[PATCH] uvcvideo: prevent invormation loss with removing implicit casting

[PATCH] uvcvideo: prevent invormation loss with removing implicit casting

[Németh Márton]

From: Márton Németh <nm127@freemail.hu>

The uvcvideo driver supports only one input, which is input 0. For all
other input index the return value shall be EINVAL. This patch fixes the
problem when the value 0x80000000 was incorrectly casted and treated as
a zero value.

The patch was tested with v4l-test 0.10 [2] with CNF7129 webcam found on
EeePC 901.

References:
[1] V4L2 API specification, revision 0.24
    http://v4l2spec.bytesex.org/spec/r11217.htm

[2] v4l-test: Test environment for Video For Linux Two API
    http://v4l-test.sourceforge.net/

Signed-off-by: Márton Németh <nm127@freemail.hu>
---
--- linux-2.6.29-git13/drivers/media/video/uvc/uvc_v4l2.c.orig	2009-04-06 23:16:06.000000000 +0200
+++ linux-2.6.29-git13/drivers/media/video/uvc/uvc_v4l2.c	2009-04-08 00:37:01.000000000 +0200
@@ -648,7 +648,7 @@ static long uvc_v4l2_do_ioctl(struct fil

 	case VIDIOC_S_INPUT:
 	{
-		u8 input = *(u32 *)arg + 1;
+		u32 input = *(u32 *)arg + 1;

 		if ((ret = uvc_acquire_privileges(handle)) < 0)
 			return ret;

Re: [PATCH] uvcvideo: prevent invormation loss with removing implicit casting

[Laurent Pinchart]

On Wednesday 08 April 2009 01:11:53 Németh Márton wrote:
> From: Márton Németh <nm127@freemail.hu>
>
> The uvcvideo driver supports only one input, which is input 0. For all
> other input index the return value shall be EINVAL. This patch fixes the
> problem when the value 0x80000000 was incorrectly casted and treated as
> a zero value.
>
> The patch was tested with v4l-test 0.10 [2] with CNF7129 webcam found on
> EeePC 901.
>
> References:
> [1] V4L2 API specification, revision 0.24
>     http://v4l2spec.bytesex.org/spec/r11217.htm
>
> [2] v4l-test: Test environment for Video For Linux Two API
>     http://v4l-test.sourceforge.net/
>
> Signed-off-by: Márton Németh <nm127@freemail.hu>

Acked-by: Laurent Pinchart <laurent.pinchart@skynet.be>

> ---
> --- linux-2.6.29-git13/drivers/media/video/uvc/uvc_v4l2.c.orig	2009-04-06
> 23:16:06.000000000 +0200 +++
> linux-2.6.29-git13/drivers/media/video/uvc/uvc_v4l2.c	2009-04-08
> 00:37:01.000000000 +0200 @@ -648,7 +648,7 @@ static long
> uvc_v4l2_do_ioctl(struct fil
>
>  	case VIDIOC_S_INPUT:
>  	{
> -		u8 input = *(u32 *)arg + 1;
> +		u32 input = *(u32 *)arg + 1;
>
>  		if ((ret = uvc_acquire_privileges(handle)) < 0)
>  			return ret;