Subject: Re: Miscellaneous OS features: capabilities
To: None <firstname.lastname@example.org>
From: Nate Hill <email@example.com>
Date: 08/11/2003 04:15:05
On Mon August 11 2003 02:14, David Young wrote:
> On Fri, Aug 08, 2003 at 07:39:22AM -0400, Sporleder, Matthew wrote:
> > Speaking of de-rooting-
> > Could you just add a /dev/ports/ directory or something along
> > those lines to then chown specific ports to any user you wanted:
> > <daemon>d, for example?
> Take it a step further. Grant the daemon *process* only the
> privileges it needs, using the imaginary "cap" command.
> CAP(1) NetBSD Reference Manual
> cap - an imaginary program which runs a command with
> restricted privileges
> cap [capabilities] [command [arguments]]
> cap runs a command with only the capabilities assigned to it
> on the cap command line. Capabilities are assigned using the
> options -u, -c, -C, -m, -b, -l, -R, -i, -o, -s, -r, -w, -a, and -x.
> -b port/proto command may bind the given port
> -l port/proto command may listen(2) for connections on
> the given port
> -R host:port/proto command may connect(2) to the given
> host/port -i nblocks command may read only nblocks blocks
> from any disk in a second
> -o nblocks command may write only nblocks blocks from
> any disk in a second
> -s nblocks:dev command may store only nblocks blocks on
> the block device dev
> -r filename command may read from the given file
> -w filename " " write to " " "
> -a filename " " append to " " "
> -x filename " " execute " " "
> -n filename " " create " " "
> -c secs command (and children if -g; see below)
> may use at most secs seconds, total.
> -C millisecs command (and children if -g; see below)
> may run for at most millisecs milliseconds in a second. -m size
> [k|m|p] maximum core size for this command and all of its
> children in kilobytes (k), megabytes (m), or pages (p) .
> Run a command with no capabilities to find out the minimal
> capabilities it requires, if that information was compiled
> into the executable.
> There is a capability modifier, -g. All of the capabilities
> following -g may be delegated to child processes.
> Et cetera, et cetera.
This could be done quite easily. A nice front-end to a set-uid
systrace is needed.
Nate Hill <firstname.lastname@example.org>