[wellylug] /dev/dsp permission

[Sam Cannell]

Edouard Chalaron wrote:

>Ok things are back. The purpose was to allow any user to play sound by 
>/dev/dsp...........; I failed.... :-(
>
>But I found this, which may explain my troubles (only root can play on 
>/dev/dsp)
>
>"By default the script in Readme.linux that creates the sound device files 
>only allows the devices to be read by user root. This is to plug a potential 
>security hole. In a networked environment, external users could conceivably 
>log in remotely to a Linux PC with a sound card and microphone and eavesdrop. 
>If you are not worried about this, you can change the permissions used in the 
>script. 
>
>With the default setup, users can still play sound files. This is not a 
>security risk but is a potential for nuisance."
>
>Maybe my troubles are coming from here. Where can I find this script or does 
>anybody know how to correct this ?
>Thanks again
>Edouard
>
>  
>
Running 'ls -lH /dev/dsp' should show you something like:

sam at sam:~$ ls -lH /dev/dsp
crw-rw-r--    1 root     audio     14,   3 Jan  1  1970 /dev/dsp

(the -H tells ls to dereference the symbolic link and show the 
information about the real device node)

Note the 'root     audio'.  The audio group is allowed to write to 
/dev/dsp, which is what you want.

As the user you want to be able to access the sound device as, run the 
command 'groups'.
It should display something like:

sam at sam:~$ groups
sam

That means that my user is only in the group 'sam'.

As root, run 'usermod -G audio username', where username is the user you 
want to be able to access the sound device.

The -G option tells usermod to change the secondary groups that the user 
is a member of.  To specify more than one, for example, to allow the 
user to access the modem, the command would be 'usermod -G audio,dialout 
username'

Then, log out and in again.  Running 'groups' now should display 
something like:

sam at sam:~$ groups
sam audio

You should now be able to access /dev/dsp.