From: Pavel Machek <pavel@suse.cz>
To: Ulrich Drepper <drepper@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
dwmw2@infradead.org, drepper@redhat.com, mingo@elte.hu,
tglx@tglx.de
Subject: Re: [PATCH 12/13] hrtimer: create a "timer_slack" field in the task struct
Date: Wed, 17 Sep 2008 09:42:06 +0200 [thread overview]
Message-ID: <20080917074206.GF2659@elf.ucw.cz> (raw)
In-Reply-To: <a36005b50809140904h690d00b0sa66f166a64850114@mail.gmail.com>
On Sun 2008-09-14 09:04:08, Ulrich Drepper wrote:
> On Sun, Sep 14, 2008 at 8:57 AM, Pavel Machek <pavel@suse.cz> wrote:
> >> LD_PRELOAD and other variables are ignored in security-relevant
> >> contexts and environments are cleared in many situations. Sure, you
> >
> > ...but that's okay, right? You would not want passwd to inherit huge
> > slack specified by attacker...?
>
> No, it's not OK. There are enough apps which are privileged and need
> to be handled this way. Take the X server, for instance.
_Need_ to be handled? They are not handled that way today, and it
still seems to work ok.
(Plus X is no longer setuid on new distros...)
So -- how do you prevent user from setting excessively high slack and
interfering with ping or passwd?
> > Well, it is not too much, but... is the cost for userspace really
> > significant? You'd clearly want it stored in environment, not
> > filesystem...
>
> You cannot really use the environment for anything meaningful.
> Especially for this case, you couldn't change the setting for a
> running process. What a fully-userlevel implementation would have
Is this important enough to warrant setting for already-running
processes? I don't think so...
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2008-09-17 7:40 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-01 23:03 [PATCH 0/13] Turn hrtimers into a range capable timer Arjan van de Ven
2008-09-01 23:05 ` [PATCH 1/13] hrtimer: add abstraction functions for accessing the "expires" member Arjan van de Ven
2008-09-01 23:05 ` [PATCH 2/13] hrtimer: convert kvm to the new hrtimer apis Arjan van de Ven
2008-09-01 23:06 ` [PATCH 3/13] hrtimer: convert timerfd " Arjan van de Ven
2008-09-01 23:07 ` [PATCH 4/13] hrtimer: convert net::sched_cbq " Arjan van de Ven
2008-09-01 23:08 ` [PATCH 5/13] hrtimer: convert kernel/* " Arjan van de Ven
2008-09-01 23:09 ` [PATCH 6/13] hrtimer: convert powerpc/oprofile " Arjan van de Ven
2008-09-01 23:09 ` [PATCH 7/13] hrtimer: convert kvm-ia64 " Arjan van de Ven
2008-09-01 23:10 ` [PATCH 8/13] hrtimer: convert s390 " Arjan van de Ven
2008-09-01 23:11 ` [PATCH 9/13] hrtimer: convert sound/ " Arjan van de Ven
2008-09-01 23:12 ` [PATCH 10/13] hrtimer: rename the "expires" struct member to avoid accidental usage Arjan van de Ven
2008-09-01 23:12 ` Arjan van de Ven
2008-09-01 23:13 ` [PATCH 11/13] hrtimer: turn hrtimers into range timers Arjan van de Ven
2008-09-02 8:22 ` Peter Zijlstra
2008-09-02 11:08 ` Peter Zijlstra
2008-09-02 11:15 ` Peter Zijlstra
2008-09-02 13:06 ` Arjan van de Ven
2008-09-02 13:05 ` Arjan van de Ven
2008-09-02 13:47 ` Peter Zijlstra
2008-09-02 16:02 ` Arjan van de Ven
2008-09-01 23:14 ` [PATCH 12/13] hrtimer: create a "timer_slack" field in the task struct Arjan van de Ven
2008-09-02 10:04 ` Pavel Machek
2008-09-02 13:03 ` Arjan van de Ven
2008-09-08 13:27 ` Pavel Machek
2008-09-08 13:40 ` Arjan van de Ven
2008-09-08 14:15 ` Pavel Machek
2008-09-08 14:22 ` Arjan van de Ven
2008-09-13 16:24 ` Pavel Machek
2008-09-14 15:21 ` Ulrich Drepper
2008-09-14 15:27 ` Arjan van de Ven
2008-09-14 15:57 ` Pavel Machek
2008-09-14 16:04 ` Ulrich Drepper
2008-09-14 16:14 ` Arjan van de Ven
2008-09-17 7:42 ` Pavel Machek [this message]
2008-09-30 5:16 ` KOSAKI Motohiro
2008-09-30 8:28 ` Arjan van de Ven
2008-09-30 8:54 ` KOSAKI Motohiro
2008-09-01 23:14 ` [PATCH 13/13] hrtimer: make select() and poll() use the hrtimer range feature Arjan van de Ven
2008-09-02 8:22 ` Peter Zijlstra
2008-09-02 16:03 ` Arjan van de Ven
2008-09-06 14:56 ` [PATCH 0/13] Turn hrtimers into a range capable timer Ingo Molnar
2008-09-06 16:30 ` Arjan van de Ven
2008-09-06 16:33 ` Ingo Molnar
2008-09-12 3:39 ` Rusty Russell
2008-09-12 5:42 ` Arjan van de Ven
2008-09-12 20:24 ` Thomas Gleixner
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