From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753239AbeEUQ5Z (ORCPT ); Mon, 21 May 2018 12:57:25 -0400 Received: from gateway21.websitewelcome.com ([192.185.45.133]:35588 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753130AbeEUQ5U (ORCPT ); Mon, 21 May 2018 12:57:20 -0400 X-Authority-Reason: nr=8 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-Type: text/plain; charset=us-ascii 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: 9 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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; } -- 2.7.4