From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751477AbdFGJ3o (ORCPT ); Wed, 7 Jun 2017 05:29:44 -0400 Received: from ozlabs.org ([103.22.144.67]:46061 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751008AbdFGJ3n (ORCPT ); Wed, 7 Jun 2017 05:29:43 -0400 From: Michael Ellerman To: Daniel Micay , Bhupesh Sharma , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Cc: bhupesh.linux@gmail.com, Anton Blanchard , Daniel Cashman , Kees Cook , Benjamin Herrenschmidt Subject: Re: [kernel-hardening] [PATCH] powerpc: Increase ELF_ET_DYN_BASE to 1TB for 64-bit applications In-Reply-To: <1496665366.343.1.camel@gmail.com> References: <1496642591-1373-1-git-send-email-bhsharma@redhat.com> <1496665366.343.1.camel@gmail.com> User-Agent: Notmuch/0.21 (https://notmuchmail.org) Date: Wed, 07 Jun 2017 19:29:37 +1000 Message-ID: <87d1agp2m6.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Daniel Micay writes: > Rather than doing this, the base should just be split for an ELF > interpreter like PaX. I don't quite parse that, I think you mean PaX uses a different base for an ELF interpreter vs a regular ET_DYN? That would be cool. How do you know that it's an ELF interpreter you're loading? Is it just something that's PIE but doesn't request an interpreter? Is the PaX code somewhere I can look at? > It makes sense for a standalone executable to be as low in the address > space as possible. More or less. There are performance reasons why 1T could be good for us, but I want to see some performance numbers to justify that change. And it does mean you have a bit less address space to play with. cheers