Meshcomod support

[BigBen500]

Hi,

i found this error in the log of the meshcore ingestor container:

[2026-04-18T20:59:12.052Z] [potato-mesh] [debug] context=handlers.upsert_node long_name='Meshcomod' node_id='!4d455348' short_name='4d45' Queued node upsert payload
ERROR:asyncio:Task exception was never retrieved
future: <Task finished name='Task-4186' coro=<MessageReader.handle_rx() done, defined at /usr/local/lib/python3.12/site-packages/meshcore/reader.py:65> exception=IndexError('index out of range')>
IndexError: index out of range
[2026-04-18T20:59:12.052Z] [potato-mesh] [debug] context=queue.queue_post_json path='/api/positions' priority=90 Forwarding payload to API: from_id="!88a2ccec" id=6984181869353220516 ingestor="!1d2b53a3" latitude=52.488441 longitude=13.847499 node_id="!88a2ccec" node_num=2292370668 position_time=1776593017 rx_iso="2026-04-18T20:59:12Z" rx_time=1776545952
[2026-04-18T20:59:12.052Z] [potato-mesh] [debug] context=queue.queue_post_json path='/api/nodes' priority=20 Forwarding payload to API: !4d455348={"lastHeard": 0, "lora_freq": 869.618, "modem_preset": "SF8/BW62/CR8", "protocol": "meshcore", "user": {"longName": "Meshcomod", "publicKey": "4d455348434d0000000000000000000000000000000000000000000000000000", "role": "COMPANION", "shortName": "4d45"}} ingestor="!1d2b53a3"
Traceback (most recent call last):
  File "/usr/local/lib/python3.12/site-packages/meshcore/reader.py", line 365, in handle_rx
    path_hash_mode = dbuf.read(1)[0]
                     ~~~~~~~~~~~~^^^
IndexError: index out of range

Do you have any clue what the reason can be?

The nodes list is populated by the ingestor. The chat window only shows the log tab with some advert messages, but there is no channel tab with messages heard by the underlying node. Is this a misconfiguration or also caused by the above mentioned error?

[l5yth]

Hey, which version are you using?

[BigBen500]

Version 0.6.1

[l5yth]

The crash right after an upsert for node !4d455348 whose pubkey decodes to ASCII MESHCM\x00… strongly suggests a malformed/crafted advertisement packet.

{"longName": "Meshcomod", "publicKey": "4d455348434d0000000000000000000000000000000000000000000000000000", "role": "COMPANION", "shortName": "4d45"}

This cannot be right. Let me investigate.

Which Meshcore firmware/version are you running?

[l5yth]

#759 does not fix it but it catches the crash and wraps this in a warning message. To investigate this further, I need to better understand which meshcore client you are using.

[BigBen500]

The crash right after an upsert for node !4d455348 whose pubkey decodes to ASCII MESHCM\x00… strongly suggests a malformed/crafted advertisement packet.

{"longName": "Meshcomod", "publicKey": "4d455348434d0000000000000000000000000000000000000000000000000000", "role": "COMPANION", "shortName": "4d45"}

This cannot be right. Let me investigate.

Which Meshcore firmware/version are you running?

It is a custom Meshcore Firmware: Meshcomod (https://github.com/ALLFATHER-BV/meshcomod) Version: 1.15.0.3 based on official 1.15. (https://flasher.meshcomod.com/)
I think the issue is that the problematic companion with the malformed package seems to be no real companion but instead a "virtual" local only (not send to the mesh) contact. This is used as alternative way to configure device by sending cli commands to this virtual contact (as stated here: https://github.com/ALLFATHER-BV/meshcomod#easy-recommended).
So maybe your workaround, catching the crash, is enough for now. The decision is yours.

The problem with not showing messages in the channel tabs is not relevant anymore. The ingestor now runs fine, ignoring the malformed package. Also there was a misconfiguration by me. I had to configure the channel I want to observe in the official client app for my monitoring device. After the channels are configured, the messages are also shown in potatomesh.

[l5yth]

I'll look into it.