Well it is a blocker if the permissions are too permissive such that it would break the Linux security model (e.g. allow one user to use the cron mechanism to run commands as another user! or e.g. allow one user to access information that is supposed to be private to another user). In other words, Linux is trying to stop you shooting yourself in the foot. On a single user device, yeah, it probably doesn’t make much difference.
A few other general comments about crontab:
- On a single user device, I would tend to use the system crontab file and specify the user that the command is to run under on each line of the file. That way everything that is going to happen is centralised for your easy maintenance. (For example, that may better manage load, rather than inadvertently kicking off multiple jobs at the exact same time.)
- I would tend not to specify I/O redirection in the command to be executed by cron. I don’t think it is explicitly specified as working, although there is an example in the
manpage using it, and whether it works could be affected by implementation changes. - Consequently I would always specify a shell script as the command to execute and redirect I/O inside the shell script in one way or other. In other words, the shell script keeps its own log file and doesn’t rely on the behaviour of cron.
Doing anything every minute may be bad for runtime on battery. It may be better to use the firewall to enforce use of the VPN if that is your intention. If the VPN if flaky, it may be better to investigate why that is and, if applicable, find a better provider.