Problem in __init__() of TCPSession class

[lidllohntsich]

Brief description

Problem found in scapy/session.py

class TCPSession(IPSession):
    """A Session that matches seq/ack packets together to dissect
    special protocols, such as HTTP.
    DEV: implement a class-function `tcp_reassemble` in your Packet class::
        @classmethod
        def tcp_reassemble(cls, data, metadata):
            # data = the reassembled data from the same request/flow
            # metadata = empty dictionary, that can be used to store data
            [...]
            # If the packet is available, return it. Otherwise don't.
            # Whenever you return a packet, the buffer will be discarded.
            return pkt
            # Otherwise, maybe store stuff in metadata, and return None,
            # as you need additional data.
            return None
    For more details and a real example, see:
    https://scapy.readthedocs.io/en/latest/usage.html#how-to-use-tcpsession-to-defragment-tcp-packets
    :param app: Whether the socket is on application layer = has no TCP
                layer. This is used for instance if you are using a native
                TCP socket. Default to False
    

    fmt = ('TCP {IP:%IP.src%}{IPv6:%IPv6.src%}:%r,TCP.sport% > ' +
           '{IP:%IP.dst%}{IPv6:%IPv6.dst%}:%r,TCP.dport%')

    def __init__(self, app=False, *args, **kwargs):
    

this should probably be changed to:

def __init__(self, *args, app=False, **kwargs):

Without this change, 'app' would be overridden by the first positional argument, which is most likely not the intention.

Scapy version

2.4.5rc1.dev412

Python version

3.6.9

Operating system

Linux 4.15.0-175

Additional environment information

No response

How to reproduce

def f(a=1, *args):
    assert a == 1
    for i in args:
        assert i == 11

def f2(*args, a=1):
    assert a == 1
    for i in args:
        assert i == 11

f(11, 11)  # this will fail
f2(11, 11)

Actual result

No response

Expected result

No response

Related resources

No response