feat: add KNX Data Secure support and related configurations

Signed-off-by: Tony <tonylu@tony-cloud.com>

apps/gateway/main/Kconfig.projbuild

@@ -621,6 +621,41 @@ config GATEWAY_START_KNX_BRIDGE_ENABLED
         Starts the KNXnet/IP tunneling/multicast listener at boot. Disabled by
         default so UDP port 3671 is opened only after provisioning or explicit start.
 
+config GATEWAY_KNX_DATA_SECURE_SUPPORTED
+    bool "Enable KNX Data Secure support"
+    depends on GATEWAY_KNX_BRIDGE_SUPPORTED
+    default n
+    help
+        Compiles the OpenKNX SecurityInterfaceObject and SecureApplicationLayer
+        into the ETS runtime. This is the application-layer security path used
+        for secure KNX group-object and ETS tool traffic.
+
+config GATEWAY_KNX_IP_SECURE_SUPPORTED
+    bool "Enable KNXnet/IP Secure support"
+    depends on GATEWAY_KNX_BRIDGE_SUPPORTED
+    default n
+    help
+        Builds gateway support for KNXnet/IP Secure tunneling and routing. The
+        secure session transport is implemented by the gateway-owned KNX/IP
+        router and is separate from KNX Data Secure APDU handling.
+
+config GATEWAY_KNX_SECURITY_DEV_ENDPOINTS
+    bool "Enable KNX security development HTTP endpoints"
+    depends on GATEWAY_KNX_DATA_SECURE_SUPPORTED || GATEWAY_KNX_IP_SECURE_SUPPORTED
+    default n
+    help
+        Exposes development-only HTTP actions for reading, writing, generating,
+        and resetting KNX security material. Disable this for production builds.
+
+config GATEWAY_KNX_SECURITY_PLAIN_NVS
+    bool "Store KNX security material in plain NVS"
+    depends on GATEWAY_KNX_DATA_SECURE_SUPPORTED || GATEWAY_KNX_IP_SECURE_SUPPORTED
+    default y
+    help
+        Stores development KNX security material in normal NVS. This is useful
+        during bring-up, but production builds should replace it with encrypted
+        NVS, flash encryption, and secure boot before exposing real keys.
+
 config GATEWAY_KNX_MAIN_GROUP
     int "KNX DALI main group"
     depends on GATEWAY_KNX_BRIDGE_SUPPORTED

apps/gateway/sdkconfig

@@ -688,6 +688,10 @@ CONFIG_GATEWAY_BACNET_BRIDGE_SUPPORTED=y
 # CONFIG_GATEWAY_START_BACNET_BRIDGE_ENABLED is not set
 CONFIG_GATEWAY_KNX_BRIDGE_SUPPORTED=y
 CONFIG_GATEWAY_START_KNX_BRIDGE_ENABLED=y
+CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED=y
+# CONFIG_GATEWAY_KNX_IP_SECURE_SUPPORTED is not set
+# CONFIG_GATEWAY_KNX_SECURITY_DEV_ENDPOINTS is not set
+CONFIG_GATEWAY_KNX_SECURITY_PLAIN_NVS=y
 CONFIG_GATEWAY_KNX_MAIN_GROUP=0
 CONFIG_GATEWAY_KNX_TUNNEL_ENABLED=y
 CONFIG_GATEWAY_KNX_MULTICAST_ENABLED=y

apps/gateway/sdkconfig.defaults

@@ -15,4 +15,5 @@ CONFIG_ETH_USE_SPI_ETHERNET=y
 CONFIG_ETH_SPI_ETHERNET_W5500=y
 CONFIG_GATEWAY_ETHERNET_SUPPORTED=y
 CONFIG_GATEWAY_START_ETHERNET_ENABLED=y
-CONFIG_GATEWAY_ETHERNET_IGNORE_INIT_FAILURE=y
+CONFIG_GATEWAY_ETHERNET_IGNORE_INIT_FAILURE=y
+CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED=y

components/gateway_bridge/src/gateway_bridge.cpp

@@ -16,6 +16,7 @@
 #include "gateway_modbus.hpp"
 #include "gateway_provisioning.hpp"
 #include "openknx_idf/ets_memory_loader.h"
+#include "openknx_idf/security_storage.h"
 
 #include "cJSON.h"
 #include "driver/uart.h"
@@ -121,6 +122,25 @@ GatewayBridgeHttpResponse ErrorResponse(esp_err_t err, const char* message) {
   return GatewayBridgeHttpResponse{err, body};
 }
 
+cJSON* FactoryFdskInfoToCjson(const openknx::FactoryFdskInfo& fdsk_info,
+                              bool include_secret_strings) {
+  cJSON* root = cJSON_CreateObject();
+  if (root == nullptr) {
+    return nullptr;
+  }
+  cJSON_AddBoolToObject(root, "available", fdsk_info.available);
+  if (fdsk_info.available) {
+    cJSON_AddStringToObject(root, "serialNumber", fdsk_info.serialNumber.c_str());
+    cJSON_AddNumberToObject(root, "labelLength", static_cast<double>(fdsk_info.label.size()));
+    cJSON_AddNumberToObject(root, "qrCodeLength", static_cast<double>(fdsk_info.qrCode.size()));
+    if (include_secret_strings) {
+      cJSON_AddStringToObject(root, "label", fdsk_info.label.c_str());
+      cJSON_AddStringToObject(root, "qrCode", fdsk_info.qrCode.c_str());
+    }
+  }
+  return root;
+}
+
 const char* JsonString(const cJSON* parent, const char* name) {
   const cJSON* item = cJSON_GetObjectItemCaseSensitive(parent, name);
   return cJSON_IsString(item) && item->valuestring != nullptr ? item->valuestring : nullptr;
@@ -2041,6 +2061,40 @@ struct GatewayBridgeService::ChannelRuntime {
       cJSON_AddStringToObject(knx_json, "lastError",
                               knx_last_error.empty() ? router_error.c_str()
                                                      : knx_last_error.c_str());
+      cJSON* security_json = cJSON_CreateObject();
+      if (security_json != nullptr) {
+#if defined(CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED)
+        cJSON_AddBoolToObject(security_json, "dataSecureCompiled", true);
+#else
+        cJSON_AddBoolToObject(security_json, "dataSecureCompiled", false);
+#endif
+#if defined(CONFIG_GATEWAY_KNX_IP_SECURE_SUPPORTED)
+        cJSON_AddBoolToObject(security_json, "knxnetIpSecureCompiled", true);
+#else
+        cJSON_AddBoolToObject(security_json, "knxnetIpSecureCompiled", false);
+#endif
+        cJSON_AddBoolToObject(security_json, "knxnetIpSecureImplemented", false);
+#if defined(CONFIG_GATEWAY_KNX_SECURITY_DEV_ENDPOINTS)
+        cJSON_AddBoolToObject(security_json, "developmentEndpointsEnabled", true);
+#else
+        cJSON_AddBoolToObject(security_json, "developmentEndpointsEnabled", false);
+#endif
+#if defined(CONFIG_GATEWAY_KNX_SECURITY_PLAIN_NVS)
+        cJSON_AddBoolToObject(security_json, "plainNvsStorage", true);
+        cJSON_AddStringToObject(security_json, "storage", "plain_nvs_development");
+#else
+        cJSON_AddBoolToObject(security_json, "plainNvsStorage", false);
+        cJSON_AddStringToObject(security_json, "storage", "none");
+#endif
+#if defined(CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED)
+        const auto fdsk_info = openknx::LoadFactoryFdskInfo();
+        cJSON* fdsk_json = FactoryFdskInfoToCjson(fdsk_info, false);
+        if (fdsk_json != nullptr) {
+          cJSON_AddItemToObject(security_json, "factorySetupKey", fdsk_json);
+        }
+#endif
+        cJSON_AddItemToObject(knx_json, "security", security_json);
+      }
       if (effective_knx.has_value()) {
         cJSON_AddBoolToObject(knx_json, "daliRouterEnabled", effective_knx->dali_router_enabled);
         cJSON_AddBoolToObject(knx_json, "ipRouterEnabled", effective_knx->ip_router_enabled);
@@ -4008,6 +4062,36 @@ GatewayBridgeHttpResponse GatewayBridgeService::handlePost(
     }
     return handleGet("knx", gateway_id.value());
   }
+  if (action == "knx_security_read_factory_key") {
+#if defined(CONFIG_GATEWAY_KNX_SECURITY_DEV_ENDPOINTS) && \
+    defined(CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED)
+    cJSON* body_root = body.empty() ? nullptr : cJSON_ParseWithLength(body.data(), body.size());
+    if (body_root == nullptr) {
+      return ErrorResponse(ESP_ERR_INVALID_ARG, "confirmation JSON is required");
+    }
+    const char* confirm = JsonString(body_root, "confirm");
+    const bool confirmed = confirm != nullptr &&
+                           std::string_view(confirm) == "read-factory-setup-key";
+    cJSON_Delete(body_root);
+    if (!confirmed) {
+      return ErrorResponse(ESP_ERR_INVALID_ARG, "factory setup key read confirmation is required");
+    }
+    cJSON* response = cJSON_CreateObject();
+    if (response == nullptr) {
+      return ErrorResponse(ESP_ERR_NO_MEM, "failed to allocate security response");
+    }
+    cJSON* fdsk_json = FactoryFdskInfoToCjson(openknx::LoadFactoryFdskInfo(), true);
+    if (fdsk_json == nullptr) {
+      cJSON_Delete(response);
+      return ErrorResponse(ESP_ERR_NO_MEM, "failed to allocate factory setup key response");
+    }
+    cJSON_AddItemToObject(response, "factorySetupKey", fdsk_json);
+    return JsonOk(response);
+#else
+    return ErrorResponse(ESP_ERR_NOT_SUPPORTED,
+                         "KNX security development endpoints are disabled");
+#endif
+  }
   if (action == "bacnet_start") {
     const esp_err_t err = runtime->startBacnet();
     if (err != ESP_OK) {

components/openknx_idf/CMakeLists.txt

@@ -13,6 +13,12 @@ file(GLOB OPENKNX_SRCS
     "${OPENKNX_ROOT}/src/knx/*.cpp"
 )
 
+if(CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED)
+    list(APPEND OPENKNX_SRCS
+        "${OPENKNX_ROOT}/src/knx/aes.c"
+    )
+endif()
+
 set(TPUART_SRCS
     "${TPUART_ROOT}/src/TPUart/DataLinkLayer.cpp"
     "${TPUART_ROOT}/src/TPUart/Receiver.cpp"
@@ -31,6 +37,7 @@ idf_component_register(
         "src/esp_idf_platform.cpp"
         "src/ets_device_runtime.cpp"
         "src/ets_memory_loader.cpp"
+        "src/security_storage.cpp"
         "src/tpuart_uart_interface.cpp"
         ${OPENKNX_SRCS}
         ${TPUART_SRCS}
@@ -42,11 +49,13 @@ idf_component_register(
         esp_driver_gpio
         esp_driver_uart
         esp_netif
+        esp_system
         esp_timer
         esp_wifi
         freertos
         log
         lwip
+        mbedtls
         nvs_flash
 )
 
@@ -58,6 +67,10 @@ target_compile_definitions(${COMPONENT_LIB} PUBLIC
     USE_CEMI_SERVER
 )
 
+if(CONFIG_GATEWAY_KNX_DATA_SECURE_SUPPORTED)
+    target_compile_definitions(${COMPONENT_LIB} PUBLIC USE_DATASECURE)
+endif()
+
 target_compile_options(${COMPONENT_LIB} PRIVATE
     -Wno-unused-parameter
 )

components/openknx_idf/include/openknx_idf/openknx_idf.h

@@ -3,6 +3,7 @@
 #include "openknx_idf/ets_memory_loader.h"
 #include "openknx_idf/ets_device_runtime.h"
 #include "openknx_idf/esp_idf_platform.h"
+#include "openknx_idf/security_storage.h"
 #include "openknx_idf/tpuart_uart_interface.h"
 
 #include "knx/bau07B0.h"

components/openknx_idf/include/openknx_idf/security_storage.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+
+namespace gateway::openknx {
+
+struct FactoryFdskInfo {
+  bool available{false};
+  std::string serialNumber;
+  std::string label;
+  std::string qrCode;
+};
+
+bool LoadFactoryFdsk(uint8_t* data, size_t len);
+FactoryFdskInfo LoadFactoryFdskInfo();
+
+}  // namespace gateway::openknx

components/openknx_idf/src/security_storage.cpp

@@ -0,0 +1,181 @@
+#include "openknx_idf/security_storage.h"
+
+#include "esp_log.h"
+#include "esp_mac.h"
+#include "esp_random.h"
+#include "nvs.h"
+#include "nvs_flash.h"
+
+#include <algorithm>
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <string>
+
+namespace {
+
+constexpr const char* kTag = "openknx_sec";
+constexpr const char* kNamespace = "knx_sec";
+constexpr const char* kFactoryFdskKey = "factory_fdsk";
+constexpr size_t kFdskSize = 16;
+constexpr size_t kSerialSize = 6;
+constexpr size_t kFdskQrSize = 36;
+constexpr uint8_t kCrc4Tab[16] = {
+  0x0, 0x3, 0x6, 0x5, 0xc, 0xf, 0xa, 0x9,
+  0xb, 0x8, 0xd, 0xe, 0x7, 0x4, 0x1, 0x2,
+};
+constexpr char kBase32Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
+constexpr char kHexAlphabet[] = "0123456789ABCDEF";
+
+bool ensureNvsReady() {
+  const esp_err_t err = nvs_flash_init();
+  if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+    if (nvs_flash_erase() != ESP_OK) {
+      return false;
+    }
+    return nvs_flash_init() == ESP_OK;
+  }
+  return err == ESP_OK || err == ESP_ERR_INVALID_STATE;
+}
+
+bool plausibleKey(const uint8_t* data) {
+  const bool all_zero = std::all_of(data, data + kFdskSize, [](uint8_t value) {
+    return value == 0x00;
+  });
+  const bool all_ff = std::all_of(data, data + kFdskSize, [](uint8_t value) {
+    return value == 0xff;
+  });
+  return !all_zero && !all_ff;
+}
+
+void generateKey(uint8_t* data) {
+  do {
+    esp_fill_random(data, kFdskSize);
+  } while (!plausibleKey(data));
+}
+
+uint8_t crc4Array(const uint8_t* data, size_t len) {
+  uint8_t crc = 0;
+  for (size_t i = 0; i < len; ++i) {
+    crc = kCrc4Tab[crc ^ (data[i] >> 4)];
+    crc = kCrc4Tab[crc ^ (data[i] & 0x0f)];
+  }
+  return crc;
+}
+
+std::string toBase32NoPadding(const uint8_t* data, size_t len) {
+  std::string result;
+  result.reserve(((len * 8) + 4) / 5);
+
+  uint32_t buffer = 0;
+  int bits_left = 0;
+  for (size_t i = 0; i < len; ++i) {
+    buffer = (buffer << 8) | data[i];
+    bits_left += 8;
+    while (bits_left >= 5) {
+      const uint8_t index = static_cast<uint8_t>((buffer >> (bits_left - 5)) & 0x1f);
+      result.push_back(kBase32Alphabet[index]);
+      bits_left -= 5;
+    }
+  }
+
+  if (bits_left > 0) {
+    const uint8_t index = static_cast<uint8_t>((buffer << (5 - bits_left)) & 0x1f);
+    result.push_back(kBase32Alphabet[index]);
+  }
+  return result;
+}
+
+std::string toHex(const uint8_t* data, size_t len) {
+  std::string result;
+  result.reserve(len * 2);
+  for (size_t i = 0; i < len; ++i) {
+    result.push_back(kHexAlphabet[(data[i] >> 4) & 0x0f]);
+    result.push_back(kHexAlphabet[data[i] & 0x0f]);
+  }
+  return result;
+}
+
+std::string generateFdskQrCode(const uint8_t* serial, const uint8_t* key) {
+  std::array<uint8_t, kSerialSize + kFdskSize + 1> buffer{};
+  std::copy(serial, serial + kSerialSize, buffer.begin());
+  std::copy(key, key + kFdskSize, buffer.begin() + kSerialSize);
+  buffer[kSerialSize + kFdskSize] = static_cast<uint8_t>((crc4Array(buffer.data(), buffer.size() - 1) << 4) & 0xff);
+
+  std::string encoded = toBase32NoPadding(buffer.data(), buffer.size());
+  if (encoded.size() > kFdskQrSize) {
+    encoded.resize(kFdskQrSize);
+  }
+  return encoded;
+}
+
+std::string formatFdskLabel(const std::string& qr_code) {
+  std::string label;
+  label.reserve(qr_code.size() + (qr_code.size() / 6));
+  for (size_t i = 0; i < qr_code.size(); ++i) {
+    if (i != 0 && (i % 6) == 0) {
+      label.push_back('-');
+    }
+    label.push_back(qr_code[i]);
+  }
+  return label;
+}
+
+}  // namespace
+
+namespace gateway::openknx {
+
+bool LoadFactoryFdsk(uint8_t* data, size_t len) {
+  if (data == nullptr || len < kFdskSize || !ensureNvsReady()) {
+    return false;
+  }
+
+  nvs_handle_t handle = 0;
+  esp_err_t err = nvs_open(kNamespace, NVS_READWRITE, &handle);
+  if (err != ESP_OK) {
+    ESP_LOGW(kTag, "failed to open KNX security NVS namespace: %s", esp_err_to_name(err));
+    return false;
+  }
+
+  size_t stored_size = kFdskSize;
+  err = nvs_get_blob(handle, kFactoryFdskKey, data, &stored_size);
+  if (err == ESP_OK && stored_size == kFdskSize && plausibleKey(data)) {
+    nvs_close(handle);
+    return true;
+  }
+
+  generateKey(data);
+  err = nvs_set_blob(handle, kFactoryFdskKey, data, kFdskSize);
+  if (err == ESP_OK) {
+    err = nvs_commit(handle);
+  }
+  nvs_close(handle);
+
+  if (err != ESP_OK) {
+    ESP_LOGW(kTag, "failed to store generated KNX factory FDSK: %s", esp_err_to_name(err));
+    return false;
+  }
+  return true;
+}
+
+FactoryFdskInfo LoadFactoryFdskInfo() {
+  FactoryFdskInfo info;
+  std::array<uint8_t, kFdskSize> key{};
+  std::array<uint8_t, kSerialSize> serial{};
+  if (!LoadFactoryFdsk(key.data(), key.size()) ||
+      esp_read_mac(serial.data(), ESP_MAC_WIFI_STA) != ESP_OK) {
+    return info;
+  }
+
+  info.available = true;
+  info.serialNumber = toHex(serial.data(), serial.size());
+  info.qrCode = generateFdskQrCode(serial.data(), key.data());
+  info.label = formatFdskLabel(info.qrCode);
+  return info;
+}
+
+}  // namespace gateway::openknx
+
+extern "C" bool knx_platform_get_fdsk(uint8_t* data, size_t len) {
+  return gateway::openknx::LoadFactoryFdsk(data, len);
+}