2022-05-30 10:46:06

by Greg Kroah-Hartman

Subject: Re: [PATCH] staging: rtl8712: Fix pointer dereferenced before checking

On Mon, May 30, 2022 at 04:22:11PM +0800, baihaowen wrote:
> 在 2022/5/30 下午4:14, Greg Kroah-Hartman 写道:
> > On Mon, May 30, 2022 at 04:05:32PM +0800, Haowen Bai wrote:
> >> The padapter->recvpriv.signal_qual_data is dereferencing before null
> >> checking, so move it after checking.
> >>
> >> Signed-off-by: Haowen Bai <[email protected]>
> >> ---
> >> drivers/staging/rtl8712/rtl8712_recv.c | 4 +++-
> >> 1 file changed, 3 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/staging/rtl8712/rtl8712_recv.c b/drivers/staging/rtl8712/rtl8712_recv.c
> >> index 7f1fdd058551..8ed94b259dbe 100644
> >> --- a/drivers/staging/rtl8712/rtl8712_recv.c
> >> +++ b/drivers/staging/rtl8712/rtl8712_recv.c
> >> @@ -863,10 +863,12 @@ static void process_link_qual(struct _adapter *padapter,
> >> {
> >> u32 last_evm = 0, tmpVal;
> >> struct rx_pkt_attrib *pattrib;
> >> - struct smooth_rssi_data *sqd = &padapter->recvpriv.signal_qual_data;
> >> + struct smooth_rssi_data *sqd;
> >>
> >> if (!prframe || !padapter)
> >> return;
> >> +
> >> + sqd = &padapter->recvpriv.signal_qual_data;
> > How can padapter ever be NULL in this codepath?
> >
> > thanks,
> >
> > greg k-h
> Just the original  code, show me
>
> if (!prframe || !padapter)
>
> It would be null, and then return.

Again, trace things backwards, how can padapter ever be NULL?

2022-05-30 11:54:21

by baihaowen

Subject: Re: [PATCH] staging: rtl8712: Fix pointer dereferenced before checking

在 2022/5/30 下午4:26, Greg Kroah-Hartman 写道:
> On Mon, May 30, 2022 at 04:22:11PM +0800, baihaowen wrote:
>> 在 2022/5/30 下午4:14, Greg Kroah-Hartman 写道:
>>> On Mon, May 30, 2022 at 04:05:32PM +0800, Haowen Bai wrote:
>>>> The padapter->recvpriv.signal_qual_data is dereferencing before null
>>>> checking, so move it after checking.
>>>>
>>>> Signed-off-by: Haowen Bai <[email protected]>
>>>> ---
>>>> drivers/staging/rtl8712/rtl8712_recv.c | 4 +++-
>>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/staging/rtl8712/rtl8712_recv.c b/drivers/staging/rtl8712/rtl8712_recv.c
>>>> index 7f1fdd058551..8ed94b259dbe 100644
>>>> --- a/drivers/staging/rtl8712/rtl8712_recv.c
>>>> +++ b/drivers/staging/rtl8712/rtl8712_recv.c
>>>> @@ -863,10 +863,12 @@ static void process_link_qual(struct _adapter *padapter,
>>>> {
>>>> u32 last_evm = 0, tmpVal;
>>>> struct rx_pkt_attrib *pattrib;
>>>> - struct smooth_rssi_data *sqd = &padapter->recvpriv.signal_qual_data;
>>>> + struct smooth_rssi_data *sqd;
>>>>
>>>> if (!prframe || !padapter)
>>>> return;
>>>> +
>>>> + sqd = &padapter->recvpriv.signal_qual_data;
>>> How can padapter ever be NULL in this codepath?
>>>
>>> thanks,
>>>
>>> greg k-h
>> Just the original  code, show me
>>
>> if (!prframe || !padapter)
>>
>> It would be null, and then return.
> Again, trace things backwards, how can padapter ever be NULL?

padapter will not be null, since it's initialized by netdev_priv(pnetdev) and return if pnetdev is null. r871xu_drv_init() ...... pnetdev = r8712_init_netdev(); if (!pnetdev) goto error; padapter = netdev_priv(pnetdev); status = r8712_init_drv_sw(padapter); ......

--
Haowen Bai