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 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;
          }

Thanks
Stanislaw