Licensed channel defaults, phone map growth, and payload read bounds (#11286)

* Strip the default PSK when licensed defaults are installed

* Only record rate-limited portnums from the phone

* Bound payload reads by the received size

src/MessageStore.cpp

@@ -215,7 +215,12 @@ const StoredMessage *MessageStore::tryAddFromPacket(const meshtastic_MeshPacket
     sm.channelIndex = packet.channel;
 
     const char *payload = reinterpret_cast<const char *>(packet.decoded.payload.bytes);
-    size_t len = strnlen(payload, MAX_MESSAGE_SIZE - 1);
+    // payload.bytes is not NUL-terminated, so bound by the received size too: a shorter message
+    // stored after a longer one would otherwise pick up the previous occupant's trailing bytes.
+    size_t avail = packet.decoded.payload.size;
+    if (avail > MAX_MESSAGE_SIZE - 1)
+        avail = MAX_MESSAGE_SIZE - 1;
+    size_t len = strnlen(payload, avail);
     sm.textOffset = storeTextInPool(payload, len);
     sm.textLength = len;
 

src/mesh/NodeDB.cpp

@@ -741,6 +741,10 @@ void NodeDB::resetRadioConfig(bool is_fresh_install)
         LOG_INFO("Set default channel and radio preferences!");
 
         channels.initDefaults();
+        // Defaults ship the public PSK, so strip it again before onConfigChanged() publishes hashes;
+        // loadFromDisk's sanitation is a no-op when the channel file was absent or corrupt.
+        if (owner.is_licensed)
+            channels.ensureLicensedOperation();
     }
 
     channels.onConfigChanged();

src/mesh/PhoneAPI.cpp

@@ -1855,7 +1855,12 @@ bool PhoneAPI::handleToRadioPacket(meshtastic_MeshPacket &p)
         p.want_ack = true;
     }
 
-    lastPortNumToRadio[p.decoded.portnum] = millis();
+    // Only the rate-limited ports above are ever read back, so recording any other portnum would let
+    // a client grow this map without bound by cycling through them.
+    if (IS_ONE_OF(p.decoded.portnum, meshtastic_PortNum_TRACEROUTE_APP, meshtastic_PortNum_POSITION_APP,
+                  meshtastic_PortNum_WAYPOINT_APP, meshtastic_PortNum_ALERT_APP, meshtastic_PortNum_TELEMETRY_APP,
+                  meshtastic_PortNum_TEXT_MESSAGE_APP))
+        lastPortNumToRadio[p.decoded.portnum] = millis();
     service->handleToRadio(p);
     return true;
 }

src/modules/DropzoneModule.cpp

@@ -32,14 +32,17 @@ ProcessMessage DropzoneModule::handleReceived(const meshtastic_MeshPacket &mp)
     auto &p = mp.decoded;
     char matchCompare[54];
     auto incomingMessage = reinterpret_cast<const char *>(p.payload.bytes);
-    sprintf(matchCompare, "%s conditions", owner.short_name);
-    if (strncasecmp(incomingMessage, matchCompare, strlen(matchCompare)) == 0) {
+    // payload.bytes is not NUL-terminated, so a comparison longer than the received size would read
+    // whatever the previous occupant of the packet left behind.
+    const size_t received = p.payload.size;
+    snprintf(matchCompare, sizeof(matchCompare), "%s conditions", owner.short_name);
+    if (received >= strlen(matchCompare) && strncasecmp(incomingMessage, matchCompare, strlen(matchCompare)) == 0) {
         LOG_DEBUG("Received dropzone conditions request");
         startSendConditions = millis();
     }
 
-    sprintf(matchCompare, "%s conditions", owner.long_name);
-    if (strncasecmp(incomingMessage, matchCompare, strlen(matchCompare)) == 0) {
+    snprintf(matchCompare, sizeof(matchCompare), "%s conditions", owner.long_name);
+    if (received >= strlen(matchCompare) && strncasecmp(incomingMessage, matchCompare, strlen(matchCompare)) == 0) {
         LOG_DEBUG("Received dropzone conditions request");
         startSendConditions = millis();
     }