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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, 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 54FC7C43381 for ; Wed, 27 Mar 2019 19:21:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23F6521734 for ; Wed, 27 Mar 2019 19:21:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553714462; bh=tY6m4gMFrbq290y8iLZ6xF/E/AavLNKoa550KMQGXfM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=j2BEaWZomubZBk8xuCt4v8iHoRgvF/K4jUEntVEkqnIbI2EjxOo+yQvlVLzDbF+Wt TdgGMN+2j5MDh7pMj4rZ3Moc5jccHgRotXQ+zhSyO2c4hkLptYZ1CaysUzi8jyW76s rRTcFf4N79LO7mXk9w0mswaNtmToBrDHhjuKrjTI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388813AbfC0TVA (ORCPT ); Wed, 27 Mar 2019 15:21:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:48934 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388089AbfC0SHG (ORCPT ); Wed, 27 Mar 2019 14:07:06 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AC2A12183F; Wed, 27 Mar 2019 18:07:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710026; bh=tY6m4gMFrbq290y8iLZ6xF/E/AavLNKoa550KMQGXfM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pII9+LTrObQaGbko5geEVCOYHzyhCup7ud5XkbcoIzchE2NoZhbb2+iCtRY4EqgyC 08mpIIzwtkW3vODWad8x0qxVdzvTIgUCMIy2wCbrCT8nmEBSICEjUxdZm1nKpngkd5 hqum8jyiV328rSJNnx8PJSUhNWa3DkzuuH3TWZfQ= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Coly Li , Jens Axboe , Sasha Levin , linux-bcache@vger.kernel.org Subject: [PATCH AUTOSEL 5.0 163/262] bcache: improve sysfs_strtoul_clamp() Date: Wed, 27 Mar 2019 14:00:18 -0400 Message-Id: <20190327180158.10245-163-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327180158.10245-1-sashal@kernel.org> References: <20190327180158.10245-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Coly Li [ 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 3fe82425859c..0ad2715a884e 100644 --- a/drivers/md/bcache/sysfs.h +++ b/drivers/md/bcache/sysfs.h @@ -81,9 +81,16 @@ 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