Re: [PATCH v3] media: v4l2-compat-ioctl32: fix missing length copy in put_v4l2_buffer32

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Tiffany,

Thank you for the patch.

On Friday 15 January 2016 17:13:36 Tiffany Lin wrote:
> In v4l2-compliance utility, test QUERYBUF required correct length
> value to go through each planar to check planar's length in
> multi-planar buffer type
> 
> Signed-off-by: Tiffany Lin <tiffany.lin@mediatek.com>
> ---
>  drivers/media/v4l2-core/v4l2-compat-ioctl32.c |   21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c index 327e83a..6181470
> 100644
> --- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> +++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
> @@ -426,10 +426,10 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp,
> struct v4l2_buffer32 __user &up->timestamp.tv_usec))
>  			return -EFAULT;
> 
> -	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
> -		if (get_user(kp->length, &up->length))
> -			return -EFAULT;
> +	if (get_user(kp->length, &up->length))
> +		return -EFAULT;

I'd move this to the first block of get_user() calls at the beginning of the 
function.

> 
> +	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
>  		num_planes = kp->length;
>  		if (num_planes == 0) {
>  			kp->m.planes = NULL;
> @@ -462,16 +462,14 @@ static int get_v4l2_buffer32(struct v4l2_buffer *kp,
> struct v4l2_buffer32 __user } else {
>  		switch (kp->memory) {
>  		case V4L2_MEMORY_MMAP:
> -			if (get_user(kp->length, &up->length) ||
> -				get_user(kp->m.offset, &up->m.offset))
> +			if (get_user(kp->m.offset, &up->m.offset))
>  				return -EFAULT;
>  			break;
>  		case V4L2_MEMORY_USERPTR:
>  			{
>  			compat_long_t tmp;
> 
> -			if (get_user(kp->length, &up->length) ||
> -			    get_user(tmp, &up->m.userptr))
> +			if (get_user(tmp, &up->m.userptr))
>  				return -EFAULT;
> 
>  			kp->m.userptr = (unsigned long)compat_ptr(tmp);
> @@ -516,6 +514,9 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp,
> struct v4l2_buffer32 __user put_user(kp->reserved, &up->reserved))
>  			return -EFAULT;
> 
> +	if (put_user(kp->length, &up->length))
> +		return -EFAULT;

Same here.

>  	if (V4L2_TYPE_IS_MULTIPLANAR(kp->type)) {
>  		num_planes = kp->length;
>  		if (num_planes == 0)
> @@ -536,13 +537,11 @@ static int put_v4l2_buffer32(struct v4l2_buffer *kp,
> struct v4l2_buffer32 __user } else {
>  		switch (kp->memory) {
>  		case V4L2_MEMORY_MMAP:
> -			if (put_user(kp->length, &up->length) ||
> -				put_user(kp->m.offset, &up->m.offset))
> +			if (put_user(kp->m.offset, &up->m.offset))
>  				return -EFAULT;
>  			break;
>  		case V4L2_MEMORY_USERPTR:
> -			if (put_user(kp->length, &up->length) ||
> -				put_user(kp->m.userptr, &up->m.userptr))
> +			if (put_user(kp->m.userptr, &up->m.userptr))
>  				return -EFAULT;
>  			break;
>  		case V4L2_MEMORY_OVERLAY:

-- 
Regards,

Laurent Pinchart