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=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 719D4C3276C for ; Thu, 2 Jan 2020 22:27:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4763120863 for ; Thu, 2 Jan 2020 22:27:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004045; bh=wQT4xWXNIzsEabQI1mSrwFFkt4xowQeeU7x6mRr+IQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Aupz1tzN5SVah9CcoExHcgK3lIvJs+9xUgJkL5ZG/AeO/CsRd2rM6A6apSpYsAkcG FQNMiaYVYxCTr4gfPG46DwxGJOEWdfwzvbS0w91LITGMi7ospi1RiKlhMwkWetIRW/ pHDuDDjxozD4Jik/yegUT34tYYHesDtaM1uPNQ6s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727922AbgABW1Y (ORCPT ); Thu, 2 Jan 2020 17:27:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:55650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729291AbgABW1V (ORCPT ); Thu, 2 Jan 2020 17:27:21 -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 8F91E20863; Thu, 2 Jan 2020 22:27:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578004041; bh=wQT4xWXNIzsEabQI1mSrwFFkt4xowQeeU7x6mRr+IQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zYzUHfOhb3qRe6z+avFrsVJvUe+s8Vgee1eTxOuwW1+1MXrcdef8HoKHiGC+B3V48 awP8niVAcVL8ypFv6F1USw7dEQX2j5rEfrWk0VcSQ32QEwSi69njbi1xwh2OoVECkG R/JL0JL2J4EqYOeKS5JVlvUjy98B0PCYRT8PVX5E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lionel Koenig , Takashi Iwai Subject: [PATCH 4.9 004/171] ALSA: pcm: Avoid possible info leaks from PCM stream buffers Date: Thu, 2 Jan 2020 23:05:35 +0100 Message-Id: <20200102220547.519128833@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200102220546.960200039@linuxfoundation.org> References: <20200102220546.960200039@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 @@ -587,6 +587,10 @@ 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) + memset(runtime->dma_area, 0, runtime->dma_bytes); + snd_pcm_timer_resolution_change(substream); snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP);