Re: [PATCH 39/64] mac80211: Use memset_after() to clear tx status

Johannes Berg
2021-08-13T18:19:56Z

On Fri, 2021-08-13 at 09:08 -0700, Kees Cook wrote:
> >
> > The common helper should also clear ack_signal, but that was broken by
> > commit e3e1a0bcb3f1 ("mac80211: reduce IEEE80211_TX_MAX_RATES"), because
> > that commit changed the order of the fields and updated carl9170 and p54
> > properly but not the common helper...
>
> It looks like p54 actually uses the rates, which is why it does this
> manually. I can't see why carl9170 does this manually, though.

mac80211 also uses the rates later again on status reporting, it just
expects the # of attempts to be filled etc. I haven't looked at
carl9170, but I would expect it to do something there and do it
correctly, even though old it's a well-written driver and uses mac80211
rate control, so this would need to be correct for decent performance.

But I guess it could be that the helper could be used because the rates
were already handed to the firmware, and the code was just copy/pasted
from p54 (the drivers were, IIRC, developed by the same folks)

johannes