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Date:      Sun, 31 Dec 1995 16:30:25 +1100
From:      Bruce Evans <bde@zeta.org.au>
To:        joerg_wunsch@uriah.heep.sax.de, smpatel@wam.umd.edu
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: /dev/io
Message-ID:  <199512310530.QAA18597@godzilla.zeta.org.au>

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>> Is there any good reason why access to /dev/io is allowed for members
>> of group kmem?  Note that this will give any setgid kmem program
>> _full_ (read and write) access to the io registers (since open() is
>> the only important action for this device).

It's a bug.

>While we're on the topic of /dev/io, I have a couple of comments about it. 
>It seems unintuitive to offer a process IO permission by opening a device
>(especially since opening it with RDONLY or RDWR is irrelevant).  I know

It allows fine access control using the file's ownership and
permissions.  Since is no such things as O_OPENONLY or O_IOCTLONLY, and
no file permission bit for ioctl, the file bits are no use for controlling
ioctl access.

Bruce



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