wifi: iwlwifi: mvm: fix a crash when we run out of stations

A DoS tool that injects loads of authentication frames made our AP
crash. The iwl_mvm_is_dup() function couldn't find the per-queue
dup_data which was not allocated.

The root cause for that is that we ran out of stations in the firmware
and we didn't really add the station to the firmware, yet we didn't
return an error to mac80211.
Mac80211 was thinking that we have the station and because of that,
sta_info::uploaded was set to 1. This allowed
ieee80211_find_sta_by_ifaddr() to return a valid station object, but
that ieee80211_sta didn't have any iwl_mvm_sta object initialized and
that caused the crash mentioned earlier when we got Rx on that station.

Cc: stable@vger.kernel.org
Fixes: 57974a55 ("wifi: iwlwifi: mvm: refactor iwl_mvm_mac_sta_state_common()")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240206175739.1f76c44b2486.I6a00955e2842f15f0a089db2f834adb9d10fbe35@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

@@ -3687,6 +3687,9 @@ iwl_mvm_sta_state_notexist_to_none(struct iwl_mvm *mvm,
 					   NL80211_TDLS_SETUP);
 	}
 
+	if (ret)
+		return ret;
+
 	for_each_sta_active_link(vif, sta, link_sta, i)
 		link_sta->agg.max_rc_amsdu_len = 1;
 

drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c

@@ -505,6 +505,10 @@ static bool iwl_mvm_is_dup(struct ieee80211_sta *sta, int queue,
 		return false;
 
 	mvm_sta = iwl_mvm_sta_from_mac80211(sta);
+
+	if (WARN_ON_ONCE(!mvm_sta->dup_data))
+		return false;
+
 	dup_data = &mvm_sta->dup_data[queue];
 
 	/*