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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8148C433EF for ; Fri, 26 Nov 2021 16:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378247AbhKZQNv (ORCPT ); Fri, 26 Nov 2021 11:13:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350849AbhKZQLu (ORCPT ); Fri, 26 Nov 2021 11:11:50 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FB3DC0613F8 for ; Fri, 26 Nov 2021 08:00:47 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 63D19B82811 for ; Fri, 26 Nov 2021 16:00:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56AC1C93056; Fri, 26 Nov 2021 16:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637942444; bh=sh5Y1OU5oIIWp8xfzoyHNKbaEp5XLI12ojMxCu7QGaw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JsXGxA4njB2sDXx0XoQYp3rGyHOXQQUk8Yno+fh9ozvbBK4p6UBLBBR5ejMuiu1Wq 7ZsncU5ceiy96v5CP5lPqBbxfmcTTpXzWCi2NOOZnsfrnIZ2ObWCm8ETESco56HTRP f+xlemGO8wRD3uJjTz45ZmR4H/ttg81igIv7pOPg= Date: Fri, 26 Nov 2021 17:00:41 +0100 From: Greg Kroah-Hartman To: Christophe Leroy Cc: Evgeniy Polyakov , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kernel test robot Subject: Re: [PATCH] w1: Misuse of get_user()/put_user() reported by sparse Message-ID: References: <2163689da6544c289254b3c69848acc36db998f5.1637313047.git.christophe.leroy@csgroup.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2163689da6544c289254b3c69848acc36db998f5.1637313047.git.christophe.leroy@csgroup.eu> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 19, 2021 at 10:15:09AM +0100, Christophe Leroy wrote: > sparse warnings: (new ones prefixed by >>) > >> drivers/w1/slaves/w1_ds28e04.c:342:13: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected char [noderef] __user *_pu_addr @@ got char *buf @@ > drivers/w1/slaves/w1_ds28e04.c:342:13: sparse: expected char [noderef] __user *_pu_addr > drivers/w1/slaves/w1_ds28e04.c:342:13: sparse: got char *buf > >> drivers/w1/slaves/w1_ds28e04.c:356:13: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected char const [noderef] __user *_gu_addr @@ got char const *buf @@ > drivers/w1/slaves/w1_ds28e04.c:356:13: sparse: expected char const [noderef] __user *_gu_addr > drivers/w1/slaves/w1_ds28e04.c:356:13: sparse: got char const *buf > > The buffer buf is a failsafe buffer in kernel space, it's not user > memory hence doesn't deserve the use of get_user() or put_user(). > > Access 'buf' content directly. > > Reported-by: kernel test robot > Link: https://lore.kernel.org/lkml/202111190526.K5vb7NWC-lkp@intel.com/T/ > Signed-off-by: Christophe Leroy > --- > drivers/w1/slaves/w1_ds28e04.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/drivers/w1/slaves/w1_ds28e04.c b/drivers/w1/slaves/w1_ds28e04.c > index e4f336111edc..d75bb16fb7a1 100644 > --- a/drivers/w1/slaves/w1_ds28e04.c > +++ b/drivers/w1/slaves/w1_ds28e04.c > @@ -339,10 +339,7 @@ static BIN_ATTR_RW(pio, 1); > static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > - if (put_user(w1_enable_crccheck + 0x30, buf)) > - return -EFAULT; > - > - return sizeof(w1_enable_crccheck); > + return sprintf(buf, "%d", w1_enable_crccheck); This should be sysfs_emit(), right? > } > > static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, > @@ -353,11 +350,8 @@ static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, > if (count != 1 || !buf) > return -EINVAL; > > - if (get_user(val, buf)) > - return -EFAULT; > - > /* convert to decimal */ > - val = val - 0x30; > + val = *buf - 0x30; Why not use a proper function that can parse a string and turn it into a number? thanks, greg k-h