Re: Soundcard packet and permissions
* p jay <redrangerhood@lycos.com> [2006 Jan 10 02:15 -0600]:
> p jay wrote:
>
> >On Sunday 08 January 2006 12:10, Ray Wells wrote:
> >
> >
> >>vk4akm wrote:
> >>Change permissions on listen to 4755.
> >>
> >>Do "chmod 4755 listen" (no " ") and that will sort it out.
> >>Re: Soundcard packet and permissions
> >>Ray, VK2TV
> >>
> >>
> >
> >Why?
> >
> >
> >
> >Would you like to explain your question?
>
> Yes: I want you to explain what your response does and why it was required by this user.
This is a bit mask the kernel uses to determine who may access this
file and in what way. Listen is not working because it must open some
privileged device files.
Normally, listen probably has a default permission of 0755 which means
the owner can Read, Write, and eXecute the file. The user IDs in the
file's group can Read and eXecute the file. Everyone else can Read
and eXecute the file. This corresponds to a bit mask of:
000 111 101 101 (0755)
When listen runs it can only access system resources that match your
user ID (this is somewhat complicated, so Google is your friend) or
the group(s) your user ID membership matches. We can tell the system
that this particular file should be allowed to access the system
resources it needs by changing the bit mask using the command above to
set the SetUID bit:
100 111 101 101 (4755)
Now you'll be able to run listen as a normal user as it will be able to
open the devices it needs.
I must caution that the SUID bit is considered a security risk. An
attacker can expliot a flaw in the program to get privileged access. A
way around the SUID bit is the sudo command which can be setup so that
you can run listen without a password.
> "The technoguru gene is occasionally omitted during some reproductive cycles."
> --me tonight
It has nothing to do with a "technoguru gene". Rather it has
everything to do with one's willingness to do some searches for
information that one is unclear on and asking questions when that isn't
clear enough. It also means that one should not be offended by a terse
answer, although terse questions are sometimes not appreciated as
highly. ;-)
HTH,
73, de Nate >>
--
Wireless | Amateur Radio Station N0NB | Successfully Microsoft
Amateur radio exams; ham radio; Linux info @ | free since January 1998.
http://www.qsl.net/n0nb/ | "Debian, the choice of
My Kawasaki KZ-650 SR @ | a GNU generation!"
http://www.networksplus.net/n0nb/ | http://www.debian.org
Reply to: