[Courses] [Linux commands]: /etc/crontab, crontab- setuid?

[Carla Schroder]

On Monday 09 February 2004 6:59 pm, olearyck at slu.edu wrote:
> > I'm saying that as my normal user I can't even create or edit a cron job 
at
> > all.  Even adding my user to the 'cron' group doesn't change this.  This 
is
> > probably just a feature of gentoo because it tends to be very security
> > consious by default.
> OK, I was being silly.  I had to add my user to the cron group and then log 
> back in.  Now I can create my own cron jobs.  
> 

 Ok, now it makes sense. Red Hat and Debian don't use /etc/groups for cron 
privileges, they use setgid:

$ stat  /usr/bin/crontab
  File: `/usr/bin/crontab'
<snip>
Access: (2755/-rwxr-sr-x)  Uid: (    0/    root)   Gid: (  110/ crontab)

Which lets system users run the command with the privileges of the 'crontab' 
group, without having to be listed in /etc/groups.

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Carla Schroder
www.tuxcomputing.com
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