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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 6B289C10F0E for ; Thu, 18 Apr 2019 06:04:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D822204FD for ; Thu, 18 Apr 2019 06:04:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387418AbfDRGER (ORCPT ); Thu, 18 Apr 2019 02:04:17 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:44073 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725836AbfDRGEQ (ORCPT ); Thu, 18 Apr 2019 02:04:16 -0400 X-Originating-IP: 79.86.19.127 Received: from [192.168.0.11] (127.19.86.79.rev.sfr.net [79.86.19.127]) (Authenticated sender: alex@ghiti.fr) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id DC0F4240004; Thu, 18 Apr 2019 06:04:08 +0000 (UTC) Subject: Re: [PATCH v3 06/11] arm: Use STACK_TOP when computing mmap base address To: Kees Cook Cc: Andrew Morton , Christoph Hellwig , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Paul Burton , James Hogan , Palmer Dabbelt , Albert Ou , Alexander Viro , Luis Chamberlain , LKML , linux-arm-kernel , linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, "linux-fsdevel@vger.kernel.org" , Linux-MM References: <20190417052247.17809-1-alex@ghiti.fr> <20190417052247.17809-7-alex@ghiti.fr> From: Alex Ghiti Message-ID: <9fdc1de9-8552-da1b-7d05-0596969ddad2@ghiti.fr> Date: Thu, 18 Apr 2019 02:04:08 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: sv-FI Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/18/19 1:27 AM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 12:29 AM Alexandre Ghiti wrote: >> mmap base address must be computed wrt stack top address, using TASK_SIZE >> is wrong since STACK_TOP and TASK_SIZE are not equivalent. >> >> Signed-off-by: Alexandre Ghiti >> --- >> arch/arm/mm/mmap.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c >> index bff3d00bda5b..0b94b674aa91 100644 >> --- a/arch/arm/mm/mmap.c >> +++ b/arch/arm/mm/mmap.c >> @@ -19,7 +19,7 @@ >> >> /* gap between mmap and stack */ >> #define MIN_GAP (128*1024*1024UL) >> -#define MAX_GAP ((TASK_SIZE)/6*5) >> +#define MAX_GAP ((STACK_TOP)/6*5) > Parens around STACK_TOP aren't needed, but you'll be removing it > entirely, so I can't complain. ;) > >> #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) >> >> static int mmap_is_legacy(struct rlimit *rlim_stack) >> @@ -51,7 +51,7 @@ static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) >> else if (gap > MAX_GAP) >> gap = MAX_GAP; >> >> - return PAGE_ALIGN(TASK_SIZE - gap - rnd); >> + return PAGE_ALIGN(STACK_TOP - gap - rnd); >> } >> >> /* >> -- >> 2.20.1 >> > Acked-by: Kees Cook Thanks ! >