Add option to preserve private key for factory reset (config) (#4679)

* Add option to preserve private key for factory reset (config)

* Typo fix

* Copy the key in the right direction, and set the size.

* Don't set the key size back to 0 right after setting it to 32.

* Set the key size before using it to do a memcpy.

* Use the right key_size for backing up private_key

* Don't factoryReset() for a missing nodeDB

* Disable Bluetooth in AdminModule when resetting device settings or nodeDB to avoid race

* Add checks for valid objects before deinit bluetooth

* Add disableBluetooth to handleSetConfig, handleSetModuleConfig, and commit settings

---------

Co-authored-by: Jonathan Bennett <jbennett@incomsystems.biz>

src/mesh/NodeDB.cpp

@@ -245,7 +245,7 @@ bool NodeDB::factoryReset(bool eraseBleBonds)
 #endif
     // second, install default state (this will deal with the duplicate mac address issue)
     installDefaultDeviceState();
-    installDefaultConfig();
+    installDefaultConfig(!eraseBleBonds); // Also preserve the private key if we're not erasing BLE bonds
     installDefaultModuleConfig();
     installDefaultChannels();
     // third, write everything to disk
@@ -268,8 +268,13 @@ bool NodeDB::factoryReset(bool eraseBleBonds)
     return true;
 }
 
-void NodeDB::installDefaultConfig()
+void NodeDB::installDefaultConfig(bool preserveKey = false)
 {
+    uint8_t private_key_temp[32];
+    bool shouldPreserveKey = preserveKey && config.has_security && config.security.private_key.size > 0;
+    if (shouldPreserveKey) {
+        memcpy(private_key_temp, config.security.private_key.bytes, config.security.private_key.size);
+    }
     LOG_INFO("Installing default LocalConfig\n");
     memset(&config, 0, sizeof(meshtastic_LocalConfig));
     config.version = DEVICESTATE_CUR_VER;
@@ -310,8 +315,14 @@ void NodeDB::installDefaultConfig()
 #else
     config.security.admin_key[0].size = 0;
 #endif
-    config.security.public_key.size = 0;
+    if (shouldPreserveKey) {
+        config.security.private_key.size = 32;
+        memcpy(config.security.private_key.bytes, private_key_temp, config.security.private_key.size);
+        printBytes("Restored key", config.security.private_key.bytes, config.security.private_key.size);
+    } else {
         config.security.private_key.size = 0;
+    }
+    config.security.public_key.size = 0;
 #ifdef PIN_GPS_EN
     config.position.gps_en_gpio = PIN_GPS_EN;
 #endif
@@ -714,7 +725,7 @@ void NodeDB::loadFromDisk()
     //} else {
     if (devicestate.version < DEVICESTATE_MIN_VER) {
         LOG_WARN("Devicestate %d is old, discarding\n", devicestate.version);
-        factoryReset();
+        installDefaultDeviceState();
     } else {
         LOG_INFO("Loaded saved devicestate version %d, with nodecount: %d\n", devicestate.version,
                  devicestate.node_db_lite.size());
@@ -730,7 +741,7 @@ void NodeDB::loadFromDisk()
     } else {
         if (config.version < DEVICESTATE_MIN_VER) {
             LOG_WARN("config %d is old, discarding\n", config.version);
-            installDefaultConfig();
+            installDefaultConfig(true);
         } else {
             LOG_INFO("Loaded saved config version %d\n", config.version);
         }
@@ -1043,7 +1054,7 @@ bool NodeDB::updateUser(uint32_t nodeId, meshtastic_User &p, uint8_t channelInde
     if (p.public_key.size > 0) {
         printBytes("Incoming Pubkey: ", p.public_key.bytes, 32);
         if (info->user.public_key.size > 0) { // if we have a key for this user already, don't overwrite with a new one
-            LOG_INFO("Public Key set for node, not updateing!\n");
+            LOG_INFO("Public Key set for node, not updating!\n");
             // we copy the key into the incoming packet, to prevent overwrite
             memcpy(p.public_key.bytes, info->user.public_key.bytes, 32);
         } else {

src/mesh/NodeDB.h

@@ -182,7 +182,8 @@ class NodeDB
     void cleanupMeshDB();
 
     /// Reinit device state from scratch (not loading from disk)
-    void installDefaultDeviceState(), installDefaultChannels(), installDefaultConfig(), installDefaultModuleConfig();
+    void installDefaultDeviceState(), installDefaultChannels(), installDefaultConfig(bool preserveKey),
+        installDefaultModuleConfig();
 
     /// write to flash
     /// @return true if the save was successful

src/modules/AdminModule.cpp

@@ -186,18 +186,22 @@ bool AdminModule::handleReceivedProtobuf(const meshtastic_MeshPacket &mp, meshta
         break;
     }
     case meshtastic_AdminMessage_factory_reset_config_tag: {
+        disableBluetooth();
         LOG_INFO("Initiating factory config reset\n");
         nodeDB->factoryReset();
+        LOG_INFO("Factory config reset finished, rebooting soon.\n");
         reboot(DEFAULT_REBOOT_SECONDS);
         break;
     }
     case meshtastic_AdminMessage_factory_reset_device_tag: {
+        disableBluetooth();
         LOG_INFO("Initiating full factory reset\n");
         nodeDB->factoryReset(true);
         reboot(DEFAULT_REBOOT_SECONDS);
         break;
     }
     case meshtastic_AdminMessage_nodedb_reset_tag: {
+        disableBluetooth();
         LOG_INFO("Initiating node-db reset\n");
         nodeDB->resetNodes();
         reboot(DEFAULT_REBOOT_SECONDS);
@@ -209,6 +213,7 @@ bool AdminModule::handleReceivedProtobuf(const meshtastic_MeshPacket &mp, meshta
         break;
     }
     case meshtastic_AdminMessage_commit_edit_settings_tag: {
+        disableBluetooth();
         LOG_INFO("Committing transaction for edited settings\n");
         hasOpenEditTransaction = false;
         saveChanges(SEGMENT_CONFIG | SEGMENT_MODULECONFIG | SEGMENT_DEVICESTATE | SEGMENT_CHANNELS);
@@ -559,12 +564,16 @@ void AdminModule::handleSetConfig(const meshtastic_Config &c)
 
         break;
     }
+    if (requiresReboot) {
+        disableBluetooth();
+    }
 
     saveChanges(changes, requiresReboot);
 }
 
 void AdminModule::handleSetModuleConfig(const meshtastic_ModuleConfig &c)
 {
+    disableBluetooth();
     switch (c.which_payload_variant) {
     case meshtastic_ModuleConfig_mqtt_tag:
         LOG_INFO("Setting module config: MQTT\n");
@@ -636,7 +645,6 @@ void AdminModule::handleSetModuleConfig(const meshtastic_ModuleConfig &c)
         moduleConfig.paxcounter = c.payload_variant.paxcounter;
         break;
     }
-
     saveChanges(SEGMENT_MODULECONFIG);
 }
 
@@ -1031,3 +1039,16 @@ bool AdminModule::messageIsRequest(meshtastic_AdminMessage *r)
     else
         return false;
 }
+
+void disableBluetooth()
+{
+#if HAS_BLUETOOTH
+#ifdef ARCH_ESP32
+    if (nimbleBluetooth)
+        nimbleBluetooth->deinit();
+#elif defined(ARCH_NRF52)
+    if (nrf52Bluetooth)
+        nrf52Bluetooth->shutdown();
+#endif
+#endif
+}

src/modules/AdminModule.h

@@ -60,3 +60,5 @@ class AdminModule : public ProtobufModule<meshtastic_AdminMessage>, public Obser
 };
 
 extern AdminModule *adminModule;
+
+void disableBluetooth();