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 4D9E3C43381 for ; Wed, 27 Mar 2019 19:02:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20F1C206B7 for ; Wed, 27 Mar 2019 19:02:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553713343; bh=+UVlh/mmCwZPFjknKpC3gc1db+dbUUC4PwzYWi+3frs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RgWooPSfGWbYubKD8EM+Trin05kxN8iirZJPKW1vVUl6dgBq+pAJnKTiKhztJ+kl9 tmxqZ4CXC2PVRFZAlXwbgHBxtereyDedbGP/xBWr6dh0bI5sBAM3cbu672Zt/Zag5S qwhlQpE/FR1idYBCg7/owsHVXjugszpTKN6CvqRA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389760AbfC0TCV (ORCPT ); Wed, 27 Mar 2019 15:02:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:56636 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389505AbfC0SNt (ORCPT ); Wed, 27 Mar 2019 14:13:49 -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 617D6217F9; Wed, 27 Mar 2019 18:13:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553710429; bh=+UVlh/mmCwZPFjknKpC3gc1db+dbUUC4PwzYWi+3frs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sWC8fDicGVC+rIBiFSDHBtfdb9H9QGvOQLTUQgzEDwIbUJO2YiR3lJ+nRmEEeVoPj QFzJCiOt4a42RfkoYyRGMh4l7ipXsnPxRTBD3ZR0f2qBnsWbOIKooI44869f2iafsh +eyst80kvesVexoHrk3+bJx/HTGlF14hUaYDVSow= 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 4.19 115/192] bcache: fix potential div-zero error of writeback_rate_i_term_inverse Date: Wed, 27 Mar 2019 14:09:07 -0400 Message-Id: <20190327181025.13507-115-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190327181025.13507-1-sashal@kernel.org> References: <20190327181025.13507-1-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 01c7c4452a26..503ad954ccc0 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -283,7 +283,9 @@ 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