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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 C03F0C43387 for ; Wed, 19 Dec 2018 13:37:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D6FD21841 for ; Wed, 19 Dec 2018 13:37:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728967AbeLSNh0 (ORCPT ); Wed, 19 Dec 2018 08:37:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:56726 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726833AbeLSNh0 (ORCPT ); Wed, 19 Dec 2018 08:37:26 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6052CACC6; Wed, 19 Dec 2018 13:37:24 +0000 (UTC) Date: Wed, 19 Dec 2018 14:37:23 +0100 Message-ID: From: Takashi Iwai To: " Gustavo A. R. Silva " Cc: "Jaroslav Kysela" , , Subject: Re: [PATCH] ALSA: rme9652: Fix potential Spectre v1 vulnerability In-Reply-To: <20181218171834.GA14211@embeddedor> References: <20181218171834.GA14211@embeddedor> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/26 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 18 Dec 2018 18:18:34 +0100, Gustavo A. R. Silva wrote: > > info->channel 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: > > sound/pci/rme9652/hdsp.c:4100 snd_hdsp_channel_info() warn: potential spectre issue 'hdsp->channel_map' [r] (local cap) > > Fix this by sanitizing info->channel before using it to index hdsp->channel_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]. > > Also, notice that I refactored the code a bit in order to get rid of the > following checkpatch warning: > > ERROR: do not use assignment in if condition > FILE: sound/pci/rme9652/hdsp.c:4103: > if ((mapped_channel = hdsp->channel_map[info->channel]) < 0) > > > [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 > > Cc: stable@vger.kernel.org > Signed-off-by: Gustavo A. R. Silva Applied, thanks. Takashi