Re: [PATCH] futex: futex_find_get_task make credentials checkconditional
From: Michal Hocko
Date: Wed Jun 30 2010 - 03:01:26 EST
On Tue 29-06-10 09:41:02, Linus Torvalds wrote:
> On Tue, Jun 29, 2010 at 1:42 AM, Michal Hocko <mhocko@xxxxxxx> wrote:
> > futex_find_get_task is currently used (through lookup_pi_state) from two
> > contexts, futex_requeue and futex_lock_pi_atomic. While credentials check
> > makes sense in the first code path, the second one is more problematic
> > because this check requires that the PI lock holder (pid parameter) has
> > the same uid and euid as the process's euid which is trying to lock the
> > same futex (current).
> So exactly why does it make sense to check the credentials in the
> first code path then?
I though that requeue needs this for security reasons (don't let requeue
process for other user), but when I thought about that again you are
right and the only what matters should be accessibility of the shared
SUSE LINUX s.r.o.
190 00 Praha 9
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