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From: j@uriah.heep.sax.de (J Wunsch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: chmod'ing msdos fs and mount problems
Date: 20 Dec 1995 15:35:41 GMT
Organization: Private BSD site, Dresden
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Message-ID: <4b9agd$9jc@uriah.heep.sax.de>
References: <4acqam$2m8@ccshst05.cs.uoguelph.ca> <4aojb3$4ir@agate.berkeley.edu>
Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
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mconst@soda.CSUA.Berkeley.EDU (Michael Constant) writes:
> The YossMan <yossman@osiris.cs.uoguelph.ca> wrote:
> >I am mounting two msdos filesystems, /dos and /dos2, at bootup. I want
> >to change the permissions so that no one but root will be able to even
> >look at the filessystems.
MOUNT_MSDOS(8) UNIX System Manager's Manual MOUNT_MSDOS(8)
NAME
mount_msdos - mount an MS-DOS file system
SYNOPSIS
mount_msdos [-u uid] [-g gid] [-m mask] special node
DESCRIPTION
..
The options are as follows:
-u Set the owner of the files in the file system to uid. The default
owner is the owner of the directory on which the file system is
being mounted.
-g Set the group of the files in the file system to gid. The default
group is the group of the directory on which the file system is
being mounted.
-m Specify the maximum file permissions for files in the file sys-
tem. (For example, a mask of 755 specifies that, by default, the
owner should have read, write, and execute permissions for files,
but others should only have read and execute permissions. See
chmod(1) for more information about octal file modes.) Only the
nine low-order bits of mask are used. The default mask is taken
from the directory on which the file system is being mounted.
So you should pass the above options to mount_msdos. I think this
could be done by specifying -m=0700 (for example) in the `options'
field of fstab(5). (I cannot test it due to an apparent lack of DOS
partitions. :)
> You have the right command, but the wrong timing. You must execute
> the chmod command when the /dos partition is *unmounted*. So, this
> sequence of commands should work:
>
> # cd /
> # umount /dos
> # chmod 700 dos
> # mount -a
This does only work due to the behaviour of mount_msdos quoted above
(last sentence of my quote). Normally, permissions of a mount point
directory are (mostly) shadowed by the mount itself, so changing them
is _not_ the most recommended way.
--
cheers, J"org
joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)