Bitmessage/PyBitmessage-2024-11-30
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changed the way the client stores and sends ackData to head off theoretical attacks involving PayloadLength values that do not match the true payload length of the sent data

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Jonathan Warren 2012-12-19 11:51:51 -05:00
parent 27aa86e741
commit 7cef4958ca
1 changed files with 12 additions and 7 deletions
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19
bitmessagemain.py
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@ -226,6 +226,7 @@ class receiveDataThread(QThread):
self.initiatedConnection = False self.initiatedConnection = False
else: else:
self.initiatedConnection = True self.initiatedConnection = True
self.ackDataThatWeHaveYetToSend = [] #When we receive a message bound for us, we store the acknowledgement that we need to send (the ackdata) here until we are done processing all other data received from this peer.
def run(self): def run(self):
@ -288,7 +289,7 @@ class receiveDataThread(QThread):
self.data = "" self.data = ""
if verbose >= 2: if verbose >= 2:
printLock.acquire() printLock.acquire()
sys.stderr.write('The magic bytes were not correct. This may indicate a problem with the program code, or a transmission error occurred.\n') sys.stderr.write('The magic bytes were not correct.\n')
printLock.release() printLock.release()
elif len(self.data) < 20: #if so little of the data has arrived that we can't even unpack the payload length elif len(self.data) < 20: #if so little of the data has arrived that we can't even unpack the payload length
pass pass
@ -350,9 +351,12 @@ class receiveDataThread(QThread):
self.sendgetdata(objectHash) self.sendgetdata(objectHash)
del self.objectsThatWeHaveYetToGet[objectHash] #It is possible that the remote node doesn't respond with the object. In that case, we'll very likely get it from someone else anyway. del self.objectsThatWeHaveYetToGet[objectHash] #It is possible that the remote node doesn't respond with the object. In that case, we'll very likely get it from someone else anyway.
break break
printLock.acquire() if len(self.objectsThatWeHaveYetToGet) > 0:
print 'within processData, length of objectsThatWeHaveYetToGet is now', len(self.objectsThatWeHaveYetToGet) printLock.acquire()
printLock.release() print 'within processData, number of objectsThatWeHaveYetToGet is now', len(self.objectsThatWeHaveYetToGet)
printLock.release()
if len(self.ackDataThatWeHaveYetToSend) > 0:
self.data = self.ackDataThatWeHaveYetToSend.pop()
self.processData() self.processData()
else: else:
print 'Checksum incorrect. Clearing this message.' print 'Checksum incorrect. Clearing this message.'
@ -781,7 +785,7 @@ class receiveDataThread(QThread):
else: else:
body = 'Unknown encoding type.\n\n' + repr(message) body = 'Unknown encoding type.\n\n' + repr(message)
subject = '' subject = ''
print 'within recmsg, inventoryHash is', inventoryHash print 'within recmsg, inventoryHash is', repr(inventoryHash)
if messageEncodingType <> 0: if messageEncodingType <> 0:
sqlLock.acquire() sqlLock.acquire()
t = (inventoryHash,toAddress,fromAddress,subject,int(time.time()),body,'inbox') t = (inventoryHash,toAddress,fromAddress,subject,int(time.time()),body,'inbox')
@ -799,7 +803,7 @@ class receiveDataThread(QThread):
#We'll need to make sure that our client will properly process the ackData; if the packet is malformed, we could clear out self.data and an attacker could use that behavior to determine that we were capable of decoding this message. #We'll need to make sure that our client will properly process the ackData; if the packet is malformed, we could clear out self.data and an attacker could use that behavior to determine that we were capable of decoding this message.
ackDataValidThusFar = True ackDataValidThusFar = True
if len(ackData) < 24: if len(ackData) < 24:
print 'The length of Ackdata is unreasonably short. Not sending ackData.' print 'The length of ackData is unreasonably short. Not sending ackData.'
ackDataValidThusFar = False ackDataValidThusFar = False
if ackData[0:4] != '\xe9\xbe\xb4\xd9': if ackData[0:4] != '\xe9\xbe\xb4\xd9':
print 'Ackdata magic bytes were wrong. Not sending ackData.' print 'Ackdata magic bytes were wrong. Not sending ackData.'
@ -811,7 +815,8 @@ class receiveDataThread(QThread):
ackDataValidThusFar = False ackDataValidThusFar = False
if ackDataValidThusFar: if ackDataValidThusFar:
print 'ackData is valid. Will process it.' print 'ackData is valid. Will process it.'
self.data = self.data[:self.payloadLength+24] + ackData + self.data[self.payloadLength+24:] #self.data = self.data[:self.payloadLength+24] + ackData + self.data[self.payloadLength+24:]
self.ackDataThatWeHaveYetToSend.append(ackData) #When we have processed all data
#print 'self.data after:', repr(self.data) #print 'self.data after:', repr(self.data)
'''if ackData[4:16] == 'msg\x00\x00\x00\x00\x00\x00\x00\x00\x00': '''if ackData[4:16] == 'msg\x00\x00\x00\x00\x00\x00\x00\x00\x00':
inventoryHash = calculateInventoryHash(ackData[24:]) inventoryHash = calculateInventoryHash(ackData[24:])