Redefining udev permissions on a given device (/dev/isdninfo)

Felix Schwarz felix.schwarz at web.de
Wed May 2 11:31:08 UTC 2007


Hi,

I'm using Fedora Core 6. My ISDN card (Fritz!Card PCI v2) was detected by Fedora 
and works flawlessly.

Now, udev sets the permissions on /dev/isdninfo in a very secure way so that I 
can't access as a ordinary user.
 > [fs at ws2 ~]$ ls -la /dev/isdninfo
 > crw------- 1 root root 45, 255 28. Apr 13:23 /dev/isdninfo

I like to have the permissions that way:
 > [fs at ws2 ~]$ ls -la /dev/isdninfo
 > crw-rw---- 1 root dialout 45, 255 28. Apr 13:23 /dev/isdninfo

How can I configure udev so that the permissions will be set appropriately?

I think the basic permissions are set in /etc/udev/rules.d/50-udev.rules
 > [root at ws2 udev]# grep -R isdn /etc/udev/
 > /etc/udev/rules.d/50-udev.rules:KERNEL=="isdn*",        NAME="%k", MODE="0660"
 > /etc/udev/rules.d/50-udev.rules:KERNEL=="isdnctrl*",    NAME="%k", MODE="0660"
 > /etc/udev/rules.d/50-udev.rules:KERNEL=="isdnctrl0",    SYMLINK+="isdnctrl"
What I do understand is that /dev/isdninfo has the mode 0600 after booting (not 
0660 as in the mode setting above).

Changing /etc/udev/rules.d/50-udev.rules (even though this is discouraged) to
 > KERNEL=="isdn*",                NAME="%k", MODE="0660", GROUP="dialout"
showed no effect.

Same goes with creating /etc/udev/rules.d/99-isdninfo.rules:
 > KERNEL="isdninfo", MODE="0660", GROUP="dialout"

[1] ("Customizing Udev on Fedora" / "Permissions") suggests that one should 
create a .permissions file in /etc/udev/permissions.d/. According to [2] this is 
obsolete since udev 053 but I tried nevertheless:
 > [root at ws2 udev]# cat /etc/udev/permissions.d/99-isdninfo.permissions
 > isdninfo:root:dialout:0644

No effect either.

So basically I am stuck and don't know how to redefine the permissions on 
/dev/isdninfo.

Any help is appreciated!

fs

[1] http://docs.fedoraproject.org/udev/
[2] http://www.jetico.com/linux/bcrypt-help/l_probl.htm




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