cron not running labca (Ubuntu 20.04 tested)

[tjmullicani]

On Ubuntu, within the docker containers, cron is not able to execute the /etc/cron.d/labca (/labca/cron_d) file since it is group-writable.

root@machine:~# docker ps
...
5ade9ea1d15f   letsencrypt/boulder-tools:go1.19.5_2023-01-10   "./control.sh"
...
root@machine:~# docker exec -it 5ade9ea1d15f bash
root@5ade9ea1d15f:/labca# ls -l /etc/cron.d/labca
lrwxrwxrwx 1 root root  13 Feb 18 03:58 labca -> /labca/cron_d
root@5ade9ea1d15f:/labca# ls -l /labca/cron_d
-rw-rw-r-- 1 root root 397 Feb 18 04:36 /labca/cron_d

The solution is to remove group writable permissions from /labca/cron_d

root@5ade9ea1d15f:/labca# chmod g-w /lab/cron_d
root@5ade9ea1d15f:/labca# ls -l /labca/cron_d
-rw-r--r-- 1 root root 397 Feb 18 04:36 /labca/cron_d

References:
https://bugs.launchpad.net/ubuntu/+source/cron/+bug/723423
https://serverfault.com/a/1040206

[hakwerk]

I don't see this issue on any of my test machines, but it should be safe to always remove the group write so it will be included in the next release.

[hakwerk]

Was included in release v23.03