Re: [PATCH v2] wifi: 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 04:41:49PM +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().
> 
> Besides, if the STA il data is uninitialized, return early instead of
> setting il_sta to NULL, consistent with the handling in
> il3945_rs_tx_status().
> 
> Signed-off-by: Tuo Li <islituo@gmail.com>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>

Thanks
Stanislaw
> ---
> v2:
> * Return early for uninitialized STA il data and align D_RATE messages with
>   il3945_rs_tx_status(). Add a wifi: prefix to the patch title.
>   Thanks to Stanislaw Gruszka for the helpful advice.
> ---
>  drivers/net/wireless/intel/iwlegacy/3945-rs.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/wireless/intel/iwlegacy/3945-rs.c b/drivers/net/wireless/intel/iwlegacy/3945-rs.c
> index 1826c37c090c..c509c89bba00 100644
> --- a/drivers/net/wireless/intel/iwlegacy/3945-rs.c
> +++ b/drivers/net/wireless/intel/iwlegacy/3945-rs.c
> @@ -626,10 +626,15 @@ 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 to update!\n");
> +		return;
> +	}
> +
>  	/* Treat uninitialized rate scaling data same as non-existing. */
> -	if (rs_sta && !rs_sta->il) {
> -		D_RATE("Rate scaling information not initialized yet.\n");
> -		il_sta = NULL;
> +	if (!rs_sta->il) {
> +		D_RATE("leave: STA il data uninitialized!\n");
> +		return;
>  	}
>  
>  	rate_mask = sta->deflink.supp_rates[sband->band];
> -- 
> 2.43.0
>