From: rick@ee.uwm.edu (Rick Miller, Linux Device Registrar) Subject: Re: /dev/modem problems Date: 6 Apr 1993 10:18:24 GMT
Michael.Whitlatch@f460.n3625.z1.fidonet.org (Michael Whitlatch) writes:
>
> JJ> What needs to be done so that /dev/modem can be accessed by other
>users?
> JJ> Currently only root can access /dev/modem. Both /dev/modem and
> JJ> /dev/ttyS1 are fully accessable but "Accessed denied" errors
>always
> JJ> come up.
> JJ> Any ideas?
>
> You have to change the permissions to allow global group and user
>access to them, hex 777 which will give you permissions of like this:
>lrwxrwxrwx root root etc etc etc modem => /dev/ttyS1
> A couple of books that have helped me ALOT are Sybex "Understanding
>UNIX" and Sams "Tricks of the Unix Masters" by The Waite Group, good
>reading! And good resources.
I don't mean to be insulting, but I really don't think your books have
helped you *enough* yet...
1.) Setting the modem permissions to global read-write-execute is a good
way to open yourself a great big security hole. *ANYONE* could
dial out. Even if you only have one modem, any dial-in customer
would find it simple to write a time-delayed shell-script to make
several transcontinental telephone calls.
2.) The "777" isn't in hex, it's OCTAL. Each digit represents three bits.
3.) /dev/modem should be linked to a dial-OUT device ("/dev/cua??"),
NOT to a dial-in line. The kernel won't help you otherwise.
Try instead setting the group of your dial-out line to something like
"uucp", and then adding users to the uucp group. Change the permissions
on /dev/cua01 to be writeable by group.
Rick Miller <rick@ee.uwm.edu> | <ricxjo@discus.mil.wi.us> Ricxjo Muelisto
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