Re: [PATCH] media: usbvision: Fix a use after free in v4l2_release()

From: Hans Verkuil <hverkuil@xs4all.nl>
To: Hillf Danton <hdanton@sina.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	syzbot <syzbot+75287f75e2fedd69d680@syzkaller.appspotmail.com>,
	Alan Stern <stern@rowland.harvard.edu>,
	Allison Randal <allison@lohutok.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Souptick Joarder <jrdr.linux@gmail.com>,
	andreyknvl@google.com, bnvandana@gmail.com,
	linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
	linux-usb@vger.kernel.org, mchehab@kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH] media: usbvision: Fix a use after free in v4l2_release()
Date: Fri, 14 Feb 2020 14:34:49 +0100	[thread overview]
Message-ID: <feb28930-0a50-b43b-e639-37adc5a60743@xs4all.nl> (raw)
In-Reply-To: <20200214124825.12568-1-hdanton@sina.com>

On 2/14/20 1:48 PM, Hillf Danton wrote:
> 
> On Fri, 14 Feb 2020 13:21:03 +0100 Hans Verkuil wrote:
>> On 2/14/20 1:14 PM, Hillf Danton wrote:
>>>
>>> On Fri, 14 Feb 2020 12:30:29 +0100 Hans Verkuil wrote:
>>>>
>>>> Hillf, if you want your patch to be merged, then make sure it is CC-ed to
>>>> linux-media as well.
>>>
>>> Please pick it up if it makes a sense to you and it was sent with
>>> linux-media added on the Cc list as it is known for a while that
>>> my mail agent is rejected @vger.kernel.org for what I am not clear
>>> about. It makes my day occasionally :P
>>
>> I don't I ever received the full patch, only replies to your patch.
>>
> 
> =========
> Please take a look at the Cc tag in the snippet from
> https://lore.kernel.org/lkml/b1d071e2-0428-a08c-392d-3ca5d4a7e710@xs4all.nl/T/#m13f2c16b7cd1892f6a0b58b72ce37979cb6940b9
> 
> 
>> Subject: [PATCH] media: usbvision: add the release callback for video device
>> From: Hillf Danton <hdanton@sina.com>
>>
>> To fix the UAF syzbot reported,
>>
>> BUG: KASAN: use-after-free in v4l2_release+0x2f1/0x390 drivers/media/v4l2-core/v4l2-dev.c:459
>>
>> a release cb which is a simple wrapper of usbvision_release() is added
>> for releasing resources as the last reference to the usbvision video
>> device goes away.
>>
>> Reported-by: syzbot <syzbot+75287f75e2fedd69d680@syzkaller.appspotmail.com>
>> Fixes: 2aa689dd8057 ("[media] usbvision: embed video_device")
>> Cc: Hans Verkuil <hans.verkuil@cisco.com>

Ah, my work email. And I always delete posts mailed to that if it is also CC-ed
to linux-media. Which didn't actually arrive there in your case. And it's no longer
in my trash folder either.

So please mail me a properly formatted patch so I can forward it to linux-media
for you.

Regards,

	Hans

>> Signed-off-by: Hillf Danton <hdanton@sina.com>
>> ---
> =========
> 
>> Please mail your patch directly to me so I have a clean version.
> 