Re: [PATCH] iwlegacy: 3945-rs: fix possible null-pointer dereferences in il3945_rs_get_rate()

[Tuo Li]

On Wed, Jan 7, 2026 at 4:06 PM Stanislaw Gruszka <stf_xl@xxxxx> wrote:
>
> On Wed, Jan 07, 2026 at 08:44:40AM +0100, Stanislaw Gruszka wrote:
> > On Wed, Jan 07, 2026 at 03:10:01PM +0800, Tuo Li wrote:
> > > In this function, il_sta is assigned to rs_sta, and rs_sta is dereferenced
> > > at several points. If il_sta is NULL, this can lead to null-pointer
> > > dereferences. To fix this issue, add an early check for il_sta and return
> > > if it is NULL, consistent with the handling in il3945_rs_tx_status().
> > >
> > > Signed-off-by: Tuo Li <islituo@xxxxxxxxx>
> > > ---
> > >  drivers/net/wireless/intel/iwlegacy/3945-rs.c | 7 ++++++-
> > >  1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/wireless/intel/iwlegacy/3945-rs.c b/drivers/net/wireless/intel/iwlegacy/3945-rs.c
> > > index 1826c37c090c..c13268093a6e 100644
> > > --- a/drivers/net/wireless/intel/iwlegacy/3945-rs.c
> > > +++ b/drivers/net/wireless/intel/iwlegacy/3945-rs.c
> > > @@ -626,8 +626,13 @@ il3945_rs_get_rate(void *il_r, struct ieee80211_sta *sta, void *il_sta,
> > >
> > >     D_RATE("enter\n");
> > >
> > > +   if (!il_sta) {
> > > +           D_RATE("leave: No STA il data available!\n");
> > > +           return;
> > > +   }
> > > +
> > >     /* Treat uninitialized rate scaling data same as non-existing. */
> > > -   if (rs_sta && !rs_sta->il) {
> > > +   if (!rs_sta->il) {
> > >             D_RATE("Rate scaling information not initialized yet.\n");
> > >             il_sta = NULL;
> > Please also change to return here instead of setting il_sta to NULL.
> > And make D_RATE messages similar to il3945_rs_tx_status() i.e. :
> >
> >           if (!il_sta) {
> >                   D_RATE("leave: No STA il data to update!\n");
> >                   return;
> >           }
> >
> >           /* Treat uninitialized rate scaling data same as non-existing. */
> >           if (!rs_sta->il) {
> >                   D_RATE("leave: STA il data uninitialized!\n");
> >                   return;
> >           }
>
> Please also add 'wifi:' prefix to the patch title.
>
> Thanks
> Stanislaw

Hi Stanislaw,

Thank you for your reply. I will update the patch according to your
suggestions and submit a v2.

Sincerely,
Tuo