[media] uvcvideo: Fix integer overflow in uvc_ioctl_ctrl_map()
There is a potential integer overflow in uvc_ioctl_ctrl_map(). When a
large xmap->menu_count is passed from the userspace, the subsequent call
to kmalloc() will allocate a buffer smaller than expected.
map->menu_count and map->menu_info would later be used in a loop (e.g.
in uvc_query_v4l2_ctrl), which leads to out-of-bound access.
The patch checks the ioctl argument and returns -EINVAL for zero or too
large values in xmap->menu_count.
Signed-off-by: Haogang Chen <haogangchen@gmail.com>
[laurent.pinchart@ideasonboard.com Prevent excessive memory consumption]
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/uvc/uvc_v4l2.c b/drivers/media/video/uvc/uvc_v4l2.c
index b1dc3e5..2ae4f88 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -58,6 +58,15 @@
break;
case V4L2_CTRL_TYPE_MENU:
+ /* Prevent excessive memory consumption, as well as integer
+ * overflows.
+ */
+ if (xmap->menu_count == 0 ||
+ xmap->menu_count > UVC_MAX_CONTROL_MENU_ENTRIES) {
+ ret = -EINVAL;
+ goto done;
+ }
+
size = xmap->menu_count * sizeof(*map->menu_info);
map->menu_info = kmalloc(size, GFP_KERNEL);
if (map->menu_info == NULL) {