Copyright (c) 2012, Sergej Srepfler [email protected] EAP calculations use parts of hostapd code http://w1.fi/hostapd Copyright (c) 2004-2008, Jouni Malinen and contributors. All rights reserved. EAP-SIM calculations use a3a8 code http://www.scard.org/gsm Copyright 1998, Marc Briceno, Ian Goldberg, and David Wagner. All rights reserved.
This program is licensed under the BSD license (the one with advertisement clause removed).
If you are like me, you just hate that "itch". Something that is bothering you, and the best solution is to scratch it. Well - this is my scratch.
There is no portable diameter client. At least I don't know about it. I have been toying with the idea to write one for a long time, but... the amount of work seemed high, and there never was enough "need" for me to do it - until now. Luckily for me, I stumbled upon the Python Diameter Library. Unfortunately, I could not use it on my project, so I just used some ideas and here is the result. Also I "borrowed" from hostapd server all the EAP calculations I needed (since I could not find python implementation - and even when I did (milenage and hmac1) - it did not work on target platform without additional installations).
The goal was to have:
- a PORTABLE diameter client (that means no installation required, just unpack and run, without changing existing applications on system)
- primary usage is TESTING
- must work on x86 Solaris 10, Linux and Windows
- dictionary is mandatory (to easily test mismatched AVP or modify values)
- unknown AVPs need to be easily manageable (inserted without defining in dictionary)
- the client should be able to perform necessary EAP (AKA and AKA') calculations
- must be able to send deliberately malformed packet
And it worked. Like a charm. So I got carried away and added support for radius. And DHCP. And LDAP. And SNMP is planned :-) Now on more serious note:
- DHCP client was done simple as a proof that python can easily send RAW packets. But it is not tested enough, especially in multi-homed environment (more than one network card).
- Similar goes for LDAP library. I tried a new approach, but - yuck: I don't like it. It will most definitely be rewritten (as soon as I figure out more about schema and other stuff. And have more time).
Original name had diameter in it. But as the project grew, that name had to be omitted. Finally, name was settled to PYthon Protocol Simulator (pronounced as "pipes").
- no installation required (well, almost. You'll need to install python 2.X on windows platform.)
- tested with python 2.4-2.7
- use simplified dictionary (minimal features - user must know what is needed)
- easy encode unknown AVPs as HEX-stream (just copy it from wireshark)
- client examples included
- supported protocols: RADIUS, DIAMETER, DHCP, LDAP
- EAP: calculate SIM keys
- EAP: calculate AKA keys
- EAP: calculate AKA' keys
- EAP: calculate hmac1
- EAP: calculate hmac256
- EAP: decode AT_ENCR_DATA to get Pseudonym/Re-auth Identity
- EAP: HSS simulator
- RADIUS: encrypt/decrypt password
- tested on Linux, Solaris 10-x86 and Windows XP
I did not bother too much to analyze/decode packets. Wireshark is much better tool for such details. It should be rather easy to add support if you need it (e.g. extend simplified dictionary, define enumerated AVPS...). Please note that it is not fully tested (I never needed some types, and I'm not developing it as universal library, so be warned...)
Initial diameter code and some ideas are based on the code from http://i1.dk/PythonDiameter/ You will probably fail to see similarity, but... encoding part is essentially the same, although approach is totally different. EAP-AKA and EAP-AKA' calculations use parts of the code from http://w1.fi/hostapd/ Dictionary is based on the data from the Wireshark dictionary http://www.wireshark.org Parts of radius code are based on the code from http://pypi.python.org/pypi/pyrad A3A8 calculation use code from http://www.scard.org/gsm Parts od DHCP code are based on http://pydhcplib.sourcearchive.com/documentation/0.6.2-2/main.html
RFC 2104 - HMAC: Keyed-Hashing for Message Authentication RFC 2865 - RADIUS RFC 2866 - RADIUS Accounting RFC 3588 - Diameter Base Protocol RFC 3748 - Extensible Authentication Protocol (EAP) RFC 4186 - EAP-SIM RFC 4187 - EAP-AKA RFC 4740 - Diameter Session Initiation Protocol (SIP) Application RFC 5448 - EAP-AKA' 3GPP TS 35.206 - Specification of Milenage Algorithm Set FIPS 186-2 + Change Notice - Pseudo Random Function and probably some others I forgot to mention while researching some issue For DHCP check list at http://www.zytrax.com/books/dhcp/apc/ For LDAP I'm still digging, so it will not be listed here yet
Feel free to modify the code/refactor it to be more concise. I did not 'plan' to write it as it is now. I had too little time to came up with this tool, so you can called it 'glued together', not designed. And it was written with the idea that almost anyone could take a look at the code and make modifications to suit his needs, so no fancy coding or too language-specific features were used. Mostly :-) So - if you like OOP or want to have more consistent feel - rewrite it to suit your needs. I definitely don't plan to. Adding a feature I need heavily (or a bug fix) is a highly possible. But no other plans. Yet :-) This was never intended to be "heavy traffic" tool, but simple (and versatile) testing tool. I know that for DHCP you have Options, not AVPs, but... to stick with similar naming/code, I just renamed them. So now you do have DHCP dictionary (with necessary modifications) :-) In LDAP I tried not to use dictionary, but I don't like how the code looks like. So it is possible I'll switch to "dictionary approach". And I do not like how code decodes LDAP packet (not decoding itself, but determining relations between them (parent/child)). So it will probaly change also.
I "hate" unmaintainable dictionaries. So this one is as simple as I could make it without too much fuss. You have basic types. You can define "typedefs" which are encoded as basic types. You have vendors and AVPs. Only minimum of fields are present. Enumerated types are unlisted by design, so the dictionary can survive without update (It means that value will not be decoded, but left as integer). Including other dictionaries is not something I needed at design time. So feel free to modify it to full blown dictionary. I did when experimenting, and then choose to "simplify" it. Since AVP packing is done by hand, I have full freedom to put inside whatever I want. No rules to stop me :-) Exactly what I needed. But then - your mileage might wary. I even included the code I used to create dictionary from wireshark dictionary.
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