Tag Archives: crontab

How use crontab / cron with Jailkit on Ubuntu 12

Recently I began testing jailkit on Ubuntu 12 and 12.04 and wanted users to have access to cron and crontab I read a lot of the documentation for man cron and have a pretty good understanding of how Vixie Cron works. There is a bit of a conflict with permissions of Cron and Jailkit. Jailkit wants most everything inside the jail (most often /home/jail/) to be owned by root and in the root group, and basically nothing to be writable by the jailed users (except for /home/jail/tmp/ and the users home directories in /home/jail/home/*) Cron, on the other hand, doesn’t want you to edit the crontab files for the users directly. They live in /var/spool/cron/crontabs cron searches its spool area (/var/spool/cron/crontabs) for crontab files (which are named after accounts in /etc/passwd); crontabs found are loaded into memory. Note that crontabs in this directory should not be accessed directly – the crontab command should be used to access and update them. More information is given from man crontab: There is one file for each user’s crontab under the /var/spool/cron/crontabs directory. Users are not allowed to edit the files under that directory directly to ensure that only users allowed by the system to run periodic tasks can add them, and only syntactically correct crontabs will be written there. This is enforced by having the directory writable only by the crontab group and configuring crontab command with the setgid bid set for that specific group. That’s great, but… How do I set up … Continue reading

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