On Tue, Mar 03, 2015 at 06:28:42PM +0530, Tapasweni Pathak wrote:
> This patch fixes multiple instances of null pointer dereference in this code.
>
> ep->udc is assigned to udc. ep is just an offset from _ep. _ep is then
> checked for NULL. udc is dereferenced under the NULL check for _ep, making
> an invalid pointer reference.
>
> udc is then checked for NULL, if NULL, it is then dereferenced as
> udc->dev.
>
> To fix these issues, shift assignment of udc by dereferencing ep after
> null check for _ep, replace both dev_dbg statements with pr_debug.
>
> Found using Coccinelle.
>
> Signed-off-by: Tapasweni Pathak <tapaswenipathak@xxxxxxxxx>
> Suggested-by : Julia Lawall <julia.lawall@xxxxxxx>
> Reviewed-by : Julia Lawall <julia.lawall@xxxxxxx>
> ---
> drivers/usb/gadget/udc/lpc32xx_udc.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/lpc32xx_udc.c b/drivers/usb/gadget/udc/lpc32xx_udc.c
> index 27fd413..6398539 100644
> --- a/drivers/usb/gadget/udc/lpc32xx_udc.c
> +++ b/drivers/usb/gadget/udc/lpc32xx_udc.c
> @@ -1807,17 +1807,16 @@ static int lpc32xx_ep_queue(struct usb_ep *_ep,
> !list_empty(&req->queue))
> return -EINVAL;
>
> - udc = ep->udc;
> -
> if (!_ep) {
> - dev_dbg(udc->dev, "invalid ep\n");
> + pr_debug("invalid ep\n");
> return -EINVAL;
> }
>
> + udc = ep->udc;
>
> if ((!udc) || (!udc->driver) ||
> (udc->gadget.speed == USB_SPEED_UNKNOWN)) {
> - dev_dbg(udc->dev, "invalid device\n");
> + pr_debug("invalid device\n");
> return -EINVAL;
> }
>
It is driver code, we'd better use dev_dbg. If _ep exists,
both ep and udc should exist. So, how about just checking
_ep at the beginning:
diff --git a/drivers/usb/gadget/udc/lpc32xx_udc.c b/drivers/usb/gadget/udc/lpc32xx_udc.c
index 27fd413..c65de0e 100644
--- a/drivers/usb/gadget/udc/lpc32xx_udc.c
+++ b/drivers/usb/gadget/udc/lpc32xx_udc.c
@@ -1803,7 +1803,7 @@ static int lpc32xx_ep_queue(struct usb_ep *_ep,
req = container_of(_req, struct lpc32xx_request, req);
ep = container_of(_ep, struct lpc32xx_ep, ep);
- if (!_req || !_req->complete || !_req->buf ||
+ if (!_ep || !_req || !_req->complete || !_req->buf ||
!list_empty(&req->queue))
return -EINVAL;
@@ -1815,8 +1815,7 @@ static int lpc32xx_ep_queue(struct usb_ep *_ep,
}
- if ((!udc) || (!udc->driver) ||
- (udc->gadget.speed == USB_SPEED_UNKNOWN)) {
+ if ((!udc->driver) || (udc->gadget.speed == USB_SPEED_UNKNOWN)) {
dev_dbg(udc->dev, "invalid device\n");
return -EINVAL;
}
--
Best Regards,
Peter Chen
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