From: Cyrill Gorcunov <gorcunov@openvz.org>
To: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Pavel Emelyanov <xemul@parallels.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, Randy Dunlap <rdunlap@xenotime.net>,
Darren Hart <dvhart@linux.intel.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrew Morton <akpm@linux-foundation.org>,
Jiri Kosina <jkosina@suse.cz>,
David Howells <dhowells@redhat.com>,
"Serge E. Hallyn" <serge.hallyn@canonical.com>,
linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com,
spender@grsecurity.net
Subject: Re: [PATCH v2] futex: mark get_robust_list as deprecated
Date: Fri, 3 Aug 2012 15:35:38 +0400 [thread overview]
Message-ID: <20120803113538.GD11952@moon> (raw)
In-Reply-To: <CAFLxGvxXLoeaQFQwrBmaUpk6qHi2qn2piTCJ4atTcrg2UC7oAw@mail.gmail.com>
On Fri, Aug 03, 2012 at 01:30:31PM +0200, richard -rw- weinberger wrote:
> On Fri, Aug 3, 2012 at 1:27 PM, Cyrill Gorcunov <gorcunov@openvz.org> wrote:
> > On Fri, Aug 03, 2012 at 01:19:24PM +0200, richard -rw- weinberger wrote:
> >> >>
> >> >> CRIU folks, how do you deal with futex robust lists?
> >> >
> >> > Well, I believe we were over-optimistic in claiming that we don't need this
> >> > syscall (to be fair I think we simply yet not faced the problem Eric points).
> >> > So we need some way to fetch this address and set it back. If get_robust_list
> >> > get deprecated maybe we could print it out in /proc/pid/stat or something?
> >>
> >> Kees, you said get_robust_list() can be used to bypass ASLR.
> >> How? What makes it worse than /proc/pid/maps?
> >>
> >> If the robust list address itself is bad, removing get_robust_list()
> >> and putting the information into /proc is useless.
> >
> > Look, the /proc entry might check for some CAP and do not allow
> > a regular user to fetch this address.
>
> We could also add another check to get_robust_list().
> It does already ptrace_may_access().
Yes, and I'm definitely not against that ;) The problem is that this
syscall was marked as deprecated and if people want to drop it we
need to find a way to provide this address back in a sake of c/r.
If c/r is the only _one_ who needs this facility than providing the
address via /proc might be worth thing to do (since I can wrap
it with CONFIG_CHECKPOINT_RESTORE and a regular kernel won't see
this snippet at all).
Cyrill
next prev parent reply other threads:[~2012-08-03 11:35 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-19 23:12 [PATCH] futex: do not leak robust list to unprivileged process Kees Cook
2012-03-20 13:31 ` Serge Hallyn
2012-03-20 17:02 ` Thomas Gleixner
2012-03-20 17:11 ` Kees Cook
2012-03-20 17:23 ` Ingo Molnar
2012-03-22 23:46 ` Thomas Gleixner
2012-03-23 17:58 ` [PATCH] futex: mark get_robust_list as deprecated Kees Cook
2012-03-23 18:27 ` Thomas Gleixner
2012-03-23 19:08 ` Kees Cook
2012-03-23 19:08 ` [PATCH v2] " Kees Cook
2012-03-23 22:06 ` Eric W. Biederman
2012-03-23 22:10 ` Kees Cook
2012-03-30 5:05 ` Matt Helsley
2012-03-30 6:14 ` Pavel Emelyanov
2012-03-30 22:51 ` Gene Cooperman
2012-03-27 18:05 ` Josh Boyer
2012-03-27 19:13 ` Peter Zijlstra
2012-03-29 9:56 ` [tip:core/locking] futex: Mark " tip-bot for Kees Cook
2012-08-02 10:35 ` [PATCH v2] futex: mark " richard -rw- weinberger
2012-08-02 11:11 ` Eric W. Biederman
2012-08-03 10:17 ` richard -rw- weinberger
2012-08-03 11:02 ` Cyrill Gorcunov
2012-08-03 11:19 ` richard -rw- weinberger
2012-08-03 11:27 ` Cyrill Gorcunov
2012-08-03 11:30 ` richard -rw- weinberger
2012-08-03 11:35 ` Cyrill Gorcunov [this message]
2012-08-03 11:38 ` richard -rw- weinberger
2012-08-03 12:38 ` Pavel Emelyanov
2012-08-03 12:58 ` Eric W. Biederman
2012-08-03 13:00 ` richard -rw- weinberger
2012-08-03 17:16 ` Kees Cook
2012-03-28 18:33 ` [PATCH] futex: do not leak robust list to unprivileged process Kees Cook
2012-03-28 21:24 ` Thomas Gleixner
2012-03-29 9:55 ` [tip:core/locking] futex: Do " tip-bot for Kees Cook
2012-06-19 1:41 ` Wanlong Gao
2012-06-19 2:24 ` Serge Hallyn
2012-06-19 2:32 ` Wanlong Gao
2012-06-19 3:13 ` Serge Hallyn
2012-06-19 3:21 ` Wanlong Gao
2012-06-19 12:23 ` Serge Hallyn
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