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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 178CCC43387 for ; Wed, 9 Jan 2019 19:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E614020859 for ; Wed, 9 Jan 2019 19:02:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728100AbfAITCn (ORCPT ); Wed, 9 Jan 2019 14:02:43 -0500 Received: from gateway21.websitewelcome.com ([192.185.45.210]:40501 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726469AbfAITCm (ORCPT ); Wed, 9 Jan 2019 14:02:42 -0500 Received: from cm11.websitewelcome.com (cm11.websitewelcome.com [100.42.49.5]) by gateway21.websitewelcome.com (Postfix) with ESMTP id D9929400D6ABC for ; Wed, 9 Jan 2019 13:02:41 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id hJ7hgAmU7dnCehJ7hgGZnV; Wed, 09 Jan 2019 13:02:41 -0600 X-Authority-Reason: nr=8 Received: from [189.250.130.205] (port=45770 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1ghJ7g-000MPi-KO; Wed, 09 Jan 2019 13:02:41 -0600 Date: Wed, 9 Jan 2019 13:02:36 -0600 From: "Gustavo A. R. Silva" To: Arnd Bergmann , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] char/mwave: fix potential Spectre v1 vulnerability Message-ID: <20190109190236.GA19068@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) 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: 189.250.130.205 X-Source-L: No X-Exim-ID: 1ghJ7g-000MPi-KO X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.130.205]:45770 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ipcnum is 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: drivers/char/mwave/mwavedd.c:299 mwave_ioctl() warn: potential spectre issue 'pDrvData->IPCs' [w] (local cap) Fix this by sanitizing ipcnum before using it to index pDrvData->IPCs. 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/char/mwave/mwavedd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/char/mwave/mwavedd.c b/drivers/char/mwave/mwavedd.c index b5e3103c1175..e43c876a9223 100644 --- a/drivers/char/mwave/mwavedd.c +++ b/drivers/char/mwave/mwavedd.c @@ -59,6 +59,7 @@ #include #include #include +#include #include "smapi.h" #include "mwavedd.h" #include "3780i.h" @@ -289,6 +290,8 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd, ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); PRINTK_3(TRACE_MWAVE, "mwavedd::mwave_ioctl IOCTL_MW_REGISTER_IPC" " ipcnum %x entry usIntCount %x\n", @@ -317,6 +320,8 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd, " Invalid ipcnum %x\n", ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); PRINTK_3(TRACE_MWAVE, "mwavedd::mwave_ioctl IOCTL_MW_GET_IPC" " ipcnum %x, usIntCount %x\n", @@ -383,6 +388,8 @@ static long mwave_ioctl(struct file *file, unsigned int iocmd, ipcnum); return -EINVAL; } + ipcnum = array_index_nospec(ipcnum, + ARRAY_SIZE(pDrvData->IPCs)); mutex_lock(&mwave_mutex); if (pDrvData->IPCs[ipcnum].bIsEnabled == true) { pDrvData->IPCs[ipcnum].bIsEnabled = false; -- 2.20.1