Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752517AbdHPWu0 (ORCPT ); Wed, 16 Aug 2017 18:50:26 -0400 Received: from mail-it0-f52.google.com ([209.85.214.52]:38388 "EHLO mail-it0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752352AbdHPWuZ (ORCPT ); Wed, 16 Aug 2017 18:50:25 -0400 MIME-Version: 1.0 In-Reply-To: <20170816224650.1089-2-labbott@redhat.com> References: <20170816224650.1089-1-labbott@redhat.com> <20170816224650.1089-2-labbott@redhat.com> From: Kees Cook Date: Wed, 16 Aug 2017 15:50:24 -0700 X-Google-Sender-Auth: CIOSVwbwmFMMlI_168t5gdi_59A Message-ID: Subject: Re: [PATCHv2 1/2] init: Move stack canary initialization after setup_arch To: Laura Abbott Cc: Laura Abbott , "kernel-hardening@lists.openwall.com" , LKML , Linux-MM , Andrew Morton , Daniel Micay Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1718 Lines: 60 On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott wrote: > From: Laura Abbott > > Stack canary intialization involves getting a random number. > Getting this random number may involve accessing caches or other > architectural specific features which are not available until > after the architecture is setup. Move the stack canary initialization > later to accomodate this. > > Signed-off-by: Laura Abbott > Signed-off-by: Laura Abbott Acked-by: Kees Cook -Kees > --- > v2: Also moved add_latent_entropy per suggestion of Kees. > --- > init/main.c | 11 +++++------ > 1 file changed, 5 insertions(+), 6 deletions(-) > > diff --git a/init/main.c b/init/main.c > index 052481fbe363..21d599eaad06 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -515,12 +515,6 @@ asmlinkage __visible void __init start_kernel(void) > smp_setup_processor_id(); > debug_objects_early_init(); > > - /* > - * Set up the initial canary ASAP: > - */ > - add_latent_entropy(); > - boot_init_stack_canary(); > - > cgroup_init_early(); > > local_irq_disable(); > @@ -534,6 +528,11 @@ asmlinkage __visible void __init start_kernel(void) > page_address_init(); > pr_notice("%s", linux_banner); > setup_arch(&command_line); > + /* > + * Set up the the initial canary and entropy after arch > + */ > + add_latent_entropy(); > + boot_init_stack_canary(); > mm_init_cpumask(&init_mm); > setup_command_line(command_line); > setup_nr_cpu_ids(); > -- > 2.13.0 > -- Kees Cook Pixel Security