Re: [PATCH] gspca: add missing .type field check in VIDIOC_G_PARM

["Németh Márton" <nm127@freemail.hu>]

David Ellingsworth wrote:
> 2009/3/18 Németh Márton <nm127@freemail.hu>:
>> From: Márton Németh <nm127@freemail.hu>
>>
>> The gspca webcam driver does not check the .type field of struct v4l2_streamparm.
>> This field is an input parameter for the driver according to V4L2 API specification,
>> revision 0.24 [1]. Add the missing check.
>>
>> The missing check was recognised by v4l-test 0.10 [2] together with gspca_sunplus driver
>> and with "Trust 610 LCD POWERC@M ZOOM" webcam. This patch was verified also with
>> v4l-test 0.10.
>>
>> References:
>> [1] V4L2 API specification, revision 0.24
>>    http://v4l2spec.bytesex.org/spec/r11680.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-rc8/drivers/media/video/gspca/gspca.c.orig     2009-03-14 12:29:38.000000000 +0100
>> +++ linux-2.6.29-rc8/drivers/media/video/gspca/gspca.c  2009-03-18 16:51:03.000000000 +0100
>> @@ -1320,6 +1320,9 @@ static int vidioc_g_parm(struct file *fi
>>  {
>>        struct gspca_dev *gspca_dev = priv;
>>
>> +       if (parm->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>> +               return -EINVAL;
>> +
>>        memset(parm, 0, sizeof *parm);
>>        parm->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> ^^^^^^^^^^^^^^^^^^^
> This line should be deleted as it's no longer needed.

Because memset() clears the whole parm structure this line is necessary. In other
drivers the following code is there:

    tmp = parm->type;
    memset(parm, 0, sizeof(*parm));
    parm->type = parm;

Maybe changing the code similar to this would be easier to read?

	Márton Németh