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

[Leo Li]

> -----Original Message-----
> From: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Sent: Wednesday, June 28, 2023 2:40 PM
> To: Leo Li <leoyang.li@xxxxxxx>; Ma Ke <make_ruc2021@xxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; linuxppc-
> dev@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] usb: gadget: fsl_qe_udc: validate endpoint index for
> ch9 udc
> 
> 
> 
> Le 28/06/2023 à 19:04, Leo Li a écrit :
> >
> >
> >> -----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?
> 
> But we are at the start of a code block aren't we ?

But they were at the beginning of a { } block which is compliant with the C89 standard.  I know gcc is more relaxed from this.  But it is probably still good to stick to the standard?

> 
> The only missing thing is the blank line between the declarations and the
> code, so that we clearly see where declarations end and where code start.
> 
> >
> >>   		struct qe_ep *target_ep = &udc->eps[pipe];
> >>   		u16 usep;
> >>
> >> --
> >> 2.37.2
> >