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From: jrvalverde@cnb.csic.es (Jose R. Valverde)
Subject: [TUHS] historical users and groups
Date: Wed, 14 Jan 2009 14:33:02 +0100	[thread overview]
Message-ID: <20090114143302.0e0e607b@cnb.csic.es> (raw)
In-Reply-To: <Pine.NEB.4.64.0901131824440.26223@tx.reedmedia.net>

A bit of digging brought out the following snippet from 4.3BSD System
Manager Manual:

     System security  changes  require  adding  several  new
``well-known''  groups  to  /etc/group.  The groups that are
needed by the system as distributed are:

...

Only users in the ``wheel'' group are  permitted  to  su  to
``root''.    Most   programs   that  manage  directories  in
/usr/spool now run set-group-id to ``daemon'' so that  users
cannot  directly  access the files in the spool directories.
The special files that access kernel memory,  /dev/kmem  and
/dev/mem,  are  made readable only by group ``kmem''.  Stan-
dard system programs that require this access are made  set-
group-id  to  that  group.  The group ``sys'' is intended to
control access to system sources, and other  sources  belong
to  group ``staff.'' Rather than make user's terminals writ-
able by all users, they are now placed in group ``tty''  and
made only group writable.  Programs that should legitimately
have access to write on user's terminals such  as  talk  and
write  now  run  set-group-id  to ``tty''.  The ``operator''
group controls access to disks.  By default, disks are read-
able  by group ``operator'', so that programs such as df can
access the file system information without being set-user-id
to ``root''.

     Several new users have also been added to the group  of
``well-known'' users in /etc/passwd.  The current list is:

...

The ``daemon'' user is used for daemon processes that do not
need  root  privileges.  The ``operator'' user-id is used as
an account for dumpers so that they can log in without  hav-
ing  the root password.  By placing them in the ``operator''
group, they can get read access to the disks.  The  ``uucp''
login has existed long before 4.3BSD, and is noted here just
to provide a common user-id.  The password entry  ``nobody''
has been added to specify the user with least privilege.
 


So my previous recollections were not totally correct. Sorry. I guess as
one grows older memory starts to fail. As for today's usefulness... if 
you google each user/group up you'll see they still are meaningful in
many setups.

				j
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  parent reply	other threads:[~2009-01-14 13:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-14  0:59 Jeremy C. Reed
2009-01-14 13:00 ` Jose R. Valverde
2009-01-15 17:15   ` Jason Stevens
2009-01-16  5:52     ` Angus Robinson
2009-01-14 13:33 ` Jose R. Valverde [this message]
2009-01-14 17:15 ` Tim Bradshaw
2009-01-14 17:36   ` John Cowan
     [not found] <mailman.1.1231898401.13466.tuhs@minnie.tuhs.org>
2009-01-14  7:28 ` Robert Harker

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