From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:55858 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729919AbeIXSSx (ORCPT ); Mon, 24 Sep 2018 14:18:53 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH 4.14 083/173] misc: hmc6352: fix potential Spectre v1 Date: Mon, 24 Sep 2018 13:51:57 +0200 Message-Id: <20180924113122.169647464@linuxfoundation.org> In-Reply-To: <20180924113114.334025954@linuxfoundation.org> References: <20180924113114.334025954@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo A. R. Silva commit de916736aaaadddbd6061472969f667b14204aa9 upstream. val 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/misc/hmc6352.c:54 compass_store() warn: potential spectre issue 'map' [r] Fix this by sanitizing val before using it to index map 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 Signed-off-by: Greg Kroah-Hartman --- drivers/misc/hmc6352.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/misc/hmc6352.c +++ b/drivers/misc/hmc6352.c @@ -27,6 +27,7 @@ #include #include #include +#include static DEFINE_MUTEX(compass_mutex); @@ -50,6 +51,7 @@ static int compass_store(struct device * return ret; if (val >= strlen(map)) return -EINVAL; + val = array_index_nospec(val, strlen(map)); mutex_lock(&compass_mutex); ret = compass_command(c, map[val]); mutex_unlock(&compass_mutex);