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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 C0B56C67790 for ; Fri, 27 Jul 2018 10:27:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FE47208A2 for ; Fri, 27 Jul 2018 10:27:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7FE47208A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388641AbeG0LtC (ORCPT ); Fri, 27 Jul 2018 07:49:02 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:42340 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730340AbeG0LtB (ORCPT ); Fri, 27 Jul 2018 07:49:01 -0400 Received: from localhost (unknown [89.188.5.116]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 68D13CD1; Fri, 27 Jul 2018 10:27:44 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+52f83f0ea8df16932f7f@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 3.18 03/27] ALSA: rawmidi: Change resized buffers atomically Date: Fri, 27 Jul 2018 12:26:40 +0200 Message-Id: <20180727102649.168841256@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180727102649.049641021@linuxfoundation.org> References: <20180727102649.049641021@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 39675f7a7c7e7702f7d5341f1e0d01db746543a0 upstream. The SNDRV_RAWMIDI_IOCTL_PARAMS ioctl may resize the buffers and the current code is racy. For example, the sequencer client may write to buffer while it being resized. As a simple workaround, let's switch to the resized buffer inside the stream runtime lock. Reported-by: syzbot+52f83f0ea8df16932f7f@syzkaller.appspotmail.com Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/rawmidi.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -645,7 +645,7 @@ static int snd_rawmidi_info_select_user( int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream, struct snd_rawmidi_params * params) { - char *newbuf; + char *newbuf, *oldbuf; struct snd_rawmidi_runtime *runtime = substream->runtime; if (substream->append && substream->use_count > 1) @@ -658,13 +658,17 @@ int snd_rawmidi_output_params(struct snd return -EINVAL; } if (params->buffer_size != runtime->buffer_size) { - newbuf = krealloc(runtime->buffer, params->buffer_size, - GFP_KERNEL); + newbuf = kmalloc(params->buffer_size, GFP_KERNEL); if (!newbuf) return -ENOMEM; + spin_lock_irq(&runtime->lock); + oldbuf = runtime->buffer; runtime->buffer = newbuf; runtime->buffer_size = params->buffer_size; runtime->avail = runtime->buffer_size; + runtime->appl_ptr = runtime->hw_ptr = 0; + spin_unlock_irq(&runtime->lock); + kfree(oldbuf); } runtime->avail_min = params->avail_min; substream->active_sensing = !params->no_active_sensing; @@ -675,7 +679,7 @@ EXPORT_SYMBOL(snd_rawmidi_output_params) int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream, struct snd_rawmidi_params * params) { - char *newbuf; + char *newbuf, *oldbuf; struct snd_rawmidi_runtime *runtime = substream->runtime; snd_rawmidi_drain_input(substream); @@ -686,12 +690,16 @@ int snd_rawmidi_input_params(struct snd_ return -EINVAL; } if (params->buffer_size != runtime->buffer_size) { - newbuf = krealloc(runtime->buffer, params->buffer_size, - GFP_KERNEL); + newbuf = kmalloc(params->buffer_size, GFP_KERNEL); if (!newbuf) return -ENOMEM; + spin_lock_irq(&runtime->lock); + oldbuf = runtime->buffer; runtime->buffer = newbuf; runtime->buffer_size = params->buffer_size; + runtime->appl_ptr = runtime->hw_ptr = 0; + spin_unlock_irq(&runtime->lock); + kfree(oldbuf); } runtime->avail_min = params->avail_min; return 0;