Re: foreign fs security features (was Re: NCPFS overhaul)

Raul Miller (rdm@test.legislate.com)
Mon, 6 Apr 1998 08:47:10 -0400


Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> A directory fred exists you cannot see
> You do
> mkdir fred
> do you
> a) return -EEXIST revealing the invisible space
> b) create another fred

Ah, come on, this is security by obscurity: you're just hiding
names from people that can't see them.

The usual "secure" thing to do is "pause a second, then return an
error". What this means in a world of plentiful parallel resources
(cheap fork) is maybe best left to the imagination. I suppose you could
make the penalty cumulative on a per user basis: if another request
which impacts on a hidden resource comes in while one is still pending.
[But you'd want to be able to disable this for people who don't care
about enforcing the obscurity, and just want to interoperate.]

-- 
Raul

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