wifi: iwlwifi: mvm: fix ptk_pn memory leak

If adding a key to firmware fails we leak the allocated ptk_pn.
This shouldn't happen in practice, but we should still fix it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230414130637.99446ffd02bc.I82a2ad6ec1395f188e0a1677cc619e3fcb1feac9@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

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

@@ -4107,7 +4107,7 @@ static int __iwl_mvm_mac_set_key(struct ieee80211_hw *hw,
 	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
 	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
 	struct iwl_mvm_sta *mvmsta = NULL;
-	struct iwl_mvm_key_pn *ptk_pn;
+	struct iwl_mvm_key_pn *ptk_pn = NULL;
 	int keyidx = key->keyidx;
 	u32 sec_key_id = WIDE_ID(DATA_PATH_GROUP, SEC_KEY_CMD);
 	u8 sec_key_ver = iwl_fw_lookup_cmd_ver(mvm->fw, sec_key_id, 0);
@@ -4265,6 +4265,10 @@ static int __iwl_mvm_mac_set_key(struct ieee80211_hw *hw,
 		if (ret) {
 			IWL_WARN(mvm, "set key failed\n");
 			key->hw_key_idx = STA_KEY_IDX_INVALID;
+			if (ptk_pn) {
+				RCU_INIT_POINTER(mvmsta->ptk_pn[keyidx], NULL);
+				kfree(ptk_pn);
+			}
 			/*
 			 * can't add key for RX, but we don't need it
 			 * in the device for TX so still return 0,