PyBitmessage-2021-04-27/src/protocol.py

645 lines
24 KiB
Python

# pylint: disable=too-many-boolean-expressions,too-many-return-statements,too-many-locals,too-many-statements
"""
protocol.py
===========
Low-level protocol-related functions.
"""
from __future__ import absolute_import
import base64
from binascii import hexlify
import hashlib
import os
import random
import socket
import ssl
from struct import pack, unpack, Struct
import sys
import time
import traceback
import defaults
import highlevelcrypto
import state
from addresses import calculateInventoryHash, encodeVarint, decodeVarint, decodeAddress, varintDecodeError
from bmconfigparser import BMConfigParser
from debug import logger
from helper_sql import sqlExecute
from inventory import Inventory
from queues import objectProcessorQueue
from version import softwareVersion
# Service flags
NODE_NETWORK = 1
NODE_SSL = 2
NODE_DANDELION = 8
# Bitfield flags
BITFIELD_DOESACK = 1
# Error types
STATUS_WARNING = 0
STATUS_ERROR = 1
STATUS_FATAL = 2
# Object types
OBJECT_GETPUBKEY = 0
OBJECT_PUBKEY = 1
OBJECT_MSG = 2
OBJECT_BROADCAST = 3
OBJECT_I2P = 0x493250
OBJECT_ADDR = 0x61646472
eightBytesOfRandomDataUsedToDetectConnectionsToSelf = pack(
'>Q', random.randrange(1, 18446744073709551615))
# Compiled struct for packing/unpacking headers
# New code should use CreatePacket instead of Header.pack
Header = Struct('!L12sL4s')
VersionPacket = Struct('>LqQ20s4s36sH')
def calculateDoubleHash(data):
return hashlib.sha512(hashlib.sha512(data).digest()).digest()
def calculateRipeHash(data):
return hashlib.new("ripemd160", hashlib.sha512(data).digest()).digest()
def calculateAddressTag(version, stream, ripe):
doubleHash = calculateDoubleHash(
encodeVarint(version) +
encodeVarint(stream) +
ripe
)
return doubleHash[: 32], doubleHash[32: ]
# ip addresses
def encodeHost(host):
"""Encode a given host to be used in low-level socket operations"""
if host.find('.onion') > -1:
return '\xfd\x87\xd8\x7e\xeb\x43' + base64.b32decode(host.split(".")[0], True)
elif host.find(':') == -1:
return '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF' + \
socket.inet_aton(host)
return socket.inet_pton(socket.AF_INET6, host)
def networkType(host):
"""Determine if a host is IPv4, IPv6 or an onion address"""
if host.find('.onion') > -1:
return 'onion'
elif host.find(':') == -1:
return 'IPv4'
return 'IPv6'
def checkIPAddress(host, private=False):
"""Returns hostStandardFormat if it is a valid IP address, otherwise returns False"""
if host[0:12] == '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF':
hostStandardFormat = socket.inet_ntop(socket.AF_INET, host[12:])
return checkIPv4Address(host[12:], hostStandardFormat, private)
elif host[0:6] == '\xfd\x87\xd8\x7e\xeb\x43':
# Onion, based on BMD/bitcoind
hostStandardFormat = base64.b32encode(host[6:]).lower() + ".onion"
if private:
return False
return hostStandardFormat
else:
try:
hostStandardFormat = socket.inet_ntop(socket.AF_INET6, host)
except ValueError:
return False
if hostStandardFormat == "":
# This can happen on Windows systems which are not 64-bit compatible
# so let us drop the IPv6 address.
return False
return checkIPv6Address(host, hostStandardFormat, private)
def checkIPv4Address(host, hostStandardFormat, private=False):
"""Returns hostStandardFormat if it is an IPv4 address, otherwise returns False"""
if host[0] == '\x7F': # 127/8
if not private:
logger.debug('Ignoring IP address in loopback range: %s', hostStandardFormat)
return hostStandardFormat if private else False
if host[0] == '\x0A': # 10/8
if not private:
logger.debug('Ignoring IP address in private range: %s', hostStandardFormat)
return hostStandardFormat if private else False
if host[0:2] == '\xC0\xA8': # 192.168/16
if not private:
logger.debug('Ignoring IP address in private range: %s', hostStandardFormat)
return hostStandardFormat if private else False
if host[0:2] >= '\xAC\x10' and host[0:2] < '\xAC\x20': # 172.16/12
if not private:
logger.debug('Ignoring IP address in private range: %s', hostStandardFormat)
return hostStandardFormat if private else False
return False if private else hostStandardFormat
def checkIPv6Address(host, hostStandardFormat, private=False):
"""Returns hostStandardFormat if it is an IPv6 address, otherwise returns False"""
if host == ('\x00' * 15) + '\x01':
if not private:
logger.debug('Ignoring loopback address: %s', hostStandardFormat)
return False
if host[0] == '\xFE' and (ord(host[1]) & 0xc0) == 0x80:
if not private:
logger.debug('Ignoring local address: %s', hostStandardFormat)
return hostStandardFormat if private else False
if (ord(host[0]) & 0xfe) == 0xfc:
if not private:
logger.debug('Ignoring unique local address: %s', hostStandardFormat)
return hostStandardFormat if private else False
return False if private else hostStandardFormat
def haveSSL(server=False):
"""
Predicate to check if ECDSA server support is required and available
python < 2.7.9's ssl library does not support ECDSA server due to
missing initialisation of available curves, but client works ok
"""
if not server:
return True
elif sys.version_info >= (2, 7, 9):
return True
return False
def checkSocksIP(host):
"""Predicate to check if we're using a SOCKS proxy"""
try:
if state.socksIP is None or not state.socksIP:
state.socksIP = socket.gethostbyname(BMConfigParser().get("bitmessagesettings", "sockshostname"))
# uninitialised
except NameError:
state.socksIP = socket.gethostbyname(BMConfigParser().get("bitmessagesettings", "sockshostname"))
# resolving failure
except socket.gaierror:
state.socksIP = BMConfigParser().get("bitmessagesettings", "sockshostname")
return state.socksIP == host
def isProofOfWorkSufficient(data,
nonceTrialsPerByte=0,
payloadLengthExtraBytes=0,
recvTime=0):
"""
Validate an object's Proof of Work using method described in:
https://bitmessage.org/wiki/Proof_of_work
Arguments:
int nonceTrialsPerByte (default: from default.py)
int payloadLengthExtraBytes (default: from default.py)
float recvTime (optional) UNIX epoch time when object was
received from the network (default: current system time)
Returns:
True if PoW valid and sufficient, False in all other cases
"""
if nonceTrialsPerByte < defaults.networkDefaultProofOfWorkNonceTrialsPerByte:
nonceTrialsPerByte = defaults.networkDefaultProofOfWorkNonceTrialsPerByte
if payloadLengthExtraBytes < defaults.networkDefaultPayloadLengthExtraBytes:
payloadLengthExtraBytes = defaults.networkDefaultPayloadLengthExtraBytes
endOfLifeTime, = unpack('>Q', data[8:16])
TTL = endOfLifeTime - (int(recvTime) if recvTime else int(time.time()))
if TTL < 300:
TTL = 300
POW, = unpack('>Q', hashlib.sha512(hashlib.sha512(data[
:8] + hashlib.sha512(data[8:]).digest()).digest()).digest()[0:8])
return POW <= 2 ** 64 / (nonceTrialsPerByte *
(len(data) + payloadLengthExtraBytes +
((TTL * (len(data) + payloadLengthExtraBytes)) / (2 ** 16))))
# Packet creation
def CreatePacket(command, payload=''):
"""Construct and return a number of bytes from a payload"""
payload_length = len(payload)
checksum = hashlib.sha512(payload).digest()[0:4]
b = bytearray(Header.size + payload_length)
Header.pack_into(b, 0, 0xE9BEB4D9, command, payload_length, checksum)
b[Header.size:] = payload
return bytes(b)
def assembleVersionMessage(remoteHost, remotePort, participatingStreams, server=False, nodeid=None):
"""Construct the payload of a version message, return the resultng bytes of running CreatePacket() on it"""
payload = ''
payload += pack('>L', 3) # protocol version.
# bitflags of the services I offer.
payload += pack(
'>q',
NODE_NETWORK |
(NODE_SSL if haveSSL(server) else 0) |
(NODE_DANDELION if state.dandelion else 0)
)
payload += pack('>q', int(time.time()))
payload += pack(
'>q', 1) # boolservices of remote connection; ignored by the remote host.
if checkSocksIP(remoteHost) and server: # prevent leaking of tor outbound IP
payload += encodeHost('127.0.0.1')
payload += pack('>H', 8444)
else:
payload += encodeHost(remoteHost)
payload += pack('>H', remotePort) # remote IPv6 and port
# bitflags of the services I offer.
payload += pack(
'>q',
NODE_NETWORK |
(NODE_SSL if haveSSL(server) else 0) |
(NODE_DANDELION if state.dandelion else 0)
)
# = 127.0.0.1. This will be ignored by the remote host. The actual remote connected IP will be used.
payload += '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF' + pack('>L', 2130706433)
# we have a separate extPort and incoming over clearnet or outgoing through clearnet
if BMConfigParser().safeGetBoolean('bitmessagesettings', 'upnp') and state.extPort \
and ((server and not checkSocksIP(remoteHost)) or
(BMConfigParser().get("bitmessagesettings", "socksproxytype") == "none" and not server)):
payload += pack('>H', state.extPort)
elif checkSocksIP(remoteHost) and server: # incoming connection over Tor
payload += pack('>H', BMConfigParser().getint('bitmessagesettings', 'onionport'))
else: # no extPort and not incoming over Tor
payload += pack('>H', BMConfigParser().getint('bitmessagesettings', 'port'))
random.seed()
if nodeid is not None:
payload += nodeid[0:8]
else:
payload += eightBytesOfRandomDataUsedToDetectConnectionsToSelf
userAgent = '/PyBitmessage:' + softwareVersion + '/'
payload += encodeVarint(len(userAgent))
payload += userAgent
# Streams
payload += encodeVarint(len(participatingStreams))
count = 0
for stream in sorted(participatingStreams):
payload += encodeVarint(stream)
count += 1
# protocol limit, see specification
if count >= 160000:
break
return CreatePacket('version', payload)
def assembleErrorMessage(fatal=0, banTime=0, inventoryVector='', errorText=''):
"""Construct the payload of an error message, return the resultng bytes of running CreatePacket() on it"""
payload = encodeVarint(fatal)
payload += encodeVarint(banTime)
payload += encodeVarint(len(inventoryVector))
payload += inventoryVector
payload += encodeVarint(len(errorText))
payload += errorText
return CreatePacket('error', payload)
# Packet decoding
def decryptAndCheckV4Pubkey(payload, address, cryptor):
status, version, stream, ripe = decodeAddress(address)
readPosition = 20
try:
embeddedVersion, readLength = decodeVarint(payload[readPosition: readPosition + 9])
readPosition += readLength
embeddedStream, readLength = decodeVarint(payload[readPosition: readPosition + 9])
readPosition += readLength
except:
return None
if embeddedVersion != 4:
logger.info("Pubkey decryption failed due to address version mismatch")
return None
if embeddedStream != stream:
logger.info("Pubkey decryption failed due to stream number mismatch")
return None
result = payload[20: readPosition]
tag = payload[readPosition: readPosition + 32]
readPosition += 32
if len(tag) < 32:
return None
signedData = payload[8: readPosition]
ciphertext = payload[readPosition: ]
try:
plaintext = cryptor.decrypt(ciphertext)
except:
logger.info("Pubkey decryption failed")
return None
readPosition = 0
try:
bitfield = unpack(">I", plaintext[readPosition: readPosition + 4])
readPosition += 4
except:
return None
publicSigningKey = "\x04" + plaintext[readPosition: readPosition + 64]
readPosition += 64
publicEncryptionKey = "\x04" + plaintext[readPosition: readPosition + 64]
readPosition += 64
if len(publicSigningKey) != 65 or len(publicEncryptionKey) != 65:
return None
embeddedRipe = calculateRipeHash(publicSigningKey + publicEncryptionKey)
if embeddedRipe != ripe:
logger.info("Pubkey decryption failed due to RIPE mismatch")
return None
try:
byteDifficulty, readLength = decodeVarint(plaintext[readPosition: readPosition + 9])
readPosition += readLength
lengthExtension, readLength = decodeVarint(plaintext[readPosition: readPosition + 9])
readPosition += readLength
except:
return None
result += plaintext[: readPosition]
signedData += plaintext[: readPosition]
signatureLength, readLength = decodeVarint(plaintext[readPosition: readPosition + 9])
readPosition += readLength
signature = plaintext[readPosition: readPosition + signatureLength]
if len(signature) != signatureLength:
return None
if not highlevelcrypto.verify(signedData, signature, hexlify(publicSigningKey)):
logger.info("Invalid signature on a pubkey")
return None
return result
def checkAndShareObjectWithPeers(data):
"""
This function is called after either receiving an object off of the wire
or after receiving one as ackdata.
Returns the length of time that we should reserve to process this message
if we are receiving it off of the wire.
"""
if len(data) > 2 ** 18:
logger.info('The payload length of this object is too large (%s bytes). Ignoring it.', len(data))
return 0
# Let us check to make sure that the proof of work is sufficient.
if not isProofOfWorkSufficient(data):
logger.info('Proof of work is insufficient.')
return 0
endOfLifeTime, = unpack('>Q', data[8:16])
# The TTL may not be larger than 28 days + 3 hours of wiggle room
if endOfLifeTime - int(time.time()) > 28 * 24 * 60 * 60 + 10800:
logger.info('This object\'s End of Life time is too far in the future. Ignoring it. Time is %s', endOfLifeTime)
return 0
if endOfLifeTime - int(time.time()) < - 3600: # The EOL time was more than an hour ago. That's too much.
logger.info(
'This object\'s End of Life time was more than an hour ago. Ignoring the object. Time is %s',
endOfLifeTime)
return 0
intObjectType, = unpack('>I', data[16:20])
try:
if intObjectType == 0:
_checkAndShareGetpubkeyWithPeers(data)
return 0.1
elif intObjectType == 1:
_checkAndSharePubkeyWithPeers(data)
return 0.1
elif intObjectType == 2:
_checkAndShareMsgWithPeers(data)
return 0.6
elif intObjectType == 3:
_checkAndShareBroadcastWithPeers(data)
return 0.6
_checkAndShareUndefinedObjectWithPeers(data)
return 0.6
except varintDecodeError as err:
logger.debug(
"There was a problem with a varint while checking to see whether it was appropriate to share an object"
" with peers. Some details: %s", err
)
except Exception:
logger.critical(
'There was a problem while checking to see whether it was appropriate to share an object with peers.'
' This is definitely a bug! %s%s' % os.linesep, traceback.format_exc()
)
return 0
def _checkAndShareUndefinedObjectWithPeers(data):
# pylint: disable=unused-variable
embeddedTime, = unpack('>Q', data[8:16])
readPosition = 20 # bypass nonce, time, and object type
objectVersion, objectVersionLength = decodeVarint(
data[readPosition:readPosition + 9])
readPosition += objectVersionLength
streamNumber, streamNumberLength = decodeVarint(
data[readPosition:readPosition + 9])
if streamNumber not in state.streamsInWhichIAmParticipating:
logger.debug('The streamNumber %s isn\'t one we are interested in.', streamNumber)
return
inventoryHash = calculateInventoryHash(data)
if inventoryHash in Inventory():
logger.debug('We have already received this undefined object. Ignoring.')
return
objectType, = unpack('>I', data[16:20])
Inventory()[inventoryHash] = (
objectType, streamNumber, data, embeddedTime, '')
logger.debug('advertising inv with hash: %s', hexlify(inventoryHash))
broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))
def _checkAndShareMsgWithPeers(data):
embeddedTime, = unpack('>Q', data[8:16])
readPosition = 20 # bypass nonce, time, and object type
objectVersion, objectVersionLength = decodeVarint( # pylint: disable=unused-variable
data[readPosition:readPosition + 9])
readPosition += objectVersionLength
streamNumber, streamNumberLength = decodeVarint(
data[readPosition:readPosition + 9])
if streamNumber not in state.streamsInWhichIAmParticipating:
logger.debug('The streamNumber %s isn\'t one we are interested in.', streamNumber)
return
readPosition += streamNumberLength
inventoryHash = calculateInventoryHash(data)
if inventoryHash in Inventory():
logger.debug('We have already received this msg message. Ignoring.')
return
# This msg message is valid. Let's let our peers know about it.
objectType = 2
Inventory()[inventoryHash] = (
objectType, streamNumber, data, embeddedTime, '')
logger.debug('advertising inv with hash: %s', hexlify(inventoryHash))
broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))
# Now let's enqueue it to be processed ourselves.
objectProcessorQueue.put((objectType, data))
def _checkAndShareGetpubkeyWithPeers(data):
# pylint: disable=unused-variable
if len(data) < 42:
logger.info('getpubkey message doesn\'t contain enough data. Ignoring.')
return
if len(data) > 200:
logger.info('getpubkey is abnormally long. Sanity check failed. Ignoring object.')
embeddedTime, = unpack('>Q', data[8:16])
readPosition = 20 # bypass the nonce, time, and object type
requestedAddressVersionNumber, addressVersionLength = decodeVarint(
data[readPosition:readPosition + 10])
readPosition += addressVersionLength
streamNumber, streamNumberLength = decodeVarint(
data[readPosition:readPosition + 10])
if streamNumber not in state.streamsInWhichIAmParticipating:
logger.debug('The streamNumber %s isn\'t one we are interested in.', streamNumber)
return
readPosition += streamNumberLength
inventoryHash = calculateInventoryHash(data)
if inventoryHash in Inventory():
logger.debug('We have already received this getpubkey request. Ignoring it.')
return
objectType = 0
Inventory()[inventoryHash] = (
objectType, streamNumber, data, embeddedTime, '')
# This getpubkey request is valid. Forward to peers.
logger.debug('advertising inv with hash: %s', hexlify(inventoryHash))
broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))
# Now let's queue it to be processed ourselves.
objectProcessorQueue.put((objectType, data))
def _checkAndSharePubkeyWithPeers(data):
if len(data) < 146 or len(data) > 440: # sanity check
return
embeddedTime, = unpack('>Q', data[8:16])
readPosition = 20 # bypass the nonce, time, and object type
addressVersion, varintLength = decodeVarint(
data[readPosition:readPosition + 10])
readPosition += varintLength
streamNumber, varintLength = decodeVarint(
data[readPosition:readPosition + 10])
readPosition += varintLength
if streamNumber not in state.streamsInWhichIAmParticipating:
logger.debug('The streamNumber %s isn\'t one we are interested in.', streamNumber)
return
if addressVersion >= 4:
tag = data[readPosition:readPosition + 32]
logger.debug('tag in received pubkey is: %s', hexlify(tag))
else:
tag = ''
inventoryHash = calculateInventoryHash(data)
if inventoryHash in Inventory():
logger.debug('We have already received this pubkey. Ignoring it.')
return
objectType = 1
Inventory()[inventoryHash] = (
objectType, streamNumber, data, embeddedTime, tag)
# This object is valid. Forward it to peers.
logger.debug('advertising inv with hash: %s', hexlify(inventoryHash))
broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))
# Now let's queue it to be processed ourselves.
objectProcessorQueue.put((objectType, data))
def _checkAndShareBroadcastWithPeers(data):
if len(data) < 180:
logger.debug(
'The payload length of this broadcast packet is unreasonably low. '
'Someone is probably trying funny business. Ignoring message.')
return
embeddedTime, = unpack('>Q', data[8:16])
readPosition = 20 # bypass the nonce, time, and object type
broadcastVersion, broadcastVersionLength = decodeVarint(
data[readPosition:readPosition + 10])
readPosition += broadcastVersionLength
if broadcastVersion >= 2:
streamNumber, streamNumberLength = decodeVarint(data[readPosition:readPosition + 10])
readPosition += streamNumberLength
if streamNumber not in state.streamsInWhichIAmParticipating:
logger.debug('The streamNumber %s isn\'t one we are interested in.', streamNumber)
return
if broadcastVersion >= 3:
tag = data[readPosition:readPosition + 32]
else:
tag = ''
inventoryHash = calculateInventoryHash(data)
if inventoryHash in Inventory():
logger.debug('We have already received this broadcast object. Ignoring.')
return
# It is valid. Let's let our peers know about it.
objectType = 3
Inventory()[inventoryHash] = (
objectType, streamNumber, data, embeddedTime, tag)
# This object is valid. Forward it to peers.
logger.debug('advertising inv with hash: %s', hexlify(inventoryHash))
broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))
# Now let's queue it to be processed ourselves.
objectProcessorQueue.put((objectType, data))
def broadcastToSendDataQueues(data):
"""
If you want to command all of the sendDataThreads to do something, like shutdown or send some data, this
function puts your data into the queues for each of the sendDataThreads. The sendDataThreads are
responsible for putting their queue into (and out of) the sendDataQueues list.
"""
for q in state.sendDataQueues:
q.put(data)
# sslProtocolVersion
if sys.version_info >= (2, 7, 13):
# this means TLSv1 or higher
# in the future change to
# ssl.PROTOCOL_TLS1.2
sslProtocolVersion = ssl.PROTOCOL_TLS # pylint: disable=no-member
elif sys.version_info >= (2, 7, 9):
# this means any SSL/TLS. SSLv2 and 3 are excluded with an option after context is created
sslProtocolVersion = ssl.PROTOCOL_SSLv23
else:
# this means TLSv1, there is no way to set "TLSv1 or higher" or
# "TLSv1.2" in < 2.7.9
sslProtocolVersion = ssl.PROTOCOL_TLSv1
# ciphers
if ssl.OPENSSL_VERSION_NUMBER >= 0x10100000 and not ssl.OPENSSL_VERSION.startswith("LibreSSL"):
sslProtocolCiphers = "AECDH-AES256-SHA@SECLEVEL=0"
else:
sslProtocolCiphers = "AECDH-AES256-SHA"