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How are cron.allow and cron.deny read?


 
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Top Forums UNIX for Dummies Questions & Answers How are cron.allow and cron.deny read?
# 1  
Old 08-02-2012
Question How are cron.allow and cron.deny read?

Hi, all!

I was working on my Debian, minding my own business but then I wanted to see what happened if the same user was included on both cron.allow and cron.deny Smilie

I would have bet that cron.deny was going to override cron.allow for security reasons, but my computer proved me wrong: cron.allow seems to override cron.deny, so if you are on both, you can still cron jobs.

I'm curious about this. Does cron read these files alphabetically? How is this behavior explained? I've been googling the answer but I only found tutorials on how to use cron.

Thanks!!
# 2  
Old 08-02-2012
If cron.allow exists, then only the users listed in the allow file are are permitted to use cron. Otherwise, all users are allowed to use cron except the ones listed in deny. If cron.allow exists, cron.deny is ignored.
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# 3  
Old 08-03-2012
Oh, ok. So if cron.allow exists then cron.deny is simply ignored.

How does that work? Is it like a "shortcutted" OR? Something like "great! I found cron.allow, I won't even bother to check for cron.deny"

Maybe I'm going too deep into the internals of cron, but I'm just curious.
# 4  
Old 08-03-2012
When all users except a, b, c are implicitly denied by using cron.allow, what's left for cron.deny to do?

It also prevents the question of which should "win" when a user is simultaneously in cron.allow and cron.deny. There's a clear and unambiguous answer this way.
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