[socal-piggies] Mocking sockets

[Steve Wedig]

I see, Paramiko's socket dependency isn't inverted, so you are unable to
provide an alternate implementation of that interface.

I don't know if this will work, but you could try overriding the socket
module's import, replacing it with your own implementation of the same
interface.

Here are some discussions that suggest it may work, as long as you override
the import before Paramiko gets imported:
http://stackoverflow.com/questions/1096216/override-namespace-in-python
http://stackoverflow.com/questions/3012473/how-do-i-override-a-python-import

On Tue, Jul 31, 2012 at 4:17 PM, Jathan McCollum <jathan at gmail.com> wrote:

> Ok, a little background...
>
> On the heels of BlackHat and DefCon I discovered a new tool called FakeNet
> (http://practicalmalwareanalysis.com/fakenet/) that is intended to run on
> Windows XP. It allows you to hijack all socket connections received by the
> system, and has an embedded Python 2.7.3 interpreter. I want to try using
> this for a single-system dummy test network.
>
> The catch is, because of the custom socket I/O, the _socket.so module was
> intentionally excluded. In order to do socket calls you must import
> FakeNet. Here is a simple example:
>
> def FN_NewConnection(context):
>     """Simple echo server that prints Python version upon connection"""
>     import sys
>     FakeNet.sendData(context, sys.version)
>     while True:
>         bytes = FakeNet.recvData(context, 4096)
>         if bytes == "":
>             break
>         else:
>             FakeNet.sendData(context, bytes)
>
> It's a greatly simplified interface. It handles the buildup/teardown of
> the session, and all you have to do is worry about send/recv.
>
> The device allows for custom modules. I am trying to mock an SSH server
> and actually negotiate with the client. I want to use this for... You
> guessed it... testing interaction with SSH endpoints without actually
> having to connect to anything.
>
> For this I want to use Paramiko, but the problem is that Paramiko imports
> the socket module all over the place, so I wanted to see if I could force
> it (somehow) to use FakeNet's send/recv calls, and just mock the rest.
>
> Steve, thanks for the reminder of dependency inversion. :)
>
> On Mon, Jul 30, 2012 at 6:18 PM, Andrew Kou <andrew.kou at gmail.com> wrote:
>
>> Jathan,
>>
>> What requirements do you have of the mocked object?
>>
>> - Andrew
>>
>>
>>
>> On Mon, Jul 30, 2012 at 4:38 PM, Jathan McCollum <jathan at gmail.com>wrote:
>>
>>> I have a need to mock the socket module, but without actually importing
>>> it first. I know some pretty sophisticated mocking can be done with Mox,
>>> but it requires that you import the real module into the namespace first.
>>>
>>> I am doing some work on an embedded system that doesn't have _socket.so,
>>> which means I can't actually import the socket module, but I need to do
>>> some mocking of connections.
>>>
>>> Anyone have any pointers? Thanks in advance!
>>>
>>> --
>>> Jathan.
>>> --
>>>
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>>>
>>
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>
>
> --
> Jathan.
> --
>
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>


-- 
Steve Wedig
http://www.linkedin.com/in/wedig
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