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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 34052C10F0E for ; Mon, 15 Apr 2019 22:34:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E88C020818 for ; Mon, 15 Apr 2019 22:34:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728005AbfDOWe2 (ORCPT ); Mon, 15 Apr 2019 18:34:28 -0400 Received: from mx2.suse.de ([195.135.220.15]:54328 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726085AbfDOWe2 (ORCPT ); Mon, 15 Apr 2019 18:34:28 -0400 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 04E71AD05; Mon, 15 Apr 2019 22:34:25 +0000 (UTC) Date: Tue, 16 Apr 2019 00:34:25 +0200 Message-ID: From: Takashi Iwai To: " Gustavo A. R. Silva " Cc: "Jaroslav Kysela" , , Subject: Re: [PATCH] ALSA: isa/wavefront: Fix potential Spectre v1 vulnerabilities In-Reply-To: <52a533e5-f106-db5f-35f7-2dd85672f541@embeddedor.com> References: <20190326183202.GA17285@embeddedor> <52a533e5-f106-db5f-35f7-2dd85672f541@embeddedor.com> 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/25.3 (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 Mon, 15 Apr 2019 21:35:17 +0200, Gustavo A. R. Silva wrote: > > Hi all, > > Friendly ping: > > Who can take this? All platforms that support ISA boards are so old and they don't suffer from Spectre at all. thanks, Takashi > > Thanks > -- > Gustavo > > On 3/26/19 1:32 PM, Gustavo A. R. Silva wrote: > > header->number and i are 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/isa/wavefront/wavefront_synth.c:792 wavefront_send_patch() warn: potential spectre issue 'dev->patch_status' [w] (local cap) > > sound/isa/wavefront/wavefront_synth.c:819 wavefront_send_program() warn: potential spectre issue 'dev->prog_status' [w] (local cap) > > sound/isa/wavefront/wavefront_synth.c:1197 wavefront_send_alias() warn: potential spectre issue 'dev->sample_status' [w] > > sound/isa/wavefront/wavefront_synth.c:1248 wavefront_send_multisample() warn: potential spectre issue 'dev->sample_status' [w] > > sound/isa/wavefront/wavefront_synth.c:1548 wavefront_synth_control() warn: potential spectre issue 'dev->sample_status' [r] (local cap) > > > > Fix this by sanitizing header->number and i before using them to index > > dev->patch_status, dev->prog_status, dev->sample_status. > > > > 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/isa/wavefront/wavefront_synth.c | 17 +++++++++++++++++ > > 1 file changed, 17 insertions(+) > > > > diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c > > index 0b1e4b34b299..a78e125dfdf9 100644 > > --- a/sound/isa/wavefront/wavefront_synth.c > > +++ b/sound/isa/wavefront/wavefront_synth.c > > @@ -31,6 +31,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -788,6 +789,8 @@ wavefront_send_patch (snd_wavefront_t *dev, wavefront_patch_info *header) > > > > if (header->number >= ARRAY_SIZE(dev->patch_status)) > > return -EINVAL; > > + header->number = array_index_nospec(header->number, > > + ARRAY_SIZE(dev->patch_status)); > > > > dev->patch_status[header->number] |= WF_SLOT_FILLED; > > > > @@ -815,6 +818,8 @@ wavefront_send_program (snd_wavefront_t *dev, wavefront_patch_info *header) > > > > if (header->number >= ARRAY_SIZE(dev->prog_status)) > > return -EINVAL; > > + header->number = array_index_nospec(header->number, > > + ARRAY_SIZE(dev->prog_status)); > > > > dev->prog_status[header->number] = WF_SLOT_USED; > > > > @@ -1194,6 +1199,11 @@ wavefront_send_alias (snd_wavefront_t *dev, wavefront_patch_info *header) > > return -EIO; > > } > > > > + if (header->number >= ARRAY_SIZE(dev->sample_status)) > > + return -EINVAL; > > + header->number = array_index_nospec(header->number, > > + ARRAY_SIZE(dev->sample_status)); > > + > > dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_ALIAS); > > > > return (0); > > @@ -1245,6 +1255,12 @@ wavefront_send_multisample (snd_wavefront_t *dev, wavefront_patch_info *header) > > return -EIO; > > } > > > > + if (header->number >= ARRAY_SIZE(dev->sample_status)) { > > + kfree(msample_hdr); > > + return -EINVAL; > > + } > > + header->number = array_index_nospec(header->number, > > + ARRAY_SIZE(dev->sample_status)); > > dev->sample_status[header->number] = (WF_SLOT_FILLED|WF_ST_MULTISAMPLE); > > > > kfree(msample_hdr); > > @@ -1545,6 +1561,7 @@ wavefront_synth_control (snd_wavefront_card_t *acard, > > wc->status = EINVAL; > > return -EINVAL; > > } > > + i = array_index_nospec(i, WF_MAX_SAMPLE); > > wc->rbuf[0] = dev->sample_status[i]; > > wc->status = 0; > > return 0; > > >