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genesis                 1 import hashlib
9985-single-thread      2 import serpent
9985-single-thread      3 from serpent import Serpent
9985-single-thread      4 from serpent import serpent_cbc_encrypt 
9985-single-thread      5 from serpent import serpent_cbc_decrypt 
genesis                 6 from commands import BROADCAST
genesis                 7 from commands import DIRECT 
9990-keep-ephemer...    8 from commands import IGNORE 
9985-single-thread      9 from message import Message
genesis                10 import base64
genesis                11 import binascii
genesis                12 import time
genesis                13 import struct
genesis                14 import sys
genesis                15 import hmac
genesis                16 import random
9990-keep-ephemer...   17 import os 
genesis                18 import pprint
9987-embargoing        19 import logging
genesis                20 pp = pprint.PrettyPrinter(indent=4)
genesis                21 
genesis                22 PACKET_SIZE = 496 
genesis                23 MAX_SPEAKER_SIZE = 32
genesis                24 TS_ACCEPTABLE_SKEW = 60 * 15
genesis                25 BLACK_PACKET_FORMAT = "<448s48s"
genesis                26 RED_PACKET_FORMAT = "<16sBBxB428s"
genesis                27 RED_PACKET_LENGTH_WITH_PADDING = 448
genesis                28 MESSAGE_PACKET_FORMAT = "<q32s32s32s324s"
genesis                29 MAX_MESSAGE_LENGTH = 428
genesis                30 MAX_BOUNCES = 3
9991-improved-log...   31 STALE_PACKET = 0
9991-improved-log...   32 DUPLICATE_PACKET = 1
9991-improved-log...   33 MALFORMED_PACKET = 2
9991-improved-log...   34 INVALID_SIGNATURE = 3
9990-keep-ephemer...   35 IGNORED = 4
9985-single-thread     36 MESSAGE_LOGGING_FORMAT = "[%s:%d %s] <- %s %s %s"
genesis                37 
genesis                38 class Infosec(object): 
9987-embargoing        39     def __init__(self, state=None):
9987-embargoing        40         self.state = state
genesis                41 
9987-embargoing        42     def message(self, message):
9985-single-thread     43         if not message.speaker:
9985-single-thread     44             logging.error("aborting message send due speaker not being set")
9985-single-thread     45             return
9985-single-thread     46 
9987-embargoing        47         # if we are not rebroadcasting we need to set the timestamp
9987-embargoing        48         if message.timestamp == None:
9987-embargoing        49             message.original = True
9987-embargoing        50             message.timestamp = int(time.time())
9987-embargoing        51         else:
9987-embargoing        52             message.original = False
9987-embargoing        53 
9987-embargoing        54         target_peer = (self.state.get_peer_by_handle(message.handle)
9987-embargoing        55                         if message.command == DIRECT
9987-embargoing        56                         else None)
9987-embargoing        57 
9987-embargoing        58         if target_peer and not target_peer.get_key():
9987-embargoing        59             logging.debug("No key for peer associated with %s" % message.handle)
9987-embargoing        60             return
9987-embargoing        61 
9987-embargoing        62         if message.command == DIRECT and target_peer == None:
9987-embargoing        63             logging.debug("Aborting message: unknown handle: %s" % message.handle)
9987-embargoing        64             return
9987-embargoing        65 
9986-rebroadcast-...   66         if message.message_bytes == None:
9986-rebroadcast-...   67             message_bytes = self.get_message_bytes(message, target_peer)
9986-rebroadcast-...   68         else:
9986-rebroadcast-...   69             message_bytes = message.message_bytes 
9986-rebroadcast-...   70 
9985-single-thread     71         message_hash = binascii.hexlify(hashlib.sha256(message_bytes).digest())
9985-single-thread     72 
9987-embargoing        73         if message.command != IGNORE:
9987-embargoing        74             logging.debug("generated message_hash: %s" % message_hash)
9987-embargoing        75             self.state.add_to_dedup_queue(message_hash)
9987-embargoing        76             self.state.log(message.speaker, message_bytes, target_peer)
9987-embargoing        77 
9987-embargoing        78         if message.command == DIRECT:
9987-embargoing        79             signed_packet_bytes = self.pack(target_peer, message, message_bytes)
9987-embargoing        80             target_peer.send(signed_packet_bytes)
9985-single-thread     81             logging.info(MESSAGE_LOGGING_FORMAT % (target_peer.address,
9985-single-thread     82                 target_peer.port,
9985-single-thread     83                 target_peer.handles[0],
9985-single-thread     84                 message.body,
9985-single-thread     85                 message.bounces,
9985-single-thread     86                 message_hash))
9985-single-thread     87 
9987-embargoing        88         elif message.command == BROADCAST or message.command == IGNORE:
9986-rebroadcast-...   89             # sanity check
9986-rebroadcast-...   90             if message.message_bytes and message_bytes != message_bytes:
9985-single-thread     91                 logging.error("aborting send: message modified by station!")
9986-rebroadcast-...   92                 return
9986-rebroadcast-...   93 
9987-embargoing        94             for peer in self.state.get_keyed_peers():
9987-embargoing        95                 
9987-embargoing        96                 # we don't want to send a broadcast back to the originator
9987-embargoing        97                 if message.peer and (peer.peer_id == message.peer.peer_id):
9986-rebroadcast-...   98                     continue 
9987-embargoing        99 
9987-embargoing       100                 signed_packet_bytes = self.pack(peer, message, message_bytes)
9987-embargoing       101                 peer.send(signed_packet_bytes)
9985-single-thread    102                 if message.command != IGNORE:
9985-single-thread    103                     logging.info(MESSAGE_LOGGING_FORMAT % (peer.address,
9985-single-thread    104                         peer.port,
9985-single-thread    105                         peer.handles[0],
9985-single-thread    106                         message.body,
9985-single-thread    107                         message.bounces,
9985-single-thread    108                         message_hash))
9987-embargoing       109 
9987-embargoing       110     def get_message_bytes(self, message, peer=None):
9987-embargoing       111         timestamp = message.timestamp
9987-embargoing       112         command = message.command
9987-embargoing       113         speaker = self._pad(message.speaker, MAX_SPEAKER_SIZE)
genesis               114 
genesis               115         # let's generate the self_chain value from the last message or set it to zero if 
genesis               116         # there this is the first message
genesis               117         
9990-keep-ephemer...  118         if message.original:
genesis               119             if command == DIRECT:
9987-embargoing       120                 self_chain = self.state.get_last_message_hash(message.speaker, peer.peer_id)
genesis               121             elif command == BROADCAST:
9987-embargoing       122                 self_chain = self.state.get_last_message_hash(message.speaker)
9990-keep-ephemer...  123             elif command == IGNORE:
9990-keep-ephemer...  124                 self_chain = "\x00" * 32
genesis               125             net_chain = "\x00" * 32
genesis               126         else:
9990-keep-ephemer...  127             self_chain = message.self_chain 
9990-keep-ephemer...  128             net_chain = message.net_chain
genesis               129 
genesis               130         # pack message bytes
genesis               131 
9987-embargoing       132         if message.command != IGNORE:
9987-embargoing       133             logging.debug("packing message bytes: %s" % message.body)
9987-embargoing       134         else:
9987-embargoing       135             logging.debug("packing rubbish message bytes: %s" % binascii.hexlify(message.body))
9987-embargoing       136 
9987-embargoing       137         message_bytes = struct.pack(MESSAGE_PACKET_FORMAT, message.timestamp, self_chain, net_chain, speaker, message.body)
9988-hash-dedup       138         return message_bytes
genesis               139 
9987-embargoing       140     def pack(self, peer, message, message_bytes):
9988-hash-dedup       141         key_bytes = base64.b64decode(peer.get_key())
9988-hash-dedup       142         signing_key = key_bytes[:32]
9988-hash-dedup       143         cipher_key = key_bytes[32:]
genesis               144 
genesis               145         # pack packet bytes
genesis               146 
genesis               147         nonce = self._generate_nonce(16)
9990-keep-ephemer...  148         bounces = message.bounces 
genesis               149         version = 0xfe
9988-hash-dedup       150         red_packet_bytes = struct.pack(RED_PACKET_FORMAT, nonce, bounces, version, message.command, self._pad(message_bytes, MAX_MESSAGE_LENGTH))
genesis               151 
genesis               152         # encrypt packet
genesis               153 
genesis               154         serpent = Serpent(cipher_key)
genesis               155         black_packet_bytes = serpent_cbc_encrypt(cipher_key, red_packet_bytes)
genesis               156 
genesis               157         # sign packet
genesis               158 
genesis               159         signature_bytes = hmac.new(signing_key, black_packet_bytes, hashlib.sha384).digest()
genesis               160 
genesis               161         # pack the signed black packet
genesis               162 
genesis               163         signed_packet_bytes = struct.pack(BLACK_PACKET_FORMAT, black_packet_bytes, signature_bytes)
genesis               164 
genesis               165         return signed_packet_bytes
genesis               166     
genesis               167     def unpack(self, peer, black_packet):
genesis               168         # unpack the black packet
genesis               169 
genesis               170         key_bytes = base64.b64decode(peer.get_key())
genesis               171         signing_key = key_bytes[:32]
genesis               172         cipher_key = key_bytes[32:]
genesis               173 
genesis               174         try:
genesis               175             black_packet_bytes, signature_bytes = struct.unpack(BLACK_PACKET_FORMAT, black_packet)
genesis               176         except:
9987-embargoing       177             logging.error("Discarding malformed black packet from %s" % peer.get_key())
9987-embargoing       178             return Message({ "error_code": MALFORMED_PACKET })
genesis               179 
genesis               180         # check signature
genesis               181 
genesis               182         signature_check_bytes = hmac.new(signing_key, black_packet_bytes, hashlib.sha384).digest()
genesis               183 
genesis               184         if(signature_check_bytes != signature_bytes):
9987-embargoing       185             return Message({ "error_code": INVALID_SIGNATURE })
genesis               186 
genesis               187         # try to decrypt black packet
genesis               188         
genesis               189         serpent = Serpent(cipher_key)
genesis               190         red_packet_bytes = serpent_cbc_decrypt(cipher_key, black_packet_bytes)
genesis               191 
genesis               192         # unpack red packet
genesis               193 
genesis               194         nonce, bounces, version, command, message_bytes = struct.unpack(RED_PACKET_FORMAT, red_packet_bytes)
genesis               195 
9987-embargoing       196         # compute message_hash
9987-embargoing       197 
9987-embargoing       198         message_hash = binascii.hexlify(hashlib.sha256(message_bytes).digest())
9987-embargoing       199 
genesis               200         # unpack message
genesis               201 
9987-embargoing       202         int_ts, self_chain, net_chain, speaker, body = struct.unpack(MESSAGE_PACKET_FORMAT, message_bytes)
9987-embargoing       203         
9987-embargoing       204         # remove padding from speaker
9987-embargoing       205 
9987-embargoing       206         for index, byte in enumerate(speaker):
9987-embargoing       207             if byte == '\x00':
9987-embargoing       208                 speaker = speaker[0:index]
9987-embargoing       209                 break 
9987-embargoing       210 
9987-embargoing       211         # remove padding from body
9987-embargoing       212 
9987-embargoing       213         for index, byte in enumerate(body):
9987-embargoing       214             if byte == '\x00':
9987-embargoing       215                 body = body[0:index]
9987-embargoing       216                 break 
9989-show-wot-nicks   217 
9989-show-wot-nicks   218         # nothing to be done for an IGNORE command
9989-show-wot-nicks   219 
9989-show-wot-nicks   220         if command == IGNORE:
9989-show-wot-nicks   221             return Message({"speaker": speaker, "error_code": IGNORED})
9989-show-wot-nicks   222 
genesis               223         # check timestamp
genesis               224 
genesis               225         if(int_ts not in self._ts_range()):
9987-embargoing       226             return Message({ "error_code": STALE_PACKET })
genesis               227 
genesis               228         # check self_chain
genesis               229 
genesis               230         if command == DIRECT:
9987-embargoing       231             self_chain_check = self.state.get_last_message_hash(speaker, peer.peer_id)
genesis               232         elif command == BROADCAST:
9987-embargoing       233             self_chain_check = self.state.get_last_message_hash(speaker)
genesis               234 
genesis               235         self_chain_valid = (self_chain_check == self_chain)
genesis               236 
genesis               237         # log this message for use in the self_chain check
genesis               238 
9987-embargoing       239         self.state.log(speaker, message_bytes, peer if (command == DIRECT) else None)
genesis               240 
9987-embargoing       241         # build message object
genesis               242 
9987-embargoing       243         message = Message({ 
9990-keep-ephemer...  244                         "peer": peer,
9987-embargoing       245                         "body": body.rstrip(),
9990-keep-ephemer...  246                         "timestamp": int_ts,
9990-keep-ephemer...  247                         "command": command,
9990-keep-ephemer...  248                         "speaker": speaker,
9990-keep-ephemer...  249                         "bounces": bounces,
9990-keep-ephemer...  250                         "self_chain": self_chain,
9990-keep-ephemer...  251                         "net_chain": net_chain,
9990-keep-ephemer...  252                         "self_chain_valid": self_chain_valid,
9986-rebroadcast-...  253                         "message_hash": message_hash,
9986-rebroadcast-...  254                         "message_bytes": message_bytes
9987-embargoing       255                         })
9987-embargoing       256 
9987-embargoing       257         # check for duplicates
9987-embargoing       258 
9987-embargoing       259         if(self.state.is_duplicate_message(message_hash)):
9987-embargoing       260             message.error_code = DUPLICATE_PACKET
9987-embargoing       261             return message
9987-embargoing       262 
9987-embargoing       263         return message
genesis               264 
genesis               265     def _pad(self, text, size):
9987-embargoing       266         return text.ljust(size, "\x00")
genesis               267 
genesis               268     def _ts_range(self):
genesis               269         current_ts = int(time.time())
genesis               270         return range(current_ts - TS_ACCEPTABLE_SKEW, current_ts + TS_ACCEPTABLE_SKEW)
genesis               271 
genesis               272     def _generate_nonce(self, length=8):
genesis               273         """Generate pseudorandom number."""
genesis               274         return ''.join([str(random.randint(0, 9)) for i in range(length)])
9990-keep-ephemer...  275 
9990-keep-ephemer...  276     def gen_rubbish_body(self):
9990-keep-ephemer...  277         return os.urandom(MAX_MESSAGE_LENGTH)