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Date:      Sun, 14 Apr 2002 21:33:24 +0100
From:      Scott Mitchell <scott.mitchell@mail.com>
To:        dillama <dillama1@excite.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: What does nodev actually do?
Message-ID:  <20020414213324.E18618@fishballoon.dyndns.org>
In-Reply-To: <20020414173915.D95B8B6BB@xmxpita.excite.com>; from dillama1@excite.com on Sun, Apr 14, 2002 at 01:39:15PM -0400
References:  <20020414173915.D95B8B6BB@xmxpita.excite.com>

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On Sun, Apr 14, 2002 at 01:39:15PM -0400, dillama wrote:
> 
> Can anyone explain what the "nodev" option in mounting a drive does? How
> does it make things more secure (according to the handbook)?

It tells the system to ignore any files on the mounted drive that claim to
be 'device nodes' -- the special files (typically found in /dev) that give
access to the physical hardware on your machine.  Specifying 'nodev'
prevents someone from mounting a filesystem containing a world-writable
disk device node, then using that to write random data all over your disks,
for example.  I'm not sure if that would work even without 'nodev' though;
anyone know if I could just construct a UFS floppy containing device nodes,
mount it as myself, then us it for evil?  Or would I have to mount it as
root?

Probably no harm in using 'nodev' on any filesystem apart from your root
partition (you need those devices in /dev :-), unless there's a specific
reason to be using devices on some other filesystem.

	Scott

-- 
===========================================================================
Scott Mitchell          | PGP Key ID | "Eagles may soar, but weasels
Cambridge, England      | 0x54B171B9 |  don't get sucked into jet engines"
scott.mitchell@mail.com | 0xAA775B8B |      -- Anon

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