Date: Wed, 17 Jan 2001 00:03:13 -0600 From: Dan Nelson <dnelson@emsphone.com> To: Greg Black <gjb@gbch.net> Cc: Michael Bacarella <mbac@mmap.nyct.net>, hackers@FreeBSD.ORG Subject: Re: Permissions on crontab.. Message-ID: <20010117000313.A28355@dan.emsphone.com> In-Reply-To: <nospam-3a652ec18b151ad@maxim.gbch.net>; from "Greg Black" on Wed Jan 17 15:33:53 GMT 2001 References: <20010117001842.A28301@mmap.nyct.net> <nospam-3a652ec18b151ad@maxim.gbch.net>
next in thread | previous in thread | raw e-mail | index | archive | help
In the last episode (Jan 17), Greg Black said: > Michael Bacarella wrote: > > Why is crontab suid root? > > > > I say to myself "To update /var/cron/tabs/ and to signal cron". > > > > Could crontab run suid 'cron'? > > > > If those are the only two things it needs to do, run cron as gid > > 'cron' and make /var/cron/tabs/ group writable by 'cron'. > > It has to run jobs as the correct user and must be able to setuid > accordingly. Not quite. As far as I can tell, crontab is setuid root for the sole purpose of being able to write to /var/cron/tabs. Cron checks the timestamp on the directory every minute, so crontab doesn't have to signal it for changes to get noticed. If you're paranoid, you can probably "chgrp cron /var/cron/tabs" and make crontab setgid cron without any ill effects. Cron itself must stay setuid root, of course, so it can run user crontabs as that user. Or it might need to be setuid for some other reason, since OpenBSD runs their crontab setuid root, and they usually are pretty security-paranoid. -- Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010117000313.A28355>