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 0F029C433EF for ; Fri, 26 Nov 2021 17:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233706AbhKZR3u (ORCPT ); Fri, 26 Nov 2021 12:29:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231688AbhKZR1s (ORCPT ); Fri, 26 Nov 2021 12:27:48 -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 75B3FC061D5F for ; Fri, 26 Nov 2021 08:54:54 -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 E75F2B82852 for ; Fri, 26 Nov 2021 16:54:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C749C93056; Fri, 26 Nov 2021 16:54:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637945689; bh=1PCvk2DH5u3SLpbi5pVnYhcvH/Q/+cP55AdCX0C5mjA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XBWUv1BEPpNclpWJ7rMiE/azLyXortkDHaFyEjLW0ZeSEMcU9LDlmXETIVRP7MIOr VtrNUstDVvLsXW/2alD27U3oPENJEuTw4kvWKPA8EkS+N6ZYM5ugAnlB/pYtcFcP7P 2Y1ArzujMAwo2T3rNZtl6+R5OjMnW4K09ai4Qiow= Date: Fri, 26 Nov 2021 17:54:46 +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 v2] w1: Misuse of get_user()/put_user() reported by sparse Message-ID: References: <926b572075a26835f4e39d05710cd1b75fd4d5a4.1637945194.git.christophe.leroy@csgroup.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <926b572075a26835f4e39d05710cd1b75fd4d5a4.1637945194.git.christophe.leroy@csgroup.eu> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 26, 2021 at 05:47:58PM +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 > --- > v2: Use sysfs_emit() and kstrtobool() > --- > drivers/w1/slaves/w1_ds28e04.c | 25 +++---------------------- > 1 file changed, 3 insertions(+), 22 deletions(-) > > diff --git a/drivers/w1/slaves/w1_ds28e04.c b/drivers/w1/slaves/w1_ds28e04.c > index e4f336111edc..98f80f412cfd 100644 > --- a/drivers/w1/slaves/w1_ds28e04.c > +++ b/drivers/w1/slaves/w1_ds28e04.c > @@ -32,7 +32,7 @@ static int w1_strong_pullup = 1; > module_param_named(strong_pullup, w1_strong_pullup, int, 0); > > /* enable/disable CRC checking on DS28E04-100 memory accesses */ > -static char w1_enable_crccheck = 1; > +static bool w1_enable_crccheck = true; > > #define W1_EEPROM_SIZE 512 > #define W1_PAGE_COUNT 16 > @@ -339,32 +339,13 @@ 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 sysfs_emit(buf, "%d\n", w1_enable_crccheck); > } > > static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, > const char *buf, size_t count) > { > - char val; > - > - if (count != 1 || !buf) > - return -EINVAL; > - > - if (get_user(val, buf)) > - return -EFAULT; > - > - /* convert to decimal */ > - val = val - 0x30; > - if (val != 0 && val != 1) > - return -EINVAL; > - > - /* set the new value */ > - w1_enable_crccheck = val; > - > - return sizeof(w1_enable_crccheck); > + return kstrtobool(buf, &w1_enable_crccheck) ? : count; Please spell this line out, using ? : is unreadable at times. thanks, greg k-h