Re: DoS with POSIX file locks?

[Arjan van de Ven <arjan@infradead.org>]

On Mon, 2006-03-20 at 14:24 +0100, Miklos Szeredi wrote:
> > > > Right.  Um.  I took it out back in March 2003 after enough people
> > > > convinced me it wasn't worth trying to account for all the memory
> > > > processes use, and the userbeans project would take care of it anyway.
> > > > Haha.
> > > > 
> > > > It's hard to fix the accounting.  You have to deal with one thread
> > > > allocating the lock, and then a different thread freeing it.  We never
> > > > actually accounted for posix locks (which are the ones we really needed
> > > > to!) and on occasion had current->locks go negative, with all kinds of
> > > > associated badness.
> > > 
> > > Things look fairly straightforward if the accounting is done in
> > > files_struct instead of task_struct. 
> > 
> > that's the wrong place; you can send fd's over unix sockets to other
> > processes....
> 
> POSIX locks have no association with fd's.  Only the inode and the
> "owner" is relevant

but the point is that with unix sockets you can send inodes to other
processes.. who don't share files_struct


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