Permissions for /dev/softsynth

Permissions for /dev/softsynth

[Hynek Hanke]

Hello,

I'm preparing a Debian package for SpeechD-Up and I'm puzzled with the
permissions to the /dev/softsynth device and the /proc/speakup/
controlls. The device is sometimes created by the user and sometimes
automatically, the proc tree is allways created when loading Speakup.
Is there some convention about who should be the owner and group
of /dev/softsynth and /proc/speakup?

I've been using the device as root so far, but this doesn't allow
me to run SpeechD-Up under a different user (e.g. speechd-up).
Making /dev/softsynth world readable is not an option too as it will
typically contain a complete log of users activity on the system
consoles, so it must be protected.

One more thing to consider is that there might be other interfaces
than SpeechD-Up wanting to access /dev/softsynth and /proc/speakup/ .

So it seems to me that it would be most sensible to create a group
with the name ''speakup'' and make /dev/softsynth and /proc/speakup
readable/writable by this group. Include user speechd-up in group
speakup and run SpeechD-Up with this user.

Should this be the correct approach, who will set the group ownership
for /dev/softsynth and /proc/speakup ? Should Speakup do it? Should it
be some user-space script? Which one?

The ownership change cannot be made in time of installation of
SpeechD-Up as there is not any guarantee that Speakup will already
be installed and that the device won't be deleted/re-created later (in
case of dynamically created device, it will).

I'd like to know your opinion.

Thank you,
Hynek Hanke

Re: Permissions for /dev/softsynth

[Kirk Reiser]

Hello Hynek: Setting up a speakup group is probably a good idea if one
wishes to keep things owned by group/users other than root.  I have
always set things owned by root.root with permissions of 770/660 when
necessary to protect against other prying eyes.  Most often these days
a system is only used by the person that owns it so protection isn't
typically a serious issue but certainly could be in labs and other
places there are more than a single user.  Until now I have allowed
most speakup settings to be changed by anyone except where they are
an option which can damage the operation of the machine if not well
understood.  In those cases one must be logged in as root to modify
them.  This could be considered a security problem but I never really
thought about it that way because playing with the nondangerous
option could be slightly iritating but not really detramental.  From
that respect loadkeys is another example of an insecure program which
anyone can run to change the standard kernel keyboard maps, iritating
if done but not necessarily fatal.

If you're looking for official sanction I say go for it.  I'm an
anarchist afterall! 'grin'

  Kirk

-- 

Kirk Reiser				The Computer Braille Facility
e-mail: kirk@braille.uwo.ca		University of Western Ontario
phone: (519) 661-3061

Re: Permissions for /dev/softsynth

[Hynek Hanke]

Kirk Reiser píše v Čt 28. 12. 2006 v 14:23 -0500:
> If you're looking for official sanction I say go for it.

Please, do you know what should I do to make sure the softsynth device
(and also /proc/) is created with group speakup each time
it is created?

I could do it from /etc/init.d/speechd-up, but this is extremely
ugly and may have side effects on other applications using the interface
at the time.

Thank you,
Hynek Hanke

Re: Permissions for /dev/softsynth

[Luke Yelavich]

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On Fri, Dec 29, 2006 at 07:04:12AM EST, Hynek Hanke wrote:
> Kirk Reiser píše v Čt 28. 12. 2006 v 14:23 -0500:
> > If you're looking for official sanction I say go for it.
> 
> Please, do you know what should I do to make sure the softsynth device
> (and also /proc/) is created with group speakup each time
> it is created?

The permissions can be set for /dev/softsynth using udev. As far as I 
have gathered, the device node is created by the speakup_sftsyn module. 
It is just a matter of getting an udev rule included for it.

As for /proc/speakup, IMO thats best done in the speakup code, whether 
it be a parameter to the module, or on the kernel command-line, as 
different distros may want to have the speakup group as different group 
numbers.
- -- 
Luke Yelavich
GPG key: 0xD06320CE 
	 (http://www.themuso.com/themuso-gpg-key.txt)
Email & MSN: themuso@themuso.com
Jabber: themuso@jabber.org.au
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Re: Permissions for /dev/softsynth

[Kirk Reiser]

I will check into the control I can have over the udev system.  I
haven't done much with it up until now.

Luke's point about different distributions having their own way of
setting up permissions is also good to keep in mind.

  Kirk

-- 

Kirk Reiser				The Computer Braille Facility
e-mail: kirk@braille.uwo.ca		University of Western Ontario
phone: (519) 661-3061

Re: Permissions for /dev/softsynth

[Chris Norman]

Could you not just use chown?

HTH,

Chris Norman
<!-- cnorman@rnibncw.ac.uk -->
----- Original Message ----- 
From: "Luke Yelavich" <themuso@themuso.com>
To: <speakup@braille.uwo.ca>
Sent: Thursday, December 28, 2006 8:34 PM
Subject: Re: Permissions for /dev/softsynth


> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Fri, Dec 29, 2006 at 07:04:12AM EST, Hynek Hanke wrote:
>> Kirk Reiser píše v Čt 28. 12. 2006 v 14:23 -0500:
>> > If you're looking for official sanction I say go for it.
>>
>> Please, do you know what should I do to make sure the softsynth device
>> (and also /proc/) is created with group speakup each time
>> it is created?
>
> The permissions can be set for /dev/softsynth using udev. As far as I
> have gathered, the device node is created by the speakup_sftsyn module.
> It is just a matter of getting an udev rule included for it.
>
> As for /proc/speakup, IMO thats best done in the speakup code, whether
> it be a parameter to the module, or on the kernel command-line, as
> different distros may want to have the speakup group as different group
> numbers.
> - -- 
> Luke Yelavich
> GPG key: 0xD06320CE
> (http://www.themuso.com/themuso-gpg-key.txt)
> Email & MSN: themuso@themuso.com
> Jabber: themuso@jabber.org.au
> -----BEGIN PGP SIGNATURE-----
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>
> iD8DBQFFlCpmjVefwtBjIM4RAkafAJ0WyitcX7oxOaBl4wXvoARnqxxMDQCgj+R8
> +XFz87Gpt0FfJ9WzT417Qy8=
> =HAsp
> -----END PGP SIGNATURE-----
>
> _______________________________________________
> Speakup mailing list
> Speakup@braille.uwo.ca
> http://speech.braille.uwo.ca/mailman/listinfo/speakup
> 

Re: Permissions for /dev/softsynth

[Luke Yelavich]

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On Fri, Dec 29, 2006 at 11:12:00AM EST, Chris Norman wrote:
> Could you not just use chown?

You could, but if the mechanics to set such permissions are available at 
the kernel/udev level, one is better off using them, as the correct 
permissions are set, as soon as the device node/proc interface is 
created.
- -- 
Luke Yelavich
GPG key: 0xD06320CE 
	 (http://www.themuso.com/themuso-gpg-key.txt)
Email & MSN: themuso@themuso.com
Jabber: themuso@jabber.org.au
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