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=unavailable 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 1A18CC43381 for ; Wed, 27 Mar 2019 19:23:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD68E206C0 for ; Wed, 27 Mar 2019 19:23:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553714581; bh=PYJunr7DZonYf/OZbjaiM+S8S8YjIl8g6WUtZd3wjXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QfzIoeNKnMHewEGOOrHCchFt8p1x5vHOn0cCV0pFrgC9R87w1FRRp9Us3zeRpO6Dj eLsdKrIZcz9T4RWfZRI4UPWUnF5WvRLlH5flneig1v8SJ3vvkx8Rueo2yXowbN1/d4 uqTK9V8kHAMjxywu0hkpiw0idNUQrL1Z7wMbfkG4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728301AbfC0TXB (ORCPT ); Wed, 27 Mar 2019 15:23:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:48908 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388086AbfC0SHG (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 9B7F721850; Wed, 27 Mar 2019 18:07:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710025; bh=PYJunr7DZonYf/OZbjaiM+S8S8YjIl8g6WUtZd3wjXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uBJfKnAEUdTUJVhUU9SSa6U2UqUSS9dETjBNpBW4SCCCUY6wo+mLxwHXKh9dcMTsw o9bwc90cvsKX7hjGN3pM04eUG/7eW792mQc4xC5Podb8rN+ronIHJu0i96tpG9G3ch 2FrV7ovPmIKGG5Qn5LxmNV/BIiz/0NEqg1BKoiWM= 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 5.0 162/262] bcache: fix potential div-zero error of writeback_rate_i_term_inverse Date: Wed, 27 Mar 2019 14:00:17 -0400 Message-Id: <20190327180158.10245-162-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 c3b75a2199cdbfc1c335155fe143d842604b1baa ] dc->writeback_rate_i_term_inverse can be set via sysfs interface. It is in type unsigned int, and convert from input string by d_strtoul(). The problem is d_strtoul() does not check valid range of the input, if 4294967296 is written into sysfs file writeback_rate_i_term_inverse, an overflow of unsigned integer will happen and value 0 is set to dc->writeback_rate_i_term_inverse. In writeback.c:__update_writeback_rate(), there are following lines of code, integral_scaled = div_s64(dc->writeback_rate_integral, dc->writeback_rate_i_term_inverse); If dc->writeback_rate_i_term_inverse is set to 0 via sysfs interface, a div-zero error might be triggered in the above code. Therefore we need to add a range limitation in the sysfs interface, this is what this patch does, use sysfs_stroul_clamp() to replace d_strtoul() and restrict the input range in [1, UINT_MAX]. Signed-off-by: Coly Li Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/md/bcache/sysfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index f98cda32065d..28e0d5a5e25b 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -287,7 +287,9 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_rate_update_seconds, dc->writeback_rate_update_seconds, 1, WRITEBACK_RATE_UPDATE_SECS_MAX); - d_strtoul(writeback_rate_i_term_inverse); + sysfs_strtoul_clamp(writeback_rate_i_term_inverse, + dc->writeback_rate_i_term_inverse, + 1, UINT_MAX); d_strtoul_nonzero(writeback_rate_p_term_inverse); d_strtoul_nonzero(writeback_rate_minimum); -- 2.19.1