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,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 11C2BC4332E for ; Tue, 5 Jan 2021 09:29:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9B752222A for ; Tue, 5 Jan 2021 09:29:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728355AbhAEJ3s (ORCPT ); Tue, 5 Jan 2021 04:29:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:49296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728354AbhAEJ3k (ORCPT ); Tue, 5 Jan 2021 04:29:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id A730622AB0; Tue, 5 Jan 2021 09:28:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609838939; bh=lAXHsb70nJP+WYyBcH4Sr0dYyef1OZUZJDEgRu/5+Wg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nds2YlR4RIbUGw1EdK1Gz2eBRkaaSlRm7iUO15Ar9fxmzB6yRZrhV7iTJTXmfrhW7 hxGsCaJmFqzTB3os0MsRF0rQ0X54DG5FxyEV1FGUTre/ci6QF+GOu4E7zqWYT/TWuc +7/OwiNQHEFAsxoyLPYuA4ZFE+PGyu6KRJ1t0rjg= 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 4.19 28/29] ALSA: pcm: Clear the full allocated memory at hw_params Date: Tue, 5 Jan 2021 10:29:14 +0100 Message-Id: <20210105090822.182761949@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210105090818.518271884@linuxfoundation.org> References: <20210105090818.518271884@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: stable@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 7c12b0deb4eb5..db62dbe7eaa8a 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -753,8 +753,13 @@ 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