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* [PATCH 1/1] usb: musb: gadget: misplaced out of bounds check
@ 2018-03-19  7:12 Heinrich Schuchardt
  2018-03-19 16:26 ` Bin Liu
  0 siblings, 1 reply; 2+ messages in thread
From: Heinrich Schuchardt @ 2018-03-19  7:12 UTC (permalink / raw)
  To: Bin Liu; +Cc: Greg Kroah-Hartman, linux-usb, linux-kernel, Heinrich Schuchardt

musb->endpoints[] has array size MUSB_C_NUM_EPS.
We must check array bounds before accessing the array and not afterwards.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
 drivers/usb/musb/musb_gadget_ep0.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
index 18da4873e52e..482e7c2f8dc7 100644
--- a/drivers/usb/musb/musb_gadget_ep0.c
+++ b/drivers/usb/musb/musb_gadget_ep0.c
@@ -88,6 +88,11 @@ static int service_tx_status_request(
 			break;
 		}
 
+		if (epnum >= MUSB_C_NUM_EPS) {
+			handled = -EINVAL;
+			break;
+		}
+
 		is_in = epnum & USB_DIR_IN;
 		if (is_in) {
 			epnum &= 0x0f;
@@ -97,7 +102,7 @@ static int service_tx_status_request(
 		}
 		regs = musb->endpoints[epnum].regs;
 
-		if (epnum >= MUSB_C_NUM_EPS || !ep->desc) {
+		if (!ep->desc) {
 			handled = -EINVAL;
 			break;
 		}
-- 
2.16.2

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH 1/1] usb: musb: gadget: misplaced out of bounds check
  2018-03-19  7:12 [PATCH 1/1] usb: musb: gadget: misplaced out of bounds check Heinrich Schuchardt
@ 2018-03-19 16:26 ` Bin Liu
  0 siblings, 0 replies; 2+ messages in thread
From: Bin Liu @ 2018-03-19 16:26 UTC (permalink / raw)
  To: Heinrich Schuchardt; +Cc: Greg Kroah-Hartman, linux-usb, linux-kernel

Hi,

On Mon, Mar 19, 2018 at 08:12:28AM +0100, Heinrich Schuchardt wrote:
> musb->endpoints[] has array size MUSB_C_NUM_EPS.
> We must check array bounds before accessing the array and not afterwards.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> ---
>  drivers/usb/musb/musb_gadget_ep0.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c
> index 18da4873e52e..482e7c2f8dc7 100644
> --- a/drivers/usb/musb/musb_gadget_ep0.c
> +++ b/drivers/usb/musb/musb_gadget_ep0.c
> @@ -88,6 +88,11 @@ static int service_tx_status_request(
>  			break;
>  		}
>  
> +		if (epnum >= MUSB_C_NUM_EPS) {

only the LSB 4 bits are the EP number, bit7 is the direction flag. So
you can only compare the LSB 4 bits here.

Regards,
-Bin.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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