Document changes to file upload permissions in Django 1.11

[Yaroslav Demidenko]

This bug find in prod server (nginx, supervisor + gunicorn)

I have models: MainModel() and

SubModel(models.Model):
    main_id = FK(MainModel)
    im1 = ImageField()
    im2 = ImageField()
    im3 = ImageField()

When I fill SubModel object in admin (as InlineAdmin) and click save button, all images are saved, but permissions == 0600.
If I fill any two imgs (or one), all is well.
Django 1.10.5 - this bug not found.

Sorry for my English.

[Tim Graham]

Have you set settings.FILE_UPLOAD_PERMISSIONS? Can you reproduce the problem in a non-production environment? It's unclear if someone could reproduce the problem based on the little information you provided. Can you provide a minimal sample project that reproduces the issue? Can you ​bisect the regression to determine where the behavior changed?

[Xavier Ordoquy]

Been hitting the same issue although it's somewhat inconsistent. Some context:

• Only have one FileField on the model.
• So far, it's been happening and reproduced on production with only one file (24 uploaded files)

We'll set FILE_UPLOAD_PERMISSIONS and see if that fixes the issue.

Meanwhile, here's the raw unedited model. I don't think it has anything fancy and no signal:

@python_2_unicode_compatible
class Livret(models.Model):
    bDisplay = models.BooleanField("Utilisé ce semestre", default=True)
    nom = models.CharField(_("Nom"), max_length=255, blank=False, null=False)
    file = models.FileField(_("Fichier"), upload_to="PDF")
    infos = models.TextField(blank=True, null=True)
    tags = TaggableManager(blank=True)
    events = models.ManyToManyField(Event, related_name='livrets', verbose_name=("Events"), blank=True)

    def __str__(self):
        return self.nom

[Simen Heggestøyl]

We've hit the same issue, and I've identified f734e2d4b2fc4391a4d097b80357724815c1d414 as the offending commit.

The issue seems to be that when FILE_UPLOAD_PERMISSIONS is None, the default system permissions are used. This worked fine for us, because our system default is 644, which is what we wanted. After f734e2d4b2fc4391a4d097b80357724815c1d414 however, when the uploaded file is sufficiently large, the system's permissions for temporary files is used instead (which was 600 in our case).

Setting FILE_UPLOAD_PERMISSIONS explicitly fixes the issue, but I think this behavioral change should be mentioned in the release notes.

[Tim Graham]

The behavior might also be mentioned somewhere in the file upload documentation.

[René Fleschenberg]

Are you sure that we should consider this a documentation bug? I think it doesn't make sense to use different permissions depending on the file size.

I know I am late to the party, but just in case it is of any use, I set up a minimal project that demonstrates the issue: ​https://github.com/rfleschenberg/django-file-upload-bug

[Tim Graham]

No, I'm not sure. I don't think I investigated the issue in detail.

[Claude Paroz]

See ​this PR as a possible approach.

[Tim Graham]

As I mentioned in the PR discussion, the new behavior seems consistent with the ​original documentation added with the introduction of the FILE_UPLOAD_PERMISSIONS setting:

On most platforms, temporary files will have a mode of 0600, and files saved from memory will be saved using thesystem's standard umask.

By default, MemoryFileUploadHandler is used for files up to settings.FILE_UPLOAD_MAX_MEMORY_SIZE, otherwise TemporaryFileUploadHandler is used.

If we decide not to make a change (probably the discussion should move to django-developers), then we could at least add a note to the deployment checklist. Carlton proposed adding a system check that warns if the FILE_UPLOAD_PERMISSIONS setting isn't set but that feels a bit heavy handed as none of the open source Django projects I checked have specified this setting so presumably it isn't a common issue.

[Tim Graham]

The ​django-developers discussion about changing the upload behavior hasn't received any replies. I'll proceed with the documentation patches, and we can open a new ticket if there's a later consensus to make a code change.

[Tim Graham <timograham@…>]

In ef70af77:

Refs #28540 -- Added FILE_UPLOAD_PERMISSIONS to deployment checklist.

[Tim Graham <timograham@…>]

In 89d4d412:

Fixed #28540 -- Doc'd a change to file upload permissions in Django 1.11.

Behavior changed in f734e2d4b2fc4391a4d097b80357724815c1d414
(refs #27334).

[Tim Graham <timograham@…>]

In 1e8c68f:

[2.1.x] Refs #28540 -- Added FILE_UPLOAD_PERMISSIONS to deployment checklist.

Backport of ef70af77ec53160d5ffa060c1bdf5ed93322d84f from master

[Tim Graham <timograham@…>]

In 37c0a336:

[2.1.x] Fixed #28540 -- Doc'd a change to file upload permissions in Django 1.11.

Behavior changed in f734e2d4b2fc4391a4d097b80357724815c1d414
(refs #27334).

Backport of 89d4d412404d31ef34ae3170c0c056eff55b2a17 from master

[Tim Graham <timograham@…>]

In b113c6ad:

[2.0.x] Fixed #28540 -- Doc'd a change to file upload permissions in Django 1.11.

Behavior changed in f734e2d4b2fc4391a4d097b80357724815c1d414
(refs #27334).

Backport of 89d4d412404d31ef34ae3170c0c056eff55b2a17 from master

[Tim Graham <timograham@…>]

In ceae3069:

[1.11.x] Fixed #28540 -- Doc'd a change to file upload permissions in Django 1.11.

Behavior changed in f734e2d4b2fc4391a4d097b80357724815c1d414
(refs #27334).

Backport of 89d4d412404d31ef34ae3170c0c056eff55b2a17 from master