From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: [PATCH] can: af_can: Fix Spectre v1 vulnerability Date: Fri, 21 Dec 2018 15:22:29 -0600 Message-ID: <20181221212229.GA32635@embeddedor> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" To: Oliver Hartkopp , Marc Kleine-Budde , "David S. Miller" Return-path: Received: from gateway22.websitewelcome.com ([192.185.47.129]:41283 "EHLO gateway22.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729293AbeLUVme (ORCPT ); Fri, 21 Dec 2018 16:42:34 -0500 Received: from cm10.websitewelcome.com (cm10.websitewelcome.com [100.42.49.4]) by gateway22.websitewelcome.com (Postfix) with ESMTP id 07E5720D5A for ; Fri, 21 Dec 2018 15:22:30 -0600 (CST) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: protocol 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: net/can/af_can.c:115 can_get_proto() warn: potential spectre issue 'proto_tab' [w] Fix this by sanitizing protocol before using it to index proto_tab. 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 Signed-off-by: Gustavo A. R. Silva --- net/can/af_can.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/can/af_can.c b/net/can/af_can.c index 1684ba5b51eb..cade7250c6d4 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -59,6 +59,7 @@ #include #include #include +#include #include #include @@ -136,6 +137,7 @@ static int can_create(struct net *net, struct socket *sock, int protocol, if (protocol < 0 || protocol >= CAN_NPROTO) return -EINVAL; + protocol = array_index_nospec(protocol, CAN_NPROTO); cp = can_get_proto(protocol); -- 2.20.1