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SubjectRe: [PATCH] staging: r8188eu: fix a potential NULL pointer dereference
On Sun, Apr 24, 2022 at 5:17 AM Fabio M. De Francesco
<fmdefrancesco@gmail.com> wrote:
>
> On sabato 23 aprile 2022 20:47:48 CEST Vihas Makwana wrote:
> > recvframe_chk_defrag() performs a NULL check on psta, but if that check
> > fails then it dereferences it, which it shouldn't do as psta is NULL.
> >
> > Set pdefrag_q to NULL if above check fails and let the code after it
> handle
> > that case.
> >
> > Fixes: 1cc18a22b96b ("staging: r8188eu: Add files for new driver - part
> 5")
> > Signed-off-by: Vihas Makwana <makvihas@gmail.com>
> > ---
> > drivers/staging/r8188eu/core/rtw_recv.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/staging/r8188eu/core/rtw_recv.c b/drivers/staging/
> r8188eu/core/rtw_recv.c
> > index c1005ddaa..db54bceff 100644
> > --- a/drivers/staging/r8188eu/core/rtw_recv.c
> > +++ b/drivers/staging/r8188eu/core/rtw_recv.c
> > @@ -1244,7 +1244,7 @@ struct recv_frame *recvframe_chk_defrag(struct
> adapter *padapter, struct recv_fr
> > pdefrag_q = NULL;
> > }
> > } else {
> > - pdefrag_q = &psta->sta_recvpriv.defrag_q;
> > + pdefrag_q = NULL;
>
> Hi Vihas,
>
> To me the code looks like this...
>
> struct sta_info *psta;
> ...
> psta = rtw_get_stainfo(pstapriv, psta_addr);
> /* The code is about to test if "psta" is a valid pointer */
> if (!psta) {
> /* "psta" is NULL */
> ...
> } else {
> /* "psta" is not NULL */
> ...
>
> > }
> >
>
> Also, even if "psta" were NULL (but it isn't), your change would still be
> no good.
>
> Please be very careful with these types of changes next time :)
>
> Thanks,
>
> Fabio M. De Francesco
>
> > if ((ismfrag == 0) && (fragnum == 0))
> > --
Oh yea, sorry about this. I don't know how I missed this.
Thanks for clarification Fabio. Will take care next time.


--
Thanks,
Vihas

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