The kernel knows that
- Uids are different
- One uid (0) is more equal than the others.
Using gid 0 is not a horrible idea, but I think that using any uid or gid
*except* 0 is a Bad Thing. Modprobe can set the permissions if different
ones are wanted.
I'd prefer having a default mode of 000, to make it clear that you really
have to make a decision about the permissions, and the kernel isn't going
to do it for you. Failing that, 0600 (which might be needed so that
init can open /dev/console). Failing that, a device can specify initial
permissions if it knows, that e.g. /dev/null is harmless.
But I'd rather force the issue into user-space where it has to be dealt
with anyway.
-- -Colin