Re: [patch 0/6] lightweight robust futexes: -V3

Ingo Molnar
2006-02-16T20:25:53Z

* Daniel Walker <dwalker@mvista.com> wrote:

> On Thu, 2006-02-16 at 18:24 +0100, Ingo Molnar wrote:
> > * Daniel Walker <dwalker@mvista.com> wrote:
> >
> > > Another thing I noticed was that futex_offset on the surface looks
> > > like a malicious users dream variable .. [...]
> >
> > i have no idea what you mean by that - could you explain whatever threat
> > you have in mind, in more detail?
>
> As I said, "on the surface" you could manipulate the
> futex_offset to access memory unrelated to the futex structure .
> That's all I'm referring too ..

and? You can 'manipulate' arbitrary userspace memory, be that used by
the kernel or not, and you can do a sys_futex(FUTEX_WAKE) on any
arbitrary userspace memory address too (this is a core property of
futexes). You must have meant something specific when you said "on the
surface looks like a malicious users dream variable". In other words:
please move your statement out of innuendo by backing it up with
specifics (or by retracting it) - right now it's hanging in the air :)

Ingo