this post was submitted on 30 Aug 2023
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EDIT

TO EVERYONE ASKING TO OPEN AN ISSUE ON GITHUB, IT HAS BEEN OPEN SINCE JULY 6: https://github.com/LemmyNet/lemmy/issues/3504

June 24 - https://github.com/LemmyNet/lemmy/issues/3236

TO EVERYONE SAYING THAT THIS IS NOT A CONCERN: Everybody has different laws in their countries (in other words, not everyone is American), and whether or not an admin is liable for such content residing in their servers without their knowledge, don't you think it's still an issue anyway? Are you not bothered by the fact that somebody could be sharing illegal images from your server without you ever knowing? Is that okay with you? OR are you only saying this because you're NOT an admin? Different admins have already responded in the comments and have suggested ways to solve the problem because they are genuinely concerned about this problem as much as I am. Thank you to all the hard working admins. I appreciate and love you all.


ORIGINAL POST

cross-posted from: https://lemmy.ca/post/4273025

You can upload images to a Lemmy instance without anyone knowing that the image is there if the admins are not regularly checking their pictrs database.

To do this, you create a post on any Lemmy instance, upload an image, and never click the "Create" button. The post is never created but the image is uploaded. Because the post isn't created, nobody knows that the image is uploaded.

You can also go to any post, upload a picture in the comment, copy the URL and never post the comment. You can also upload an image as your avatar or banner and just close the tab. The image will still reside in the server.

You can (possibly) do the same with community icons and banners.

Why does this matter?

Because anyone can upload illegal images without the admin knowing and the admin will be liable for it. With everything that has been going on lately, I wanted to remind all of you about this. Don't think that disabling cache is enough. Bad actors can secretly stash illegal images on your Lemmy instance if you aren't checking!

These bad actors can then share these links around and you would never know! They can report it to the FBI and if you haven't taken it down (because you did not know) for a certain period, say goodbye to your instance and see you in court.

Only your backend admins who have access to the database (or object storage or whatever) can check this, meaning non-backend admins and moderators WILL NOT BE ABLE TO MONITOR THESE, and regular users WILL NOT BE ABLE TO REPORT THESE.

Aren't these images deleted if they aren't used for the post/comment/banner/avatar/icon?

NOPE! The image actually stays uploaded! Lemmy doesn't check if the images are used! Try it out yourself. Just make sure to copy the link by copying the link text or copying it by clicking the image then "copy image link".

How come this hasn't been addressed before?

I don't know. I am fairly certain that this has been brought up before. Nobody paid attention but I'm bringing it up again after all the shit that happened in the past week. I can't even find it on the GitHub issue tracker.

I'm an instance administrator, what the fuck do I do?

Check your pictrs images (good luck) or nuke it. Disable pictrs, restrict sign ups, or watch your database like a hawk. You can also delete your instance.

Good luck.

(page 2) 50 comments
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[–] [email protected] 5 points 1 year ago (1 children)

Funny, I couldn't even get pict-rs working on my instance. I don't need it, either. I just upload to an FTP server when I need to share something.

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[–] [email protected] 3 points 1 year ago

I'm not using lemmy. But I was thinking of making a process to periodically scan the object storage and check for a reference to a post, comment etc and if none are found delete it. In most cases the images are deleted but sometimes they don't seem to be.

Probably lemmy could have a similar process created.

[–] [email protected] 2 points 1 year ago (7 children)

It would not be difficult to use SQL to delete any images that are not associated with a post or active as an avatar etc. So, set that to be run periodically and it would solve this problem.

[–] [email protected] 2 points 1 year ago (1 children)

Checking every single image ID against all stored text blobs is not trivial. Most platforms don't do this. It's cheaper to just ignore the unused images.

[–] [email protected] 1 points 1 year ago

Yeah, this is only if what OP was saying was a real legal threat, which I don’t think it is.

[–] [email protected] 1 points 1 year ago (1 children)

I'm not knowledgeable with SQL. If you know or if anyone knows how to fix it with a script or built into Lemmy, please share.

[–] [email protected] 2 points 1 year ago (1 children)

I haven't worked with Lemmy, but I certainly could craft a script to do that if I was familiar with the database structure. Perhaps I'll try installing it and running an instance. In the meantime, surely there's someone with an instance and SQL skills who could figure that out.

[–] relative_iterator 1 points 1 year ago

Yeah it shouldn’t be hard at all. Just need to know the link between images and posts.

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