[media] v4l: Check pad arguments for [gs]_frame_interval

VIDIOC_SUBDEV_[GS]_FRAME_INTERVAL IOCTLs argument structs contain the pad
field but the validity check was missing. There should be no implications
security-wise from this since no driver currently uses the pad field in the
struct.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/v4l2-core/v4l2-subdev.c

@@ -305,11 +305,23 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 					fse);
 	}
 
-	case VIDIOC_SUBDEV_G_FRAME_INTERVAL:
+	case VIDIOC_SUBDEV_G_FRAME_INTERVAL: {
+		struct v4l2_subdev_frame_interval *fi = arg;
+
+		if (fi->pad >= sd->entity.num_pads)
+			return -EINVAL;
+
 		return v4l2_subdev_call(sd, video, g_frame_interval, arg);
+	}
+
+	case VIDIOC_SUBDEV_S_FRAME_INTERVAL: {
+		struct v4l2_subdev_frame_interval *fi = arg;
+
+		if (fi->pad >= sd->entity.num_pads)
+			return -EINVAL;
 
-	case VIDIOC_SUBDEV_S_FRAME_INTERVAL:
 		return v4l2_subdev_call(sd, video, s_frame_interval, arg);
+	}
 
 	case VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL: {
 		struct v4l2_subdev_frame_interval_enum *fie = arg;