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=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 6DFFBC43387 for ; Fri, 21 Dec 2018 21:41:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F0D421920 for ; Fri, 21 Dec 2018 21:41:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390610AbeLUVlV (ORCPT ); Fri, 21 Dec 2018 16:41:21 -0500 Received: from gateway21.websitewelcome.com ([192.185.45.2]:35457 "EHLO gateway21.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388574AbeLUVlU (ORCPT ); Fri, 21 Dec 2018 16:41:20 -0500 Received: from cm10.websitewelcome.com (cm10.websitewelcome.com [100.42.49.4]) by gateway21.websitewelcome.com (Postfix) with ESMTP id AE33A400C452F for ; Fri, 21 Dec 2018 15:41:19 -0600 (CST) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id aSXngsjiw2PzOaSXngcMne; Fri, 21 Dec 2018 15:41:19 -0600 X-Authority-Reason: nr=8 Received: from [189.250.106.44] (port=35208 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1gaSXn-000bw3-27; Fri, 21 Dec 2018 15:41:19 -0600 Date: Fri, 21 Dec 2018 15:41:17 -0600 From: "Gustavo A. R. Silva" To: Remi Denis-Courmont , "David S. Miller" Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] phonet: af_phonet: Fix Spectre v1 vulnerability Message-ID: <20181221214117.GA1539@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: 189.250.106.44 X-Source-L: No X-Exim-ID: 1gaSXn-000bw3-27 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.106.44]:35208 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 10 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 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/phonet/af_phonet.c:48 phonet_proto_get() warn: potential spectre issue 'proto_tab' [w] (local cap) 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/phonet/af_phonet.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c index 3b0ef691f5b1..d4b2abd78858 100644 --- a/net/phonet/af_phonet.c +++ b/net/phonet/af_phonet.c @@ -34,6 +34,8 @@ #include #include +#include + /* Transport protocol registration */ static const struct phonet_protocol *proto_tab[PHONET_NPROTO] __read_mostly; @@ -43,6 +45,7 @@ static const struct phonet_protocol *phonet_proto_get(unsigned int protocol) if (protocol >= PHONET_NPROTO) return NULL; + protocol = array_index_nospec(protocol, PHONET_NPROTO); rcu_read_lock(); pp = rcu_dereference(proto_tab[protocol]); -- 2.20.1