From patchwork Wed Aug 15 13:14:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 10566581 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 19156139A for ; Wed, 15 Aug 2018 13:35:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 004DF285D9 for ; Wed, 15 Aug 2018 13:35:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E49992890A; Wed, 15 Aug 2018 13:35:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6E8AD285D9 for ; Wed, 15 Aug 2018 13:35:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729264AbeHOQ1u (ORCPT ); Wed, 15 Aug 2018 12:27:50 -0400 Received: from gateway22.websitewelcome.com ([192.185.47.168]:46217 "EHLO gateway22.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729128AbeHOQ1u (ORCPT ); Wed, 15 Aug 2018 12:27:50 -0400 X-Greylist: delayed 1230 seconds by postgrey-1.27 at vger.kernel.org; Wed, 15 Aug 2018 12:27:50 EDT Received: from cm15.websitewelcome.com (cm15.websitewelcome.com [100.42.49.9]) by gateway22.websitewelcome.com (Postfix) with ESMTP id A4EA645867 for ; Wed, 15 Aug 2018 08:15:12 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id pvdIfcSbqbXuJpvdZf0CFX; Wed, 15 Aug 2018 08:15:11 -0500 X-Authority-Reason: nr=8 Received: from [189.250.37.72] (port=56832 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1fpvdH-001imY-55; Wed, 15 Aug 2018 08:14:39 -0500 Date: Wed, 15 Aug 2018 08:14:37 -0500 From: "Gustavo A. R. Silva" To: Guenter Roeck , Jean Delvare Cc: linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] hwmon: (nct6775) Fix potential Spectre v1 Message-ID: <20180815131437.GA25639@embeddedor.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.250.37.72 X-Source-L: No X-Exim-ID: 1fpvdH-001imY-55 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.37.72]:56832 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP val can be indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: vers/hwmon/nct6775.c:2698 store_pwm_weight_temp_sel() warn: potential spectre issue 'data->temp_src' [r] Fix this by sanitizing val before using it to index data->temp_src Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva --- drivers/hwmon/nct6775.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/hwmon/nct6775.c b/drivers/hwmon/nct6775.c index c6bd61e..944f5b6 100644 --- a/drivers/hwmon/nct6775.c +++ b/drivers/hwmon/nct6775.c @@ -63,6 +63,7 @@ #include #include #include +#include #include "lm75.h" #define USE_ALTERNATE @@ -2689,6 +2690,7 @@ store_pwm_weight_temp_sel(struct device *dev, struct device_attribute *attr, return err; if (val > NUM_TEMP) return -EINVAL; + val = array_index_nospec(val, NUM_TEMP + 1); if (val && (!(data->have_temp & BIT(val - 1)) || !data->temp_src[val - 1])) return -EINVAL;