This is a big problem. At the time of writing:

1. Users cannot delete their images on Lemmy
2. If a user deletes their account, their images don’t get deleted
3. There is no WUI for admins to delete images on Lemmy
4. It is very difficult for admins to find & delete images on Lemmy (via the CLI)
5. The Lemmy team didn’t bother documenting how admins can delete images on Lemmy

How to purge images in Lemmy

pict-rs is a third-party simple image hosting service that runs along-side Lemmy for instances that allow users to upload media.

At the time of writing, there is no WUI for admins to find and delete images. You have to manually query the pict-rs database and execute an API call from the command-line. Worse: Lemmy has no documentation telling instance admins how to delete images 🤦

For the purposes of this example, let's assume you're trying to delete the following image

https://monero.town/pictrs/image/001665df-3b25-415f-8a59-3d836bb68dd1.webp

There are two API endpoints in pict-rs that can be used to delete an image

Method One: /image/delete/{delete_token}/{alias}

This API call is publicly-accessible, but it first requires you to obtain the image's `delete_token`

The `delete_token` is first returned by Lemmy when POSTing to the `/pictrs/image` endpoint

{
   "msg":"ok",
   "files":[
      {
         "file":"001665df-3b25-415f-8a59-3d836bb68dd1.webp",
         "delete_token":"d88b7f32-a56f-4679-bd93-4f334764d381"
      }
   ]
}

Two pieces of information are returned here:

1. file (aka the "alias") is the server filename of the uploaded image
2. delete_token is the token needed to delete the image

Of course, if you didn't capture this image's `delete_token` at upload-time, then you must fetch it from the postgres DB.

First, open a shell on your running postgres container. If you installed Lemmy with docker compose, use `docker compose ps` to get the "SERVICE" name of your postgres host, and then enter it with `docker exec`

docker compose ps --format "table {{.Service}}\t{{.Image}}\t{{.Name}}"
docker compose exec <docker_service_name> /bin/bash

For example:

user@host:/home/user/lemmy# docker compose ps --format "table {{.Service}}\t{{.Image}}\t{{.Name}}"
SERVICE    IMAGE                            NAME
lemmy      dessalines/lemmy:0.19.3          lemmy-lemmy-1
lemmy-ui   dessalines/lemmy-ui:0.19.3       lemmy-lemmy-ui-1
pictrs     docker.io/asonix/pictrs:0.5.4    lemmy-pictrs-1
postfix    docker.io/mwader/postfix-relay   lemmy-postfix-1
postgres   docker.io/postgres:15-alpine     lemmy-postgres-1
proxy      docker.io/library/nginx          lemmy-proxy-1
user@host:/home/user/lemmy# 

user@host:/home/user/lemmy# docker compose exec postgres /bin/bash
postgres:/# 

Connect to the database as the `lemmy` user

psql -U lemmy

For example

postgres:/# psql -U lemmy
psql (15.5)
Type "help" for help.

lemmy=# 

Query for the image by the "alias" (the filename)

select * from image_upload where pictrs_alias = '<image_filename>';

For example

lemmy=# select * from image_upload where pictrs_alias = '001665df-3b25-415f-8a59-3d836bb68dd1.webp';
 local_user_id | pictrs_alias | pictrs_delete_token | published 
---------------+--------------+---------------------+-----------
1149 | 001665df-3b25-415f-8a59-3d836bb68dd1.webp | d88b7f32-a56f-4679-bd93-4f334764d381 | 2024-02-07 11:10:17.158741+00
(1 row)

lemmy=# 

Now, take the `pictrs_delete_token` from the above output, and use it to delete the image.

The following command should be able to be run on any computer connected to the internet.

curl -i "https://<instance_domain>/pictrs/image/delete/<pictrs_delete_token>/<image_filename>"

For example:

user@disp9140:~$ curl -i "https://monero.town/pictrs/image/delete/d88b7f32-a56f-4679-bd93-4f334764d381/001665df-3b25-415f-8a59-3d836bb68dd1.webp"

HTTP/2 204 No Content
server: nginx
date: Fri, 09 Feb 2024 15:37:48 GMT
vary: Origin, Access-Control-Request-Method, Access-Control-Request-Headers
cache-control: private
referrer-policy: same-origin
x-content-type-options: nosniff
x-frame-options: DENY
x-xss-protection: 1; mode=block
X-Firefox-Spdy: h2
user@disp9140:~$ 

ⓘ Note: If you get an `incorrect_login` error, then try [a] logging into the instance in your web browser and then [b] pasting the "https://<instance_domain>/pictrs/image/delete/<pictrs_delete_token>/<image_filename>" URL into your web browser.

The image should be deleted.

Method Two: /internal/purge?alias={alias}

Alternatively, you could execute the deletion directly inside the pictrs container. This eliminates the need to fetch the `delete_token`.

First, open a shell on your running `pictrs` container. If you installed Lemmy with docker compose, use `docker compose ps` to get the "SERVICE" name of your postgres host, and then enter it with `docker exec`

docker compose ps --format "table {{.Service}}\t{{.Image}}\t{{.Name}}"
docker compose exec <docker_service_name> /bin/sh

For example:

user@host:/home/user/lemmy# docker compose ps --format "table {{.Service}}\t{{.Image}}\t{{.Name}}"
SERVICE    IMAGE                            NAME
lemmy      dessalines/lemmy:0.19.3          lemmy-lemmy-1
lemmy-ui   dessalines/lemmy-ui:0.19.3       lemmy-lemmy-ui-1
pictrs     docker.io/asonix/pictrs:0.5.4    lemmy-pictrs-1
postfix    docker.io/mwader/postfix-relay   lemmy-postfix-1
postgres   docker.io/postgres:15-alpine     lemmy-postgres-1
proxy      docker.io/library/nginx          lemmy-proxy-1
user@host:/home/user/lemmy# 

user@host:/home/user/lemmy# docker compose exec pictrs /bin/sh
~ $ 

Execute the following command inside the `pictrs` container.

wget --server-response --post-data "" --header "X-Api-Token: ${PICTRS__SERVER__API_KEY}" "http://127.0.0.1:8080/internal/purge?alias<image_filename>"

For example:

~ $ wget --server-response --post-data "" --header "X-Api-Token: ${PICTRS__SERVER__API_KEY}" "http://127.0.0.1:8080/internal/purge?alias=001665df-3b25-415f-8a59-3d836bb68dd1.webp"
Connecting to 127.0.0.1:8080 (127.0.0.1:8080)
HTTP/1.1 200 OK
content-length: 67
connection: close
content-type: application/json
date: Wed, 14 Feb 2024 12:56:24 GMT

saving to 'purge?alias=001665df-3b25-415f-8a59-3d836bb68dd1.webp'
purge?alias=001665df 100% |*****************************************************************************************************************************************************************************************************************************| 67 0:00:00 ETA
'purge?alias=001665df-3b25-415f-8a59-3d836bb68dd1.webp' saved

~ $ 

ⓘ Note: There's an error in the pict-rs reference documentation. It says you can POST to `/internal/delete`, but that just returns 404 Not Found.

The image should be deleted

Further Reading

Unfortunately, it seems that the Lemmy develoeprs are not taking these moral and legal (GDPR) risks seriously (they said it may take years before they address them), and they threatened to ban me for trying to highlight the severity of this risk, get them to tag GDPR-related bugs, and to prioritize them.

• lemmy #4433: Deleted Account should delete uploaded media (pictures) too
• lemmy #4441: Users unable to delete their images (pictrs API)
• lemmy #4434: Unapproved users cannot delete their accounts/data
• lemmy #3973: Banned users cannot delete their accounts/data
• lemmy #4445: Create an interface for local users to view and remove images
• lemmy-ui #2359: Allow users to delete images they uploaded
• lemmy-ui #2360: Allow admins to view & delete uploaded images
• lemmy-ui #2361: private_message_disclaimer to include user's matrix handle
• jerboa #1361: UI for deleting uploaded files
• jerboa #1362: Setting to hide "upload media" button
• jerboa #1363: Add "confirm upload" step to UX
• lemmy-docs #293: Document image moderation

If GDPR-compliance is important to you on the fediverse, then please provide feedback to the Lemmy developers in the GitHub links above.

Attribution

This comment was copied from the following article: Nightmare on Lemmy Street (A Fediverse GDPR Horror Story)

Nightmare on Lemmy Street (A Fediverse GDPR Horror Story)

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

Yes, it’s clearly disclosed in my profile that I am the founder of the BusKill project.

This is a PSA that our sale has started. I’ve had inquiries from members of our community asking about Black Friday sales.

10% off is barely any discount anyway.

Sorry, we’re a very small open-source shop. I’ve paid myself nothing so-far. The price just barely breaks-even for the business.

All of this is explained in-detail in “The Finances” section here.

Prices would drop dramatically if we could do production runs (and actually sell) >10,000 units at a time. Currently we only sell a few cables per month. If you want to help, please tell all your security-conscious friends about BusKill :)

Hi, this is not spam but a useful PSA that’s full of information, not just about the sale.

BusKill is useful for many groups, including human rights defenders, activists, journalists, whistleblowers, etc. You can read more about the use-cases of our community at our documentation here:

• https://docs.buskill.in/buskill-app/en/stable/introduction/what.html#who-uses-buskill

Yes, BusKill works with any USB drive.

• https://github.com/buskill/buskill-app

In fact, the BusKill cable is just a USB Drive. The only thing “fancy” that it has is a magnetic coupler in the middle of the 1-meter cable so that it will breakaway at any angle. But, if you’d like, you can build your own. The instructions are here:

• https://docs.buskill.in/buskill-app/en/stable/hardware_dev/bom.html

It’s run by the folks at dys2p.

Besides running ProxyStore in Leipzig, they have published some pretty great articles:

• Random Mosaic – Detecting unauthorized physical access with beans, lentils and colored rice
• Revealing Traces in printouts and scans
• On the security of the Linux disk encryption LUKS

You can follow them on Mastodon here https://chaos.social/@dys2p

Yes BusKill works similarly – any USB drive can use the BusKill software

• https://github.com/buskill/buskill-app

The BusKill cable is just nice because it includes a magnetic breakaway, so it works when the laptop is snatched-away at any angle. There’s actually a ton of anti-forensics software like usbkill and BusKill; we enumerate them all on our documentation’s Similar Projects section

• https://docs.buskill.in/buskill-app/en/stable/attribution.html#similar-projects

You may want to check ^ it out :)

I made a video of this (demo in Windows, MacOS, Linux, TAILS, and QubesOS) with the old DIY model here (sorry for the terrible audio quality)

• https://www.buskill.in/demo-2/

We’re currently working on an updated video with someone who is much better at video production than me; it should be finished in early 2024.

I’ve paid myself nothing so-far. The price just barely breaks-even for the business. There’s one-time costs like a few grand for a CNC’d injection mold and assembly jig, but also certification fees, product boxes, cardstock paper for documentation inserts, printing fees, artist commissions, packaging materials, warehousing, shipping, other logistics fees, etc.

All of this is explained in-detail in “The Finances” section here.

I prefer open-source hardware to be designed using common off-the-shelf items that are easily found everywhere in the world. Unfortunately, the one vendor of a USB-A magnetic breakaway couplers decided to EOL their product shortly after I published a guide on how to build your own BusKill cable. After we published, they all got sold-out, and we had to go to manufacturers for a custom component.

Prices would drop dramatically if we could do production runs (and actually sell) >10,000 units at a time. Currently we only sell a few cables per month. If you want to help, please tell all your security-conscious friends about BusKill :)

It should only be posted once to this community. It’s also been cross-posted to other relevant communities.

Unfortunately, that’s what it costs to make open-source hardware at small-scale.

There’s a cheaper $59 cable available or you could build your own.

Good bot