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=HEADER_FROM_DIFFERENT_DOMAINS, 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 D1A8DC43381 for ; Thu, 21 Mar 2019 00:03:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A45F8218D4 for ; Thu, 21 Mar 2019 00:03:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727707AbfCUADm (ORCPT ); Wed, 20 Mar 2019 20:03:42 -0400 Received: from gateway34.websitewelcome.com ([192.185.148.200]:45862 "EHLO gateway34.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbfCUADm (ORCPT ); Wed, 20 Mar 2019 20:03:42 -0400 Received: from cm11.websitewelcome.com (cm11.websitewelcome.com [100.42.49.5]) by gateway34.websitewelcome.com (Postfix) with ESMTP id 3F6B01116C61 for ; Wed, 20 Mar 2019 18:42:05 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 6kqThYPoednCe6kqThQPQL; Wed, 20 Mar 2019 18:42:05 -0500 X-Authority-Reason: nr=8 Received: from [189.250.100.204] (port=43236 helo=embeddedor) by gator4166.hostgator.com with esmtpa (Exim 4.91) (envelope-from ) id 1h6kqS-001BBG-AJ; Wed, 20 Mar 2019 18:42:04 -0500 Date: Wed, 20 Mar 2019 18:42:01 -0500 From: "Gustavo A. R. Silva" To: Jaroslav Kysela , Takashi Iwai Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] ALSA: seq: oss: Fix Spectre v1 vulnerability Message-ID: <20190320234201.GA24574@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: 189.250.100.204 X-Source-L: No X-Exim-ID: 1h6kqS-001BBG-AJ X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: (embeddedor) [189.250.100.204]:43236 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 12 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 dev 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/core/seq/oss/seq_oss_synth.c:626 snd_seq_oss_synth_make_info() warn: potential spectre issue 'dp->synths' [w] (local cap) Fix this by sanitizing dev before using it to index dp->synths. 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://lore.kernel.org/lkml/20180423164740.GY17484@dhcp22.suse.cz/ Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva --- sound/core/seq/oss/seq_oss_synth.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/sound/core/seq/oss/seq_oss_synth.c b/sound/core/seq/oss/seq_oss_synth.c index 278ebb993122..c93945917235 100644 --- a/sound/core/seq/oss/seq_oss_synth.c +++ b/sound/core/seq/oss/seq_oss_synth.c @@ -617,13 +617,14 @@ int snd_seq_oss_synth_make_info(struct seq_oss_devinfo *dp, int dev, struct synth_info *inf) { struct seq_oss_synth *rec; + struct seq_oss_synthinfo *info = get_synthinfo_nospec(dp, dev); - if (dev < 0 || dev >= dp->max_synthdev) + if (!info) return -ENXIO; - if (dp->synths[dev].is_midi) { + if (info->is_midi) { struct midi_info minf; - snd_seq_oss_midi_make_info(dp, dp->synths[dev].midi_mapped, &minf); + snd_seq_oss_midi_make_info(dp, info->midi_mapped, &minf); inf->synth_type = SYNTH_TYPE_MIDI; inf->synth_subtype = 0; inf->nr_voices = 16; -- 2.21.0