11mo ago

PSA: You can't delete photos uploaded to Lemmy. So don't (accidentally) upload a nude

tech.michaelaltfield.net /2024/03/04/lemmy-fediverse-gdpr/

267 comments

You can't delete any text in comments or posts either - or at least not reliably, as any federated instance could choose to ignore deletions.
You should basically consider what you write or post here public, and probably public for good. But here's the thing - same goes for the entire rest of the Internet as well, basically.
- You should generally think similarly about anything you post anywhere on the internet that has open access. If it's viewable anonymously, anyone could save and mirror it.
  The only difference is it's almost guaranteed on a federated platform.
  
  I feel like, after over a decade of smartphones and snapchat and such, a younger generation needs to be thought better what putting content on the Internet means on a fundamental level, and those of us old enough to remember the more open web need to be reminded.
  If you don't want everyone to see it, and I mean everyone, then you shouldn't put it online. For all intents and purposes, once you hit send, it's now a part of the internet. You might get lucky and be able to remove it, but that's the exception, not the rule.
- If that’s the case then I need to say this: “Penis ass butt cock fart”
  
  @NineMileTower@lemmy.world, 2024
  Never forget
- I didnt know about that. This is a bit scary to be honest, and the first time I feel a bit taken aback with lemmy
  
  You also know that all votes are technically public and can be viewed by any instance admin that's federated with the server a community is on, right? There's no way to see that in the Lemmy UI at the moment but the data is there on the server.
  
  I mean you could say the same thing about reddit - anyone could scrape reddit and save comments and stuff, even if you later delete them.
  If someone can see something on their computer, they can save it and you won't be able to take it away. I mean... it's just how the internet works.
  
  The deletion should federate across almost all instances, but there's no guarantee and also someone will almost certainly one day set up an archive server that just listens to all activity on Lemmy like uneddit used to be for reddit.
  
  That's pretty much how everything on the Internet works, FYI. Lemmy is just upfront about it
  
  Lemmy and other services built on ActivityPub work by sending content to every server that hosts a user who has subscribed to a community or another user. Those servers could be anything from vanilla Lemmy hosted in a datacenter to an ad-hoc, informally-specified, bug-ridden, slow implementation of half of ActivityPub running on a jailbroken smart light bulb. Most of them will be online to receive a delete request and will handle it correctly most of the time, but that cannot be guaranteed.
  Anything you share to the world that way is out in the world and cannot be reliably rescinded. Discussion groups implemented as email lists used to be popular, and the same was true there, but more so since there isn't a mechanism intended to edit or delete an email message after it is sent. Something similar is true of anything that functions as a public website; a great many things published to the web are available from sites like archive.org, like old forum posts.
  
  I don’t know if this works on Lemmy, but Reddit used to be like this and a solution was to edit your comment to different text first (something like ‘I like turtles’), wait about a week to allow the new text to be archived, and then delete it.
  ‘I like turtles’ wasn’t special, but makes it easy to scroll through your comments later when deleting things.
  In Lemmy, your username will still show up with deleted comments, but in theory the edited text will replace the original comment you want to delete in archived views. This method doesn’t work with post images, though.
  Someone correct me if I’m wrong here, please.
  e: I’ve edited this comment thrice in 2 hours. Can anyone tell, and can you differentiate my 3 edits?
  
  Just assume anything you post here will be scraped by Facebook, Google, Amazon, the CIA and the CCP, regardless of what the Lemmy devs and admins let you do with your data.
  It's a public forum. Once you post something there's no guarantee it will ever be gone.
- And seemingly nothing is actually deleted, just hidden. Boost for Lemmy currently has an interesting bug where any comment, deleted or removed, can still be seen by simply selecting "copy post text" from the menu, as the API will return what was previously there.
  PSA, if you want to delete a comment or post, be absolutely sure you first edit it to be blank.
  
  This seems like a server-side issue from Lemmy tho and one that should be pretty easy to fix. I mean, what's the point of keeping a deleted post on the server anyway?
- It's a different level of can't delete though, because if you upload a photo but never even post it, it will still be up forever. And at least a working delete protocol exists for text
  
  So... theoretically someone can use lemmy as their own image repository?
  
  Those images are likely to be cleaned up in a future update though.
- Lemmy in general is filled with potential security and privacy holes. The threat surface is just too massive.
  Not to mention it has a bunch of vulnerabilities in terms of just basic forum functionality. A rogue instance can very easily just hijack all sorts of federated content and force it into a certain state as desired. Especially if that content is old. There is not really any mechanism for tracking source authority for federated updates, and there are definitely already signs that this is getting exploited to promote certain content and fuck with vote totals IMO.
  None of this really matters at this point because Lemmy is insignificant, but it kind of places a limit on how much Lemmy can be scaled before it just becomes even more of a cringe propaganda wasteland than it already is.
  
  A rogue instance can very easily just hijack all sorts of federated content and force it into a certain state as desired.
  I'm really not sure what you mean by this, can you elaborate?
  There is not really any mechanism for tracking source authority for federated updates, and there are definitely already signs that this is getting exploited to promote certain content and fuck with vote totals IMO.
  I'm not sure what you mean by "not any mechanism for tracking source authority". Admins on their own instance are in control of what happens to the content and they'll know if another site edits content or whatever as that is sent as requests in ActivityPub.
  What are the signs you're referring to?
- Unless, of course, you expect to rely on that permanence for archival purposes, in which case the internet is a fleeting, ephemeral fart in the wind.
- Is this not illegal under GDPR? The right to retrieve and delete all data is a fundamental part of that legislation. Maybe only European hosted instances are in jurisdiction?
  
  To be clear, all major instances are well behaved and things are deleted once requested. But there's no guarantee that there is not some malicious instance out there that intentionally keeps stuff. Also sometimes communication between instances just goes wrong.

Welcome to the hell of being a lemmy admin. There's a reason why lemmy admins are fed up with the developers.
- For context, there's a lot that goes on behind the scenes when it comes to lemmy admin stuff especially in the matrix channels. There is a significant frustration and lack of confidence in the lemmy developers at this point. Even those who try to contribute to the project get eventually feeling pushed out.
  
  Based on what I've seen on the public facing part of the developer side, I get the feeling this isn't the kind of group that can build the kind of organization required to make this sustainable in the long run.
  I'm just waiting for when Beehaw releases that they've given up on Lemmy and have created a new tech stack.
  
  That sucks. As a 3rd party Lemmy app developer, I've only had positive interactions with the Lemmy devs. They're even being proactive in communications.
  
  Even those who try to contribute to the project get eventually feeling pushed out.
  Submitting a pull request to one of their repos on Github was really an experience, and I can tell you that I will never submit another one to the Lemmy project while they're still the lead devs based on that experience.
  
  That's kind of the impression I got but thought maybe I was just mistaken because I haven't actually been hands-on with this project. That's unfortunate to hear.
  
  What about kbin, isn't that entirely different software that can be developed to phase out Lemmy?
  
  Better to publish such issues on a public website than let it get buried in matrix. People other than devs & instance admins need to be aware of the risks that they’re taking when using Lemmy.
  
  Perhaps there's starting to be a Lemmy clone/alternative? I think it's named Sublinks
- Not sure I understand. How could there possibly be a solution? Isn't this an inherent problem with federation? You can't un-share information
  
  But you can delete your copy, ask others nicely to delete theirs, and refuse to accept more copies of the same thing.
  I'm not sure if Lemmy supports any of this, but it seems pretty important for e.g. child porn.
  
  There could be a legally binding contract stating that any deletion request must be forwarded to all parties it was send to, and that upon receiving such a request the data must be deleted. I do not think this would be unreasonable to ask to servers, especially as this deletion receipt could be fully automated.
  
  The images aren't federated afaik. They live on your home instance. If somebody else views them, they're loaded directly from there.
  However there's no link between the images and your account. You can't delete them yourself because Lemmy doesn't store the "delete token". They're effectively orphaned.

So what have they been doing to nuke the csam images, editing the database directly?
- Often just nuking all image uploads made during a certain time period. Which is why old image threads in Lemmy have time periods littered with broken images.
  
  I don’t understand why Lemmy needs to have a built-in image server at all. Reddit didn’t have one for the longest time and it was fine. Sure, I don’t think anyone would be particularly happy with going back to Imgur etc., but it doesn’t seem worth the trouble.
- Yes
- Often they delete all images during the time frame of a CSAM attack, as that has been the only real feasible way to ensure images weren't left behind. Though I think a few images have started using AI detection methods to remove images like that automatically (read up on that here and here), also Pict-rs now has a Log linking uploaded images to the user, so now images can be purged with the users.
- Admins can purge posts manually which actually deletes them. Or use tools like db0's lemmy-safety that tries to automatically search for CSAM and wipe it.
  I think the problem here is the user didn't finish their post which means the photo was uploaded but not associated with a post and therefore not purgeable that way.
  
  That last problem was fixed in an older version of the software. If you upload, but don't post, it will now be deleted after a time.
  You can test this pretty easily by just leaving your browser open with an image uploaded and trying to post it later.

So when I accidentally uploaded those Death Star plans...
- Don't worry. There was some little minor thing about a vent but is reported as fixed since it was discovered.
  
  I'm on the side of the Death Star engineers. Nowhere in the spec was it required that Death Stars be Jedi-proof.

How exactly does Lemmy remain in compliance with laws regarding, for example, a user's right to have all data associated with their account deleted (right to erasure, etc), or ensure that it is only kept for a time period reasonable while the user is actively using your services (data protection retention periods, etc)?
It's not a big deal for me, just strange to think Lemmy of all places would be built to be so anti user's data rights. The user is ultimately the one that decides what is done with their information/property, after all.
- Lemmy is not a singular software or website, every instance on its own need to ensure compliance with their respective laws where they are domiciled.
  But if instance A is domiciled in the EU, and the content mirrored to instance B in Zimbabwe, where no right to be forgotten exists, then a user of instance A can't invoke any laws beyond what the local admin can control.
  That's amazing for high availability of content - it's essentially mirrored in perpetuity - but a nightmare for privacy advocates. AFAIK there haven't been any court cases related to deletion requests, so that's still virgin territory.
  
  Instances located in Zimbabwe still have to comply with the GDPR, as the law applies to any entity that processes EU citizen's personal data, regardless of where this happens. Instance B would also have to comply with a deletion request, or whatever EU member state the citizen is from will impose a fine and seize assets if necessary.
- redacted
  
  GDPR does not depend on business size, there are just a few stricter requirements when you have more than 250 employees. But most of the GDPR still applies to my knowledge.
  
  Uhuh, suuureeeee. Tell that to any number of fines that has yearly been issued by my country's GDPR oversight agency on ordinary citizens.
  GDPR only applies when people file reports and when there are lawsuits. There's literally no shortage of articles of people fined for GDPR violations, all people need to do is search for them.
  When someone files the inevitable court case, please let me know. I have some admin behavior bullshit I will be willing to personally get in contact with the lawyers about that I think could help it.
- Because Federation is a terrible idea
  But think of Reddit, they can delete a post but a bunch of archived websites will still have it. That doesn’t make Reddit non-compliant
  
  Why is federation bad? It's the only way to decentralize without having everyone scattered across millions of sites.
  The days prior to 2014 are gone and for the most part, the overwhelming majority of people don't want to register across dozens of sites. Everyone naturally gravitates toward massive content silos where they can get everything in one place.

That is crazy. He really did seem knowledgeable, and apart from the upload of a sensitive image, he really did what he could.
- All those feature requests seem like good stuff.
  
  And legally mandatory. Lemmy instances will get fined and shut down because of this if they do not sit up and pay attention.
- What did we miss?
  
  https://tech.michaelaltfield.net/2024/03/04/lemmy-fediverse-gdpr/

Or do.
- If this comment gets to 150 votes in either direction, I'll post my butthole.
  
  You should do it anyway.

What exactly is a KYC selfie? Is it a photo of an ID card? I figured out WUI is WebUI. The author uses some strange acronyms I never heard before.
It's very American that they can steal your identity with just one photo. My European state issued ID has data on both sides, so if someone would take a photo of it won't be enough for anything. Also if you loose it you just get a new one and noone can use the old one for anything.
- KYC is Business/Finance lingo - "Know Your Client".
  Yeah the fact that exposing one number/piece of information puts you at risk to a significant amount of other information about you being exposed is peak USA.
- KYC is "Know Your Customer" aka identity verification. Usually it would be something like a selfie of you holding your ID, proving you are the person on the card. If you think getting your identity stolen from one picture is bad, wait until you learn about social security numbers. It's a 9 digit number based on publicly available information about you that is incredibly easy to figure out, and are used as like the defacto way of verifying your identity in the US, when that was never its intended purpose.
  
  Relevant CGP Grey
- KYC = Know Your Customer, a team I just learned recently. It’s primarily related to financial transactions, to make crimes like money laundering or terrorism financing harder. Up until relatively recently this was something that primarily happened face-to-face, and it doesn’t seem like good controls have been developed for online use.
  I think some ID cards are single-sided, some are double-sided. One of the big problems is most Americans only have a state-issued ID, not a federal one, and the standards vary from state to state. They’ve tried to address this some with minimum standards for state IDs (mainly driver’s licenses) under a program called Real ID (enacted after 9/11 hijackers got state-issued IDs for false identities), but it was still optional for certain purposes, at least until recently. In my state for a long time when renewing your driver’s license it was optional to do the extra paperwork for a Real ID, but then there would be a note on the top that it was not valid for federal identification purposes, such as accessing certain government facilities or boarding an airplane. Since I have a passport I’ve never bothered with it, but it looks like this year getting a Real ID is mandatory when getting or renewing a driver’s license in my state.
  
  Minnesota just extended it to 2025 again. I can't get into federally secure buildings, but I can board a plane.
  And until I can't, I'm not going to. Part of me likes to think they haven't mandated it yet because I'm holding out.
  Which is really because of pure laziness than actual protest
  
  It's mostly a religious thing. The "left behind" Christians believe a federal ID is the "Mark of the Beast".
- Probably "know your customer" selfie. Might be a picture of their ID, a picture of themselves, or a picture with both them and ID.
- Author here. A "KYC Selfie" is a selfie photo where you hold-up a State-issued photo-identity document next to your face. This is not a US-specific thing; it's also used in the EU.
  I used to work for a bank in Europe where we used KYC seflies for authentication of customers opening new accounts (or recovering accounts from lost credentials), including European customers. Most KYC Selfies are taken with a passport (where all the information is on one-side), but if your ID has data on both sides then the entity asking you for the KYC seflie may require you to take two photos: showing both sides.
  Some countries in the EU have cryptographic authentication with eIDs. The example I linked-to in the article is Estonia, who has made auth-by-State-issued-private-key mandatory for over a decade. Currently MEPs are deciding on an eID standard, which is targeting making eIDs a requirement for all EU Member States by 2016.
  I recommend the Please Identify Yourself! talk at 37c3 about the state of eID legislation as of Dec 2023 (and how to learn from India, who did eID horribly wrong):
  https://media.ccc.de/v/37c3-12004-please_identify_yourself

OH NO,

Anyway....
- What is the name of this genre? Asking for a friend.
  
  AI prompt in the bingilator was "the fall of Rome, but the Romans are all sailor moon and the barbarians are slime monsters"
  If weird nonsense is what you want then check out !imageai@sh.itjust.works
  Guess more from this "genre"

Dear aussie.zone users,
I can delete photos. Just give me the url of the photo you need killed and I'll happily delete it for you. But also, don't (accidentally) upload a nude.
- Assuming it's not a joke that flew over my head, how could any individual instance remove the images once replicated? Is the removal from the original instance cascaded?
  
  It is my understanding that images are never federated and always reference from the source instance... But, the text is fully federated.
  
  There's no technical reason you can't delete an image that's been replicated. There's an API to replicate the data, there can also be apis to delete the replicas (and apparently there are?)
- But won't answer DMs about an instance bug where being temp banned from one community functions as an instance wide ban
  
  Huh.
  You are correct - there is a message in my inbox from you. I honestly didn't realise/see it. I'll reply privately.

I’m a developer of a Lemmy client. When you upload an image to a Lemmy instance, the instance returns a “delete token”. Later, you can ask the instance to delete the image attached to the delete token. So as long as you keep hold of the delete token for a specific image, you’re able to delete it later.
Lemmy-ui (the official frontend) will give you the option to delete an image again shortly after uploading it. However, it’s not possible to remove the image after actually creating the post, as the delete token associated with that post isn’t remembered anywhere on the Lemmy backend.
As for other Lemmy clients, YMMV. The client I work on (Mlem) deletes images if you remove them from a post before posting it, but has the same pitfall as Lemmy-ui in that it won’t delete the image if you’ve already created the post.
It would be possible to locally save the delete tokens of every image you upload, so that you can request that they be removed later. I don’t know of any clients that can do this yet, though (if someone knows of one, feel free to mention it).
Edit: clarity
- as the delete token isn’t stored anywhere on the backend.
  Backend of the app or the lemmy server? if it is not stored on the lemmy server then there will be no way to delete it even if the app stores the token.
  Also using a singular token that never expires to modify user content sounds like a bad idea. image operations like upload and delete should probably tied to the user credentials.
  
  Backend of the app or the lemmy server? if it is not stored on the lemmy server then there will be no way to delete it even if the app stores the token.
  Apologies, I worded that badly. Lemmy uses an image hosting service called pictrs to manage the images you upload, which is largely separated from the rest of the Lemmy backend. Pictrs of course stores the delete tokens matching each image, but Lemmy doesn't associate those tokens with the posts or comments they originated from as far as I know.
- whats the intent of a delete token in this context, why is it needed. it looks like bad design to me
- It would be possible to locally save the delete tokens of every image you upload, so that you can request that they be removed later. I don’t know of any clients that can do this yet, though (if someone knows of one, feel free to mention it).
  @sjmarf@sh.itjust.works I'm told Boost does this.

I hate to use it, but this is why I still find imgur useful. It works.
Some stuff on Lemmy just doesn’t have a robust feature set yet. Especially around content moderation.
- Image previews will still be cached, i believe.
  Not sure what quality lemmy would cache them at, i presume its configurable

This got me curious on how many images are on all Lemmy instances combined and how much storage it all takes up.
- I can tell you that for lemmy.ca we use 778gb
  
  Holy fucking shit balls. I contemplated seeing up an instance on a £5 VPS. Hmmmm, I think my scale is a bit off.
  
  Huh, less than I expected.

You can consider almost anything publicly posted to Lemmy as permanent. As I keep saying, please be careful.
I do think a way to automatically store the uploaded image urls and associated delete keys under your user is a necessary feature.
For personal image hosting I use postimage, but any external host that lets you modify/remove images under your account will do.
- You can consider almost anything publicly posted to ~~Lemmy~~ the internet as permanent
  FTFY
  
  Excuse me, there was an internet beyond Lemmy?!? /s

Seems that one of the problems with regards to this post has been recently fixed and will be included in the next release :)
https://github.com/LemmyNet/lemmy-ui/pull/2385
- this is reactive! and a good sign for the lemmy community
- This is only for deleting your entire account. Not deleting an individual image from your post history. At least there's a solution for now.
- Looks like we forgot to add this option in the frontend.
  I thought they failed to add the checkbox:
  We failed to add a checkbox for this parameter to lemmy-ui.
  
  ... What's the big difference? They failed to add it cause they forgot, no?

What happens when you share a link to an image? Does Lemmy just save the link or does it make a copy of the image?
- The link. It only saves the image if you upload it directly, since converting it to a link, and embedding the link is how Lemmy handles image uploads.

Isn't this in violation of the gdpr?
- If that were the case, wouldn't the entire Fediverse be against it? Since they can't really be deleted because it gets sent everywhere.
  
  Yes and no.
  let's say I have a website that hosts user generated content like a forum or something. Some other person just hosts a mirror of my website that is not under my control. If some user requests me to delete his data, I can do that. i cannot delete the data from the mirror site.
  Nothing else is happening in the fediverse. The only difference is, that in the fediverse the license and technology is set up to encourage mirroring content.
  
  I suspect it is the case.
  The issue doesn't seem to be the Fediverse itself, rather the fact that images uploaded to Lemmy are handled in a separate program that isn't linked to it in a way you can delete from by just deleting posts. The images aren't marked as owned by you, so can't be deleted again. You'd need some way of storing those image deletion tokens against your account, so you can manage them yourself and be able to delete them again.
  And this would have to include images that you uploaded and didn't make a post about. As far as I can tell they're just left there on the server forever. Not even sure if it tells you which user uploaded it, although it might log by IP address. I haven't looked too deeply into the code but there's potential for abuse there.

If you upload an image from your browser, there's a little popup in the corner for a few seconds that allows you to delete it again. No such thing exists in the apps though and if you miss the popup, that's it.

Damnit. I wish I known that an hour ago. I guess my butthole pic will live on with the internet for an eternity.
- It really is a nice butthole
  
  Great, now you made me want to check their profile to see if they did indeed uploaded a picture of their butthole.
  I am saved by my ultra slow internet and going to have to take your word for it.
  
  "That's America's butthole."

If you ask the instance admin nicely, they might delete it for you, with a small risk of taking down the instance if they mess with pictrs wrong.

https://media1.tenor.com/m/EDYebu-b3KwAAAAC/dont-tell-me-what-i-cant-do.gif
takes off pant
- Just the one?
  
  The other leg was already off
- hides pants in locker
  
  Is that a John Locker?

I’ll be honest, didn’t realize this was news to anyone online in general. What is posted online stays online, particularly if you wish it didn’t. Most especially if you make a stink about it.

Yea i remember coming across this issue on git the devs were being angry at the poor lad.
- How dare you make us follow the rules!
  
  What ?

I can't upload any image so I'm way ahead of you
- How? I want to block my app from being able to upload images.
  
  Join lemm.ee and you would be golden

Are you asking?😉😉
- maybe we all are? 😵

That's scary. I must be certain to not mix up my dick pics with my memes.

Might be worth heeding with anything else sensitive too. Like bank details, emails etc. Dont dox yourself.
- hey, if you type in your pw, it will show as stars ********* see!

You're telling me my penis can have a legacy?

Lawsuit waiting to happen.
PSA for admins and mods: GDPR fines can go up to 20 million euros per case. To give you an idea, Meta has been fined over 2.5 billion euros in recent years. If you think that's bad, the real worry is Germany's NetzDG.

Are you sure you want to insert a cheat code?
Yes.
Allyournudesarebelongtous
Cheat activated!

Oh really I thought it would be the other way around where private companies always keep a copy and fediverses don't 😅

I've posted a selfie and cat pics.
I am unimportant and have little to steal. Though if someone starts shooting at me for paraphrasing far left theory, I'll know I hit a nerve.
- It's not about if you're important or not, it's about if you become important to someone.
- Don't underestimate your own worth, everyone has something of at least little importance, because even someone "worthless" can be worth a lot to the right people.
  That's why it's very important to be careful what you share.

267 comments