Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 11 Aug 2017 14:41:27 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Thomas Garnier <thgarnie@...gle.com>
Cc: Herbert Xu <herbert@...dor.apana.org.au>,
	"David S . Miller" <davem@...emloft.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, "H . Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Josh Poimboeuf <jpoimboe@...hat.com>, Arnd Bergmann <arnd@...db.de>,
	Matthias Kaehlcke <mka@...omium.org>,
	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	Juergen Gross <jgross@...e.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Radim Krčmář <rkrcmar@...hat.com>,
	Joerg Roedel <joro@...tes.org>,
	Tom Lendacky <thomas.lendacky@....com>,
	Andy Lutomirski <luto@...nel.org>, Borislav Petkov <bp@...e.de>,
	Brian Gerst <brgerst@...il.com>,
	"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Tejun Heo <tj@...nel.org>, Christoph Lameter <cl@...ux.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Chris Metcalf <cmetcalf@...lanox.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	Christopher Li <sparse@...isli.org>,
	"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
	Lukas Wunner <lukas@...ner.de>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Dou Liyang <douly.fnst@...fujitsu.com>,
	Daniel Borkmann <daniel@...earbox.net>,
	Alexei Starovoitov <ast@...nel.org>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Steven Rostedt <rostedt@...dmis.org>,
	Kees Cook <keescook@...omium.org>, Rik van Riel <riel@...hat.com>,
	David Howells <dhowells@...hat.com>,
	Waiman Long <longman@...hat.com>, Kyle Huey <me@...ehuey.com>,
	Peter Foley <pefoley2@...oley.com>,
	Tim Chen <tim.c.chen@...ux.intel.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Michal Hocko <mhocko@...e.com>,
	Matthew Wilcox <mawilcox@...rosoft.com>,
	"H . J . Lu" <hjl.tools@...il.com>, Paul Bolle <pebolle@...cali.nl>,
	Rob Landley <rob@...dley.net>, Baoquan He <bhe@...hat.com>,
	Daniel Micay <danielmicay@...il.com>, x86@...nel.org,
	linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
	xen-devel@...ts.xenproject.org, kvm@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-arch@...r.kernel.org,
	linux-sparse@...r.kernel.org, kernel-hardening@...ts.openwall.com,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Borislav Petkov <bp@...en8.de>
Subject: Re: x86: PIE support and option to extend KASLR randomization


* Thomas Garnier <thgarnie@...gle.com> wrote:

> Changes:
>  - v2:
>    - Add support for global stack cookie while compiler default to fs without
>      mcmodel=kernel
>    - Change patch 7 to correctly jump out of the identity mapping on kexec load
>      preserve.
> 
> These patches make the changes necessary to build the kernel as Position
> Independent Executable (PIE) on x86_64. A PIE kernel can be relocated below
> the top 2G of the virtual address space. It allows to optionally extend the
> KASLR randomization range from 1G to 3G.

So this:

 61 files changed, 923 insertions(+), 299 deletions(-)

... is IMHO an _awful_ lot of churn and extra complexity in pretty fragile pieces 
of code, to gain what appears to be only ~1.5 more bits of randomization!

Do these changes get us closer to being able to build the kernel as truly position 
independent, i.e. to place it anywhere in the valid x86-64 address space? Or any 
other advantages?

Thanks,

	Ingo

Powered by blists - more mailing lists

Your e-mail address:

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.