Arch Linux

Giacomo Ritucci

Member

From: Bologna, Italy

Registered: 2009-10-25

Posts: 26

Very fine grained permissions on device file

I want to use a SDHC card as a raw virtualbox disk. My aim is to be able to boot from the SDHC card either from virtualbox or directly.

The problem is that VirtualBox needs read/write permissions on the device file, and I don't like the idea to chmod 666 /dev/sd* or to add my user to the "disk" group.

I'd prefer to:

• use acls to add the vboxusers group with rw permissions to the device node's access control list

• find a way to uniquely identify the sdhc disk (UUID?) in order to enable the acl thing only for that specific disk (permissions of other hard disks should not be affected)

• automate this process when the device node is created (udev?)

Is this possible or I'm drunk?

Some ideas to get started?

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One of these days I'm gonna learn to play and write myself a song

Mr.Elendig

#archlinux@freenode channel op

From: The intertubes

Registered: 2004-11-07

Posts: 4,092

Re: Very fine grained permissions on device file

Write some udev rules?

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Evil #archlinux@libera.chat channel op and general support dude.
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Giacomo Ritucci

Member

From: Bologna, Italy

Registered: 2009-10-25

Posts: 26

Re: Very fine grained permissions on device file

I searched some udevs guides and some tutorials but I can't find a way to use ACLs in udev rules.

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One of these days I'm gonna learn to play and write myself a song

djgera

Developer

From: Buenos Aires - Argentina

Registered: 2008-12-24

Posts: 723

Website

Re: Very fine grained permissions on device file

If you login a session in consolekit, then: use TAG+="udev-acl" in the udev rule (for personal usage this is good,  TAG+="udev-acl" is private to 70-acl.rules )

for example (i do not know nothing about that device, I suppose device kernel name "sdhc")

/etc/udev/rules.d/69-my-sdhc.rules (number is important)

KERNEL=="sdhc", TAG+="udev-acl"

All users logged in via console can access to that device.

Giacomo Ritucci

Member

From: Bologna, Italy

Registered: 2009-10-25

Posts: 26

Re: Very fine grained permissions on device file

Thanks, I'll give it a try.

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One of these days I'm gonna learn to play and write myself a song