From patchwork Thu Jan 7 14:31:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 358845 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=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 428B1C43603 for ; Thu, 7 Jan 2021 14:38:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D489217A0 for ; Thu, 7 Jan 2021 14:38:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727817AbhAGOiM (ORCPT ); Thu, 7 Jan 2021 09:38:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:45564 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729039AbhAGObw (ORCPT ); Thu, 7 Jan 2021 09:31:52 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 222792311E; Thu, 7 Jan 2021 14:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610029867; bh=gBkpl3m4jJGJDQ83gMnX/l9iczs2j62lLFhEFweDDFg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n7N/O91Mno5YZ1tgMhYBcnix6I8/h7eaj6I73EpE8+/zuPCpHvIScJ4RWpy3gTu4U PJnmLCSas+yGuy3GEL38Id3vuSE9ZI59QQD1x0Urrz2wgDzLUuH8GLZRmefRB9kHPx DcciREp4KWpNCrGQXPGCkOXTLAQJraHkvJXRwX7o= 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 4.14 24/29] ALSA: pcm: Clear the full allocated memory at hw_params Date: Thu, 7 Jan 2021 15:31:39 +0100 Message-Id: <20210107143056.389471030@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210107143052.973437064@linuxfoundation.org> References: <20210107143052.973437064@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 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 071e09c3d8557..c78db361cbbaa 100644 --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -721,8 +721,13 @@ 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);