2022-03-24 21:03:11

by Hangyu Hua

Subject: [PATCH] media: uvc_video: fix bit overflow in uvc_probe_video

probe->dwMaxPayloadTransferSize is a 32bit value, but bandwidth is 16bit. This
may lead to a bit overflow.

Signed-off-by: Hangyu Hua <[email protected]>
---
drivers/media/usb/uvc/uvc_video.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index 1b4cc934109e..cc4878373aa7 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -383,7 +383,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
struct uvc_streaming_control *probe)
{
struct uvc_streaming_control probe_min, probe_max;
- u16 bandwidth;
+ u32 bandwidth;
unsigned int i;
int ret;

@@ -422,7 +422,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
break;

bandwidth = probe->dwMaxPayloadTransferSize;
- if (bandwidth <= stream->maxpsize)
+ if (bandwidth <= (u32)stream->maxpsize)
break;

if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
--
2.25.1

2022-03-24 21:10:03

by Laurent Pinchart

Subject: Re: [PATCH] media: uvc_video: fix bit overflow in uvc_probe_video

Hi Hangyu,

Thank you for the patch.

On Thu, Mar 24, 2022 at 05:13:08PM +0800, Hangyu Hua wrote:
> probe->dwMaxPayloadTransferSize is a 32bit value, but bandwidth is 16bit. This
> may lead to a bit overflow.
>
> Signed-off-by: Hangyu Hua <[email protected]>
> ---
> drivers/media/usb/uvc/uvc_video.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index 1b4cc934109e..cc4878373aa7 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -383,7 +383,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
> struct uvc_streaming_control *probe)
> {
> struct uvc_streaming_control probe_min, probe_max;
> - u16 bandwidth;
> + u32 bandwidth;
> unsigned int i;
> int ret;
>
> @@ -422,7 +422,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
> break;
>
> bandwidth = probe->dwMaxPayloadTransferSize;
> - if (bandwidth <= stream->maxpsize)
> + if (bandwidth <= (u32)stream->maxpsize)

The cast to u32 isn't needed, it's implicit.

This could actually be written

if (probe->dwMaxPayloadTransferSize <= stream->maxpsize)

The bandwidth local variable can be dropped. Could you submit a v2 with
this change ?

> break;
>
> if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {

--
Regards,

Laurent Pinchart

2022-03-25 17:46:03

by Hangyu Hua

Subject: Re: [PATCH] media: uvc_video: fix bit overflow in uvc_probe_video

Thanks. I will do it.

On 2022/3/24 21:52, Laurent Pinchart wrote:
> Hi Hangyu,
>
> Thank you for the patch.
>
> On Thu, Mar 24, 2022 at 05:13:08PM +0800, Hangyu Hua wrote:
>> probe->dwMaxPayloadTransferSize is a 32bit value, but bandwidth is 16bit. This
>> may lead to a bit overflow.
>>
>> Signed-off-by: Hangyu Hua <[email protected]>
>> ---
>> drivers/media/usb/uvc/uvc_video.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
>> index 1b4cc934109e..cc4878373aa7 100644
>> --- a/drivers/media/usb/uvc/uvc_video.c
>> +++ b/drivers/media/usb/uvc/uvc_video.c
>> @@ -383,7 +383,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
>> struct uvc_streaming_control *probe)
>> {
>> struct uvc_streaming_control probe_min, probe_max;
>> - u16 bandwidth;
>> + u32 bandwidth;
>> unsigned int i;
>> int ret;
>>
>> @@ -422,7 +422,7 @@ int uvc_probe_video(struct uvc_streaming *stream,
>> break;
>>
>> bandwidth = probe->dwMaxPayloadTransferSize;
>> - if (bandwidth <= stream->maxpsize)
>> + if (bandwidth <= (u32)stream->maxpsize)
>
> The cast to u32 isn't needed, it's implicit.
>
> This could actually be written
>
> if (probe->dwMaxPayloadTransferSize <= stream->maxpsize)
>
> The bandwidth local variable can be dropped. Could you submit a v2 with
> this change ?
>
>> break;
>>
>> if (stream->dev->quirks & UVC_QUIRK_PROBE_MINMAX) {
>