From patchwork Mon May 21 16:57:17 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: 10416131 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 9A0C66053B for ; Mon, 21 May 2018 17:45:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 82E5B28484 for ; Mon, 21 May 2018 17:45:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 76E7A289A2; Mon, 21 May 2018 17:45:51 +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=unavailable 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 1C75C28484 for ; Mon, 21 May 2018 17:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753212AbeEURpu (ORCPT ); Mon, 21 May 2018 13:45:50 -0400 Received: from gateway20.websitewelcome.com ([192.185.55.25]:19068 "EHLO gateway20.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753097AbeEURpt (ORCPT ); Mon, 21 May 2018 13:45:49 -0400 X-Greylist: delayed 1500 seconds by postgrey-1.27 at vger.kernel.org; Mon, 21 May 2018 13:45:49 EDT Received: from cm10.websitewelcome.com (cm10.websitewelcome.com [100.42.49.4]) by gateway20.websitewelcome.com (Postfix) with ESMTP id 3F7F1400F061B for ; Mon, 21 May 2018 11:57:19 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id Ko7bfX2EpBcCXKo7bfRsvW; Mon, 21 May 2018 11:57:19 -0500 X-Authority-Reason: nr=8 Received: from [187.192.46.223] (port=55076 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.89_1) (envelope-from ) id 1fKo7a-0001ft-Oj; Mon, 21 May 2018 11:57:18 -0500 Date: Mon, 21 May 2018 11:57:17 -0500 From: "Gustavo A. R. Silva" To: Hans Verkuil , Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] media: si470x: fix potential Spectre variant 1 Message-ID: <20180521165717.GA9167@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: 187.192.46.223 X-Source-L: No X-Exim-ID: 1fKo7a-0001ft-Oj X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [187.192.46.223]:55076 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 8 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP band->index can be 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/media/radio/si470x/radio-si470x-common.c:758 si470x_vidioc_enum_freq_bands() warn: potential spectre issue 'bands' Fix this by sanitizing band->index before using it to index `bands' 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/media/radio/si470x/radio-si470x-common.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/media/radio/si470x/radio-si470x-common.c b/drivers/media/radio/si470x/radio-si470x-common.c index c40e175..e81f9aa 100644 --- a/drivers/media/radio/si470x/radio-si470x-common.c +++ b/drivers/media/radio/si470x/radio-si470x-common.c @@ -110,6 +110,10 @@ /* kernel includes */ #include "radio-si470x.h" +/* Hardening for Spectre-v1 */ +#include + + /************************************************************************** * Module Parameters **************************************************************************/ @@ -755,7 +759,7 @@ static int si470x_vidioc_enum_freq_bands(struct file *file, void *priv, return -EINVAL; if (band->index >= ARRAY_SIZE(bands)) return -EINVAL; - *band = bands[band->index]; + *band = bands[array_index_nospec(band->index, ARRAY_SIZE(bands))]; return 0; }