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Absence of cron.allow and cron.deny

Linux Kernel, Network, and Services configuration.
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berndbausch
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Absence of cron.allow and cron.deny

#1 Post by berndbausch »

This is on Buster (Debian 10). The crontab(1) manual page says, referring to /etc/cron.allow and /etc/cron.deny:
If neither of these files exists, then depending on site-dependent configuration parameters, only the su‐
per user will be allowed to use this command, or all users will be able to use this command.
I have searched for those "site-dependent configuration parameters" in vain. What are they?

Yes I know that I can simply create an empty cron.allow to disallow crontab, or an empty cron.deny to allow it for everybody. I am asking the question because I don't sleep well when I read vague allusions in manual pages.

CwF
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Re: Absence of cron.allow and cron.deny

#2 Post by CwF »

So as installed it's minimally configured, the files don't exist, and there are no "site-dependent configuration parameters". Then, the user adds some configuration, creates the files, and now has "site-dependent configuration parameters".

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Re: Absence of cron.allow and cron.deny

#3 Post by trinidad »

Sounds like that is the meaning. Documentation writing is all about terminology. I wonder if "user-configured-usage" wouldn't be a better way of saying it. One contributor below.

Steve Greenland <steveg@moregruel.net>

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berndbausch
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Re: Absence of cron.allow and cron.deny

#4 Post by berndbausch »

The thing is, in Centos the default is different. When none of the files exist on a Centos system, only root has the right to use crontab, and that is what the manual page says. The way it is formulated in the Debian manual page, I have to believe that there is some other configuration mechanism that defines that default.

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Re: Absence of cron.allow and cron.deny

#5 Post by CwF »

Each user can have their own cron file?

Code: Select all

$ crontab -l
$ crontab userfile.cron
..to list the default file, and to use you own.

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Re: Absence of cron.allow and cron.deny

#6 Post by Deb-fan »

Believe what CwF said pretty much sums it up. Only root can set/run crontabs default. When it comes to keeping all the doc's covered, updated and relevant it must be a monumental task. May consider volunteering time for things like man pages, often they're about as clear as mud. Maybe considers whether cron service is even enabled at all times and system start?
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Re: Absence of cron.allow and cron.deny

#7 Post by reinob »

Deb-fan wrote:Only root can set/run crontabs default
Except when that's not true :)

Debian, per default, has neither cron.allow nor cron.deny, and, per default, does allow any user to run crontab.

The manual page is precise in its language. It just doesn't tell you where that "site-dependent configuration parameters" are to be found.

Apparently, centos has other such parameters, but I don't know anything about centos.

Does anyone know where the default is configured? (perhaps a compilation default, or user/group permissions?)

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Re: Absence of cron.allow and cron.deny

#8 Post by Deb-fan »

^ Didn't know that, good to know thank you. :) Once we get these cronish mysteries solved to everyone's satisfaction can we move on to these systemd timer unit thingys? Situation is normal here, on the one-hand am tempted to Google, on the other am more tempted to be lazy and just remain ignorant about such. Better go with what I know best, lazy + ignorance wins again. :P
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