Re: silent semantic changes with reiser4

[Christoph Hellwig]

On Thu, Aug 26, 2004 at 02:48:12PM +0100, Jamie Lokier wrote:
> >  the current reiser4 semantics break that and as soon as you're having a
> >  world-writeable (e.g. /tmp) dir on it and someone is doing an opendir
> >  on it he's lost.
> 
> How does the current reiser4 semantics break that?
> 
> In a reiser4 filesystem, a file _is_ a directory.
> opendir() is supposed to succeed on it.
> 
> There's bound to be some security issue, but I'm not sure what you're
> getting at with /tmp.  What sort of sort of security problem arises
> with a world-writeable directory such as /tmp, that cannot arise with
> the standard fs semantics?

Actually you are right on that issue because it would open the
device/fifo as directory and not device/fifo (in fact I'd had to look at
the code again to see whether they actually do this only for files or
also for special files)

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