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=-10.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 B832BC433E9 for ; Thu, 3 Sep 2020 15:47:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E9A320775 for ; Thu, 3 Sep 2020 15:47:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728458AbgICPrr (ORCPT ); Thu, 3 Sep 2020 11:47:47 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:26991 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728494AbgICPrr (ORCPT ); Thu, 3 Sep 2020 11:47:47 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4Bj4vL0kzwzB09ZF; Thu, 3 Sep 2020 17:47:42 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id UBMjKOF82pyz; Thu, 3 Sep 2020 17:47:41 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4Bj4vK623nzB09ZD; Thu, 3 Sep 2020 17:47:41 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id D6B978B80B; Thu, 3 Sep 2020 17:47:40 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 8kHWzQ3JESNL; Thu, 3 Sep 2020 17:47:39 +0200 (CEST) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 79F9B8B803; Thu, 3 Sep 2020 17:47:34 +0200 (CEST) Subject: Re: [PATCH 14/14] powerpc: remove address space overrides using set_fs() To: Christoph Hellwig , Linus Torvalds , Al Viro , Michael Ellerman , x86@kernel.org Cc: linux-arch@vger.kernel.org, Kees Cook , linux-kernel@vger.kernel.org, Luis Chamberlain , linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Alexey Dobriyan References: <20200903142242.925828-1-hch@lst.de> <20200903142242.925828-15-hch@lst.de> From: Christophe Leroy Message-ID: Date: Thu, 3 Sep 2020 17:43:25 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200903142242.925828-15-hch@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Le 03/09/2020 à 16:22, Christoph Hellwig a écrit : > Stop providing the possibility to override the address space using > set_fs() now that there is no need for that any more. > > Signed-off-by: Christoph Hellwig > --- > > -static inline int __access_ok(unsigned long addr, unsigned long size, > - mm_segment_t seg) > +static inline bool __access_ok(unsigned long addr, unsigned long size) > { > - if (addr > seg.seg) > - return 0; > - return (size == 0 || size - 1 <= seg.seg - addr); > + if (addr >= TASK_SIZE_MAX) > + return false; > + return size == 0 || size <= TASK_SIZE_MAX - addr; > } You don't need to test size == 0 anymore. It used to be necessary because of the 'size - 1', as size is unsigned. Now you can directly do return size <= TASK_SIZE_MAX - addr; If size is 0, this will always be true (because you already know that addr is not >= TASK_SIZE_MAX Christophe