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

[Stanislaw Gruszka <stf_xl@wp.pl>]

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@gmail.com>
> > ---
> >  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