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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D7CF4C2D0D1 for ; Sun, 29 Dec 2019 18:11:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8134206A4 for ; Sun, 29 Dec 2019 18:11:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577643092; bh=J011jsk8+8CVo/CuBSlInnxf+uzT+GCmNPqICo3oCT8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Jik3oDzF0SFS/T3+swGy+l0br+ezy10i4Zx4wTxm1IeQLVxdeIkLMHdLgSdMNQeZ0 jozRXcLBN9xckLsEINA8QXAC8q+l2AQbtFZHAEsrWOJundwlz+wMxEJkhIyzxNjg1S /fse1jd/PfRcw37V/zGkJwztlcMecZYnGF/+iLdg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730408AbfL2RnC (ORCPT ); Sun, 29 Dec 2019 12:43:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:49692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729136AbfL2Rmz (ORCPT ); Sun, 29 Dec 2019 12:42:55 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8B1F620718; Sun, 29 Dec 2019 17:42:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577641375; bh=J011jsk8+8CVo/CuBSlInnxf+uzT+GCmNPqICo3oCT8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NwG7/hEPlb3DAiDNiboaPAISkhEcYImA1VnDaWJceOAABKXIGbmVEGNmSlKeVTo1w q4enMdgruwaIS7U86wS6AD6KL2DL7KD1+RPy85zyV+OzWr2NRkG1CUKMBS5mFQ/f7p jae581v9qTPaC9Aj3T1kMBIWHlAFPL4x45ULLs18= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lionel Koenig , Takashi Iwai Subject: [PATCH 5.4 039/434] ALSA: pcm: Avoid possible info leaks from PCM stream buffers Date: Sun, 29 Dec 2019 18:21:32 +0100 Message-Id: <20191229172704.633648787@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229172702.393141737@linuxfoundation.org> References: <20191229172702.393141737@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai commit add9d56d7b3781532208afbff5509d7382fb6efe upstream. The current PCM code doesn't initialize explicitly the buffers allocated for PCM streams, hence it might leak some uninitialized kernel data or previous stream contents by mmapping or reading the buffer before actually starting the stream. Since this is a common problem, this patch simply adds the clearance of the buffer data at hw_params callback. Although this does only zero-clear no matter which format is used, which doesn't mean the silence for some formats, but it should be OK because the intention is just to clear the previous data on the buffer. Reported-by: Lionel Koenig Cc: Link: https://lore.kernel.org/r/20191211155742.3213-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/pcm_native.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -705,6 +705,10 @@ static int snd_pcm_hw_params(struct snd_ while (runtime->boundary * 2 <= LONG_MAX - runtime->buffer_size) runtime->boundary *= 2; + /* clear the buffer for avoiding possible kernel info leaks */ + if (runtime->dma_area && !substream->ops->copy_user) + memset(runtime->dma_area, 0, runtime->dma_bytes); + snd_pcm_timer_resolution_change(substream); snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);