PyBitmessage/src/shared.py

from __future__ import division

verbose = 1
maximumAgeOfAnObjectThatIAmWillingToAccept = 216000  # This is obsolete with the change to protocol v3 but the singleCleaner thread still hasn't been updated so we need this a little longer.
lengthOfTimeToHoldOnToAllPubkeys = 2419200  # Equals 4 weeks. You could make this longer if you want but making it shorter would not be advisable because there is a very small possibility that it could keep you from obtaining a needed pubkey for a period of time.
maximumAgeOfNodesThatIAdvertiseToOthers = 10800  # Equals three hours
useVeryEasyProofOfWorkForTesting = False  # If you set this to True while on the normal network, you won't be able to send or sometimes receive messages.


# Libraries.
import os
import sys
import stat
import threading
import time
import traceback
from binascii import hexlify

# Project imports.
from addresses import *
from bmconfigparser import BMConfigParser
import highlevelcrypto
#import helper_startup
from helper_sql import *
from inventory import Inventory, PendingDownload
from queues import objectProcessorQueue
import protocol
import state


myECCryptorObjects = {}
MyECSubscriptionCryptorObjects = {}
myAddressesByHash = {} #The key in this dictionary is the RIPE hash which is encoded in an address and value is the address itself.
myAddressesByTag = {} # The key in this dictionary is the tag generated from the address.
broadcastSendersForWhichImWatching = {}
printLock = threading.Lock()
statusIconColor = 'red'
connectedHostsList = {} #List of hosts to which we are connected. Used to guarantee that the outgoingSynSender threads won't connect to the same remote node twice.
thisapp = None # singleton lock instance
alreadyAttemptedConnectionsList = {
}  # This is a list of nodes to which we have already attempted a connection
alreadyAttemptedConnectionsListLock = threading.Lock()
alreadyAttemptedConnectionsListResetTime = int(
    time.time())  # used to clear out the alreadyAttemptedConnectionsList periodically so that we will retry connecting to hosts to which we have already tried to connect.
successfullyDecryptMessageTimings = [
    ]  # A list of the amounts of time it took to successfully decrypt msg messages
ackdataForWhichImWatching = {}
clientHasReceivedIncomingConnections = False #used by API command clientStatus
numberOfMessagesProcessed = 0
numberOfBroadcastsProcessed = 0
numberOfPubkeysProcessed = 0
daemon = False
needToWriteKnownNodesToDisk = False # If True, the singleCleaner will write it to disk eventually.
maximumLengthOfTimeToBotherResendingMessages = 0
timeOffsetWrongCount = 0

def isAddressInMyAddressBook(address):
    queryreturn = sqlQuery(
        '''select address from addressbook where address=?''',
        address)
    return queryreturn != []

#At this point we should really just have a isAddressInMy(book, address)...
def isAddressInMySubscriptionsList(address):
    queryreturn = sqlQuery(
        '''select * from subscriptions where address=?''',
        str(address))
    return queryreturn != []

def isAddressInMyAddressBookSubscriptionsListOrWhitelist(address):
    if isAddressInMyAddressBook(address):
        return True

    queryreturn = sqlQuery('''SELECT address FROM whitelist where address=? and enabled = '1' ''', address)
    if queryreturn <> []:
        return True

    queryreturn = sqlQuery(
        '''select address from subscriptions where address=? and enabled = '1' ''',
        address)
    if queryreturn <> []:
        return True
    return False

def decodeWalletImportFormat(WIFstring):
    fullString = arithmetic.changebase(WIFstring,58,256)
    privkey = fullString[:-4]
    if fullString[-4:] != hashlib.sha256(hashlib.sha256(privkey).digest()).digest()[:4]:
        logger.critical('Major problem! When trying to decode one of your private keys, the checksum '
                     'failed. Here are the first 6 characters of the PRIVATE key: %s' % str(WIFstring)[:6])
        os._exit(0)
        return ""
    else:
        #checksum passed
        if privkey[0] == '\x80':
            return privkey[1:]
        else:
            logger.critical('Major problem! When trying to decode one of your private keys, the '
                         'checksum passed but the key doesn\'t begin with hex 80. Here is the '
                         'PRIVATE key: %s' % str(WIFstring))
            os._exit(0)
            return ""


def reloadMyAddressHashes():
    logger.debug('reloading keys from keys.dat file')
    myECCryptorObjects.clear()
    myAddressesByHash.clear()
    myAddressesByTag.clear()
    #myPrivateKeys.clear()

    keyfileSecure = checkSensitiveFilePermissions(state.appdata + 'keys.dat')
    configSections = BMConfigParser().sections()
    hasEnabledKeys = False
    for addressInKeysFile in configSections:
        if addressInKeysFile <> 'bitmessagesettings':
            isEnabled = BMConfigParser().getboolean(addressInKeysFile, 'enabled')
            if isEnabled:
                hasEnabledKeys = True
                status,addressVersionNumber,streamNumber,hash = decodeAddress(addressInKeysFile)
                if addressVersionNumber == 2 or addressVersionNumber == 3 or addressVersionNumber == 4:
                    # Returns a simple 32 bytes of information encoded in 64 Hex characters,
                    # or null if there was an error.
                    privEncryptionKey = hexlify(decodeWalletImportFormat(
                            BMConfigParser().get(addressInKeysFile, 'privencryptionkey')))

                    if len(privEncryptionKey) == 64:#It is 32 bytes encoded as 64 hex characters
                        myECCryptorObjects[hash] = highlevelcrypto.makeCryptor(privEncryptionKey)
                        myAddressesByHash[hash] = addressInKeysFile
                        tag = hashlib.sha512(hashlib.sha512(encodeVarint(
                            addressVersionNumber) + encodeVarint(streamNumber) + hash).digest()).digest()[32:]
                        myAddressesByTag[tag] = addressInKeysFile

                else:
                    logger.error('Error in reloadMyAddressHashes: Can\'t handle address versions other than 2, 3, or 4.\n')

    if not keyfileSecure:
        fixSensitiveFilePermissions(state.appdata + 'keys.dat', hasEnabledKeys)

def reloadBroadcastSendersForWhichImWatching():
    broadcastSendersForWhichImWatching.clear()
    MyECSubscriptionCryptorObjects.clear()
    queryreturn = sqlQuery('SELECT address FROM subscriptions where enabled=1')
    logger.debug('reloading subscriptions...')
    for row in queryreturn:
        address, = row
        status,addressVersionNumber,streamNumber,hash = decodeAddress(address)
        if addressVersionNumber == 2:
            broadcastSendersForWhichImWatching[hash] = 0
        #Now, for all addresses, even version 2 addresses, we should create Cryptor objects in a dictionary which we will use to attempt to decrypt encrypted broadcast messages.
        
        if addressVersionNumber <= 3:
            privEncryptionKey = hashlib.sha512(encodeVarint(addressVersionNumber)+encodeVarint(streamNumber)+hash).digest()[:32]
            MyECSubscriptionCryptorObjects[hash] = highlevelcrypto.makeCryptor(hexlify(privEncryptionKey))
        else:
            doubleHashOfAddressData = hashlib.sha512(hashlib.sha512(encodeVarint(
                addressVersionNumber) + encodeVarint(streamNumber) + hash).digest()).digest()
            tag = doubleHashOfAddressData[32:]
            privEncryptionKey = doubleHashOfAddressData[:32]
            MyECSubscriptionCryptorObjects[tag] = highlevelcrypto.makeCryptor(hexlify(privEncryptionKey))

def fixPotentiallyInvalidUTF8Data(text):
    try:
        unicode(text,'utf-8')
        return text
    except:
        output = 'Part of the message is corrupt. The message cannot be displayed the normal way.\n\n' + repr(text)
        return output

# Checks sensitive file permissions for inappropriate umask during keys.dat creation.
# (Or unwise subsequent chmod.)
#
# Returns true iff file appears to have appropriate permissions.
def checkSensitiveFilePermissions(filename):
    if sys.platform == 'win32':
        # TODO: This might deserve extra checks by someone familiar with
        # Windows systems.
        return True
    elif sys.platform[:7] == 'freebsd':
        # FreeBSD file systems are the same as major Linux file systems
        present_permissions = os.stat(filename)[0]
        disallowed_permissions = stat.S_IRWXG | stat.S_IRWXO
        return present_permissions & disallowed_permissions == 0
    else:
        try:
            # Skip known problems for non-Win32 filesystems without POSIX permissions.
            import subprocess
            fstype = subprocess.check_output('stat -f -c "%%T" %s' % (filename),
                                             shell=True,
                                             stderr=subprocess.STDOUT)
            if 'fuseblk' in fstype:
                logger.info('Skipping file permissions check for %s. Filesystem fuseblk detected.',
                            filename)
                return True
        except:
            # Swallow exception here, but we might run into trouble later!
            logger.error('Could not determine filesystem type. %s', filename)
        present_permissions = os.stat(filename)[0]
        disallowed_permissions = stat.S_IRWXG | stat.S_IRWXO
        return present_permissions & disallowed_permissions == 0

# Fixes permissions on a sensitive file.
def fixSensitiveFilePermissions(filename, hasEnabledKeys):
    if hasEnabledKeys:
        logger.warning('Keyfile had insecure permissions, and there were enabled keys. '
                       'The truly paranoid should stop using them immediately.')
    else:
        logger.warning('Keyfile had insecure permissions, but there were no enabled keys.')
    try:
        present_permissions = os.stat(filename)[0]
        disallowed_permissions = stat.S_IRWXG | stat.S_IRWXO
        allowed_permissions = ((1<<32)-1) ^ disallowed_permissions
        new_permissions = (
            allowed_permissions & present_permissions)
        os.chmod(filename, new_permissions)

        logger.info('Keyfile permissions automatically fixed.')

    except Exception, e:
        logger.exception('Keyfile permissions could not be fixed.')
        raise
    
def isBitSetWithinBitfield(fourByteString, n):
    # Uses MSB 0 bit numbering across 4 bytes of data
    n = 31 - n
    x, = unpack('>L', fourByteString)
    return x & 2**n != 0


def decryptAndCheckPubkeyPayload(data, address):
    """
    Version 4 pubkeys are encrypted. This function is run when we already have the 
    address to which we want to try to send a message. The 'data' may come either
    off of the wire or we might have had it already in our inventory when we tried
    to send a msg to this particular address. 
    """
    try:
        status, addressVersion, streamNumber, ripe = decodeAddress(address)
        
        readPosition = 20  # bypass the nonce, time, and object type
        embeddedAddressVersion, varintLength = decodeVarint(data[readPosition:readPosition + 10])
        readPosition += varintLength
        embeddedStreamNumber, varintLength = decodeVarint(data[readPosition:readPosition + 10])
        readPosition += varintLength
        storedData = data[20:readPosition] # We'll store the address version and stream number (and some more) in the pubkeys table.
        
        if addressVersion != embeddedAddressVersion:
            logger.info('Pubkey decryption was UNsuccessful due to address version mismatch.')
            return 'failed'
        if streamNumber != embeddedStreamNumber:
            logger.info('Pubkey decryption was UNsuccessful due to stream number mismatch.')
            return 'failed'
        
        tag = data[readPosition:readPosition + 32]
        readPosition += 32
        signedData = data[8:readPosition] # the time through the tag. More data is appended onto signedData below after the decryption. 
        encryptedData = data[readPosition:]
    
        # Let us try to decrypt the pubkey
        toAddress, cryptorObject = state.neededPubkeys[tag]
        if toAddress != address:
            logger.critical('decryptAndCheckPubkeyPayload failed due to toAddress mismatch. This is very peculiar. toAddress: %s, address %s' % (toAddress, address))
            # the only way I can think that this could happen is if someone encodes their address data two different ways.
            # That sort of address-malleability should have been caught by the UI or API and an error given to the user. 
            return 'failed'
        try:
            decryptedData = cryptorObject.decrypt(encryptedData)
        except:
            # Someone must have encrypted some data with a different key
            # but tagged it with a tag for which we are watching.
            logger.info('Pubkey decryption was unsuccessful.')
            return 'failed'
        
        readPosition = 0
        bitfieldBehaviors = decryptedData[readPosition:readPosition + 4]
        readPosition += 4
        publicSigningKey = '\x04' + decryptedData[readPosition:readPosition + 64]
        readPosition += 64
        publicEncryptionKey = '\x04' + decryptedData[readPosition:readPosition + 64]
        readPosition += 64
        specifiedNonceTrialsPerByte, specifiedNonceTrialsPerByteLength = decodeVarint(
            decryptedData[readPosition:readPosition + 10])
        readPosition += specifiedNonceTrialsPerByteLength
        specifiedPayloadLengthExtraBytes, specifiedPayloadLengthExtraBytesLength = decodeVarint(
            decryptedData[readPosition:readPosition + 10])
        readPosition += specifiedPayloadLengthExtraBytesLength
        storedData += decryptedData[:readPosition]
        signedData += decryptedData[:readPosition]
        signatureLength, signatureLengthLength = decodeVarint(
            decryptedData[readPosition:readPosition + 10])
        readPosition += signatureLengthLength
        signature = decryptedData[readPosition:readPosition + signatureLength]
        
        if highlevelcrypto.verify(signedData, signature, hexlify(publicSigningKey)):
            logger.info('ECDSA verify passed (within decryptAndCheckPubkeyPayload)')
        else:
            logger.info('ECDSA verify failed (within decryptAndCheckPubkeyPayload)')
            return 'failed'
    
        sha = hashlib.new('sha512')
        sha.update(publicSigningKey + publicEncryptionKey)
        ripeHasher = hashlib.new('ripemd160')
        ripeHasher.update(sha.digest())
        embeddedRipe = ripeHasher.digest()
    
        if embeddedRipe != ripe:
            # Although this pubkey object had the tag were were looking for and was
            # encrypted with the correct encryption key, it doesn't contain the
            # correct pubkeys. Someone is either being malicious or using buggy software.
            logger.info('Pubkey decryption was UNsuccessful due to RIPE mismatch.')
            return 'failed'
        
        # Everything checked out. Insert it into the pubkeys table.
        
        logger.info('within decryptAndCheckPubkeyPayload, addressVersion: %s, streamNumber: %s \n\
                    ripe %s\n\
                    publicSigningKey in hex: %s\n\
                    publicEncryptionKey in hex: %s' % (addressVersion,
                                                       streamNumber, 
                                                       hexlify(ripe),
                                                       hexlify(publicSigningKey),
                                                       hexlify(publicEncryptionKey)
                                                       )
                    )
    
        t = (address, addressVersion, storedData, int(time.time()), 'yes')
        sqlExecute('''INSERT INTO pubkeys VALUES (?,?,?,?,?)''', *t)
        return 'successful'
    except varintDecodeError as e:
        logger.info('Pubkey decryption was UNsuccessful due to a malformed varint.')
        return 'failed'
    except Exception as e:
        logger.critical('Pubkey decryption was UNsuccessful because of an unhandled exception! This is definitely a bug! \n%s' % traceback.format_exc())
        return 'failed'

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))
        PendingDownload().delete(calculateInventoryHash(data))
        return 0
    # Let us check to make sure that the proof of work is sufficient.
    if not protocol.isProofOfWorkSufficient(data):
        logger.info('Proof of work is insufficient.')
        PendingDownload().delete(calculateInventoryHash(data))
        return 0
    
    endOfLifeTime, = unpack('>Q', data[8:16])
    if endOfLifeTime - int(time.time()) > 28 * 24 * 60 * 60 + 10800: # The TTL may not be larger than 28 days + 3 hours of wiggle room
        logger.info('This object\'s End of Life time is too far in the future. Ignoring it. Time is %s' % endOfLifeTime)
        PendingDownload().delete(calculateInventoryHash(data))
        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)
        PendingDownload().delete(calculateInventoryHash(data))
        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
        else:
            _checkAndShareUndefinedObjectWithPeers(data)
            return 0.6
    except varintDecodeError as e:
        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" % e)
    except Exception as e:
        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! \n%s' % traceback.format_exc())
    return 0
        

def _checkAndShareUndefinedObjectWithPeers(data):
    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 not streamNumber 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))
    protocol.broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))
    
    
def _checkAndShareMsgWithPeers(data):
    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 not streamNumber 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))
    protocol.broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))

    # Now let's enqueue it to be processed ourselves.
    objectProcessorQueue.put((objectType,data))

def _checkAndShareGetpubkeyWithPeers(data):
    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 not streamNumber 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))
    protocol.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 not streamNumber 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))
    protocol.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 not streamNumber 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))
    protocol.broadcastToSendDataQueues((streamNumber, 'advertiseobject', inventoryHash))

    # Now let's queue it to be processed ourselves.
    objectProcessorQueue.put((objectType,data))

def openKeysFile():
    if 'linux' in sys.platform:
        import subprocess
        subprocess.call(["xdg-open", state.appdata + 'keys.dat'])
    else:
        os.startfile(state.appdata + 'keys.dat')

from debug import logger