[PATCH ath-next 1/4] wifi: ath12k: validate survey index when frequency is not found

[Baochen Qiang]

On 2/9/2026 11:02 AM, m.limarencko at yandex.ru wrote:
> From: Mikhail Limarenko <m.limarencko at yandex.ru>
> 
> freq_to_idx() currently returns a monotonic index even when the
> 
> frequency was never matched.
> 
> In chan info paths this can lead to out-of-bounds survey indexing

how can out-of-bound index happen? there is already the ARRAY_SIZE(ar->survey) check there
to prevent this, no?

> 
> for unexpected frequency events.
> 
> Return -EINVAL on no match and make callers reject negative
> 
> indexes.
> 
> Tested-on: QCNFA765 (WCN785x), kernel 6.18.5+deb13-amd64
> Signed-off-by: Mikhail Limarenko <m.limarencko at yandex.ru>
> ---
>  drivers/net/wireless/ath/ath12k/wmi.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
> index e647b84..422e3f8 100644
> --- a/drivers/net/wireless/ath/ath12k/wmi.c
> +++ b/drivers/net/wireless/ath/ath12k/wmi.c
> @@ -6520,7 +6520,7 @@ static int freq_to_idx(struct ath12k *ar, int freq)
>  		if (!sband)
>  			continue;
>  
> -		for (ch = 0; ch < sband->n_channels; ch++, idx++) {
> +		for (ch = 0; ch < sband->n_channels; ch++) {
>  			if (sband->channels[ch].center_freq <
>  			    KHZ_TO_MHZ(ar->freq_range.start_freq) ||
>  			    sband->channels[ch].center_freq >
> @@ -6528,12 +6528,13 @@ static int freq_to_idx(struct ath12k *ar, int freq)
>  				continue;
>  
>  			if (sband->channels[ch].center_freq == freq)
> -				goto exit;
> +				return idx;
> +
> +			idx++;
>  		}
>  	}
>  
> -exit:
> -	return idx;
> +	return -EINVAL;
>  }
>  
>  static int ath12k_pull_chan_info_ev(struct ath12k_base *ab, struct sk_buff *skb,
> @@ -7475,7 +7476,7 @@ static void ath12k_chan_info_event(struct ath12k_base *ab, struct sk_buff *skb)
>  	}
>  
>  	idx = freq_to_idx(ar, le32_to_cpu(ch_info_ev.freq));
> -	if (idx >= ARRAY_SIZE(ar->survey)) {
> +	if (idx < 0 || idx >= ARRAY_SIZE(ar->survey)) {
>  		ath12k_warn(ab, "chan info: invalid frequency %d (idx %d out of bounds)\n",
>  			    ch_info_ev.freq, idx);
>  		goto exit;
> @@ -7550,7 +7551,7 @@ ath12k_pdev_bss_chan_info_event(struct ath12k_base *ab, struct sk_buff *skb)
>  
>  	spin_lock_bh(&ar->data_lock);
>  	idx = freq_to_idx(ar, le32_to_cpu(bss_ch_info_ev.freq));
> -	if (idx >= ARRAY_SIZE(ar->survey)) {
> +	if (idx < 0 || idx >= ARRAY_SIZE(ar->survey)) {
>  		ath12k_warn(ab, "bss chan info: invalid frequency %d (idx %d out of bounds)\n",
>  			    bss_ch_info_ev.freq, idx);
>  		goto exit;