Restart Docker Container Without root privileges

Submitted ⁨⁨7⁩ ⁨months⁩ ago⁩ by ⁨crony@lemmy.cronyakatsuki.xyz⁩ to ⁨selfhosted@lemmy.world⁩

Hello, I have a mumble server running as a docker container.

I’m using lego to generate let’s encrypt certificates using dns challenge as an unprivileged user.

My problem is that I need to restart the mumble server so that it can reload the ssl certificate, which means restarting the docker container.

Is there any way to do this withuot adding the user to docker group, since there are security issues with that group where it’s easy to escalate to a root user.

I thought about maybe a user level systemd service could be able to do it, but wan’t to hear your opinions?

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Comments

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redcalcium@lemmy.institute ⁨7⁩ ⁨months⁩ ago
I think you can send a SIGUSR1 signal to mumble process to tell it to reload the ssl certificate without actually restarting mumble’s process. You can use docker kill --signal=“SIGUSR1” <container name or id>, but then you still need to give your user access to docker group. Maybe you can setup a monthly cron on root user to run that command every months?

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- crony@lemmy.cronyakatsuki.xyz ⁨7⁩ ⁨months⁩ ago
  Yea this seems like the most easy solution for mumble specifically.
  
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someonesmall@lemmy.ml ⁨7⁩ ⁨months⁩ ago
Create a sudo rule which allows the user to run only this exact command: “sudo docker restart mycontainer”

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shrugal@lemm.ee ⁨7⁩ ⁨months⁩ ago
Looks like you can create a simple binary and make it run as root with setuid.

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iluminae@lemmy.world ⁨7⁩ ⁨months⁩ ago
You could write a script that just restarts your container, make sure unprivileged users cannot edit it, and do one of two things:

make a sudoers entry for your unprivileged account to call just that script as a user in the docker group with sudo

use setuid on the script to have it execute from the docker group even from other users
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- ShawiniganHandshake@sh.itjust.works ⁨7⁩ ⁨months⁩ ago
  Most shells ignore setuid on scripts for security reasons.
  
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bjoern_tantau@swg-empire.de ⁨7⁩ ⁨months⁩ ago
Did you think about automating the certificate generation? You could put everything into a cron script. That’s more or less the reason why certificates have such a short lifetime. To force automation.

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tvcvt@lemmy.ml ⁨7⁩ ⁨months⁩ ago
Not sure how your stack works together, but sudo will let you run particular commands as a different user and you can be pretty specific with the privileges. For example you can have a script that’s only allowed to run docker compose -f /path/to/compose.yml restart containername as a user in the docker group. Maybe there’s some docker-specific approach, but this should work with traditional Unix tools and a little scripting.

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redxef@feddit.de ⁨7⁩ ⁨months⁩ ago
If a user is in the docker group they can also run docker commands.

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- raldone01@lemmy.world ⁨7⁩ ⁨months⁩ ago
  Is is effectively root.
  
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