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, 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 538CDC43381 for ; Wed, 27 Mar 2019 18:49:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26AE62075C for ; Wed, 27 Mar 2019 18:49:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553712556; bh=GmGb6Kl/aGeLec3dyl0GJleY+yGp3N92Tacy0II4kak=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=V8MJoaGwdfWzLSfitc/VxOHgAsjCW5ZTpJXcWbwHELfiWKyv9J71HpRvMWVcwgutS /tVpEPuooabcQXC2Rucy4LXlmpi9Z0WmuCYe9XLh7tOJ3p2KQGlbeZnPn6b3+Ym+sY 5OHku8RX7oBRMWbrJxUH9EDzdyNSpysc7Jp+Mg38= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391004AbfC0StO (ORCPT ); Wed, 27 Mar 2019 14:49:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:35988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390604AbfC0SSv (ORCPT ); Wed, 27 Mar 2019 14:18:51 -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 36FBC217F5; Wed, 27 Mar 2019 18:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710730; bh=GmGb6Kl/aGeLec3dyl0GJleY+yGp3N92Tacy0II4kak=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RruMriryxy64D/jXvR8kVIvsXUp4iOvQpAWAqz5FhhYe9sS+rIJlFziVZ/HI7f7qU 4Q7iDOQrTwuz/Fxc7bu68awNpjmhp90yG4lG6aQoTT2atPwXLNJa1mlBEQpIZ1L6M1 OVB55ZkG0Td78OG7WeOmr34goW70h2LPJvS/PedQ= 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 4.14 077/123] bcache: improve sysfs_strtoul_clamp() Date: Wed, 27 Mar 2019 14:15:41 -0400 Message-Id: <20190327181628.15899-77-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327181628.15899-1-sashal@kernel.org> References: <20190327181628.15899-1-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 b54fe9602529..e6e258f897ca 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