Fix long name clamping and adjust related structures for compatibility

src/mesh/NodeDB.cpp

@@ -365,6 +365,15 @@ extern void getMacAddr(uint8_t *dmac);
  * we use !macaddr (no colons).
  */
 meshtastic_User &owner = devicestate.owner;
+
+// The slim NodeInfoLite header defines the local long_name cap; the wire-facing
+// meshtastic_User stays wider so names from senders built against the older
+// 39-byte limit still decode (nanopb halts on string overflow).
+static_assert(MAX_LONG_NAME_BYTES + 1 == sizeof(meshtastic_NodeInfoLite::long_name),
+              "MAX_LONG_NAME_BYTES must match the NodeInfoLite storage width");
+static_assert(sizeof(meshtastic_User::long_name) > MAX_LONG_NAME_BYTES,
+              "wire User.long_name must be wider than the local cap so clampLongName stays in bounds");
+
 meshtastic_Position localPosition = meshtastic_Position_init_default;
 meshtastic_CriticalErrorCode error_code =
     meshtastic_CriticalErrorCode_NONE; // For the error code, only show values from this boot (discard value from flash)
@@ -1514,6 +1523,7 @@ void NodeDB::installDefaultDeviceState()
 #else
     snprintf(owner.long_name, sizeof(owner.long_name), "Meshtastic %04x", getNodeNum() & 0x0ffff);
 #endif
+    clampLongName(owner.long_name); // vendor userprefs may exceed the local cap
 #ifdef USERPREFS_CONFIG_OWNER_SHORT_NAME
     snprintf(owner.short_name, sizeof(owner.short_name), (const char *)USERPREFS_CONFIG_OWNER_SHORT_NAME);
 #else
@@ -1727,8 +1737,9 @@ void NodeDB::loadFromDisk()
         if (nodeInfoLiteHasUser(us)) {
             LOG_WARN("Restoring owner fields (long_name/short_name/is_licensed/is_unmessagable) from NodeDB for our node 0x%08x",
                      us->num);
-            memcpy(owner.long_name, us->long_name, sizeof(owner.long_name));
-            owner.long_name[sizeof(owner.long_name) - 1] = '\0';
+            // owner.long_name (40) is wider than the lite source (25); bound by the source
+            memcpy(owner.long_name, us->long_name, sizeof(us->long_name));
+            owner.long_name[sizeof(us->long_name) - 1] = '\0';
             memcpy(owner.short_name, us->short_name, sizeof(owner.short_name));
             owner.short_name[sizeof(owner.short_name) - 1] = '\0';
             owner.is_licensed = nodeInfoLiteIsLicensed(us);
@@ -1742,6 +1753,10 @@ void NodeDB::loadFromDisk()
         LOG_INFO("Loaded saved devicestate version %d", devicestate.version);
     }
 
+    // Devicestate saved by firmware that allowed 39-byte names gets clamped on
+    // first load; from here on owner never carries more than the local cap.
+    clampLongName(owner.long_name);
+
     state = loadProto(configFileName, meshtastic_LocalConfig_size, sizeof(meshtastic_LocalConfig), &meshtastic_LocalConfig_msg,
                       &config);
     if (state != LoadFileResult::LOAD_SUCCESS) {

src/mesh/generated/meshtastic/clientonly.pb.h

@@ -17,7 +17,7 @@
 typedef struct _meshtastic_DeviceProfile {
     /* Long name for the node */
     bool has_long_name;
-    char long_name[40];
+    char long_name[25];
     /* Short name of the node */
     bool has_short_name;
     char short_name[5];

src/mesh/generated/meshtastic/mesh.pb.h

@@ -774,7 +774,10 @@ typedef struct _meshtastic_User {
  Note: app developers are encouraged to also use the following standard
  node IDs "^all" (for broadcast), "^local" (for the locally connected node) */
     char id[16];
-    /* A full name for this user, i.e. "Kevin Hester" */
+    /* A full name for this user, i.e. "Kevin Hester"
+ Limited to 24 bytes of UTF-8: longer names are accepted from senders
+ built against the older 39-byte limit, but devices truncate them before
+ storing or rebroadcasting. Clients should enforce 24 bytes in their UI. */
     char long_name[40];
     /* A VERY short name, ideally two characters.
  Suitable for a tiny OLED screen */

src/mesh/generated/meshtastic/mqtt.pb.h

@@ -27,7 +27,7 @@ typedef struct _meshtastic_ServiceEnvelope {
 /* Information about a node intended to be reported unencrypted to a map using MQTT. */
 typedef struct _meshtastic_MapReport {
     /* A full name for this user, i.e. "Kevin Hester" */
-    char long_name[40];
+    char long_name[25];
     /* A VERY short name, ideally two characters.
  Suitable for a tiny OLED screen */
     char short_name[5];
@@ -126,7 +126,7 @@ extern const pb_msgdesc_t meshtastic_MapReport_msg;
 /* Maximum encoded size of messages (where known) */
 /* meshtastic_ServiceEnvelope_size depends on runtime parameters */
 #define MESHTASTIC_MESHTASTIC_MQTT_PB_H_MAX_SIZE meshtastic_MapReport_size
-#define meshtastic_MapReport_size                110
+#define meshtastic_MapReport_size                95
 
 #ifdef __cplusplus
 } /* extern "C" */

src/meshUtils.cpp

@@ -206,4 +206,10 @@ bool sanitizeUtf8(char *buf, size_t bufSize)
     }
 
     return replaced;
-}
+}
+
+void clampLongName(char *longName)
+{
+    longName[MAX_LONG_NAME_BYTES] = '\0';
+    sanitizeUtf8(longName, MAX_LONG_NAME_BYTES + 1);
+}

src/meshUtils.h

@@ -60,6 +60,17 @@ size_t pb_string_length(const char *str, size_t max_len);
 // Ensures the result is null-terminated within bufSize. Returns true if any bytes were replaced.
 bool sanitizeUtf8(char *buf, size_t bufSize);
 
+// Longest User.long_name content (bytes, excluding NUL) we store or transmit.
+// The wire decode buffer stays at 40 so names from senders built against the
+// older 39-byte limit still parse; everything we keep or send is clamped to
+// this, matching the slim NodeInfoLite storage width in deviceonly.proto.
+#define MAX_LONG_NAME_BYTES 24
+
+// Clamp a long_name buffer (at least MAX_LONG_NAME_BYTES + 1 bytes) in-place
+// to MAX_LONG_NAME_BYTES bytes of content, fixing any partial UTF-8 sequence
+// left at the cut.
+void clampLongName(char *longName);
+
 /// Calculate 2^n without calling pow() - used for spreading factor and other calculations
 inline uint32_t pow_of_2(uint32_t n)
 {

src/modules/AdminModule.cpp

@@ -620,10 +620,14 @@ void AdminModule::handleGetModuleConfigResponse(const meshtastic_MeshPacket &mp,
  * Setter methods
  */
 
-void AdminModule::handleSetOwner(const meshtastic_User &o)
+void AdminModule::handleSetOwner(meshtastic_User &o)
 {
     int changed = 0;
 
+    // Apps built against the older 39-byte limit may send longer names; clamp
+    // before the changed-compare so re-sending the same long name is a no-op.
+    clampLongName(o.long_name);
+
     if (*o.long_name) {
         changed |= strcmp(owner.long_name, o.long_name);
         strncpy(owner.long_name, o.long_name, sizeof(owner.long_name));

src/modules/AdminModule.h

@@ -58,7 +58,7 @@ class AdminModule : public ProtobufModule<meshtastic_AdminMessage>, public Obser
     /**
      * Setters
      */
-    void handleSetOwner(const meshtastic_User &o);
+    void handleSetOwner(meshtastic_User &o);
     void handleSetChannel(const meshtastic_Channel &cc);
 
   protected:

src/mqtt/MQTT.cpp

@@ -726,7 +726,9 @@ void MQTT::perhapsReportToMap()
 
     // Fill MapReport message
     meshtastic_MapReport mapReport = meshtastic_MapReport_init_default;
-    memcpy(mapReport.long_name, owner.long_name, sizeof(owner.long_name));
+    // owner.long_name (40) is wider than mapReport.long_name (25); bound by the destination
+    strncpy(mapReport.long_name, owner.long_name, sizeof(mapReport.long_name));
+    mapReport.long_name[sizeof(mapReport.long_name) - 1] = '\0';
     memcpy(mapReport.short_name, owner.short_name, sizeof(owner.short_name));
     mapReport.role = config.device.role;
     mapReport.hw_model = owner.hw_model;