Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752360AbcCQDBQ (ORCPT <rfc822;w@1wt.eu>);
	Wed, 16 Mar 2016 23:01:16 -0400
Received: from lists.s-osg.org ([54.187.51.154]:54259 "EHLO lists.s-osg.org"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1751335AbcCQDBP (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 16 Mar 2016 23:01:15 -0400
Subject: Re: [PATCH] sound/usb: Fix memory leak in media_snd_stream_delete()
 during unbind
To: mchehab@osg.samsung.com, perex@perex.cz, Takashi Iwai <tiwai@suse.com>
References: <1458183486-8113-1-git-send-email-shuahkh@osg.samsung.com>
Cc: alsa-devel@alsa-project.org, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org, Shuah Khan <shuahkh@osg.samsung.com>
From: Shuah Khan <shuahkh@osg.samsung.com>
Organization: Samsung Open Source Group
Message-ID: <56EA1DF8.9060500@osg.samsung.com>
Date: Wed, 16 Mar 2016 21:01:12 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.6.0
MIME-Version: 1.0
In-Reply-To: <1458183486-8113-1-git-send-email-shuahkh@osg.samsung.com>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2365
Lines: 53

Adding Takashi Iwai

On 03/16/2016 08:58 PM, Shuah Khan wrote:
> media_snd_stream_delete() fails to release resources during unbind. This
> leads to use-after-free in media_gobj_create() on a subsequent bind.
> 
> [ 1445.086410] BUG: KASAN: use-after-free in media_gobj_create+0x3a1/0x470 [media] at addr ffff8801ead49998
> 
> [ 1445.086771] Call Trace:
> [ 1445.086779]  [<ffffffff81ade373>] dump_stack+0x67/0x94
> [ 1445.086785]  [<ffffffff81523c29>] print_trailer+0xf9/0x150
> [ 1445.086790]  [<ffffffff81529644>] object_err+0x34/0x40
> [ 1445.086796]  [<ffffffff8152b9e1>] kasan_report_error+0x221/0x530
> [ 1445.086803]  [<ffffffff8152bfb3>] __asan_report_store8_noabort+0x43/0x50
> [ 1445.086813]  [<ffffffffa0a79341>] ? media_gobj_create+0x3a1/0x470 [media]
> [ 1445.086822]  [<ffffffffa0a79341>] media_gobj_create+0x3a1/0x470 [media]
> [ 1445.086831]  [<ffffffffa0a705a9>] media_device_register_entity+0x259/0x6f0 [media]
> [ 1445.086841]  [<ffffffffa0a70350>] ? media_device_unregister_entity_notify+0x100/0x100 [media]
> [ 1445.086846]  [<ffffffff81526232>] ? ___slab_alloc+0x172/0x500
> [ 1445.086854]  [<ffffffff81203548>] ? mark_held_locks+0xc8/0x120
> [ 1445.086859]  [<ffffffff81526610>] ? __slab_alloc+0x50/0x70
> [ 1445.086878]  [<ffffffffa0fe711c>] ? media_snd_mixer_init+0x16c/0x500 [snd_usb_audio]
> [ 1445.086884]  [<ffffffff8152b086>] ? kasan_unpoison_shadow+0x36/0x50
> [ 1445.086890]  [<ffffffff8152b086>] ? kasan_unpoison_shadow+0x36/0x50
> [ 1445.086895]  [<ffffffff8152b0fe>] ? kasan_kmalloc+0x5e/0x70
> 
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
>  sound/usb/media.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/usb/media.c b/sound/usb/media.c
> index 44a5de9..0d03773 100644
> --- a/sound/usb/media.c
> +++ b/sound/usb/media.c
> @@ -135,7 +135,7 @@ void media_snd_stream_delete(struct snd_usb_substream *subs)
>  	if (mctl && mctl->media_dev) {
>  		struct media_device *mdev;
>  
> -		mdev = subs->stream->chip->media_dev;
> +		mdev = mctl->media_dev;
>  		if (mdev && media_devnode_is_registered(&mdev->devnode)) {
>  			media_devnode_remove(mctl->intf_devnode);
>  			media_device_unregister_entity(&mctl->media_entity);
> 


-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@osg.samsung.com | (970) 217-8978