usb gadget: uvc: uvc_request_data::length field must be signed

BugLink: http://bugs.launchpad.net/bugs/996109

commit 6f6543f53f9ce136e01d7114bf6f0818ca54fb41 upstream.

The field is used to pass the UVC request data length, but can also be
used to signal an error when setting it to a negative value. Switch from
unsigned int to __s32.

Reported-by: Fernandez Gonzalo <gfernandez@copreci.es>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 2 insertions, 2 deletions

diff --git a/drivers/usb/gadget/uvc.h b/drivers/usb/gadget/uvc.h
index 5b7919460fd..01a23c1197f 100644
--- a/drivers/usb/gadget/uvc.h
+++ b/drivers/usb/gadget/uvc.h
@@ -29,7 +29,7 @@
 
 struct uvc_request_data
 {
-        unsigned int length;
+        __s32 length;
         __u8 data[60];
 };
 
diff --git a/drivers/usb/gadget/uvc_v4l2.c b/drivers/usb/gadget/uvc_v4l2.c
index 5e807f083bc..992f66b88c8 100644
--- a/drivers/usb/gadget/uvc_v4l2.c
+++ b/drivers/usb/gadget/uvc_v4l2.c
@@ -41,7 +41,7 @@ uvc_send_response(struct uvc_device *uvc, struct uvc_request_data *data)
         if (data->length < 0)
                 return usb_ep_set_halt(cdev->gadget->ep0);
 
-        req->length = min(uvc->event_length, data->length);
+        req->length = min_t(unsigned int, uvc->event_length, data->length);
         req->zero = data->length < uvc->event_length;
         req->dma = DMA_ADDR_INVALID;