Re: [PATCH] wifi: mac80211: reject station association if AP is not started

On lip 23, 2026 11:14, Johannes Berg wrote:
> On Thu, 2026-07-23 at 08:11 +0000, syzbot wrote:
> > From: Slawomir Stepien <[email protected]>
> 
> I'm a bit confused? Did syzbot just pick up another patch?

Hi Johannes!

No, this issue has been found by syzbot while doing fuzzing testing.

> > dereferences the NULL chanctx_conf, triggering a WARN_ON:
> 
> That can't be right?

Yeah, right. I will rephrase it in v2.

> > Fix this by rejecting the addition or modification of a station to the
> > associated state if the AP has not been started (chanctx_conf is NULL).
> 
> That's a proxy for "AP is started", but not a good one, I think we
> actually have a flag or so somewhere? Maybe even reject it in cfg80211?

I haven't seen a good place for rejection, but let me double check.

> > Exempt Multi-Link Operation (MLO) interfaces from this check, as they
> > handle chanctx_conf per-link rather than globally on the VIF.
> 
> Feels like that's only necessary because the proxy is bad.
> 
> Also maybe a similar issue arises if an MLO AP is only half-started, and
> stations are added to all links, or so?

Not sure about MLO, but your suggestion sounds logical and such case might be the same as this one.
I will take a look at this too.

-- 
Slawomir Stepien