From: Johannes Weiner <hannes@cmpxchg.org>
To: Luigi Semenzato <semenzato@google.com>
Cc: Ric Mason <ric.masonn@gmail.com>,
linux-mm@kvack.org, Hugh Dickins <hughd@google.com>
Subject: Re: security: restricting access to swap
Date: Fri, 15 Mar 2013 12:55:09 -0400 [thread overview]
Message-ID: <20130315165509.GA1108@cmpxchg.org> (raw)
In-Reply-To: <CAA25o9RPhu++JsX_8AjhqJuodRkybiYVSEifjCXX=oPnOO5fEA@mail.gmail.com>
On Fri, Mar 15, 2013 at 08:48:49AM -0700, Luigi Semenzato wrote:
> On Fri, Mar 15, 2013 at 2:04 AM, Ric Mason <ric.masonn@gmail.com> wrote:
> > On 03/12/2013 07:57 AM, Luigi Semenzato wrote:
> >>
> >> Greetings linux-mmers,
> >>
> >> before we can fully deploy zram, we must ensure it conforms to the
> >> Chrome OS security requirements. In particular, we do not want to
> >> allow user space to read/write the swap device---not even root-owned
> >> processes.
> >
> >
> > Interesting.
>
> Thank you.
>
> >>
> >> A similar restriction is available for /dev/mem under
> >> CONFIG_STRICT_DEVMEM.
> >
> >
> > Sorry, what's /dev/mem used for? and why relevant your topic?
>
> I don't know what it's used for Chrome OS, but I don't think it
> matters. The point is that /dev/mem is compiled in the kernel, and
> without CONFIG_STRICT_DEVMEM it offers a way for a root-owned process
> to read/write all of physical memory. The situation is not as dire
> with a swap device, but currently a root-owned process can open a
> block device used for swap and peek and poke its data, which means
> that a root-owned process has now potential access to the data segment
> of any other process, among other things.
How do you handle /proc/<pid>/mem?
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next prev parent reply other threads:[~2013-03-15 16:55 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-11 23:57 security: restricting access to swap Luigi Semenzato
2013-03-12 13:06 ` Konrad Rzeszutek Wilk
2013-03-12 15:46 ` Luigi Semenzato
2013-03-12 23:32 ` Simon Jeons
2013-03-15 9:04 ` Ric Mason
2013-03-15 15:48 ` Luigi Semenzato
2013-03-15 16:55 ` Johannes Weiner [this message]
2013-03-15 17:27 ` Luigi Semenzato
2013-03-15 22:19 ` Luigi Semenzato
2013-03-18 3:58 ` Hugh Dickins
2013-03-18 16:05 ` Luigi Semenzato
2013-03-18 23:43 ` KOSAKI Motohiro
2013-03-19 17:39 ` Will Drewry
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