send_mail() error on Python 2 if smtp server uses CRAM-MD5 auth method

[Slava]

send_mail('title', 'message', from_email='test@mail.com', recipient_list=['test2@mail.com'])
Traceback (most recent call last):
  File "<input>", line 1, in <module>
    send_mail('hello slafffko', 'message is here', from_email='test@artel7.com',
 recipient_list=['slavugan@gmail.com'])
  File "/home/slav/venv/luxjango/local/lib/python2.7/site-packages/django/core/m
ail/__init__.py", line 62, in send_mail
    return mail.send()
  File "/home/slav/venv/luxjango/local/lib/python2.7/site-packages/django/core/m
ail/message.py", line 303, in send
    return self.get_connection(fail_silently).send_messages([self])
  File "/home/slav/venv/luxjango/local/lib/python2.7/site-packages/django/core/m
ail/backends/smtp.py", line 100, in send_messages
    new_conn_created = self.open()
  File "/home/slav/venv/luxjango/local/lib/python2.7/site-packages/django/core/m
ail/backends/smtp.py", line 67, in open
    self.connection.login(self.username, self.password)
  File "/usr/lib/python2.7/smtplib.py", line 607, in login
    (code, resp) = self.docmd(encode_cram_md5(resp, user, password))
  File "/usr/lib/python2.7/smtplib.py", line 571, in encode_cram_md5
    response = user + " " + hmac.HMAC(password, challenge).hexdigest()
  File "/usr/lib/python2.7/hmac.py", line 75, in __init__
    self.outer.update(key.translate(trans_5C))
TypeError: character mapping must return integer, None or unicode

email backend should pass passwrord as string, not as unicode to smtplib to avoid this error

[Tim Graham]

I have no way to reproduce this -- can you submit a patch with a test?

[Claude Paroz]

Would it be possible to test with Python 3?

[Claude Paroz]

FYI, I'm currently working on a test for this in the Django test suite.

[Slava]

I have checked for python3 everything is ok, because of with python3 Django passes password as string to smtplib, so this error is relevant only for python2.
For fix in init in django/core/mail/backends/smtp.py we should add something like this:

if self.password.__class__.__name__ == 'unicode':
    try:
        self.password = str(self.password)
    except UnicodeEncodeError:
        pass

[Claude Paroz]

​PR

[Claude Paroz <claude@…>]

In fe252c0a:

Fixed #27131 -- Passed proper string type to SMTP connection login

Passing an Unicode string on Python 2 was crashing the connection.
Thanks slavugan@… for the report, and Tim Graham for the review.

[Claude Paroz]

As suggested by Tim on the pull request, a workaround on older Django could be to define email username and pasword as bytestrings.

[GitHub <noreply@…>]

In cdad96e6:

Refs #27131 -- Removed SMTPBackendTests.test_server_login().

test_server_login() was a regression test for a crash when passing
Unicode strings to SMTP server using CRAM-MD5 method on Python 2.
Python 2 is no longer supported and test_server_login() passes even
without FakeSMTPChannel.smtp_AUTH() because
smtplib.SMTPAuthenticationError is raised when AUTH is not implemented.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 8ab9536:

[4.0.x] Refs #27131 -- Removed SMTPBackendTests.test_server_login().

test_server_login() was a regression test for a crash when passing
Unicode strings to SMTP server using CRAM-MD5 method on Python 2.
Python 2 is no longer supported and test_server_login() passes even
without FakeSMTPChannel.smtp_AUTH() because
smtplib.SMTPAuthenticationError is raised when AUTH is not implemented.
Backport of cdad96e6330cd31185f7496aaf8eb316f2773d6d from main

[Mariusz Felisiak <felisiak.mariusz@…>]

In 137a9899:

[3.2.x] Refs #27131 -- Removed SMTPBackendTests.test_server_login().

test_server_login() was a regression test for a crash when passing
Unicode strings to SMTP server using CRAM-MD5 method on Python 2.
Python 2 is no longer supported and test_server_login() passes even
without FakeSMTPChannel.smtp_AUTH() because
smtplib.SMTPAuthenticationError is raised when AUTH is not implemented.
Backport of cdad96e6330cd31185f7496aaf8eb316f2773d6d from main