bug', 'library', 'expert-email']
title = 'imaplib authenticate raises TypeError if authenticator tries to abort'
updated_at = <Date 2015-07-30.21:04:24.570>
user = 'https://bugs.python.org/craigh'

bugs.python.org fields:

activity = <Date 2015-07-30.21:04:24.570>
actor = 'rbcollins'
assignee = 'none'
closed = True
closed_date = <Date 2015-07-30.21:04:24.572>
closer = 'rbcollins'
components = ['Library (Lib)', 'email']
creation = <Date 2015-03-25.22:21:23.664>
creator = 'craigh'
dependencies = []
files = ['38694', '38749', '38768']
hgrepos = []
issue_num = 23779
keywords = ['patch']
message_count = 8.0
messages = ['239283', '239656', '239658', '239701', '239752', '239803', '247698', '247699']
nosy_count = 7.0
nosy_names = ['barry', 'eric.smith', 'rbcollins', 'craigh', 'r.david.murray', 'python-dev', 'berker.peksag']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue23779'
versions = ['Python 3.4', 'Python 3.5']

[craigh]

If the authenticator object passed to the IMAP authenticate method tries to abort the handshake by returning None, TypeError is raised instead of sending the * line to the server.

>>> import imaplib
>>> imap = imaplib.IMAP4_SSL('imap.gmail.com')
>>> imap.authenticate(b'PLAIN', lambda x: None)
Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    imap.authenticate(b'PLAIN', lambda x: None)
  File "C:\Python34\lib\imaplib.py", line 380, in authenticate
    typ, dat = self._simple_command('AUTHENTICATE', mech)
  File "C:\Python34\lib\imaplib.py", line 1133, in _simple_command
    return self._command_complete(name, self._command(name, *args))
  File "C:\Python34\lib\imaplib.py", line 940, in _command
    self.send(literal)
  File "C:\Python34\lib\imaplib.py", line 276, in send
    self.sock.sendall(data)
  File "C:\Python34\lib\ssl.py", line 723, in sendall
    v = self.send(data[count:])
  File "C:\Python34\lib\ssl.py", line 684, in send
    v = self._sslobj.write(data)
TypeError: 'str' does not support the buffer interface

The problem is that _Authenticator.process returns a string instead of bytes in this case.

[berkerpeksag]

Thanks for the report and the patch, Craig. Could you convert your reproducer to a test case? imaplib tests are located in Lib/test/test_imaplib.py.

[craigh]

New patch is attached.

[bitdancer]

The patch looks good to me, except that I think it would be better if the test verified that the '*' response is received by the server (perhaps return OK if we don't get it?)

[craigh]

Okay, I attached another patch. The new version of the test returns success if the client's response is anything other than the abort line (*\r\n).

It fails with the current version of imaplib, fails if I change _Authenticator.process to output a byte-string besides *, and succeeds with the change in the patch.

[bitdancer]

Looks good to me, thanks.

[python-dev]

New changeset fe55a36a335b by Robert Collins in branch '3.4':
Issue bpo-23779: imaplib raises TypeError if authenticator tries to abort.
https://hg.python.org/cpython/rev/fe55a36a335b

New changeset b6f04b9d8c12 by Robert Collins in branch '3.5':
Issue bpo-23779: imaplib raises TypeError if authenticator tries to abort.
https://hg.python.org/cpython/rev/b6f04b9d8c12

New changeset 0879f2c53289 by Robert Collins in branch 'default':
Issue bpo-23779: imaplib raises TypeError if authenticator tries to abort.
https://hg.python.org/cpython/rev/0879f2c53289

[rbtcollins]

Thanks for the patch. Applied to 3.4 through 3.6.