Re: [PATCH wireless-next] wifi: mac80211: reject VHT opmode for unsupported channel widths

["Nicolas Escande" <nico.escande@gmail.com>]

On Wed Jul 2, 2025 at 8:59 AM CEST, Moon Hee Lee wrote:
> VHT operating mode notifications must not be processed when the channel
> width is 5 MHz or 10 MHz, as the VHT specification does not support these
> narrow widths.

Hello,
Is this really specific for VHT ? or for HE /EHT as well ?

>
> Without validation, a malformed notification using 10 MHz can reach
> ieee80211_chan_width_to_rx_bw(), triggering a WARN_ON due to the invalid
> width. This issue was reported by syzbot.
>
> Reject these widths early in sta_link_apply_parameters() when
> opmode_notif is used.
>
> Reported-by: syzbot+ededba317ddeca8b3f08@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=ededba317ddeca8b3f08
> Fixes: 751e7489c1d7 ("wifi: mac80211: expose ieee80211_chan_width_to_rx_bw() to drivers")
> Tested-by: syzbot+ededba317ddeca8b3f08@syzkaller.appspotmail.com
> Signed-off-by: Moon Hee Lee <moonhee.lee.ca@gmail.com>
> ---
>  net/mac80211/cfg.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
> index 56540c3701ed..5a6ae093a8bd 100644
> --- a/net/mac80211/cfg.c
> +++ b/net/mac80211/cfg.c
> @@ -1981,6 +1981,21 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
>  	ieee80211_sta_init_nss(link_sta);
>  
>  	if (params->opmode_notif_used) {
> +		enum nl80211_chan_width width = link->conf->chanreq.oper.width;
> +
> +		switch (width) {
> +		case NL80211_CHAN_WIDTH_20_NOHT:
Because this seems weird for VHT
> +		case NL80211_CHAN_WIDTH_20:
> +		case NL80211_CHAN_WIDTH_40:
> +		case NL80211_CHAN_WIDTH_80:
> +		case NL80211_CHAN_WIDTH_160:
> +		case NL80211_CHAN_WIDTH_80P80:
> +		case NL80211_CHAN_WIDTH_320:
And this did not exist for VHT either
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +
>  		/* returned value is only needed for rc update, but the
>  		 * rc isn't initialized here yet, so ignore it
>  		 */