Re: [PATCH v3 2/3] staging: rtl8712: fix uninit-value in r871xu_drv_init()

[Pavel Skripkin]

Hi Pavel,

On 5/6/22 15:27, Pavel Skripkin wrote:
> Hi Wang,
>
> On 5/6/22 14:59, Wang Cheng wrote:
> > Reported-and-tested-by: syzbot+6f5ecd144854c0d8580b@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Wang Cheng <wanngchenng@xxxxxxxxx>
> > ---
> >   drivers/staging/rtl8712/usb_intf.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/staging/rtl8712/usb_intf.c b/drivers/staging/rtl8712/usb_intf.c
> > index ee4c61f85a07..50dcd3ecb685 100644
> > --- a/drivers/staging/rtl8712/usb_intf.c
> > +++ b/drivers/staging/rtl8712/usb_intf.c
> > @@ -538,13 +538,13 @@ static int r871xu_drv_init(struct usb_interface *pusb_intf,
> >   		} else {
> >   			AutoloadFail = false;
> >   		}
> > -		if (((mac[0] == 0xff) && (mac[1] == 0xff) &&
> > +		if ((!AutoloadFail) ||
> > +		    ((mac[0] == 0xff) && (mac[1] == 0xff) &&
> >   		     (mac[2] == 0xff) && (mac[3] == 0xff) &&
> >   		     (mac[4] == 0xff) && (mac[5] == 0xff)) ||
> >   		    ((mac[0] == 0x00) && (mac[1] == 0x00) &&
> >   		     (mac[2] == 0x00) && (mac[3] == 0x00) &&
> > -		     (mac[4] == 0x00) && (mac[5] == 0x00)) ||
> > -		     (!AutoloadFail)) {
> > +		     (mac[4] == 0x00) && (mac[5] == 0x00))) {
> >   			mac[0] = 0x00;
> >   			mac[1] = 0xe0;
> >   			mac[2] = 0x4c;
>
> Hmm,
>
> the whole r871xu_drv_init() looks odd, but it's unrelated.
>
> I see that this patch does not help with below kernel path
>
> r871xu_drv_init()
>     if (tmpU1b & _EEPROM_EN) <- true [1]
> 	if (!r8712_initmac || !mac_pton(r8712_initmac, mac)) <- (*)
> 		if ((!AutoloadFail) ||	<- false, since [1] branch taken
> 			[code touches stack data]
>
> (*) false because of r8712_initmac is equal to NULL

Oops, I am blind, ignore that one, please. The whole idea is wrong.

I need to go to sleep earlier today

sorry about that,


With regards,
Pavel Skripkin

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