Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.debian.user > #196374 > unrolled thread

What's the difference between the dialout and tty groups?

Back to article view | Back to linux.debian.user

Contents

  What's the difference between the dialout and tty groups? "Martin McCormick" <martin.m@suddenlink.net> - 2018-06-03 21:20 +0200
    Re: What's the difference between the dialout and tty groups? Cindy-Sue Causey <butterflybytes@gmail.com> - 2018-06-03 23:30 +0200
      Re: What's the difference between the dialout and tty groups? "Martin McCormick" <martin.m@suddenlink.net> - 2018-06-04 15:10 +0200
        Re: What's the difference between the dialout and tty groups? <tomas@tuxteam.de> - 2018-06-04 15:10 +0200
          Re: What's the difference between the dialout and tty groups? Stefan Monnier <monnier@iro.umontreal.ca> - 2018-06-04 17:00 +0200
            Re: What's the difference between the dialout and tty groups? <tomas@tuxteam.de> - 2018-06-04 17:00 +0200

#196374 — What's the difference between the dialout and tty groups?

	I added myself to both the dialout and tty groups on a
stretch installation in order to use the serial ports from the
user level.  It works fine.  Then I looked at a debian jessie
installation and found that I had only added myself to dialout
and it still works fine.

	What is group tty actually for?

This is more of an idle curiosity question than it is one of
something's broken and I need help.

	I am a retired systems engineer who setup unix systems
for coworkers to use so I know you can sometimes have too much
power at the user level and accidentally make it easier to make a
mess of things.

Thank you.
Martin McCormick

[toc] | [next] | [standalone]

#196382

On 6/3/18, Martin McCormick <martin.m@suddenlink.net> wrote:
> 	I added myself to both the dialout and tty groups on a
> stretch installation in order to use the serial ports from the
> user level.  It works fine.  Then I looked at a debian jessie
> installation and found that I had only added myself to dialout
> and it still works fine.
>
> 	What is group tty actually for?
>
> This is more of an idle curiosity question than it is one of
> something's broken and I need help.
>
> 	I am a retired systems engineer who setup unix systems
> for coworkers to use so I know you can sometimes have too much
> power at the user level and accidentally make it easier to make a
> mess of things.


Hi, Martin.. I found these descriptions on the Debian Wiki
SystemGroups page [0]:

tty: TTY devices are owned by this group. This is used by write and
wall to enable them to write to other people's TTYs, but it is not
intended to be used directly.

dialout: Full and direct access to serial ports. Members of this group
can reconfigure the modem, dial anywhere, etc.

What's on the System Groups wiki page is about as far as I'm versed in
it. So far, that's been enough *for me*. I, too, have read at least
once out there that we need to be members of as few groups as possible
for computer safety reasons.

Cindy :)

[0] https://wiki.debian.org/SystemGroups

-- 
Cindy-Sue Causey
Talking Rock, Pickens County, Georgia, USA

* runs with duct tape *

[toc] | [prev] | [next] | [standalone]

#196395

Cindy-Sue Causey <butterflybytes@gmail.com> writes:
> Hi, Martin.. I found these descriptions on the Debian Wiki
> SystemGroups page [0]:
> 
> tty: TTY devices are owned by this group. This is used by write and
> wall to enable them to write to other people's TTYs, but it is not
> intended to be used directly.
> 
> dialout: Full and direct access to serial ports. Members of this group
> can reconfigure the modem, dial anywhere, etc.
> 
> What's on the System Groups wiki page is about as far as I'm versed in
> it. So far, that's been enough *for me*. I, too, have read at least
> once out there that we need to be members of as few groups as possible
> for computer safety reasons.
> 
> Cindy :)

	Thank you.  Interestingly enough, one of the programs I
wrote before retiring was a shell script which later turned in to a perl
program which constantly scanned the log of our dhcp servers for
Oklahoma State University, trolling for Mac addresses of
equipment that had been reported as stolen on campus.  It ran on
a FreeBSD unix box which has much the same general feel as Linux
but is philosophically somewhat different so, occasionally, you
run in to shell scripts or other types of programs that will run
perfectly on the box they were developed on but either run
slightly differently or not at all on the other.

	When I matched a Mac address against our stolen goods
list, I used wall to mess up the screens of everybody else logged
in to our group unix work station to let them
know that the purloined machine was on our network and to
immediately call campus police, sometimes, a specific detective,
to tell them where the device was being used.

	We cought a few thieves that way and had a few false
alarms when systems turned out not to be stolen but their owners
forgot to tell us there was no problem.  Wall, in the wrong hands
can be quite a nuisance so that's the sort of power one must be
careful about.  In this case, it doesn't really matter since I am
the only user.  

	By the way, one of the thieves we cought stole somebody's
laptop one day and began using it in his job the very next day.
He was some campus department's IT support person, but not for
long.

Martin WB5AGZ

[toc] | [prev] | [next] | [standalone]

#196396

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Mon, Jun 04, 2018 at 08:03:16AM -0500, Martin McCormick wrote:

[...]

>                                 [...]  Wall, in the wrong hands
> can be quite a nuisance so that's the sort of power one must be
> careful about.  In this case, it doesn't really matter since I am
> the only user.  

It has since been superseded by Javascript, web page popups and
targeted ads.

Cheers
- -- t
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iEYEARECAAYFAlsVOZsACgkQBcgs9XrR2kYeEwCbByOCz5dam31rZDhlpVLjX9fJ
G6YAnjP3QrGRkGLpZaUravNsufuaqoQ8
=2tfO
-----END PGP SIGNATURE-----

[toc] | [prev] | [next] | [standalone]

#196402

>>                                 [...]  Wall, in the wrong hands
>> can be quite a nuisance so that's the sort of power one must be
>> careful about.  In this case, it doesn't really matter since I am
>> the only user.  
> It has since been superseded by Javascript, web page popups and
> targeted ads.

The upside is that those powerful new tools are (pretty much) *only*
available to those with the wrong hands.


        Stefan

[toc] | [prev] | [next] | [standalone]

#196403

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Mon, Jun 04, 2018 at 10:51:01AM -0400, Stefan Monnier wrote:

[wall...]

> > It has since been superseded by Javascript, web page popups and
> > targeted ads.
> 
> The upside is that those powerful new tools are (pretty much) *only*
> available to those with the wrong hands.

You have a fine sense of irony :-)

Cheers
- -- t
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iEYEARECAAYFAlsVUtkACgkQBcgs9XrR2kZIpQCeLyTyByfcTbgMzX2eoVbNsbTt
RE4AmwfU2kgyIPUGg+AjWVpQUCLVjP8G
=SwOL
-----END PGP SIGNATURE-----

[toc] | [prev] | [standalone]

Back to top | Article view | linux.debian.user

csiph-web