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=-9.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 A883EC10F11 for ; Wed, 24 Apr 2019 18:13:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 701F020652 for ; Wed, 24 Apr 2019 18:13:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556129631; bh=9eRShUYR5yadJs5e5s0yTcDTOdNe1UqYKYluOKNEnWk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ng2kbpvIzr1iWBNmKq5qayG64q56QFdYa/omCIzVvRKYIlPgTE0o1mDp50HY6XGuE zxCJNlylsPMYhtA5y1s0GQkikPBLXaRmXiNacSOVCcOjcc4AoZWIk8xZaiyemTFxvB ymWRdegK1a96ij1BYT5I7+1380dcv8hG5uZrZ5Qc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387489AbfDXRLy (ORCPT ); Wed, 24 Apr 2019 13:11:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:35498 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387424AbfDXRLw (ORCPT ); Wed, 24 Apr 2019 13:11:52 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 64CFC218FE; Wed, 24 Apr 2019 17:11:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556125911; bh=9eRShUYR5yadJs5e5s0yTcDTOdNe1UqYKYluOKNEnWk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K8qqYnCWNu7XDqyJLCyL7jPNRATVVCr38xxM5zIQ/bU75NHs8E3qGjLNgDDaJVu6Q 1iK5AIaP2N+aZ2HzSiU86L4I7Ya7FeyNttsWu0qY5XHmFtngB53DMdfAF6AmP3SxRp UfFnZepEr9AqhbfbzGTgqm6dqUaoIqDc5FJzADgk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Coly Li , Jens Axboe , Sasha Levin Subject: [PATCH 3.18 027/104] bcache: improve sysfs_strtoul_clamp() Date: Wed, 24 Apr 2019 19:08:44 +0200 Message-Id: <20190424170855.765519825@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170839.996641496@linuxfoundation.org> References: <20190424170839.996641496@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 596b5a5dd1bc2fa019fdaaae522ef331deef927f ] Currently sysfs_strtoul_clamp() is defined as, 82 #define sysfs_strtoul_clamp(file, var, min, max) \ 83 do { \ 84 if (attr == &sysfs_ ## file) \ 85 return strtoul_safe_clamp(buf, var, min, max) \ 86 ?: (ssize_t) size; \ 87 } while (0) The problem is, if bit width of var is less then unsigned long, min and max may not protect var from integer overflow, because overflow happens in strtoul_safe_clamp() before checking min and max. To fix such overflow in sysfs_strtoul_clamp(), to make min and max take effect, this patch adds an unsigned long variable, and uses it to macro strtoul_safe_clamp() to convert an unsigned long value in range defined by [min, max]. Then assign this value to var. By this method, if bit width of var is less than unsigned long, integer overflow won't happen before min and max are checking. Now sysfs_strtoul_clamp() can properly handle smaller data type like unsigned int, of cause min and max should be defined in range of unsigned int too. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/md/bcache/sysfs.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h index 0526fe92a683..e7a3c12aa66f 100644 --- a/drivers/md/bcache/sysfs.h +++ b/drivers/md/bcache/sysfs.h @@ -80,9 +80,16 @@ do { \ #define sysfs_strtoul_clamp(file, var, min, max) \ do { \ - if (attr == &sysfs_ ## file) \ - return strtoul_safe_clamp(buf, var, min, max) \ - ?: (ssize_t) size; \ + if (attr == &sysfs_ ## file) { \ + unsigned long v = 0; \ + ssize_t ret; \ + ret = strtoul_safe_clamp(buf, v, min, max); \ + if (!ret) { \ + var = v; \ + return size; \ + } \ + return ret; \ + } \ } while (0) #define strtoul_or_return(cp) \ -- 2.19.1