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Regression: ImportError for HeaderWriteError in long-running process post-Python update for CVE-2024-6923 #124170

Description

@julian-klode

Bug report

Bug description:

Pull request #122233 introduced a new class HeaderWriteError in commit 0976339 and imports that from email.generator.

This breaks running applications that have imported other parts of email before the update, and then try to import the generator past the update.

Now this is a bit silly, but it is what email.message.Message.as_string() does, it imports email.generator inside the function - which may happen at any point of the program run-time rather than at startup.

For example, the following pseudo-code will fail, assuming it has not generated another email earlier or manually imported the email.generator module.

import email.message
<do something for a long time, such as wait for a web form, Python is being upgraded here>
msg = <prepare a message>
msg.as_string()

A particular instance of the issue is the unattended-upgrades package in Ubuntu and Debian, which will install the security update and then may send an email and fail there due to the ImportError, see https://bugs.launchpad.net/ubuntu/+source/python3.8/+bug/2080940.

I'm wondering if it's feasible to add a workaround to the stable branches:

Cchange the email.generator module import:

from email.errors import HeaderWriteError

to graciously support the previous version email.errors:

try:
    from email.errors import HeaderWriteError
except ImportError:
    from email.errors import MessageError as HeaderWriteError

This is a safe change, existing applications, where the import fails can't be having except HeaderWriteError statements anyway.

Thanks.

CPython versions tested on:

3.12

Operating systems tested on:

No response

Activity

  1. julian-klode commented on Sep 17, 2024

    @julian-klode
    Author

    I think the real fix is to not lazily import modules like this in the standard library, but I assume there's a reason email.generators is lazily imported?

  2. jimkoeleman commented on Sep 18, 2024

    @jimkoeleman

    Since yesterday I have the same error on my servers, using Python 3.8. It happens to crash my unicorn workers resulting in bad gateway errors for end users. Until I manually restart my servers. Happened yesterday and also today in the morning.

  3. muzomer commented on Sep 18, 2024

    @muzomer

    It happened to one of our servers as well. Running:

    • Django 4.2.16
    • gunicorn: 22.0.0
    • Python 3.8.10

    We upgraded recently to Django 4.2.16, commit django/django@bf4888d might be related.

    Error
    gunicorn[1014232]: [18/Sep/2024 10:58:11][common.services.pandora_service._user_access_token:187][Root=1-66ea9623-5aee4eae0266bcd41a3a1159][DEBUG] Token retrieved in : 9.248 ms
    gunicorn[1182738]: [2024-09-18 08:58:11 +0000] [1182738] [ERROR] Exception in worker process
    gunicorn[1182738]: Traceback (most recent call last):
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/arbiter.py", line 609, in spawn_worker
    gunicorn[1182738]:     worker.init_process()
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/workers/ggevent.py", line 147, in init_process
    gunicorn[1182738]:     super().init_process()
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/workers/base.py", line 134, in init_process
    gunicorn[1182738]:     self.load_wsgi()
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/workers/base.py", line 146, in load_wsgi
    gunicorn[1182738]:     self.wsgi = self.app.wsgi()
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/app/base.py", line 67, in wsgi
    gunicorn[1182738]:     self.callable = self.load()
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/app/wsgiapp.py", line 58, in load
    gunicorn[1182738]:     return self.load_wsgiapp()
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/app/wsgiapp.py", line 48, in load_wsgiapp
    gunicorn[1182738]:     return util.import_app(self.app_uri)
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/gunicorn/util.py", line 371, in import_app
    gunicorn[1182738]:     mod = importlib.import_module(module)
    gunicorn[1182738]:   File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    gunicorn[1182738]:     return _bootstrap._gcd_import(name[level:], package, level)
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 991, in _find_and_load
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 961, in _find_and_load_unlocked
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 991, in _find_and_load
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
    gunicorn[1182738]:   File "<frozen importlib._bootstrap_external>", line 848, in exec_module
    gunicorn[1182738]:   File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
    gunicorn[1182738]:   File "/opt/cloud/current/pix4uav/pix4d/__init__.py", line 3, in <module>
    gunicorn[1182738]:     from .celery import app as celery_app  # noqa
    gunicorn[1182738]:   File "/opt/cloud/current/pix4uav/pix4d/celery.py", line 16, in <module>
    gunicorn[1182738]:     from .settings.sentry import before_send
    gunicorn[1182738]:   File "/opt/cloud/current/pix4uav/pix4d/settings/sentry.py", line 5, in <module>
    gunicorn[1182738]:     from sentry_sdk.integrations.django import DjangoIntegration
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/sentry_sdk/integrations/django/__init__.py", line 61, in <module>
    gunicorn[1182738]:     from sentry_sdk.integrations.django.middleware import patch_django_middlewares
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/sentry_sdk/integrations/django/middleware.py", line 38, in <module>
    gunicorn[1182738]:     from .asgi import _asgi_middleware_mixin_factory
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/sentry_sdk/integrations/django/asgi.py", line 13, in <module>
    gunicorn[1182738]:     from django.core.handlers.wsgi import WSGIRequest
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/django/core/handlers/wsgi.py", line 5, in <module>
    gunicorn[1182738]:     from django.core.handlers import base
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 12, in <module>
    gunicorn[1182738]:     from django.utils.log import log_response
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/django/utils/log.py", line 6, in <module>
    gunicorn[1182738]:     from django.core import mail
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/django/core/mail/__init__.py", line 10, in <module>
    gunicorn[1182738]:     from django.core.mail.message import (
    gunicorn[1182738]:   File "/opt/cloud/releases/20240913T095509/.venv/lib/python3.8/site-packages/django/core/mail/message.py", line 4, in <module>
    gunicorn[1182738]:     from email import generator, message_from_string
    gunicorn[1182738]:   File "/usr/lib/python3.8/email/generator.py", line 17, in <module>
    gunicorn[1182738]:     from email.errors import HeaderWriteError
    gunicorn[1182738]: ImportError: cannot import name 'HeaderWriteError' from 'email.errors' (/usr/lib/python3.8/email/errors.py)
    gunicorn[1182738]: [2024-09-18 08:58:11 +0000] [1182738] [INFO] Worker exiting (pid: 1182738)
    gunicorn[1014225]: [2024-09-18 08:58:11 +0000] [1014225] [ERROR] Worker (pid:1182738) exited with code 3
    gunicorn[1014228]: [2024-09-18 10:58:12 +0200] [1014228] [INFO] Worker exiting (pid: 1014228)
    gunicorn[1014235]: [2024-09-18 10:58:12 +0200] [1014235] [INFO] Worker exiting (pid: 1014235)
    gunicorn[1014232]: [2024-09-18 10:58:12 +0200] [1014232] [INFO] Worker exiting (pid: 1014232)
    gunicorn[1014229]: [2024-09-18 10:58:12 +0200] [1014229] [INFO] Worker exiting (pid: 1014229)
    gunicorn[1014225]: [2024-09-18 08:58:17 +0000] [1014225] [ERROR] Shutting down: Master
    gunicorn[1014225]: [2024-09-18 08:58:17 +0000] [1014225] [ERROR] Reason: Worker failed to boot.
    systemd[1]: gunicorn.service: Main process exited, code=exited, status=3/NOTIMPLEMENTED
    systemd[1]: gunicorn.service: Failed with result 'exit-code'.
  4. jimkoeleman commented on Sep 18, 2024

    @jimkoeleman

    We run on Django 3.2.9 (..i know), got the following error log. Still no solution found for the problem.

    [2024-09-18 03:41:11 +0200] [17792] [INFO] Booting worker with pid: 17792
    [2024-09-18 04:31:45 +0200] [18105] [INFO] Booting worker with pid: 18105
    [2024-09-18 06:27:00 +0200] [20686] [INFO] Booting worker with pid: 20686
    [2024-09-18 06:27:01 +0200] [20686] [ERROR] Exception in worker process
    Traceback (most recent call last):
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker
        worker.init_process()
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/workers/base.py", line 119, in init_process
        self.load_wsgi()
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/workers/base.py", line 144, in load_wsgi
        self.wsgi = self.app.wsgi()
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/app/base.py", line 67, in wsgi
        self.callable = self.load()
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/app/wsgiapp.py", line 49, in load
        return self.load_wsgiapp()
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/app/wsgiapp.py", line 39, in load_wsgiapp
        return util.import_app(self.app_uri)
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/gunicorn/util.py", line 358, in import_app
        mod = importlib.import_module(module)
      File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
        return _bootstrap._gcd_import(name[level:], package, level)
      File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
      File "<frozen importlib._bootstrap>", line 991, in _find_and_load
      File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
      File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
      File "<frozen importlib._bootstrap_external>", line 848, in exec_module
      File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
      File "/var/www/crftwrkbn/crftr/crftr/wsgi.py", line 13, in <module>
        from django.core.wsgi import get_wsgi_application
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/django/core/wsgi.py", line 2, in <module>
        from django.core.handlers.wsgi import WSGIHandler
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/django/core/handlers/wsgi.py", line 5, in <module>
        from django.core.handlers import base
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 12, in <module>
        from django.utils.log import log_response
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/django/utils/log.py", line 6, in <module>
        from django.core import mail
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/django/core/mail/__init__.py", line 9, in <module>
        from django.core.mail.message import (
      File "/var/www/crftwrkbn/.venv/lib/python3.8/site-packages/django/core/mail/message.py", line 2, in <module>
        from email import (
      File "/usr/lib/python3.8/email/generator.py", line 17, in <module>
        from email.errors import HeaderWriteError
    ImportError: cannot import name 'HeaderWriteError' from 'email.errors' (/usr/lib/python3.8/email/errors.py)
    [2024-09-18 06:27:01 +0200] [20686] [INFO] Worker exiting (pid: 20686)
    [2024-09-18 06:27:04 +0200] [542] [INFO] Shutting down: Master
    [2024-09-18 06:27:04 +0200] [542] [INFO] Reason: Worker failed to boot. 
    
  5. JelleZijlstra commented on Sep 18, 2024

    @JelleZijlstra
    Member

    It sounds like those of you who were getting this error were upgrading Python on the file system without restarting your processes. If so, you should be able to get around the issue by restarting all Python processes to have the new code.

  6. jimkoeleman commented on Sep 18, 2024

    @jimkoeleman

    Thanks for your reply. Hmm this could mean that the server restart solved the problem. In our setup with 4 web servers it could hypothetically be that yesterday server-1 and server-2 were automatically updated, and server-3 and server-4 today so that it should not happen anymore after today. Let's wait until tomorrow morning to see if this assumption is correct.

  7. DanielRuf commented on Sep 23, 2024

    @DanielRuf
    Contributor

    The question is, is a manual restart needed because unattended-upgrades did not do some restart and this error state will persist until the restart is done?

    What are the possible options for current servers? So far I understand:

    • restart python (what is the cleanest way to do that so that current python3 processes like /usr/bin/python3 /usr/bin/networkd-dispatcher --run-startup-triggers and /usr/bin/python3 /usr/share/unattended-upgrades/unattended-upgrade-shutdown --wait-for-signal are correctly started again?)
    • do a full system restart
    • wait for the patch

    Does the error happen again on systewms which are still running but everything was upgraded by unattended-upgrades?

  8. frewper commented on Oct 22, 2024

    @frewper

    how can one disable this automatic update ?

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