[PATCH 4.13 089/109] media: uvcvideo: Prevent heap overflow when accessing mapped controls

Greg Kroah-Hartman
2017-09-24T20:43:40Z

From: Guenter Roeck <linux@roeck-us.net>

commit 7e09f7d5c790278ab98e5f2c22307ebe8ad6e8ba upstream.

The size of uvc_control_mapping is user controlled leading to a
potential heap overflow in the uvc driver. This adds a check to verify
the user provided size fits within the bounds of the defined buffer
size.

Originally-from: Richard Simmons <rssimmo@amazon.com>

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/media/usb/uvc/uvc_ctrl.c | 7 +++++++
1 file changed, 7 insertions(+)

--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -2002,6 +2002,13 @@ int uvc_ctrl_add_mapping(struct uvc_vide
goto done;
}

+ /* Validate the user-provided bit-size and offset */
+ if (mapping->size > 32 ||
+ mapping->offset + mapping->size > ctrl->info.size * 8) {
+ ret = -EINVAL;
+ goto done;
+ }
+
list_for_each_entry(map, &ctrl->info.mappings, list) {
if (mapping->id == map->id) {
uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', "