Reticulum/RNS/Identity.py
2020-08-13 12:15:56 +02:00

328 lines
12 KiB
Python

import base64
import math
import os
import RNS
import time
import atexit
from .vendor import umsgpack as umsgpack
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:
#KEYSIZE = 1536
KEYSIZE = 1024
DERKEYSIZE = KEYSIZE+272
# Non-configurable constants
PADDINGSIZE = 336 # In bits
HASHLENGTH = 256 # In bits
SIGLENGTH = KEYSIZE
ENCRYPT_CHUNKSIZE = (KEYSIZE-PADDINGSIZE)//8
DECRYPT_CHUNKSIZE = KEYSIZE//8
TRUNCATED_HASHLENGTH = 80 # In bits
# Storage
known_destinations = {}
@staticmethod
def remember(packet_hash, destination_hash, public_key, app_data = None):
Identity.known_destinations[destination_hash] = [time.time(), packet_hash, public_key, app_data]
@staticmethod
def recall(destination_hash):
RNS.log("Searching for "+RNS.prettyhexrep(destination_hash)+"...", RNS.LOG_EXTREME)
if destination_hash in Identity.known_destinations:
identity_data = Identity.known_destinations[destination_hash]
identity = Identity(public_only=True)
identity.loadPublicKey(identity_data[2])
RNS.log("Found "+RNS.prettyhexrep(destination_hash)+" in known destinations", RNS.LOG_EXTREME)
return identity
else:
RNS.log("Could not find "+RNS.prettyhexrep(destination_hash)+" in known destinations", RNS.LOG_EXTREME)
return None
@staticmethod
def saveKnownDestinations():
RNS.log("Saving known destinations to storage...", RNS.LOG_VERBOSE)
file = open(RNS.Reticulum.storagepath+"/known_destinations","wb")
umsgpack.dump(Identity.known_destinations, file)
file.close()
RNS.log("Done saving known destinations to storage", RNS.LOG_VERBOSE)
@staticmethod
def loadKnownDestinations():
if os.path.isfile(RNS.Reticulum.storagepath+"/known_destinations"):
try:
file = open(RNS.Reticulum.storagepath+"/known_destinations","rb")
Identity.known_destinations = umsgpack.load(file)
file.close()
RNS.log("Loaded "+str(len(Identity.known_destinations))+" known destination from storage", RNS.LOG_VERBOSE)
except:
RNS.log("Error loading known destinations from disk, file will be recreated on exit", RNS.LOG_ERROR)
else:
RNS.log("Destinations file does not exist, so no known destinations loaded", RNS.LOG_VERBOSE)
@staticmethod
def fullHash(data):
digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
digest.update(data)
return digest.finalize()
@staticmethod
def truncatedHash(data):
# TODO: Remove
# digest = hashes.Hash(hashes.SHA256(), backend=default_backend())
# digest.update(data)
return Identity.fullHash(data)[:(Identity.TRUNCATED_HASHLENGTH//8)]
@staticmethod
def getRandomHash():
return Identity.truncatedHash(os.urandom(10))
@staticmethod
def validateAnnounce(packet):
if packet.packet_type == RNS.Packet.ANNOUNCE:
RNS.log("Validating announce from "+RNS.prettyhexrep(packet.destination_hash), RNS.LOG_DEBUG)
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 = b""
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(public_only=True)
announced_identity.loadPublicKey(public_key)
if announced_identity.pub != None and announced_identity.validate(signature, signed_data):
RNS.Identity.remember(packet.getHash(), destination_hash, public_key)
RNS.log("Stored valid announce from "+RNS.prettyhexrep(destination_hash), RNS.LOG_DEBUG)
del announced_identity
return True
else:
RNS.log("Received invalid announce", RNS.LOG_DEBUG)
del announced_identity
return False
@staticmethod
def exitHandler():
Identity.saveKnownDestinations()
@staticmethod
def from_file(path):
identity = Identity(public_only=True)
if identity.load(path):
return identity
else:
return None
def __init__(self,public_only=False):
# Initialize keys to none
self.prv = None
self.pub = None
self.prv_bytes = None
self.pub_bytes = None
self.hash = None
self.hexhash = None
if not public_only:
self.createKeys()
def createKeys(self):
self.prv = rsa.generate_private_key(
public_exponent=65337,
key_size=Identity.KEYSIZE,
backend=default_backend()
)
self.prv_bytes = self.prv.private_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PrivateFormat.PKCS8,
encryption_algorithm=serialization.NoEncryption()
)
self.pub = self.prv.public_key()
self.pub_bytes = self.pub.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
self.updateHashes()
RNS.log("Identity keys created for "+RNS.prettyhexrep(self.hash), RNS.LOG_VERBOSE)
def getPrivateKey(self):
return self.prv_bytes
def getPublicKey(self):
return self.pub_bytes
def loadPrivateKey(self, prv_bytes):
try:
self.prv_bytes = prv_bytes
self.prv = serialization.load_der_private_key(
self.prv_bytes,
password=None,
backend=default_backend()
)
self.pub = self.prv.public_key()
self.pub_bytes = self.pub.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
self.updateHashes()
return True
except Exception as e:
RNS.log("Failed to load identity key", RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e))
return False
def loadPublicKey(self, key):
try:
self.pub_bytes = key
self.pub = load_der_public_key(self.pub_bytes, backend=default_backend())
self.updateHashes()
except Exception as e:
RNS.log("Error while loading public key, the contained exception was: "+str(e), RNS.LOG_ERROR)
def updateHashes(self):
self.hash = Identity.truncatedHash(self.pub_bytes)
self.hexhash = self.hash.hex()
def save(self, path):
try:
with open(path, "wb") as key_file:
key_file.write(self.prv_bytes)
return True
return False
except Exception as e:
RNS.log("Error while saving identity to "+str(path), RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e))
def load(self, path):
try:
with open(path, "rb") as key_file:
prv_bytes = key_file.read()
return self.loadPrivateKey(prv_bytes)
return False
except Exception as e:
RNS.log("Error while loading identity from "+str(path), RNS.LOG_ERROR)
RNS.log("The contained exception was: "+str(e))
def encrypt(self, plaintext):
if self.pub != None:
chunksize = Identity.ENCRYPT_CHUNKSIZE
chunks = int(math.ceil(len(plaintext)/(float(chunksize))))
ciphertext = b"";
for chunk in range(chunks):
start = chunk*chunksize
end = (chunk+1)*chunksize
if (chunk+1)*chunksize > len(plaintext):
end = len(plaintext)
ciphertext += self.pub.encrypt(
plaintext[start:end],
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None
)
)
return ciphertext
else:
raise KeyError("Encryption failed because identity does not hold a public key")
def decrypt(self, ciphertext):
if self.prv != None:
plaintext = None
try:
chunksize = Identity.DECRYPT_CHUNKSIZE
chunks = int(math.ceil(len(ciphertext)/(float(chunksize))))
plaintext = b"";
for chunk in range(chunks):
start = chunk*chunksize
end = (chunk+1)*chunksize
if (chunk+1)*chunksize > len(ciphertext):
end = len(ciphertext)
plaintext += self.prv.decrypt(
ciphertext[start:end],
padding.OAEP(
mgf=padding.MGF1(algorithm=hashes.SHA1()),
algorithm=hashes.SHA1(),
label=None
)
)
except:
RNS.log("Decryption by "+RNS.prettyhexrep(self.hash)+" failed", RNS.LOG_VERBOSE)
return plaintext;
else:
raise KeyError("Decryption failed because identity does not hold a private key")
def sign(self, message):
if self.prv != None:
signature = self.prv.sign(
message,
padding.PSS(
mgf=padding.MGF1(hashes.SHA256()),
salt_length=padding.PSS.MAX_LENGTH
),
hashes.SHA256()
)
return signature
else:
raise KeyError("Signing failed because identity does not hold a private key")
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 Exception as e:
return False
else:
raise KeyError("Signature validation failed because identity does not hold a public key")
def prove(self, packet, destination=None):
signature = self.sign(packet.packet_hash)
if RNS.Reticulum.should_use_implicit_proof():
proof_data = signature
else:
proof_data = packet.packet_hash + signature
if destination == None:
destination = packet.generateProofDestination()
proof = RNS.Packet(destination, proof_data, RNS.Packet.PROOF, attached_interface = packet.receiving_interface)
proof.send()
def __str__(self):
return RNS.prettyhexrep(self.hash)