From: Greg KH <gregkh@linuxfoundation.org>
To: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>,
Laura Abbott <labbott@fedoraproject.org>,
Mark Rutland <mark.rutland@arm.com>
Subject: Re: [kernel-hardening] initcall randomization
Date: Wed, 5 Oct 2016 22:23:08 +0200 [thread overview]
Message-ID: <20161005202308.GA20923@kroah.com> (raw)
In-Reply-To: <CAKv+Gu_7AdRk7O-Mt8oS=t6prJY56=nS5CS1stgfqHzJ--YD9Q@mail.gmail.com>
On Wed, Oct 05, 2016 at 06:09:01PM +0100, Ard Biesheuvel wrote:
> Did anyone ever look into whether there is anything to gain in terms
> of hardening from randomizing the order initcalls are issued at each
> level? I know entropy is hard to come by at this stage, but on recent
> UEFI systems, this is something we could potentially solve
> generically. (It may uncover some breakage as well, but only hidden
> breakage that could already surface at any time due to linker changes,
> so I think this could serve as a diagnostic option as well)
We rely on link-order init call dependancy in the kernel a lot, so be
very careful about reording them.
> Since boot time mappings are often performed in initcalls, this could
> potentially reduce the predictability of the layout of the virtual
> kernel space. But before I start experimenting with this, I thought
> I'd ask if anyone has ever looked into this.
I think you will break things, try it yourself and see :)
good luck!
greg k-h
next prev parent reply other threads:[~2016-10-05 20:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-05 17:09 [kernel-hardening] initcall randomization Ard Biesheuvel
2016-10-05 19:43 ` [kernel-hardening] " Mark Rutland
2016-10-05 20:23 ` Greg KH [this message]
2016-10-05 20:30 ` [kernel-hardening] " Kees Cook
2016-10-05 21:45 ` Ard Biesheuvel
2016-10-10 22:17 ` Kees Cook
2016-10-11 18:28 ` Ard Biesheuvel
2016-10-11 19:59 ` Kees Cook
2016-10-12 8:50 ` Ard Biesheuvel
2016-10-11 23:40 ` Mark Rutland
2016-10-12 8:55 ` Ard Biesheuvel
2016-10-12 20:19 ` Kees Cook
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