RE: [PATCH] usb: gadget: fsl_qe_udc: validate endpoint index for ch9 udc

[Leo Li]

> -----Original Message-----
> From: Ma Ke <make_ruc2021@xxxxxxx>
> Sent: Wednesday, June 28, 2023 3:15 AM
> To: Leo Li <leoyang.li@xxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; linuxppc-
> dev@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Ma Ke
> <make_ruc2021@xxxxxxx>
> Subject: [PATCH] usb: gadget: fsl_qe_udc: validate endpoint index for ch9
> udc
> 
> We should verify the bound of the array to assure that host may not
> manipulate the index to point past endpoint array.
> 
> Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>
> ---
>  drivers/usb/gadget/udc/fsl_qe_udc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/gadget/udc/fsl_qe_udc.c
> b/drivers/usb/gadget/udc/fsl_qe_udc.c
> index 3b1cc8fa30c8..f4e5cbd193b7 100644
> --- a/drivers/usb/gadget/udc/fsl_qe_udc.c
> +++ b/drivers/usb/gadget/udc/fsl_qe_udc.c
> @@ -1959,6 +1959,8 @@ static void ch9getstatus(struct qe_udc *udc, u8
> request_type, u16 value,
>  	} else if ((request_type & USB_RECIP_MASK) ==
> USB_RECIP_ENDPOINT) {
>  		/* Get endpoint status */
>  		int pipe = index & USB_ENDPOINT_NUMBER_MASK;
> +		if (pipe >= USB_MAX_ENDPOINTS)
> +			goto stall;

Thanks.  This seems to be the right thing to do.  But normally we don't mix declarations with code within a code block.  Could we re-arrange the code a little bit so declarations stay on top?

>  		struct qe_ep *target_ep = &udc->eps[pipe];
>  		u16 usep;
> 
> --
> 2.37.2