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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED 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 9B3DAC43387 for ; Sun, 23 Dec 2018 19:14:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD223217D7 for ; Sun, 23 Dec 2018 19:14:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b="pbGyShBE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725839AbeLWTOd (ORCPT ); Sun, 23 Dec 2018 14:14:33 -0500 Received: from mo4-p00-ob.smtp.rzone.de ([85.215.255.25]:18928 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725308AbeLWTOc (ORCPT ); Sun, 23 Dec 2018 14:14:32 -0500 X-Greylist: delayed 538 seconds by postgrey-1.27 at vger.kernel.org; Sun, 23 Dec 2018 14:14:31 EST DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1545592470; s=strato-dkim-0002; d=hartkopp.net; h=In-Reply-To:Date:Message-ID:From:References:Cc:To:Subject: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=E8sMHdpZ56bdbaNqESoFKn20Q1s8hoTdAcM2MB+qsRo=; b=pbGyShBEluBSCnavpXuHnB6h+XQhfX4k5LWb3gzzS/L9cgVvQmmatR0KJeHLWRQAZy LJ4Xzn+1C0NKBIlh6xg58+zBisd02XgMynKrIrx8J+VZND6p3aTSTTi1BX7QKovirkM4 WoeKe6+zxtUhJLNahvI4lQCm+dLQKxdjvnVk+8gSuaMd//9eldJdQTyAjedNoor7OKY9 cbtUgENskSft7BFxOCDKeArITS7tG47O8tVBVRYvU/G+IzsyIX1jtpAhuNcrGayFckgX hi5g9SOweBuCvh9/nw/zwSIS2EaPLoAcgsy9ne7Yam0f9f+z7giQ39lh6biRp71qeY9t zEQg== X-RZG-AUTH: ":P2MHfkW8eP4Mre39l357AZT/I7AY/7nT2yrDxb8mjG14FZxedJy6qgO1q3DbdV+MXxxxQl9RzJU=" X-RZG-CLASS-ID: mo00 Received: from [172.20.10.3] by smtp.strato.de (RZmta 44.8 DYNA|AUTH) with ESMTPSA id L0b8b9uBNJ2PHSq (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate); Sun, 23 Dec 2018 20:02:25 +0100 (CET) Subject: Re: [PATCH] can: af_can: Fix Spectre v1 vulnerability To: "Gustavo A. R. Silva" , Marc Kleine-Budde , "David S. Miller" Cc: linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20181221212229.GA32635@embeddedor> From: Oliver Hartkopp Message-ID: Date: Sun, 23 Dec 2018 20:02:18 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20181221212229.GA32635@embeddedor> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After *trying* to follow the discussion on ... https://marc.info/?l=linux-kernel&m=154554485324143&w=2 [PATCH] net: core: Fix Spectre v1 vulnerability ... I'm still not sure whether af_can.c needs this enhancement or not. Just waiting for the end of the discussion :-) Thanks to the experts! Oliver On 12/21/18 10:22 PM, Gustavo A. R. Silva wrote: > 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); > >