From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19BD7C3279B for ; Mon, 2 Jul 2018 09:58:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C68CF23E3A for ; Mon, 2 Jul 2018 09:58:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C68CF23E3A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933007AbeGBJ64 (ORCPT ); Mon, 2 Jul 2018 05:58:56 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:56310 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753269AbeGBJ6x (ORCPT ); Mon, 2 Jul 2018 05:58:53 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 41D3F18A; Mon, 2 Jul 2018 02:58:53 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 10D543F5BA; Mon, 2 Jul 2018 02:58:53 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 57EF81AE2FEE; Mon, 2 Jul 2018 10:59:32 +0100 (BST) Date: Mon, 2 Jul 2018 10:59:32 +0100 From: Will Deacon To: Kees Cook Cc: Laura Abbott , Mark Rutland , Ard Biesheuvel , Kernel Hardening , LKML , linux-arm-kernel , Alexander Popov , catalin.marinas@arm.com Subject: Re: [PATCH] arm64: Clear the stack Message-ID: <20180702095931.GB28665@arm.com> References: <20180629190553.7282-1-labbott@redhat.com> <706dc06b-0157-89cb-33a6-d0b9d811dcf0@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kees, On Fri, Jun 29, 2018 at 01:25:20PM -0700, Kees Cook wrote: > On Fri, Jun 29, 2018 at 1:22 PM, Laura Abbott wrote: > > On 06/29/2018 01:19 PM, Kees Cook wrote: > >> > >> On Fri, Jun 29, 2018 at 12:05 PM, Laura Abbott wrote: > >>> > >>> Implementation of stackleak based heavily on the x86 version > >>> > >>> Signed-off-by: Laura Abbott > >>> [...] > >>> +#define current_top_of_stack() (task_stack_page(current) + THREAD_SIZE) > >>> +#define on_thread_stack() (on_task_stack(current, > >>> current_stack_pointer)) > >> > >> > >> nit on types here. I get some warnings: > >> > >> kernel/stackleak.c:55:12: warning: assignment makes integer from > >> pointer without a cast [-Wint-conversion] > >> boundary = current_top_of_stack(); > >> ^ > >> kernel/stackleak.c:65:24: warning: assignment makes integer from > >> pointer without a cast [-Wint-conversion] > >> current->lowest_stack = current_top_of_stack() - THREAD_SIZE / 64; > >> ^ > >> > >> So I think this needs to be: > >> > >> +#define current_top_of_stack() ((unsigned long)task_stack_page(current) + > >> \ > >> + THREAD_SIZE) > >> > > > > Argh, missed that in an amend, can fix for next version if there > > are no other objections to this approach. > > No worries! I've made the change locally and will push this out to > -next unless there are objections? I'm a bit wary of conflicts in entry.S, since it's likely that we're going to have a lot going on in there for 4.19. Could I take this via arm64 instead, please, or are there dependencies on other parts of your tree? Will