Prevent anons from downloading files incompatible with CDN

Support
1

I have a site where mp4 files are returning 404s.

They have authorized_extensions set to *. The file uploads just fine. I see it in the filesystem. The permissions are right. file says that it’s an MP4 file. The record in rails looks OK:

[1] pry(main)> u=Upload.find(196082)
=> #<Upload:0x00005601a1b56348
 id: 196082,
 user_id: 1,
 original_filename: "PXL_20220617_184736219.mp4",
 filesize: 9328093,
 width: nil,
 height: nil,
 url: "/uploads/default/original/3X/5/6/5679d94dfce852f780afa5fcb7f1a29d810cc8fc.mp4",
 created_at: Fri, 17 Jun 2022 18:53:41.130790000 UTC +00:00,
 updated_at: Fri, 17 Jun 2022 18:53:41.176664000 UTC +00:00,
 sha1: "5679d94dfce852f780afa5fcb7f1a29d810cc8fc",
 origin: nil,
 retain_hours: nil,
 extension: "mp4",
 thumbnail_width: nil,
 thumbnail_height: nil,
 etag: nil,
 secure: false,
 access_control_post_id: nil,
 original_sha1: nil,
 verification_status: 1,
 animated: nil,
 security_last_changed_at: nil,
 security_last_changed_reason: nil>

but accessing it returns a 404. There were a couple of new features and bug fixes for mp4 recently, but I just ran an upgrade and it’s still not working. I don’t know where else to look.

2

The problem is that the nginx config is allowing only certain file types. Moving this to bug.

In discourse.conf is this stanza:

      # this allows us to bypass rails
      location ~* \.(gif|png|jpg|jpeg|bmp|tif|tiff|ico|webp)$ {
          add_header Access-Control-Allow-Origin *;
          try_files $uri =404;
      }

I added mp3 and mp4 to the file types (after webp and mp4s now work) to the discourse.conf inside the container. I see “bypass rails” in discourse_docker config/nginx.sample.conf. I don’t see how it gets into the template inside docker, so I don’t know how to figure out when this happened.

They have * in for allowed file types. I don’t know if there is some magic that would allow the mp3/mp4 to work if they were enumerated in the site settings, but I don’t see how that could be.

3

But the download should just work if it does not bypass Rails as well.

There is a route for it

get "uploads/:site/original/:tree:sha(.:extension)" => "uploads#show", constraints: { site: /\w+/, tree: /([a-z0-9]+\/)+/i, sha: /\h{40}/, extension: /[a-z0-9\._]+/i }

and the show method should just send the file. The nginx config would only make it more efficient by bypassing rails, but this is not a requirement.

Oh… the authorized_extensions are only for upload authorization, not for downloads (i.e. an extension not being in that list should not prevent a file from being downloaded).

I’m unable to repro this on latest tests-passed so you might want to move it back to support :wink:

EDIT I googled the site and it seems you have other problems.

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Now when I simply wget the file, it works.

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(EDIT 2 this could be because you added the mp4 extension to the nginx config? Still, for me it just works out of the box)

1 Like
4

Thanks! I’ll take a look at that first thing. I guess I should have tried safe mode!

I’m quite confused by that service worker.

Not a bug.

5

I still don’t understand that Service Worker message, but I turned off prevent_anons_from_downloading_files and now it’s working. It seems that the “prevent_anons” setting is incompatible with CDN?

6

But the uploads are not being retrieved from the CDN on that site? It just refers to a location on www

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1 Like
7

Then I’m all the more confused. I suppose that post didn’t get rebaked after the CDN got defined.

But https://www.turiver.com/t/argentina-la-sociedad-perdida/117158/7909 is getting loaded from the CDN, and changing the setting did fix it.

I also see a bunch of 404s in the console, but it’s a standard two-container site with only these plugins:

          - git clone https://github.com/discourse/docker_manager.git
          - git clone https://github.com/discourse/discourse-akismet.git
          - git clone https://github.com/discourse/discourse-spoiler-alert.git
          - git clone https://github.com/discourse/discourse-chat-integration.git
          - git clone https://github.com/discourse/discourse-solved.git
          - git clone https://github.com/discourse/discourse-cakeday.git
          - git clone https://github.com/discourse/discourse-data-explorer.git
          - git clone https://github.com/discourse/discourse-checklist.git
          - git clone https://github.com/discourse/discourse-canned-replies.git
          - git clone https://github.com/discourse/discourse-chat

And I think you’re looking at https://www.turiver.com/t/argentina-la-sociedad-perdida/117158/8017 which is pulling from the CDN when I look, but logged in and not logged in.