[177/200] V4L/DVB: uvcvideo: Prevent division by 0 when control step value is 0

Greg KH
2010-07-01T21:19:24Z

2.6.34-stable review patch. If anyone has any objections, please let me know.

------------------

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

commit cf7a50eeb6f462a0b7d1619fcb27a727a2981769 upstream.

The control step values reported by the device are used as a divisor
unchecked, which can result in a division by zero.

Check the step value and make it 1 when null.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/media/video/uvc/uvc_ctrl.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -1047,6 +1047,8 @@ int uvc_ctrl_set(struct uvc_video_chain
uvc_ctrl_data(ctrl, UVC_CTRL_DATA_MAX));
step = mapping->get(mapping, UVC_GET_RES,
uvc_ctrl_data(ctrl, UVC_CTRL_DATA_RES));
+ if (step == 0)
+ step = 1;

xctrl->value = min + (xctrl->value - min + step/2) / step * step;
xctrl->value = clamp(xctrl->value, min, max);