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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 650F0C4332E for ; Mon, 4 Jan 2021 16:02:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A69421D93 for ; Mon, 4 Jan 2021 16:02:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727854AbhADQBz (ORCPT ); Mon, 4 Jan 2021 11:01:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:39182 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728670AbhADQBu (ORCPT ); Mon, 4 Jan 2021 11:01:50 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id DA11222518; Mon, 4 Jan 2021 16:01:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609776069; bh=DzPD7MUYEs37ZsR4J4eFe2J1AKJMrumiPDtaWLyiu60=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m8Qd1AD24PAsSiXLwwZDlI009EqYH/b2Pa7B24df9T5tqCHufrIcp3dcfc2dXyjMl hOtMSGNz+dZmD4vY6Qc96+LewtkQV6QuGN6tgj+UubhrL04FgtwDq4Zx/Dmu7eyera gUV2LEH1XIKSq/msyiqYlh9fVsGc80cyezWpLUIk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Takashi Iwai , Sasha Levin Subject: [PATCH 5.4 46/47] ALSA: pcm: Clear the full allocated memory at hw_params Date: Mon, 4 Jan 2021 16:57:45 +0100 Message-Id: <20210104155707.956747898@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210104155705.740576914@linuxfoundation.org> References: <20210104155705.740576914@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takashi Iwai [ Upstream commit 618de0f4ef11acd8cf26902e65493d46cc20cc89 ] The PCM hw_params core function tries to clear up the PCM buffer before actually using for avoiding the information leak from the previous usages or the usage before a new allocation. It performs the memset() with runtime->dma_bytes, but this might still leave some remaining bytes untouched; namely, the PCM buffer size is aligned in page size for mmap, hence runtime->dma_bytes doesn't necessarily cover all PCM buffer pages, and the remaining bytes are exposed via mmap. This patch changes the memory clearance to cover the all buffer pages if the stream is supposed to be mmap-ready (that guarantees that the buffer size is aligned in page size). Reviewed-by: Lars-Peter Clausen Link: https://lore.kernel.org/r/20201218145625.2045-3-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/pcm_native.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index ec501fbaabe49..0c5b7a54ca81c 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -717,8 +717,13 @@ static int snd_pcm_hw_params(struct snd_pcm_substream *substream, 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); + if (runtime->dma_area && !substream->ops->copy_user) { + size_t size = runtime->dma_bytes; + + if (runtime->info & SNDRV_PCM_INFO_MMAP) + size = PAGE_ALIGN(size); + memset(runtime->dma_area, 0, size); + } snd_pcm_timer_resolution_change(substream); snd_pcm_set_state(substream, SNDRV_PCM_STATE_SETUP); -- 2.27.0