linux-kernel - Re: [PATCH v3 4/8] media: subdev: remove VIDIOC_DQEVENT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e3162d4c-d40d-442d-39a0-c99c4328932e@xs4all.nl>
Date:   Tue, 15 Jun 2021 10:48:37 +0200
From:   Hans Verkuil <hverkuil-cisco@...all.nl>
To:     Arnd Bergmann <arnd@...nel.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        "Lad, Prabhakar" <prabhakar.csengg@...il.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Vaibhav Gupta <vaibhavgupta40@...il.com>,
        Liu Shixin <liushixin2@...wei.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        linux-staging@...ts.linux.dev
Subject: Re: [PATCH v3 4/8] media: subdev: remove VIDIOC_DQEVENT_TIME32
 handling

On 15/06/2021 10:43, Arnd Bergmann wrote:
> On Mon, Jun 14, 2021 at 7:02 PM Laurent Pinchart
> <laurent.pinchart@...asonboard.com> wrote:
>>
>> On Mon, Jun 14, 2021 at 12:34:05PM +0200, Arnd Bergmann wrote:
>>> From: Arnd Bergmann <arnd@...db.de>
>>>
>>> Converting the VIDIOC_DQEVENT_TIME32/VIDIOC_DQEVENT32/
>>> VIDIOC_DQEVENT32_TIME32 arguments to the canonical form is done in common
>>> code, but for some reason I ended up adding another conversion helper to
>>> subdev_do_ioctl() as well. I must have concluded that this does not go
>>> through the common conversion, but it has done that since the ioctl
>>> handler was first added.
>>>
>>> I assume this one is harmless as there should be no way to arrive here
>>> from user space, but since it is dead code, it should just get removed.

I changed this to:

"I assume this one is harmless as there should be no way to arrive here
from user space if CONFIG_COMPAT_32BIT_TIME is set,"

If it is not set, then this will just fall into the default case and is
handled as if it is a potential custom ioctl, as you would expect.

Let me know if you have a better text, I can still update it.

Regards,

	Hans

>>
>> If I'm not mistaken, this could be reached when
>> !CONFIG_COMPAT_32BIT_TIME, can't it ? Still, there's no need for this
>> code in that case, so it seems fine to me.
> 
> Yes, that is correct, I missed that condition. We definitely should not handle
> the command in that case.
> 
> Hans, since you mentioned you would pick up this patch, I assume  you
> are going to reword the patch as you see fit. If you prefer me to resend it,
> let me know.
> 
>        Arnd
>