[BUG] Exception in mqtt_sendtoBroker for mqtt_mode 3

[fschaeck]

BSB-LAN Version 3.0.1-20221101130752

Architecture ESP32 NodeMCU (Joy-It)

Bus system BSB

Describe the bug When using mqtt_mode 3 an exception is thrown AFTER publishing the json message - apparently due to a buffer overflow in outBuf. Using mqtt_mode 1 or 2 this exception is not thrown but the message is also significantly shorter.

Also in function mqtt_callback(...) in BSB_LAN/include/mqtthandler.h the buffer overflow protection is reserving 4 bytes for the acknowledgement message, but 5 are needed (4 for the ACK prefix and one for the terminating nut character).

To Reproduce Steps to reproduce the behavior: Set mqtt_mode in BSB_LAN_config.h to 3, compile and upload sketch, watch the serial monitor to see the exception happening.

Logs (These logs are taken from an already modified mqtt_handler.h to pin down the problem) 12:41:55.566 -> �f`ADY 12:41:55.598 -> Using settings from config file 12:41:55.598 -> Reading done. 12:41:55.630 -> EEPROM schema v.0 Program schema v.11 12:41:55.630 -> Address EEPROM option 0: 0 12:41:55.630 -> Address EEPROM option 1: 1 12:41:55.630 -> Address EEPROM option 2: 2 12:41:55.630 -> Address EEPROM option 3: 6 12:41:55.630 -> Address EEPROM option 4: 226 12:41:55.630 -> Address EEPROM option 5: 306 12:41:55.662 -> Address EEPROM option 6: 490 12:41:55.662 -> Address EEPROM option 7: 491 12:41:55.662 -> Address EEPROM option 8: 492 12:41:55.662 -> Address EEPROM option 9: 493 12:41:55.662 -> Address EEPROM option 10: 494 12:41:55.662 -> Address EEPROM option 11: 495 12:41:55.662 -> Address EEPROM option 12: 499 12:41:55.662 -> Address EEPROM option 13: 659 12:41:55.662 -> Address EEPROM option 14: 663 12:41:55.662 -> Address EEPROM option 15: 823 12:41:55.662 -> Address EEPROM option 16: 829 12:41:55.662 -> Address EEPROM option 17: 830 12:41:55.694 -> Address EEPROM option 18: 834 12:41:55.694 -> Address EEPROM option 19: 838 12:41:55.694 -> Address EEPROM option 20: 842 12:41:55.694 -> Address EEPROM option 21: 846 12:41:55.694 -> Address EEPROM option 22: 848 12:41:55.694 -> Address EEPROM option 23: 852 12:41:55.694 -> Address EEPROM option 24: 856 12:41:55.694 -> Address EEPROM option 25: 920 12:41:55.694 -> Address EEPROM option 26: 984 12:41:55.694 -> Address EEPROM option 27: 985 12:41:55.694 -> Address EEPROM option 28: 986 12:41:55.694 -> Address EEPROM option 29: 996 12:41:55.726 -> Address EEPROM option 30: 997 12:41:55.726 -> Address EEPROM option 31: 1157 12:41:55.726 -> Address EEPROM option 32: 1158 12:41:55.726 -> Address EEPROM option 33: 1162 12:41:55.726 -> Address EEPROM option 34: 1163 12:42:07.699 -> 12:42:07.729 -> Starting MDNS service with hostname BSB-LAN 12:42:07.729 -> Update Server started on port 8080. 12:42:07.729 -> Setup complete 12:42:07.729 -> Client ID: BSB-LAN 12:42:07.729 -> Will topic: BSB-LAN/status 12:42:07.762 -> Connect to MQTT broker, updating will topic 12:42:07.762 -> Subscribed to topic 'BSB-LAN' 12:42:07.762 -> Published status 'online' to topic 'BSB-LAN/status' 12:42:26.560 -> query failed 12:42:27.571 -> query failed 12:42:28.587 -> query failed 12:42:28.587 -> 8700 12:42:28.587 -> Output topic: BSB-LAN/json 12:42:28.587 -> 12:42:28.587 -> Payload Output : {"BSB-LAN":{"id":8700,"name":"Außentemperatur","value": "","desc": "","unit": "°C","error": 261}} 12:42:28.620 -> Successfully published... 12:42:28.620 -> Guru Meditation Error: Core 1 panic'ed (LoadProhibited). Exception was unhandled. 12:42:28.620 -> 12:42:28.620 -> Core 1 register dump: 12:42:28.620 -> PC : 0x4008a431 PS : 0x00060f30 A0 : 0x800d8ab1 A1 : 0x3ffb24a0
12:42:28.620 -> A2 : 0x3ffc3e4b A3 : 0x00000000 A4 : 0x000000ff A5 : 0x0000ff00
12:42:28.620 -> A6 : 0x00ff0000 A7 : 0xff000000 A8 : 0x00000000 A9 : 0x3ffb20e0
12:42:28.653 -> A10 : 0x3ffc3e4b A11 : 0xffffffff A12 : 0x0000000d A13 : 0x3ffb22f0
12:42:28.653 -> A14 : 0x0000000d A15 : 0x3ffb22f0 SAR : 0x00000004 EXCCAUSE: 0x0000001c
12:42:28.653 -> EXCVADDR: 0x00000000 LBEG : 0x4008a431 LEND : 0x4008a43e LCOUNT : 0xffffffff
12:42:28.653 -> 12:42:28.653 -> 12:42:28.653 -> Backtrace:0x4008a42e:0x3ffb24a00x400d8aae:0x3ffb24b0 0x400ddc0e:0x3ffb2530 0x400e9bc9:0x3ffb2820 12:42:28.685 -> 12:42:28.685 -> 12:42:28.685 -> 12:42:28.685 -> 12:42:28.685 -> ELF file SHA256: 0000000000000000 12:42:28.685 -> 12:42:28.685 -> Rebooting...

Expected behavior A published json message without a subsequent exception.

Screenshots n/a

Desktop (if applicable, please complete the following information): n/a

Smartphone (if applicable, please complete the following information): n/a

Additional context Nothing to add.

[fredlcore]

Can we consider this closed due to your PR, @fschaeck?

[fschaeck]

Yes, we can! Closing it…