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
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.
Try turning wifi off on your phone, getting the IP address, and then looking up the DNS entry for that and consider if you want to whitelist that? And then do this again tomorrow and check to see if it has a different value.
Once you get to the point of “whitelist everything in
*.mobile.att.net” it becomes pointless to maintain that as a whitelist.Likewise
*.dhcp.dorm.college.eduis not useful to whitelist.Yes. I am well aware and that would be by design.
remember - if someone on a major mobile network is uploading child photography, that device is radioactive and an instance admin is going to have options they may not have in other situations.
The idea is give instance admins control over who uploads content. Perhaps they don’t want mobile users to upload content, or perhaps they do but only major carriers, by their own definition of major.
Somewhere between “everyone” and “nobody” is an answer.
giving the instance administrator tools to help quarantine bad actors only helps, which will require layers. Reverse DNS is a cost, however; perhaps the tax is worth it when hosting images, where there is already a pause point in the end user experience, and the ramifications so severe.
Larger instances may dilligaf but a smaller instance may need to be very careful…
Just sayin…
Do you have a good and reasonable reverse DNS entry for the device you’re writing this from?
FWIW, my home network comes nat’ed out as
{ip-addr}.res.provider.com.Under your approach, I wouldn’t have any system that I’d be able to upload a photo from.
why do you say that, knowing full well DNS whitelists rely on wildcards?
If you’re whitelisting
*.res.provider.comand*.mobile.att.comthe whitelist is rather meaningless because you’ve whitelisted almost everything.If you are not going to whitelist those, do you have any systems available to you (because I don’t) that would pass a theoretical whitelist that you set up?
Why does it matter? Read some of my other posts.
Would you be able to post an image if neither
*.res.provider.comnor*.mobile.att.comwere whitelisted and putting10-11-23-45.res.provider.com(and whatever it will be tomorrow) was considered to be too onerous to put in the whitelist each time your address changed?Why wouldn’t you whitelist *.mobile.att.net?
If you have whitelisted
*.mobile.att.netyou’ve whitelisted a significant portion of the mobile devices in the US with no ability to say “someone in Chicago is posting problematic content”.You’ve whitelisted 4.6 million IPv4 addresses and 7.35 x 1028 IPv6 addresses.
Why have a whitelist at all then?