/dev/lan1 permissions

[jerry1]

Has anyone seen /dev/lan1 permissions change
after reboot from 666 to 600.
What causes this?

[G. Vrijhoeven · Accepted solution]

Hi,

Did other device files have the same problem?
I am clueless.
When a server reboots it does an ioscan and a insf to create device files.
I never seen this but maybe the umask of the server changed?
Is it not possible the device file was altered before the reboot?


Gideon

[Sridhar Bhaskarla]

Hi,

As per the init script /sbin/init.d/maclan_init, it does create and then change the permissions for btlan3 and lan2 devices. But I don't think it is going to cause any problem.

Look at that script for more details.

-Sri

[Sridhar Bhaskarla]

Hi (Again),

YOu can reproduce the problem by changing the permissions on /dev/lan1 to somethingelse and then run the script with 'start' argument. The permissions should be reset back to 600.

-Sri

[Jeff Schussele]

Hi Jerry,

I'm not certain, but I think the driver & whether the instance is in use or not play a role.
I'm looking at several identical Ns that have unused Gig-E (gelan) fibre cards & they are 600 root/sys. It also has a couple unused 10/100 TX (btlan) & THEY are 666 bin/bin.

So I guess the questions are - did this system reinstance the lans at bootup and is lan1 now unused & unplumbed? And what type card is it & what driver is it using?

Rgds,
Jeff

[jerry1]

The problem is that we have a software
package that uses the MAC address of that
lan interface even though it is not used.

This is scary. I found a fixlan0 script in
rc3.d that I had wrote 3 years before.
I must have needed to fix /dev/lan0 back then
and things changed to lan1 while I was gone.


I told you, touch nothing! But you bunch of
cowboys. (Cosmonaut Lev, Armageddon)

[jerry1]

There is a script that does some strange
string checks and chmod 600 lan< >.

See /sbin/rc2.d/S462maclan
Or /sbin/init.d/maclan_init

Why do this at all.

[Sridhar Bhaskarla]

HI Jerry,

How does that software get the lan address and why would it break if the permissions get changed to 600?.

Usually you can get the MAC address by lanscan or lanadmin commands.

-Sri

[Jeff Schussele]

$ to doughnuts says it's a licensing scheme & if the perms change it can't get the MAC by a direct query to the NIC.
But as Sri points out lanscan can get all the MACs & it's executable by others.

My 2 cents,
Jeff

[jerry1]

I don't know why the application is licensed
to lan1. But what I would like to know is
why there is a strange script to even change
lan1 to 600 in the first place.