loopback device ownership
I'm playing around with the loopback filesystem and the associated
loopback devices. The question is now: who owns the devices
/dev/loop$i, block major 7, minor $i? And what is the default
protection? In analogy to other special devices, I would be tempted to
assign them to a special group -loopback- and make the protect them
rw-rw----. Users which need access to the loopback devices will be in
that group. What is the verdict?
Related to this: How to I handle mounting of these devices by a
restricted number of users? At least for the floppy devices, having
the option `user' in /etc/fstab allows any user to mount the floppy,
no matter it they are in the group floppy or not (yes, I checked the
protection on /dev/fd0). Is this a bug or a feature of mount? If I
omit the option `user', only root can mount the floppy. The only way
out seems to be a suid root wrapper with some hardcoded parameters to
mount the loopback filesystems.
BTW, does anybody have any experience with the initrd feature of the
latest kernels? I'm experimenting with heavily modularized kernels
(basically, only floppy, nfs and ext2 compiled (too bad I cannot
modularize ide) to see if I can load the required extra modules (scsi,
network drivers, ...) from the initial ram disk. If I'm not mistaken,
up to this moment, all is loaded without the kernel. So I should be
able to boot my scsi only system without compiling scsi into the
kernel. Looks like a great way to construct minimal kernels to install
a system even with very limited memory.
Cheers,
Lukas
-------------------------------------------------------------------------------
Dr. Lukas Nellen | Email: lukas@teorica0.ifisicacu.unam.mx
Depto. de Fisica Teorica, IFUNAM |
Apdo. Postal 20-364 | Tel.: +52 5 622 5014 ext. 218
01000 Mexico D.F., MEXICO | Fax: +52 5 622 5015
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