[plug] 4 Port serial cards, mgetty etc etc

[Earnshaw, Mike]

Matt, thanks!

Lesson learn't = not all distro's same ;) Thanks for the explaination on
tty, so easy when explained to you.

> -----Original Message-----
> From: Matt Kemner [mailto:zombie at wasp.net.au]
> Sent: Thursday, September 07, 2000 11:39 AM
> To: 'plug at plug.linux.org.au'
> Subject: RE: [plug] 4 Port serial cards, mgetty etc etc
> 
> 
> On Thu, 7 Sep 2000, Earnshaw, Mike wrote:
> 
> > If I follow your suggestion and chmod them to 660 that is 
> not the same
> > as the distro settings.
> 
> Then set them the same as the distro. :)
> 
> Debian sets the group to "dialout" and chmods them to "660" 
> so you can add
> people that need to be able to dial _out_ of the box to the 
> dialout group.
> 
> > Thinking this through if I had connected a modem to S[0-3] 
> it would not
> > have worked for anyone but root
> 
> Not true.  Even with mode 660 it would only "work" for people in the
> specified (in this case tty) group, which I would hope are only those
> users you trust implicitly - you see you are giving them permission to
> access the device directly, which allows them to use any of 
> your modems to
> dial _out_ and possibly rack up huge phonebills in the process.
> 
> You want to set them up so they are only writable by root (or trusted
> users) - and then when someone dials in, the appropriate 
> getty program (ie
> mgetty) will chown the device to that user - and as soon as 
> they log out,
> chown it back to root.
> 
> You can test this theory by looking at eg /dev/tty6 and then 
> going to that
> virtual terminal (alt-F6) and logging in as a user, and comparing
> ownership & permissions - then logging out and comparing again.
> 
>  - Matt
> 
>