User multiplies like a rabbit when the connection of the mobile client is lost

[noseshimself]

Describe the bug I was working on a spreadsheet using the Nextcloud Android client on ChromeOS -- usually a better combination than using the web UI. The link was not that stable and I had to reconnect a few times. Now I have multiple mes editing at once and can't get rid of them:

To Reproduce Steps to reproduce the behavior:

1. Edit in the mobile client
2. Crash the client
3. Goto 1.
4. Edit in the Web app.

Expected behavior I don't exactly know but I would expect that one of me is enough.

Screenshots See above

Client details:

• OS: Android Client 3.22.3
• Version 25
• Device: Lenovo ThinkPad C13 Yoga

Server details

Operating system: Debian 11.5

Web server: nginx

**Database:**mariadb

**PHP version:**8.1

**Nextcloud version:**25

Version of the richdocuments app 7.0.1

Version of Collabora Online 22.5.702

Logs

Nextcloud log (data/nextcloud.log)

I have no access to the logs.

Insert your Nextcloud log here

Browser log

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log
c) ...

[juliusknorr]

Are you using the built-in CODE server or a dedicated installation of Collabora?

[noseshimself]

Built-in.

I probably have to mention another fact: I'm using a mobile router that tries using a WLAN it is connected to another WLAN and losing that connection from time to time switching over to an LTE connection (with another IP address).

I guess you will need a mechanism to detect reconnections from a different IP address faster than now; it takes a few hours to get rid of all my minions.

[juliusknorr]

@timar @kendy Any idea what that could cause with the built-in CODE server? Is there maybe a timeout that could be decreased for considering users as inactive with the proxy?

[noseshimself]

I would rather try to recognize reconnections.

Define a constant UserDocConnGRMBWRGS-ID (probably a random but eternally constant GUID would be fine)

If a user is showing up opening a document "who is already there", ask him for his UserDocConnGRMBWRGS-ID. If it is the predefined constant, he is a "real user" and will be assigned a unique ID by the (proxy) server. If he provides a valid/active ID, he will be reattached to his session. If he is providing an unkown ID you know something is wrong. Being paranoid I would lock out the user and wait for a written statement signed in blood.

All in all this is smelling of an ugly approach for a DoS attack...

[cuthulino]

Looks like this is not only on mobile clients. Here someone mentioned this aswell. And I got the same Problem (using it in firefox, connected via ethernet). After some time editing the file the initial document loadscreen appears and the active users get +1.

I got the latest App and Nextcloud Version. Using the build in CODE Server and Saml-Plugin as auth-method.

[enoch85]

In our case it happens when the browser tab is closed, not pressing the X on the document. When pressing the X on the document it works as expected - so in our case it was user error.

But, would still be nice to drop the "connection" to the document even when the tab is closed.<

This is when when running the deb package installation with the Enterprise Collabora server.

[juliusknorr]

In case you are having an active enterprise subscription, maybe you can reach out through support so we can get Collabora involved accordingly.

[enoch85]

In case you are having an active enterprise subscription, maybe you can reach out through support so we can get Collabora involved accordingly.

Collabora are now informed.