wifi: mac80211: avoid out-of-bounds access in monitor

wifi: mac80211: avoid out-of-bounds access in monitor

In NAN, we don't know on what band the frame will be sent. Therefore we
set info->band to NUM_NL80211_BANDS. However, this leads to out-of-bound
access in ieee80211_add_tx_radiotap_header when we try to access the
sbands array.

Fix it by not accessing the array if the band is NUM_NL80211_BANDS.
This means that we will not report rate info for legacy rate in NAN.
But nobody really cares about it.

Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20260504101829.346c9893d136.I15919027597c04ec35c6217db6e52e2a605e5cfc@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>