[PATCH v3 wireless-next] wifi: mac80211: defer AP-side FT key upload until association

@@ -666,7 +666,15 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct wireless_dev *wdev,
 		key->conf.flags |= IEEE80211_KEY_FLAG_NO_AUTO_TX;
 
 	if (mac_addr) {
+		bool defer_hw_upload;
+
 		sta = sta_info_get_bss(sdata, mac_addr);
+		defer_hw_upload =
+			sta && pairwise && !sta->sta.epp_peer &&
+			!test_sta_flag(sta, WLAN_STA_ASSOC) &&
+			(sdata->vif.type == NL80211_IFTYPE_AP ||
+			 sdata->vif.type == NL80211_IFTYPE_AP_VLAN) &&
+			!ieee80211_hw_check(&local->hw, SW_CRYPTO_CONTROL);
 		/*
 		 * The ASSOC test makes sure the driver is ready to
 		 * receive the key. When wpa_supplicant has roamed

@@ -681,14 +689,22 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct wireless_dev *wdev,
 		 * If (re)association frame encryption support is not present,
 		 * cfg80211 will not allow key installation in non‑AP STA mode.
 		 *
-		 * TODO: accept the key if we have a station entry and
-		 *	 add it to the device after the station associates.
+		 * AP-side FT may also install a pairwise key before the
+		 * station is associated. If automatic software fallback is
+		 * allowed, keep it in mac80211 and upload it after the station
+		 * reaches ASSOC. Drivers with SW_CRYPTO_CONTROL cannot use this
+		 * path since only their set_key() return value can permit
+		 * software crypto.
 		 */
 		if (!sta || (!sta->sta.epp_peer &&
-			     !test_sta_flag(sta, WLAN_STA_ASSOC))) {
+			     !test_sta_flag(sta, WLAN_STA_ASSOC) &&
+			     !defer_hw_upload)) {
 			ieee80211_key_free_unused(key);
 			return -ENOENT;
 		}
+
+		if (defer_hw_upload)
+			key->flags |= KEY_FLAG_DEFERRED_HW_UPLOAD;
 	}
 
 	switch (sdata->vif.type) {

@@ -144,6 +144,14 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 		return -EINVAL;
 	}
 
+	if (key->flags & KEY_FLAG_DEFERRED_HW_UPLOAD) {
+		/*
+		 * Deferred keys allow automatic software fallback. Keep ret at
+		 * -EOPNOTSUPP until the station is ready for hardware upload.
+		 */
+		goto out_unsupported;
+	}
+
 	if (!key->local->ops->set_key)
 		goto out_unsupported;
 

@@ -997,6 +1005,36 @@ void ieee80211_reenable_keys(struct ieee80211_sub_if_data *sdata)
 	}
 }
 
+void ieee80211_upload_deferred_sta_keys(struct sta_info *sta)
+{
+	struct ieee80211_local *local = sta->local;
+	struct ieee80211_key *key;
+	int i, ret;
+
+	lockdep_assert_wiphy(local->hw.wiphy);
+
+	for (i = 0; i < ARRAY_SIZE(sta->ptk); i++) {
+		key = wiphy_dereference(local->hw.wiphy, sta->ptk[i]);
+		if (!key || !(key->flags & KEY_FLAG_DEFERRED_HW_UPLOAD))
+			continue;
+
+		/* Capabilities may have changed since key installation. */
+		key->conf.flags &= ~(IEEE80211_KEY_FLAG_RX_MGMT |
+				     IEEE80211_KEY_FLAG_SPP_AMSDU);
+		if (test_sta_flag(sta, WLAN_STA_MFP))
+			key->conf.flags |= IEEE80211_KEY_FLAG_RX_MGMT;
+		if (sta->sta.spp_amsdu)
+			key->conf.flags |= IEEE80211_KEY_FLAG_SPP_AMSDU;
+
+		key->flags &= ~KEY_FLAG_DEFERRED_HW_UPLOAD;
+		ret = ieee80211_key_enable_hw_accel(key);
+		if (ret)
+			sdata_err(key->sdata,
+				  "failed to enable deferred key (%d, %pM): %d\n",
+				  key->conf.keyidx, sta->sta.addr, ret);
+	}
+}
+
 static void
 ieee80211_key_iter(struct ieee80211_hw *hw,
 		   struct ieee80211_vif *vif,

@@ -32,10 +32,13 @@ struct sta_info;
  * @KEY_FLAG_UPLOADED_TO_HARDWARE: Indicates that this key is present
  *	in the hardware for TX crypto hardware acceleration.
  * @KEY_FLAG_TAINTED: Key is tainted and packets should be dropped.
+ * @KEY_FLAG_DEFERRED_HW_UPLOAD: Key upload is deferred until the station
+ *	is associated.
  */
 enum ieee80211_internal_key_flags {
 	KEY_FLAG_UPLOADED_TO_HARDWARE	= BIT(0),
 	KEY_FLAG_TAINTED		= BIT(1),
+	KEY_FLAG_DEFERRED_HW_UPLOAD	= BIT(2),
 };
 
 enum ieee80211_internal_tkip_state {

@@ -165,6 +168,7 @@ void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata,
 			 bool force_synchronize);
 void ieee80211_free_sta_keys(struct ieee80211_local *local,
 			     struct sta_info *sta);
+void ieee80211_upload_deferred_sta_keys(struct sta_info *sta);
 void ieee80211_reenable_keys(struct ieee80211_sub_if_data *sdata);
 int ieee80211_key_switch_links(struct ieee80211_sub_if_data *sdata,
 			       unsigned long del_links_mask,

@@ -1468,6 +1468,7 @@ static int _sta_info_move_state(struct sta_info *sta,
 	case IEEE80211_STA_ASSOC:
 		if (sta->sta_state == IEEE80211_STA_AUTH) {
 			set_bit(WLAN_STA_ASSOC, &sta->_flags);
+			ieee80211_upload_deferred_sta_keys(sta);
 			sta->assoc_at = ktime_get_boottime_ns();
 			if (recalc) {
 				ieee80211_recalc_min_chandef(sta->sdata, -1);