[sclug] Non-human user IDs

[Simon Huggins]

On Fri, Dec 27, 2002 at 06:03:15PM -0000, Will Dickson wrote:
> Can anyone either tell me about, or even better, point me at the section of 
> The Fine Manual which describes, the various non-human user IDs that
> are usually found on a linux box?

Hmm, I guess the closest you'll find is from the Linux Standard Base
spec.
http://www.linuxbase.org/spec/gLSB/gLSB/usernames.html

A similar thread came up on Debian lists and here is part of it listing
some of the common and less common ones:
http://lists.debian.org/debian-devel/2001/debian-devel-200108/msg00385.html

> The two I'm most interested in are "daemon" and "nobody". Do they have
> any special privileges or attributes? And is there any reason not to run a 
> system service, which does not want any special privileges, as user ID 
> daemon?

The thing is that this will vary from distribution to distribution.

It used to be true that everything ran under nobody/daemon but this is
less and less true now as a hole in one server could lead to being able
to tamper or at least read files destined for another.

The page above notes this in a footnote as so:
	The 'daemon' UID/GID was used as an unprivileged UID/GID for
	daemons to execute under in order to limit their access to the
	system. Generally daemons should now run under individual
	UID/GIDs in order to further partition daemons from one another.

Hope this helps some,

Simon.

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