From: Jason Cooper <jason@lakedaemon.net>
To: "Roberts, William C" <william.c.roberts@intel.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"keescook@chromium.org" <keescook@chromium.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"nnk@google.com" <nnk@google.com>,
"jeffv@google.com" <jeffv@google.com>,
"salyzyn@android.com" <salyzyn@android.com>,
"dcashman@android.com" <dcashman@android.com>
Subject: Re: [PATCH] [RFC] Introduce mmap randomization
Date: Tue, 26 Jul 2016 20:59:44 +0000 [thread overview]
Message-ID: <20160726205944.GM4541@io.lakedaemon.net> (raw)
In-Reply-To: <476DC76E7D1DF2438D32BFADF679FC560125F29C@ORSMSX103.amr.corp.intel.com>
Hi William,
On Tue, Jul 26, 2016 at 08:13:23PM +0000, Roberts, William C wrote:
> > > From: Jason Cooper [mailto:jason@lakedaemon.net]
> > > On Tue, Jul 26, 2016 at 11:22:26AM -0700, william.c.roberts@intel.com wrote:
> > > > Performance Measurements:
> > > > Using strace with -T option and filtering for mmap on the program ls
> > > > shows a slowdown of approximate 3.7%
> > >
> > > I think it would be helpful to show the effect on the resulting object code.
> >
> > Do you mean the maps of the process? I have some captures for whoopsie on my
> > Ubuntu system I can share.
No, I mean changes to mm/mmap.o.
> > One thing I didn't make clear in my commit message is why this is good. Right
> > now, if you know An address within in a process, you know all offsets done with
> > mmap(). For instance, an offset To libX can yield libY by adding/subtracting an
> > offset. This is meant to make rops a bit harder, or In general any mapping offset
> > mmore difficult to find/guess.
Are you able to quantify how many bits of entropy you're imposing on the
attacker? Is this a chair in the hallway or a significant increase in
the chances of crashing the program before finding the desired address?
thx,
Jason.
next prev parent reply other threads:[~2016-07-26 21:00 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-26 18:22 [PATCH] [RFC] Introduce mmap randomization william.c.roberts
2016-07-26 18:22 ` william.c.roberts
2016-07-26 20:03 ` Jason Cooper
2016-07-26 20:11 ` Roberts, William C
2016-07-26 20:13 ` Roberts, William C
2016-07-26 20:59 ` Jason Cooper [this message]
2016-07-26 21:06 ` Roberts, William C
2016-07-26 21:44 ` Jason Cooper
2016-07-26 23:51 ` Dave Hansen
2016-08-02 17:17 ` Roberts, William C
2016-08-03 18:19 ` Roberts, William C
2016-08-02 17:15 ` Roberts, William C
2016-07-27 16:59 ` Nick Kralevich
2016-07-28 21:07 ` Jason Cooper
2016-07-29 10:10 ` [kernel-hardening] " Daniel Micay
2016-07-31 22:24 ` Jason Cooper
2016-08-01 0:24 ` Daniel Micay
2016-08-02 16:57 ` Roberts, William C
2016-08-02 17:02 ` Nick Kralevich
2016-08-14 16:31 ` Pavel Machek 1
2016-07-26 20:12 ` [kernel-hardening] " Rik van Riel
2016-07-26 20:17 ` Roberts, William C
2016-07-26 20:41 ` Nick Kralevich
2016-07-26 21:02 ` Roberts, William C
2016-07-26 21:11 ` Nick Kralevich
2016-08-14 16:22 ` Pavel Machek
2016-08-04 16:53 ` [kernel-hardening] " Daniel Micay
2016-08-04 16:55 ` Roberts, William C
2016-08-04 17:10 ` Daniel Micay
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