connect_request_tunneling() raise ValueError

[theobarrague]

When I try to establish a tunnel to the KNX router I get this error :

(knx) knx@knx-Virtual-Machine:~/knx$ python main.py 
/home/knx/knx/lib/python3.7/site-packages/scapy/base_classes.py:324: SyntaxWarning: Packet 'LcEMI' has a duplicated 'reserved' field ! If you are using several ConditionalFields, have a look at MultipleTypeField instead ! This will become a SyntaxError in a future version of Scapy !
  warnings.warn(war_msg, SyntaxWarning)
Traceback (most recent call last):
  File "main.py", line 6, in <module>
    channel, knx_source = connect_request_tunneling(knxnet)
  File "/home/knx/knx/bof/layers/knx/knx_feature.py", line 259, in connect_request_tunneling
    return response.communication_channel_id, knx_source
  File "/home/knx/knx/bof/packet.py", line 114, in __getattr__
    _, value, _ = self._get_field(attr)
  File "/home/knx/knx/bof/packet.py", line 342, in _get_field
    field_and_val = parent.getfield_and_val(name)
  File "/home/knx/knx/lib/python3.7/site-packages/scapy/packet.py", line 423, in getfield_and_val
    raise ValueError
ValueError

I attach a Wireshark capture and Python script : resources.zip

[theobarrague]

After investigation, it seems to come from knx_feature.py :

    # FIX: we can't access knx_individual_address directly
    knx_source = response.scapy_pkt.connection_response_data_block.connection_data.knx_individual_address

I don't know how to fix this for now

[claire-lex]

Hi,
Thanks for the fix.
Actually this is a change in Scapy 2.4.5 where getfield_and_val now raises a ValueError if no condition was met (file scapy/packet.py). In BOF's current code, we rely on getfield_and_val not returning anything to know how to act (tested with Scapy 2.4.3).
To close this issue, we have to check every call to getfield_and_val in BOF to handle ValueError exceptions. I'm on it :p

[claire-lex]

Fixed with release 1.0.2
Thanks again for reporting this issue and submitting a fix!