From: Matt Helsley <matthltc@us.ibm.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>,
Andrew Morton <akpm@linux-foundation.org>,
richard -rw- weinberger <richard.weinberger@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Pavel Emelyanov <xemul@parallels.com>,
Kees Cook <keescook@chromium.org>, Tejun Heo <tj@kernel.org>,
Matt Helsley <matthltc@us.ibm.com>
Subject: Re: [patch 1/2] c/r: prctl: Add ability to set new mm_struct::exe_file
Date: Fri, 23 Mar 2012 10:06:14 -0700 [thread overview]
Message-ID: <20120323170614.GD27292@count0.beaverton.ibm.com> (raw)
In-Reply-To: <m14ntgxl30.fsf@fess.ebiederm.org>
On Thu, Mar 22, 2012 at 04:38:43PM -0700, Eric W. Biederman wrote:
> Cyrill Gorcunov <gorcunov@openvz.org> writes:
>
> > On Mon, Mar 19, 2012 at 03:46:49PM -0700, Andrew Morton wrote:
> >> > >>
> >> > >> What is this mysterious "security reason"?
> >> > >>
> >> > >
> >> > > Oh, sorry I should have included Matt's comment here
> >>
> >> Please send a patch with the updated changelog and improved comment?
> >>
> >
> > Andrew, take a look please, will the changelog and comments look
> > better?
>
> Can you change this to take an actual address and get the exe_file
> from an mmapped area and make certain that the mmaped_area is already
> mapped MAP_EXEC.
Do you mean PROT_EXEC/VM_EXEC?
>
> That will prevent out-right lies.
>
> At least then we will know that exe_file will at least be a file that is
> mapped executable in the process's address space. It's not a lot better
> but it makes /proc/<pid>/exe at almost as trustable as it is now.
I don't dislike the idea. However just because it's mapped with one of
those flags does not mean that a single instruction of it will ever be
executed. So it's not much better than using the fd :/.
Perhaps there is some way to use the userspace stack and/or regs to get
a reasonable instruction pointer, lookup its VMA, and use that? I'm not
sure that would work for c/r though...
Cheers,
-Matt
next prev parent reply other threads:[~2012-03-23 17:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-16 20:55 [patch 0/2] [PATCH 0/2] prctl extension in a sake of c/r Cyrill Gorcunov
2012-03-16 20:55 ` [patch 1/2] c/r: prctl: Add ability to set new mm_struct::exe_file Cyrill Gorcunov
2012-03-19 22:15 ` Andrew Morton
2012-03-19 22:39 ` Cyrill Gorcunov
2012-03-19 22:41 ` richard -rw- weinberger
2012-03-19 22:46 ` Andrew Morton
2012-03-19 22:50 ` Cyrill Gorcunov
2012-03-19 22:59 ` Andrew Morton
2012-03-19 23:12 ` Cyrill Gorcunov
2012-03-19 23:02 ` richard -rw- weinberger
2012-03-19 23:17 ` Cyrill Gorcunov
2012-03-19 23:23 ` richard -rw- weinberger
2012-03-20 6:55 ` Cyrill Gorcunov
2012-03-22 23:38 ` Eric W. Biederman
2012-03-23 6:41 ` Cyrill Gorcunov
2012-03-23 6:47 ` Cyrill Gorcunov
2012-03-23 17:06 ` Matt Helsley [this message]
2012-03-19 22:47 ` Cyrill Gorcunov
2012-03-16 20:55 ` [patch 2/2] c/r: prctl: Add ability to get clear_tid_address Cyrill Gorcunov
2012-03-19 16:51 ` Kees Cook
2012-03-19 16:55 ` Cyrill Gorcunov
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