Announce and validation

This commit is contained in:
Mark Qvist 2018-03-19 18:11:50 +01:00
parent 3ea36ff9b3
commit 82744fb9ed
6 changed files with 125 additions and 35 deletions

View File

@ -162,4 +162,18 @@ class Destination:
# Creates an announce packet for this destination.
# Application specific data can be added to the announce.
def announce(self,app_data=None):
pass
destination_hash = self.hash
random_hash = self.identity.getRandomHash()
signed_data = self.hash+self.identity.getPublicKey()+random_hash
if app_data != None:
signed_data += app_data
signature = self.identity.sign(signed_data)
announce_data = self.hash+self.identity.getPublicKey()+random_hash+signature
if app_data != None:
announce_data += app_data
FPE.Packet(self, announce_data, FPE.Packet.ANNOUNCE).send()

View File

@ -1,6 +1,4 @@
from Interfaces import *
import FPE
import ConfigParser
import jsonpickle
from vendor.configobj import ConfigObj
@ -9,8 +7,10 @@ import array
import os.path
import os
import FPE
class FlexPE:
MTU = 600
MTU = 500
router = None
config = None
destinations = []
@ -18,6 +18,7 @@ class FlexPE:
configdir = os.path.expanduser("~")+"/.flexpe"
configpath = configdir+"/config"
packetlist = []
def __init__(self,config=None):
if config != None:
@ -42,12 +43,20 @@ class FlexPE:
@staticmethod
def incoming(data):
packet = FPE.Packet(None, data)
packet.unpack()
packet_hash = FPE.Identity.fullHash(data)
for destination in FlexPE.destinations:
if destination.hash == packet.destination_hash and destination.type == packet.destination_type:
destination.receive(packet.data)
if not packet_hash in FlexPE.packetlist:
FlexPE.packetlist.append(packet_hash)
packet = FPE.Packet(None, data)
packet.unpack()
if packet.packet_type == FPE.Packet.ANNOUNCE:
FPE.Identity.validateAnnounce(packet)
if packet.packet_type == FPE.Packet.RESOURCE:
for destination in FlexPE.destinations:
if destination.hash == packet.destination_hash and destination.type == packet.destination_type:
destination.receive(packet.data)
@staticmethod
def outbound(raw):

View File

@ -1,19 +1,26 @@
import base64
import math
import os
import FPE
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.serialization import load_der_public_key
from cryptography.hazmat.primitives.serialization import load_der_private_key
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives.asymmetric import padding
class Identity:
# Configure key size
KEYSIZE = 1536;
DERKEYSIZE = 1808;
# Padding size, not configurable
PADDINGSIZE= 336;
# Storage
remembered_destinations = {}
def __init__(self):
# Initialize keys to none
self.prv = None
@ -26,12 +33,53 @@ class Identity:
self.createKeys()
@staticmethod
def getHash(pub_key):
def remember(hash, public_key, app_data = None):
FPE.log("Remembering "+FPE.hexrep(hash, False), FPE.LOG_VERBOSE)
Identity.remembered_destinations[hash] = [public_key, app_data]
@staticmethod
def recall(identity):
pass
@staticmethod
def fullHash(data):
digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
digest.update(pub_key)
digest.update(data)
return digest.finalize()
@staticmethod
def truncatedHash(data):
digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
digest.update(data)
return digest.finalize()[:10]
@staticmethod
def validateAnnounce(packet):
if packet.packet_type == FPE.Packet.ANNOUNCE:
FPE.log("Validating announce from "+FPE.hexrep(packet.destination_hash), FPE.LOG_VERBOSE)
destination_hash = packet.destination_hash
public_key = packet.data[10:Identity.DERKEYSIZE/8+10]
random_hash = packet.data[Identity.DERKEYSIZE/8+10:Identity.DERKEYSIZE/8+20]
signature = packet.data[Identity.DERKEYSIZE/8+20:Identity.DERKEYSIZE/8+20+Identity.KEYSIZE/8]
app_data = ""
if len(packet.data) > Identity.DERKEYSIZE/8+20+Identity.KEYSIZE/8:
app_data = packet.data[Identity.DERKEYSIZE/8+20+Identity.KEYSIZE/8:]
signed_data = destination_hash+public_key+random_hash+app_data
announced_identity = Identity()
announced_identity.loadPublicKey(public_key)
if announced_identity.validate(signature, signed_data):
FPE.log("Announce is valid", FPE.LOG_VERBOSE)
FPE.Identity.remember(destination_hash, public_key)
else:
FPE.log("Announce is invalid", FPE.LOG_VERBOSE)
del announced_identity
def createKeys(self):
self.prv = rsa.generate_private_key(
public_exponent=65337,
@ -49,7 +97,7 @@ class Identity:
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
self.hash = Identity.getHash(self.pub_bytes)
self.hash = Identity.truncatedHash(self.pub_bytes)
self.hexhash = self.hash.encode("hex_codec")
FPE.log("Identity keys created, private length is "+str(len(self.prv_bytes))+" public length is "+str(len(self.pub_bytes)), FPE.LOG_INFO)
@ -150,5 +198,24 @@ class Identity:
else:
raise KeyError("Signing failed because identity does not hold a private key")
def announce(self):
pass
def validate(self, signature, message):
if self.pub != None:
try:
self.pub.verify(
signature,
message,
padding.PSS(
mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH
),
hashes.SHA256()
)
return True
except:
return False
else:
raise KeyError("Signature validation failed because identity does not hold a public key")
def getRandomHash(self):
return self.truncatedHash(os.urandom(10))

View File

@ -3,11 +3,11 @@ import FPE
class Packet:
# Constants
MESSAGE = 0x00;
RESOURCE = 0x01;
RESOURCE = 0x00;
ANNOUNCE = 0x01;
LINKREQUEST = 0x02;
PROOF = 0x03;
types = [MESSAGE, RESOURCE, LINKREQUEST, PROOF]
types = [RESOURCE, ANNOUNCE, LINKREQUEST, PROOF]
HEADER_1 = 0x00; # Normal header format
HEADER_2 = 0x01; # Header format used for link packets in transport
@ -15,7 +15,7 @@ class Packet:
HEADER_4 = 0x03; # Reserved
header_types = [HEADER_1, HEADER_2, HEADER_3, HEADER_4]
def __init__(self, destination, data, packet_type = MESSAGE, transport_type = None, header_type = HEADER_1, transport_id = None):
def __init__(self, destination, data, packet_type = RESOURCE, transport_type = FPE.Transport.BROADCAST, header_type = HEADER_1, transport_id = None):
if destination != None:
if transport_type == None:
transport_type = FPE.Transport.BROADCAST
@ -53,7 +53,11 @@ class Packet:
raise IOError("Packet with header type 2 must have a transport ID")
self.header += self.destination.hash
self.ciphertext = self.destination.encrypt(self.data)
if self.packet_type != Packet.ANNOUNCE:
self.ciphertext = self.destination.encrypt(self.data)
else:
self.ciphertext = self.data
self.raw = self.header + self.ciphertext
if len(self.raw) > self.MTU:

View File

@ -58,3 +58,13 @@ def log(msg, level=3):
file = open(logfile, "a")
file.write(logstring+"\n")
file.close()
def hexprint(data):
print(hexrep(hexrep))
def hexrep(data, delimit=True):
delimiter = ":"
if not delimit:
delimiter = ""
hexrep = delimiter.join("{:02x}".format(ord(c)) for c in data)
return hexrep

18
t.py
View File

@ -19,30 +19,16 @@ identity = Identity()
d1=Destination(identity, Destination.IN, Destination.SINGLE, "messenger", "user")
d1.setCallback(testCallback)
d2=Destination(identity, Destination.IN, Destination.PLAIN, "messenger", "user")
d2.setCallback(testCallback)
# d2=Destination(identity, Destination.IN, Destination.PLAIN, "plainchat", "markqvist")
# d2.setCallback(testCallback)
#print identity.hexhash
#print d1.name
#print d1.hexhash
#print d1.identity.pub
#print "---"
#print
msg=""
for x in range(300):
msg += "a"
signed = d1.sign(msg)
sl = len(signed)
pl = len(d1.identity.pub_bytes)
#print("Signature length is "+str(sl))
#print("Minimum announce is "+str(pl+sl+8))
d1.announce()
p1=Packet(d1, msg)
p1.send()
#p1.send()
# p2=Packet(d2,"Test af msg")
# p2.send()