Updated tlslite files w/ more debug, for SSL issue
Stephen Warren <[email protected]> Sun, 04 Mar 2007 11:28:46 -0700
| Newsgroups | gmane.mail.spam.tmda.devel |
|---|---|
| Message-ID | <[email protected]> |
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Attached are two tlslite files with a few more locations instrumented to
print some debugging information, plus _shutdown should always print a
full stack trace indicating where it was called from.
Hopefully these will catch something useful!
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name="TLSRecordLayer.py"
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filename="TLSRecordLayer.py"
"""Helper class for TLSConnection."""
from __future__ import generators
from utils.compat import *
from utils.cryptomath import *
from utils.cipherfactory import createAES, createRC4, createTripleDES
from utils.codec import *
from errors import *
from messages import *
from mathtls import *
from constants import *
from utils.cryptomath import getRandomBytes
from utils import hmac
from FileObject import FileObject
import sha
import md5
import socket
import errno
import traceback
try:
GeneratorExit
except NameError:
class GeneratorExit(Exception): pass
class _ConnectionState:
def __init__(self):
self.macContext = None
self.encContext = None
self.seqnum = 0
def getSeqNumStr(self):
w = Writer(8)
w.add(self.seqnum, 8)
seqnumStr = bytesToString(w.bytes)
self.seqnum += 1
return seqnumStr
class TLSRecordLayer:
"""
This class handles data transmission for a TLS connection.
Its only subclass is L{tlslite.TLSConnection.TLSConnection}. We've
separated the code in this class from TLSConnection to make things
more readable.
@type sock: socket.socket
@ivar sock: The underlying socket object.
@type session: L{tlslite.Session.Session}
@ivar session: The session corresponding to this connection.
Due to TLS session resumption, multiple connections can correspond
to the same underlying session.
@type version: tuple
@ivar version: The TLS version being used for this connection.
(3,0) means SSL 3.0, and (3,1) means TLS 1.0.
@type closed: bool
@ivar closed: If this connection is closed.
@type resumed: bool
@ivar resumed: If this connection is based on a resumed session.
@type allegedSharedKeyUsername: str or None
@ivar allegedSharedKeyUsername: This is set to the shared-key
username asserted by the client, whether the handshake succeeded or
not. If the handshake fails, this can be inspected to
determine if a guessing attack is in progress against a particular
user account.
@type allegedSrpUsername: str or None
@ivar allegedSrpUsername: This is set to the SRP username
asserted by the client, whether the handshake succeeded or not.
If the handshake fails, this can be inspected to determine
if a guessing attack is in progress against a particular user
account.
@type closeSocket: bool
@ivar closeSocket: If the socket should be closed when the
connection is closed (writable).
If you set this to True, TLS Lite will assume the responsibility of
closing the socket when the TLS Connection is shutdown (either
through an error or through the user calling close()). The default
is False.
@type ignoreAbruptClose: bool
@ivar ignoreAbruptClose: If an abrupt close of the socket should
raise an error (writable).
If you set this to True, TLS Lite will not raise a
L{tlslite.errors.TLSAbruptCloseError} exception if the underlying
socket is unexpectedly closed. Such an unexpected closure could be
caused by an attacker. However, it also occurs with some incorrect
TLS implementations.
You should set this to True only if you're not worried about an
attacker truncating the connection, and only if necessary to avoid
spurious errors. The default is False.
@sort: __init__, read, readAsync, write, writeAsync, close, closeAsync,
getCipherImplementation, getCipherName
"""
def __init__(self, sock):
self.sock = sock
#My session object (Session instance; read-only)
self.session = None
#Am I a client or server?
self._client = None
#Buffers for processing messages
self._handshakeBuffer = []
self._readBuffer = ""
#Handshake digests
self._handshake_md5 = md5.md5()
self._handshake_sha = sha.sha()
#TLS Protocol Version
self.version = (0,0) #read-only
self._versionCheck = False #Once we choose a version, this is True
#Current and Pending connection states
self._writeState = _ConnectionState()
self._readState = _ConnectionState()
self._pendingWriteState = _ConnectionState()
self._pendingReadState = _ConnectionState()
#Is the connection open?
print "TlsRecordLayer.__init__: Set self.closed at startup"
self.closed = True #read-only
self._refCount = 0 #Used to trigger closure
#Is this a resumed (or shared-key) session?
self.resumed = False #read-only
#What username did the client claim in his handshake?
self.allegedSharedKeyUsername = None
self.allegedSrpUsername = None
#On a call to close(), do we close the socket? (writeable)
self.closeSocket = False
#If the socket is abruptly closed, do we ignore it
#and pretend the connection was shut down properly? (writeable)
self.ignoreAbruptClose = False
#Fault we will induce, for testing purposes
self.fault = None
#*********************************************************
# Public Functions START
#*********************************************************
def read(self, max=None, min=1):
"""Read some data from the TLS connection.
This function will block until at least 'min' bytes are
available (or the connection is closed).
If an exception is raised, the connection will have been
automatically closed.
@type max: int
@param max: The maximum number of bytes to return.
@type min: int
@param min: The minimum number of bytes to return
@rtype: str
@return: A string of no more than 'max' bytes, and no fewer
than 'min' (unless the connection has been closed, in which
case fewer than 'min' bytes may be returned).
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
"""
for result in self.readAsync(max, min):
pass
return result
def readAsync(self, max=None, min=1):
"""Start a read operation on the TLS connection.
This function returns a generator which behaves similarly to
read(). Successive invocations of the generator will return 0
if it is waiting to read from the socket, 1 if it is waiting
to write to the socket, or a string if the read operation has
completed.
@rtype: iterable
@return: A generator; see above for details.
"""
try:
while len(self._readBuffer)<min and not self.closed:
try:
for result in self._getMsg(ContentType.application_data):
if result in (0,1):
yield result
applicationData = result
self._readBuffer += bytesToString(applicationData.write())
except TLSRemoteAlert, alert:
if alert.description != AlertDescription.close_notify:
print "TLSRecordLayer.readAsync: Raise: Remote alert (%s)" % repr(alert.description)
raise
except TLSAbruptCloseError:
if not self.ignoreAbruptClose:
print "TLSRecordLayer.readAsync: Remote alert (abrupt close)"
raise
else:
import traceback
print "TLSRecordLayer.readAsync: Exception @ inner except:"
traceback.print_exc()
self._shutdown(True)
if max == None:
max = len(self._readBuffer)
returnStr = self._readBuffer[:max]
self._readBuffer = self._readBuffer[max:]
yield returnStr
except GeneratorExit:
print "TLSRecordLayer.readAsync: Raise: GeneratorExit"
raise
except:
import traceback
print "TLSRecordLayer.readAsync: Exception @ outer except:"
traceback.print_exc()
self._shutdown(False)
raise
def write(self, s):
"""Write some data to the TLS connection.
This function will block until all the data has been sent.
If an exception is raised, the connection will have been
automatically closed.
@type s: str
@param s: The data to transmit to the other party.
@raise socket.error: If a socket error occurs.
"""
for result in self.writeAsync(s):
pass
def writeAsync(self, s):
"""Start a write operation on the TLS connection.
This function returns a generator which behaves similarly to
write(). Successive invocations of the generator will return
1 if it is waiting to write to the socket, or will raise
StopIteration if the write operation has completed.
@rtype: iterable
@return: A generator; see above for details.
"""
try:
if self.closed:
print "TLSRecordLayer.writeAsync: Raise: Closed"
raise ValueError()
index = 0
blockSize = 16384
skipEmptyFrag = False
while 1:
startIndex = index * blockSize
endIndex = startIndex + blockSize
if startIndex >= len(s):
break
if endIndex > len(s):
endIndex = len(s)
block = stringToBytes(s[startIndex : endIndex])
applicationData = ApplicationData().create(block)
for result in self._sendMsg(applicationData, skipEmptyFrag):
yield result
skipEmptyFrag = True #only send an empy fragment on 1st message
index += 1
except:
import traceback
print "TLSRecordLayer.writeAsync: Exception:"
traceback.print_exc()
self._shutdown(False)
raise
def close(self):
"""Close the TLS connection.
This function will block until it has exchanged close_notify
alerts with the other party. After doing so, it will shut down the
TLS connection. Further attempts to read through this connection
will return "". Further attempts to write through this connection
will raise ValueError.
If makefile() has been called on this connection, the connection
will be not be closed until the connection object and all file
objects have been closed.
Even if an exception is raised, the connection will have been
closed.
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
"""
if not self.closed:
for result in self._decrefAsync():
pass
def closeAsync(self):
"""Start a close operation on the TLS connection.
This function returns a generator which behaves similarly to
close(). Successive invocations of the generator will return 0
if it is waiting to read from the socket, 1 if it is waiting
to write to the socket, or will raise StopIteration if the
close operation has completed.
@rtype: iterable
@return: A generator; see above for details.
"""
if not self.closed:
for result in self._decrefAsync():
yield result
def _decrefAsync(self):
self._refCount -= 1
if self._refCount == 0 and not self.closed:
try:
for result in self._sendMsg(Alert().create(\
AlertDescription.close_notify, AlertLevel.warning)):
yield result
alert = None
while not alert:
for result in self._getMsg((ContentType.alert, \
ContentType.application_data)):
if result in (0,1):
yield result
if result.contentType == ContentType.alert:
alert = result
if alert.description == AlertDescription.close_notify:
print "TLSRecordLayer._decrefAsync: _shutdown: Alert (close_notify)"
self._shutdown(True)
else:
print "TLSRecordLayer.readAsync: Raise: TLSRemoteAlert (abrupt close)"
raise TLSRemoteAlert(alert)
except (socket.error, TLSAbruptCloseError):
#If the other side closes the socket, that's okay
import traceback
print "TLSRecordLayer._decrefAsync: Exception (socket err/abrupt close):"
traceback.print_exc()
self._shutdown(True)
except:
import traceback
print "TLSRecordLayer._decrefAsync: Exception (general):"
traceback.print_exc()
self._shutdown(False)
raise
def getCipherName(self):
"""Get the name of the cipher used with this connection.
@rtype: str
@return: The name of the cipher used with this connection.
Either 'aes128', 'aes256', 'rc4', or '3des'.
"""
if not self._writeState.encContext:
return None
return self._writeState.encContext.name
def getCipherImplementation(self):
"""Get the name of the cipher implementation used with
this connection.
@rtype: str
@return: The name of the cipher implementation used with
this connection. Either 'python', 'cryptlib', 'openssl',
or 'pycrypto'.
"""
if not self._writeState.encContext:
return None
return self._writeState.encContext.implementation
#Emulate a socket, somewhat -
def send(self, s):
"""Send data to the TLS connection (socket emulation).
@raise socket.error: If a socket error occurs.
"""
self.write(s)
return len(s)
def sendall(self, s):
"""Send data to the TLS connection (socket emulation).
@raise socket.error: If a socket error occurs.
"""
self.write(s)
def recv(self, bufsize):
"""Get some data from the TLS connection (socket emulation).
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
"""
return self.read(bufsize)
def makefile(self, mode='r', bufsize=-1):
"""Create a file object for the TLS connection (socket emulation).
@rtype: L{tlslite.FileObject.FileObject}
"""
self._refCount += 1
return FileObject(self, mode, bufsize)
def getsockname(self):
"""Return the socket's own address (socket emulation)."""
return self.sock.getsockname()
def getpeername(self):
"""Return the remote address to which the socket is connected
(socket emulation)."""
return self.sock.getpeername()
def settimeout(self, value):
"""Set a timeout on blocking socket operations (socket emulation)."""
return self.sock.settimeout(value)
def gettimeout(self):
"""Return the timeout associated with socket operations (socket
emulation)."""
return self.sock.gettimeout()
def setsockopt(self, level, optname, value):
"""Set the value of the given socket option (socket emulation)."""
return self.sock.setsockopt(level, optname, value)
#*********************************************************
# Public Functions END
#*********************************************************
def _shutdown(self, resumable):
self._writeState = _ConnectionState()
self._readState = _ConnectionState()
#Don't do this: self._readBuffer = ""
self.version = (0,0)
self._versionCheck = False
print "TlsRecordLayer._shutdown: Set self.closed"
import traceback
traceback.print_stack()
self.closed = True
if self.closeSocket:
self.sock.close()
#Even if resumable is False, we'll never toggle this on
if not resumable and self.session:
self.session.resumable = False
def _sendError(self, alertDescription, errorStr=None):
import traceback
traceback.print_stack()
alert = Alert().create(alertDescription, AlertLevel.fatal)
for result in self._sendMsg(alert):
yield result
print "TLSRecordLayer._sendError(%s,%s): Calling _shutdown()" % (repr(alertDescription), repr(errorStr))
self._shutdown(False)
print "TLSRecordLayer._sendError(%s,%s): Raise TLSLocalAlert" % (repr(alertDescription), repr(errorStr))
raise TLSLocalAlert(alert, errorStr)
def _sendMsgs(self, msgs):
skipEmptyFrag = False
for msg in msgs:
for result in self._sendMsg(msg, skipEmptyFrag):
yield result
skipEmptyFrag = True
def _sendMsg(self, msg, skipEmptyFrag=False):
bytes = msg.write()
contentType = msg.contentType
#Whenever we're connected and asked to send a message,
#we first send an empty Application Data message. This prevents
#an attacker from launching a chosen-plaintext attack based on
#knowing the next IV.
if not self.closed and not skipEmptyFrag and self.version == (3,1):
if self._writeState.encContext:
if self._writeState.encContext.isBlockCipher:
for result in self._sendMsg(ApplicationData(),
skipEmptyFrag=True):
yield result
#Update handshake hashes
if contentType == ContentType.handshake:
bytesStr = bytesToString(bytes)
self._handshake_md5.update(bytesStr)
self._handshake_sha.update(bytesStr)
#Calculate MAC
if self._writeState.macContext:
seqnumStr = self._writeState.getSeqNumStr()
bytesStr = bytesToString(bytes)
mac = self._writeState.macContext.copy()
mac.update(seqnumStr)
mac.update(chr(contentType))
if self.version == (3,0):
mac.update( chr( int(len(bytes)/256) ) )
mac.update( chr( int(len(bytes)%256) ) )
elif self.version in ((3,1), (3,2)):
mac.update(chr(self.version[0]))
mac.update(chr(self.version[1]))
mac.update( chr( int(len(bytes)/256) ) )
mac.update( chr( int(len(bytes)%256) ) )
else:
print "TLSRecordLayer._sendMsg: Raise AssertionError"
raise AssertionError()
mac.update(bytesStr)
macString = mac.digest()
macBytes = stringToBytes(macString)
if self.fault == Fault.badMAC:
macBytes[0] = (macBytes[0]+1) % 256
#Encrypt for Block or Stream Cipher
if self._writeState.encContext:
#Add padding and encrypt (for Block Cipher):
if self._writeState.encContext.isBlockCipher:
#Add TLS 1.1 fixed block
if self.version == (3,2):
bytes = self.fixedIVBlock + bytes
#Add padding: bytes = bytes + (macBytes + paddingBytes)
currentLength = len(bytes) + len(macBytes) + 1
blockLength = self._writeState.encContext.block_size
paddingLength = blockLength-(currentLength % blockLength)
paddingBytes = createByteArraySequence([paddingLength] * \
(paddingLength+1))
if self.fault == Fault.badPadding:
paddingBytes[0] = (paddingBytes[0]+1) % 256
endBytes = concatArrays(macBytes, paddingBytes)
bytes = concatArrays(bytes, endBytes)
#Encrypt
plaintext = stringToBytes(bytes)
ciphertext = self._writeState.encContext.encrypt(plaintext)
bytes = stringToBytes(ciphertext)
#Encrypt (for Stream Cipher)
else:
bytes = concatArrays(bytes, macBytes)
plaintext = bytesToString(bytes)
ciphertext = self._writeState.encContext.encrypt(plaintext)
bytes = stringToBytes(ciphertext)
#Add record header and send
r = RecordHeader3().create(self.version, contentType, len(bytes))
s = bytesToString(concatArrays(r.write(), bytes))
while 1:
try:
bytesSent = self.sock.send(s) #Might raise socket.error
except socket.error, why:
if why[0] == errno.EWOULDBLOCK:
yield 1
continue
else:
print "TLSRecordLayer._sendMsg: Raise caught exception"
raise
if bytesSent == len(s):
return
s = s[bytesSent:]
yield 1
def _getMsg(self, expectedType, secondaryType=None, constructorType=None):
try:
if not isinstance(expectedType, tuple):
expectedType = (expectedType,)
#Spin in a loop, until we've got a non-empty record of a type we
#expect. The loop will be repeated if:
# - we receive a renegotiation attempt; we send no_renegotiation,
# then try again
# - we receive an empty application-data fragment; we try again
while 1:
for result in self._getNextRecord():
if result in (0,1):
yield result
recordHeader, p = result
#If this is an empty application-data fragment, try again
if recordHeader.type == ContentType.application_data:
if p.index == len(p.bytes):
continue
#If we received an unexpected record type...
if recordHeader.type not in expectedType:
#If we received an alert...
if recordHeader.type == ContentType.alert:
alert = Alert().parse(p)
#We either received a fatal error, a warning, or a
#close_notify. In any case, we're going to close the
#connection. In the latter two cases we respond with
#a close_notify, but ignore any socket errors, since
#the other side might have already closed the socket.
if alert.level == AlertLevel.warning or \
alert.description == AlertDescription.close_notify:
#If the sendMsg() call fails because the socket has
#already been closed, we will be forgiving and not
#report the error nor invalidate the "resumability"
#of the session.
try:
alertMsg = Alert()
alertMsg.create(AlertDescription.close_notify,
AlertLevel.warning)
for result in self._sendMsg(alertMsg):
yield result
except socket.error:
pass
if alert.description == \
AlertDescription.close_notify:
print "TLSRecordLayer._getMsg: Alert close_notify"
self._shutdown(True)
elif alert.level == AlertLevel.warning:
print "TLSRecordLayer._getMsg: Alert w/ warning level (%s, %s)" % (repr(alert.level), repr(alert.description))
self._shutdown(False)
else: #Fatal alert:
print "TLSRecordLayer._getMsg: Alert (fatal) (%s, %s)" % (repr(alert.level), repr(alert.description))
self._shutdown(False)
#Raise the alert as an exception
print "TLSRecordLayer._getMsg: Raise TLSRemoteAlert"
raise TLSRemoteAlert(alert)
#If we received a renegotiation attempt...
if recordHeader.type == ContentType.handshake:
subType = p.get(1)
reneg = False
if self._client:
if subType == HandshakeType.hello_request:
reneg = True
else:
if subType == HandshakeType.client_hello:
reneg = True
#Send no_renegotiation, then try again
if reneg:
alertMsg = Alert()
alertMsg.create(AlertDescription.no_renegotiation,
AlertLevel.warning)
for result in self._sendMsg(alertMsg):
yield result
continue
#Otherwise: this is an unexpected record, but neither an
#alert nor renegotiation
for result in self._sendError(\
AlertDescription.unexpected_message,
"received type=%d" % recordHeader.type):
yield result
break
#Parse based on content_type
if recordHeader.type == ContentType.change_cipher_spec:
yield ChangeCipherSpec().parse(p)
elif recordHeader.type == ContentType.alert:
yield Alert().parse(p)
elif recordHeader.type == ContentType.application_data:
yield ApplicationData().parse(p)
elif recordHeader.type == ContentType.handshake:
#Convert secondaryType to tuple, if it isn't already
if not isinstance(secondaryType, tuple):
secondaryType = (secondaryType,)
#If it's a handshake message, check handshake header
if recordHeader.ssl2:
subType = p.get(1)
if subType != HandshakeType.client_hello:
for result in self._sendError(\
AlertDescription.unexpected_message,
"Can only handle SSLv2 ClientHello messages"):
yield result
if HandshakeType.client_hello not in secondaryType:
for result in self._sendError(\
AlertDescription.unexpected_message):
yield result
subType = HandshakeType.client_hello
else:
subType = p.get(1)
if subType not in secondaryType:
for result in self._sendError(\
AlertDescription.unexpected_message,
"Expecting %s, got %s" % (str(secondaryType), subType)):
yield result
#Update handshake hashes
sToHash = bytesToString(p.bytes)
self._handshake_md5.update(sToHash)
self._handshake_sha.update(sToHash)
#Parse based on handshake type
if subType == HandshakeType.client_hello:
yield ClientHello(recordHeader.ssl2).parse(p)
elif subType == HandshakeType.server_hello:
yield ServerHello().parse(p)
elif subType == HandshakeType.certificate:
yield Certificate(constructorType).parse(p)
elif subType == HandshakeType.certificate_request:
yield CertificateRequest().parse(p)
elif subType == HandshakeType.certificate_verify:
yield CertificateVerify().parse(p)
elif subType == HandshakeType.server_key_exchange:
yield ServerKeyExchange(constructorType).parse(p)
elif subType == HandshakeType.server_hello_done:
yield ServerHelloDone().parse(p)
elif subType == HandshakeType.client_key_exchange:
yield ClientKeyExchange(constructorType, \
self.version).parse(p)
elif subType == HandshakeType.finished:
yield Finished(self.version).parse(p)
else:
print "TLSRecordLayer._getMsg: Raise AssertionError"
raise AssertionError()
#If an exception was raised by a Parser or Message instance:
except SyntaxError, e:
for result in self._sendError(AlertDescription.decode_error,
formatExceptionTrace(e)):
yield result
#Returns next record or next handshake message
def _getNextRecord(self):
#If there's a handshake message waiting, return it
if self._handshakeBuffer:
recordHeader, bytes = self._handshakeBuffer[0]
self._handshakeBuffer = self._handshakeBuffer[1:]
yield (recordHeader, Parser(bytes))
return
#Otherwise...
#Read the next record header
bytes = createByteArraySequence([])
recordHeaderLength = 1
ssl2 = False
while 1:
try:
s = self.sock.recv(recordHeaderLength-len(bytes))
except socket.error, why:
if why[0] == errno.EWOULDBLOCK:
yield 0
continue
else:
print "TLSRecordLayer._getNextRecord: Raise caught exception"
raise
#If the connection was abruptly closed, raise an error
if len(s)==0:
print "TLSRecordLayer._getNextRecord: Raise TLSAbruptCloseError"
raise TLSAbruptCloseError()
bytes += stringToBytes(s)
if len(bytes)==1:
if bytes[0] in ContentType.all:
ssl2 = False
recordHeaderLength = 5
elif bytes[0] == 128:
ssl2 = True
recordHeaderLength = 2
else:
print "TLSRecordLayer._getNextRecord: Raise SyntaxError"
raise SyntaxError()
if len(bytes) == recordHeaderLength:
break
#Parse the record header
if ssl2:
r = RecordHeader2().parse(Parser(bytes))
else:
r = RecordHeader3().parse(Parser(bytes))
#Check the record header fields
if r.length > 18432:
for result in self._sendError(AlertDescription.record_overflow):
yield result
#Read the record contents
bytes = createByteArraySequence([])
while 1:
try:
s = self.sock.recv(r.length - len(bytes))
except socket.error, why:
if why[0] == errno.EWOULDBLOCK:
yield 0
continue
else:
print "TLSRecordLayer._getNextRecord: Raise caught exception"
raise
#If the connection is closed, raise a socket error
if len(s)==0:
print "TLSRecordLayer._getNextRecord: Raise TLSAbruptCloseError"
raise TLSAbruptCloseError()
bytes += stringToBytes(s)
if len(bytes) == r.length:
break
#Check the record header fields (2)
#We do this after reading the contents from the socket, so that
#if there's an error, we at least don't leave extra bytes in the
#socket..
#
# THIS CHECK HAS NO SECURITY RELEVANCE (?), BUT COULD HURT INTEROP.
# SO WE LEAVE IT OUT FOR NOW.
#
#if self._versionCheck and r.version != self.version:
# for result in self._sendError(AlertDescription.protocol_version,
# "Version in header field: %s, should be %s" % (str(r.version),
# str(self.version))):
# yield result
#Decrypt the record
for result in self._decryptRecord(r.type, bytes):
if result in (0,1):
yield result
else:
break
bytes = result
p = Parser(bytes)
#If it doesn't contain handshake messages, we can just return it
if r.type != ContentType.handshake:
yield (r, p)
#If it's an SSLv2 ClientHello, we can return it as well
elif r.ssl2:
yield (r, p)
else:
#Otherwise, we loop through and add the handshake messages to the
#handshake buffer
while 1:
if p.index == len(bytes): #If we're at the end
if not self._handshakeBuffer:
for result in self._sendError(\
AlertDescription.decode_error, \
"Received empty handshake record"):
yield result
break
#There needs to be at least 4 bytes to get a header
if p.index+4 > len(bytes):
for result in self._sendError(\
AlertDescription.decode_error,
"A record has a partial handshake message (1)"):
yield result
p.get(1) # skip handshake type
msgLength = p.get(3)
if p.index+msgLength > len(bytes):
for result in self._sendError(\
AlertDescription.decode_error,
"A record has a partial handshake message (2)"):
yield result
handshakePair = (r, bytes[p.index-4 : p.index+msgLength])
self._handshakeBuffer.append(handshakePair)
p.index += msgLength
#We've moved at least one handshake message into the
#handshakeBuffer, return the first one
recordHeader, bytes = self._handshakeBuffer[0]
self._handshakeBuffer = self._handshakeBuffer[1:]
yield (recordHeader, Parser(bytes))
def _decryptRecord(self, recordType, bytes):
if self._readState.encContext:
#Decrypt if it's a block cipher
if self._readState.encContext.isBlockCipher:
blockLength = self._readState.encContext.block_size
if len(bytes) % blockLength != 0:
for result in self._sendError(\
AlertDescription.decryption_failed,
"Encrypted data not a multiple of blocksize"):
yield result
ciphertext = bytesToString(bytes)
plaintext = self._readState.encContext.decrypt(ciphertext)
if self.version == (3,2): #For TLS 1.1, remove explicit IV
plaintext = plaintext[self._readState.encContext.block_size : ]
bytes = stringToBytes(plaintext)
#Check padding
paddingGood = True
paddingLength = bytes[-1]
if (paddingLength+1) > len(bytes):
paddingGood=False
totalPaddingLength = 0
else:
if self.version == (3,0):
totalPaddingLength = paddingLength+1
elif self.version in ((3,1), (3,2)):
totalPaddingLength = paddingLength+1
paddingBytes = bytes[-totalPaddingLength:-1]
for byte in paddingBytes:
if byte != paddingLength:
paddingGood = False
totalPaddingLength = 0
else:
print "TLSRecordLayer._decryptRecord: Raise AssertionError"
raise AssertionError()
#Decrypt if it's a stream cipher
else:
paddingGood = True
ciphertext = bytesToString(bytes)
plaintext = self._readState.encContext.decrypt(ciphertext)
bytes = stringToBytes(plaintext)
totalPaddingLength = 0
#Check MAC
macGood = True
macLength = self._readState.macContext.digest_size
endLength = macLength + totalPaddingLength
if endLength > len(bytes):
macGood = False
else:
#Read MAC
startIndex = len(bytes) - endLength
endIndex = startIndex + macLength
checkBytes = bytes[startIndex : endIndex]
#Calculate MAC
seqnumStr = self._readState.getSeqNumStr()
bytes = bytes[:-endLength]
bytesStr = bytesToString(bytes)
mac = self._readState.macContext.copy()
mac.update(seqnumStr)
mac.update(chr(recordType))
if self.version == (3,0):
mac.update( chr( int(len(bytes)/256) ) )
mac.update( chr( int(len(bytes)%256) ) )
elif self.version in ((3,1), (3,2)):
mac.update(chr(self.version[0]))
mac.update(chr(self.version[1]))
mac.update( chr( int(len(bytes)/256) ) )
mac.update( chr( int(len(bytes)%256) ) )
else:
print "TLSRecordLayer._decryptRecord: Raise AssertionError"
raise AssertionError()
mac.update(bytesStr)
macString = mac.digest()
macBytes = stringToBytes(macString)
#Compare MACs
if macBytes != checkBytes:
macGood = False
if not (paddingGood and macGood):
for result in self._sendError(AlertDescription.bad_record_mac,
"MAC failure (or padding failure)"):
yield result
yield bytes
def _handshakeStart(self, client):
self._client = client
self._handshake_md5 = md5.md5()
self._handshake_sha = sha.sha()
self._handshakeBuffer = []
self.allegedSharedKeyUsername = None
self.allegedSrpUsername = None
self._refCount = 1
def _handshakeDone(self, resumed):
self.resumed = resumed
print "TLSRecordLayer._handshakeDone: Set self.closed = FALSE"
self.closed = False
def _calcPendingStates(self, clientRandom, serverRandom, implementations):
if self.session.cipherSuite in CipherSuite.aes128Suites:
macLength = 20
keyLength = 16
ivLength = 16
createCipherFunc = createAES
elif self.session.cipherSuite in CipherSuite.aes256Suites:
macLength = 20
keyLength = 32
ivLength = 16
createCipherFunc = createAES
elif self.session.cipherSuite in CipherSuite.rc4Suites:
macLength = 20
keyLength = 16
ivLength = 0
createCipherFunc = createRC4
elif self.session.cipherSuite in CipherSuite.tripleDESSuites:
macLength = 20
keyLength = 24
ivLength = 8
createCipherFunc = createTripleDES
else:
print "TLSRecordLayer._calcPendingStates: Raise AssertionError"
raise AssertionError()
if self.version == (3,0):
createMACFunc = MAC_SSL
elif self.version in ((3,1), (3,2)):
createMACFunc = hmac.HMAC
outputLength = (macLength*2) + (keyLength*2) + (ivLength*2)
#Calculate Keying Material from Master Secret
if self.version == (3,0):
keyBlock = PRF_SSL(self.session.masterSecret,
concatArrays(serverRandom, clientRandom),
outputLength)
elif self.version in ((3,1), (3,2)):
keyBlock = PRF(self.session.masterSecret,
"key expansion",
concatArrays(serverRandom,clientRandom),
outputLength)
else:
print "TLSRecordLayer._calcPendingStates: Raise AssertionError"
raise AssertionError()
#Slice up Keying Material
clientPendingState = _ConnectionState()
serverPendingState = _ConnectionState()
p = Parser(keyBlock)
clientMACBlock = bytesToString(p.getFixBytes(macLength))
serverMACBlock = bytesToString(p.getFixBytes(macLength))
clientKeyBlock = bytesToString(p.getFixBytes(keyLength))
serverKeyBlock = bytesToString(p.getFixBytes(keyLength))
clientIVBlock = bytesToString(p.getFixBytes(ivLength))
serverIVBlock = bytesToString(p.getFixBytes(ivLength))
clientPendingState.macContext = createMACFunc(clientMACBlock,
digestmod=sha)
serverPendingState.macContext = createMACFunc(serverMACBlock,
digestmod=sha)
clientPendingState.encContext = createCipherFunc(clientKeyBlock,
clientIVBlock,
implementations)
serverPendingState.encContext = createCipherFunc(serverKeyBlock,
serverIVBlock,
implementations)
#Assign new connection states to pending states
if self._client:
self._pendingWriteState = clientPendingState
self._pendingReadState = serverPendingState
else:
self._pendingWriteState = serverPendingState
self._pendingReadState = clientPendingState
if self.version == (3,2) and ivLength:
#Choose fixedIVBlock for TLS 1.1 (this is encrypted with the CBC
#residue to create the IV for each sent block)
self.fixedIVBlock = getRandomBytes(ivLength)
def _changeWriteState(self):
self._writeState = self._pendingWriteState
self._pendingWriteState = _ConnectionState()
def _changeReadState(self):
self._readState = self._pendingReadState
self._pendingReadState = _ConnectionState()
def _sendFinished(self):
#Send ChangeCipherSpec
for result in self._sendMsg(ChangeCipherSpec()):
yield result
#Switch to pending write state
self._changeWriteState()
#Calculate verification data
verifyData = self._calcFinished(True)
if self.fault == Fault.badFinished:
verifyData[0] = (verifyData[0]+1)%256
#Send Finished message under new state
finished = Finished(self.version).create(verifyData)
for result in self._sendMsg(finished):
yield result
def _getFinished(self):
#Get and check ChangeCipherSpec
for result in self._getMsg(ContentType.change_cipher_spec):
if result in (0,1):
yield result
changeCipherSpec = result
if changeCipherSpec.type != 1:
for result in self._sendError(AlertDescription.illegal_parameter,
"ChangeCipherSpec type incorrect"):
yield result
#Switch to pending read state
self._changeReadState()
#Calculate verification data
verifyData = self._calcFinished(False)
#Get and check Finished message under new state
for result in self._getMsg(ContentType.handshake,
HandshakeType.finished):
if result in (0,1):
yield result
finished = result
if finished.verify_data != verifyData:
for result in self._sendError(AlertDescription.decrypt_error,
"Finished message is incorrect"):
yield result
def _calcFinished(self, send=True):
if self.version == (3,0):
if (self._client and send) or (not self._client and not send):
senderStr = "\x43\x4C\x4E\x54"
else:
senderStr = "\x53\x52\x56\x52"
verifyData = self._calcSSLHandshakeHash(self.session.masterSecret,
senderStr)
return verifyData
elif self.version in ((3,1), (3,2)):
if (self._client and send) or (not self._client and not send):
label = "client finished"
else:
label = "server finished"
handshakeHashes = stringToBytes(self._handshake_md5.digest() + \
self._handshake_sha.digest())
verifyData = PRF(self.session.masterSecret, label, handshakeHashes,
12)
return verifyData
else:
print "TLSRecordLayer._calcFinished: Raise AssertionError"
raise AssertionError()
#Used for Finished messages and CertificateVerify messages in SSL v3
def _calcSSLHandshakeHash(self, masterSecret, label):
masterSecretStr = bytesToString(masterSecret)
imac_md5 = self._handshake_md5.copy()
imac_sha = self._handshake_sha.copy()
imac_md5.update(label + masterSecretStr + '\x36'*48)
imac_sha.update(label + masterSecretStr + '\x36'*40)
md5Str = md5.md5(masterSecretStr + ('\x5c'*48) + \
imac_md5.digest()).digest()
shaStr = sha.sha(masterSecretStr + ('\x5c'*40) + \
imac_sha.digest()).digest()
return stringToBytes(md5Str + shaStr)
--------------040007030501040607020106
Content-Type: text/plain;
name="TLSConnection.py"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="TLSConnection.py"
"""
MAIN CLASS FOR TLS LITE (START HERE!).
"""
from __future__ import generators
import socket
from utils.compat import formatExceptionTrace
from TLSRecordLayer import TLSRecordLayer
from Session import Session
from constants import *
from utils.cryptomath import getRandomBytes
from errors import *
from messages import *
from mathtls import *
from HandshakeSettings import HandshakeSettings
class TLSConnection(TLSRecordLayer):
"""
This class wraps a socket and provides TLS handshaking and data
transfer.
To use this class, create a new instance, passing a connected
socket into the constructor. Then call some handshake function.
If the handshake completes without raising an exception, then a TLS
connection has been negotiated. You can transfer data over this
connection as if it were a socket.
This class provides both synchronous and asynchronous versions of
its key functions. The synchronous versions should be used when
writing single-or multi-threaded code using blocking sockets. The
asynchronous versions should be used when performing asynchronous,
event-based I/O with non-blocking sockets.
Asynchronous I/O is a complicated subject; typically, you should
not use the asynchronous functions directly, but should use some
framework like asyncore or Twisted which TLS Lite integrates with
(see
L{tlslite.integration.TLSAsyncDispatcherMixIn.TLSAsyncDispatcherMixIn} or
L{tlslite.integration.TLSTwistedProtocolWrapper.TLSTwistedProtocolWrapper}).
"""
def __init__(self, sock):
"""Create a new TLSConnection instance.
@param sock: The socket data will be transmitted on. The
socket should already be connected. It may be in blocking or
non-blocking mode.
@type sock: L{socket.socket}
"""
TLSRecordLayer.__init__(self, sock)
def handshakeClientSRP(self, username, password, session=None,
settings=None, checker=None, async=False):
"""Perform an SRP handshake in the role of client.
This function performs a TLS/SRP handshake. SRP mutually
authenticates both parties to each other using only a
username and password. This function may also perform a
combined SRP and server-certificate handshake, if the server
chooses to authenticate itself with a certificate chain in
addition to doing SRP.
TLS/SRP is non-standard. Most TLS implementations don't
support it. See
U{http://www.ietf.org/html.charters/tls-charter.html} or
U{http://trevp.net/tlssrp/} for the latest information on
TLS/SRP.
Like any handshake function, this can be called on a closed
TLS connection, or on a TLS connection that is already open.
If called on an open connection it performs a re-handshake.
If the function completes without raising an exception, the
TLS connection will be open and available for data transfer.
If an exception is raised, the connection will have been
automatically closed (if it was ever open).
@type username: str
@param username: The SRP username.
@type password: str
@param password: The SRP password.
@type session: L{tlslite.Session.Session}
@param session: A TLS session to attempt to resume. This
session must be an SRP session performed with the same username
and password as were passed in. If the resumption does not
succeed, a full SRP handshake will be performed.
@type settings: L{tlslite.HandshakeSettings.HandshakeSettings}
@param settings: Various settings which can be used to control
the ciphersuites, certificate types, and SSL/TLS versions
offered by the client.
@type checker: L{tlslite.Checker.Checker}
@param checker: A Checker instance. This instance will be
invoked to examine the other party's authentication
credentials, if the handshake completes succesfully.
@type async: bool
@param async: If False, this function will block until the
handshake is completed. If True, this function will return a
generator. Successive invocations of the generator will
return 0 if it is waiting to read from the socket, 1 if it is
waiting to write to the socket, or will raise StopIteration if
the handshake operation is completed.
@rtype: None or an iterable
@return: If 'async' is True, a generator object will be
returned.
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
@raise tlslite.errors.TLSAuthenticationError: If the checker
doesn't like the other party's authentication credentials.
"""
handshaker = self._handshakeClientAsync(srpParams=(username, password),
session=session, settings=settings, checker=checker)
if async:
return handshaker
for result in handshaker:
pass
def handshakeClientCert(self, certChain=None, privateKey=None,
session=None, settings=None, checker=None,
async=False):
"""Perform a certificate-based handshake in the role of client.
This function performs an SSL or TLS handshake. The server
will authenticate itself using an X.509 or cryptoID certificate
chain. If the handshake succeeds, the server's certificate
chain will be stored in the session's serverCertChain attribute.
Unless a checker object is passed in, this function does no
validation or checking of the server's certificate chain.
If the server requests client authentication, the
client will send the passed-in certificate chain, and use the
passed-in private key to authenticate itself. If no
certificate chain and private key were passed in, the client
will attempt to proceed without client authentication. The
server may or may not allow this.
Like any handshake function, this can be called on a closed
TLS connection, or on a TLS connection that is already open.
If called on an open connection it performs a re-handshake.
If the function completes without raising an exception, the
TLS connection will be open and available for data transfer.
If an exception is raised, the connection will have been
automatically closed (if it was ever open).
@type certChain: L{tlslite.X509CertChain.X509CertChain} or
L{cryptoIDlib.CertChain.CertChain}
@param certChain: The certificate chain to be used if the
server requests client authentication.
@type privateKey: L{tlslite.utils.RSAKey.RSAKey}
@param privateKey: The private key to be used if the server
requests client authentication.
@type session: L{tlslite.Session.Session}
@param session: A TLS session to attempt to resume. If the
resumption does not succeed, a full handshake will be
performed.
@type settings: L{tlslite.HandshakeSettings.HandshakeSettings}
@param settings: Various settings which can be used to control
the ciphersuites, certificate types, and SSL/TLS versions
offered by the client.
@type checker: L{tlslite.Checker.Checker}
@param checker: A Checker instance. This instance will be
invoked to examine the other party's authentication
credentials, if the handshake completes succesfully.
@type async: bool
@param async: If False, this function will block until the
handshake is completed. If True, this function will return a
generator. Successive invocations of the generator will
return 0 if it is waiting to read from the socket, 1 if it is
waiting to write to the socket, or will raise StopIteration if
the handshake operation is completed.
@rtype: None or an iterable
@return: If 'async' is True, a generator object will be
returned.
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
@raise tlslite.errors.TLSAuthenticationError: If the checker
doesn't like the other party's authentication credentials.
"""
handshaker = self._handshakeClientAsync(certParams=(certChain,
privateKey), session=session, settings=settings,
checker=checker)
if async:
return handshaker
for result in handshaker:
pass
def handshakeClientUnknown(self, srpCallback=None, certCallback=None,
session=None, settings=None, checker=None,
async=False):
"""Perform a to-be-determined type of handshake in the role of client.
This function performs an SSL or TLS handshake. If the server
requests client certificate authentication, the
certCallback will be invoked and should return a (certChain,
privateKey) pair. If the callback returns None, the library
will attempt to proceed without client authentication. The
server may or may not allow this.
If the server requests SRP authentication, the srpCallback
will be invoked and should return a (username, password) pair.
If the callback returns None, the local implementation will
signal a user_canceled error alert.
After the handshake completes, the client can inspect the
connection's session attribute to determine what type of
authentication was performed.
Like any handshake function, this can be called on a closed
TLS connection, or on a TLS connection that is already open.
If called on an open connection it performs a re-handshake.
If the function completes without raising an exception, the
TLS connection will be open and available for data transfer.
If an exception is raised, the connection will have been
automatically closed (if it was ever open).
@type srpCallback: callable
@param srpCallback: The callback to be used if the server
requests SRP authentication. If None, the client will not
offer support for SRP ciphersuites.
@type certCallback: callable
@param certCallback: The callback to be used if the server
requests client certificate authentication.
@type session: L{tlslite.Session.Session}
@param session: A TLS session to attempt to resume. If the
resumption does not succeed, a full handshake will be
performed.
@type settings: L{tlslite.HandshakeSettings.HandshakeSettings}
@param settings: Various settings which can be used to control
the ciphersuites, certificate types, and SSL/TLS versions
offered by the client.
@type checker: L{tlslite.Checker.Checker}
@param checker: A Checker instance. This instance will be
invoked to examine the other party's authentication
credentials, if the handshake completes succesfully.
@type async: bool
@param async: If False, this function will block until the
handshake is completed. If True, this function will return a
generator. Successive invocations of the generator will
return 0 if it is waiting to read from the socket, 1 if it is
waiting to write to the socket, or will raise StopIteration if
the handshake operation is completed.
@rtype: None or an iterable
@return: If 'async' is True, a generator object will be
returned.
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
@raise tlslite.errors.TLSAuthenticationError: If the checker
doesn't like the other party's authentication credentials.
"""
handshaker = self._handshakeClientAsync(unknownParams=(srpCallback,
certCallback), session=session, settings=settings,
checker=checker)
if async:
return handshaker
for result in handshaker:
pass
def handshakeClientSharedKey(self, username, sharedKey, settings=None,
checker=None, async=False):
"""Perform a shared-key handshake in the role of client.
This function performs a shared-key handshake. Using shared
symmetric keys of high entropy (128 bits or greater) mutually
authenticates both parties to each other.
TLS with shared-keys is non-standard. Most TLS
implementations don't support it. See
U{http://www.ietf.org/html.charters/tls-charter.html} for the
latest information on TLS with shared-keys. If the shared-keys
Internet-Draft changes or is superceded, TLS Lite will track
those changes, so the shared-key support in later versions of
TLS Lite may become incompatible with this version.
Like any handshake function, this can be called on a closed
TLS connection, or on a TLS connection that is already open.
If called on an open connection it performs a re-handshake.
If the function completes without raising an exception, the
TLS connection will be open and available for data transfer.
If an exception is raised, the connection will have been
automatically closed (if it was ever open).
@type username: str
@param username: The shared-key username.
@type sharedKey: str
@param sharedKey: The shared key.
@type settings: L{tlslite.HandshakeSettings.HandshakeSettings}
@param settings: Various settings which can be used to control
the ciphersuites, certificate types, and SSL/TLS versions
offered by the client.
@type checker: L{tlslite.Checker.Checker}
@param checker: A Checker instance. This instance will be
invoked to examine the other party's authentication
credentials, if the handshake completes succesfully.
@type async: bool
@param async: If False, this function will block until the
handshake is completed. If True, this function will return a
generator. Successive invocations of the generator will
return 0 if it is waiting to read from the socket, 1 if it is
waiting to write to the socket, or will raise StopIteration if
the handshake operation is completed.
@rtype: None or an iterable
@return: If 'async' is True, a generator object will be
returned.
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
@raise tlslite.errors.TLSAuthenticationError: If the checker
doesn't like the other party's authentication credentials.
"""
handshaker = self._handshakeClientAsync(sharedKeyParams=(username,
sharedKey), settings=settings, checker=checker)
if async:
return handshaker
for result in handshaker:
pass
def _handshakeClientAsync(self, srpParams=(), certParams=(),
unknownParams=(), sharedKeyParams=(),
session=None, settings=None, checker=None,
recursive=False):
handshaker = self._handshakeClientAsyncHelper(srpParams=srpParams,
certParams=certParams, unknownParams=unknownParams,
sharedKeyParams=sharedKeyParams, session=session,
settings=settings, recursive=recursive)
for result in self._handshakeWrapperAsync(handshaker, checker):
yield result
def _handshakeClientAsyncHelper(self, srpParams, certParams, unknownParams,
sharedKeyParams, session, settings, recursive):
if not recursive:
self._handshakeStart(client=True)
#Unpack parameters
srpUsername = None # srpParams
password = None # srpParams
clientCertChain = None # certParams
privateKey = None # certParams
srpCallback = None # unknownParams
certCallback = None # unknownParams
#session # sharedKeyParams (or session)
#settings # settings
if srpParams:
srpUsername, password = srpParams
elif certParams:
clientCertChain, privateKey = certParams
elif unknownParams:
srpCallback, certCallback = unknownParams
elif sharedKeyParams:
session = Session()._createSharedKey(*sharedKeyParams)
if not settings:
settings = HandshakeSettings()
settings = settings._filter()
#Validate parameters
if srpUsername and not password:
raise ValueError("Caller passed a username but no password")
if password and not srpUsername:
raise ValueError("Caller passed a password but no username")
if clientCertChain and not privateKey:
raise ValueError("Caller passed a certChain but no privateKey")
if privateKey and not clientCertChain:
raise ValueError("Caller passed a privateKey but no certChain")
if clientCertChain:
foundType = False
try:
import cryptoIDlib.CertChain
if isinstance(clientCertChain, cryptoIDlib.CertChain.CertChain):
if "cryptoID" not in settings.certificateTypes:
raise ValueError("Client certificate doesn't "\
"match Handshake Settings")
settings.certificateTypes = ["cryptoID"]
foundType = True
except ImportError:
pass
if not foundType and isinstance(clientCertChain,
X509CertChain):
if "x509" not in settings.certificateTypes:
raise ValueError("Client certificate doesn't match "\
"Handshake Settings")
settings.certificateTypes = ["x509"]
foundType = True
if not foundType:
raise ValueError("Unrecognized certificate type")
if session:
if not session.valid():
session = None #ignore non-resumable sessions...
elif session.resumable and \
(session.srpUsername != srpUsername):
raise ValueError("Session username doesn't match")
#Add Faults to parameters
if srpUsername and self.fault == Fault.badUsername:
srpUsername += "GARBAGE"
if password and self.fault == Fault.badPassword:
password += "GARBAGE"
if sharedKeyParams:
identifier = sharedKeyParams[0]
sharedKey = sharedKeyParams[1]
if self.fault == Fault.badIdentifier:
identifier += "GARBAGE"
session = Session()._createSharedKey(identifier, sharedKey)
elif self.fault == Fault.badSharedKey:
sharedKey += "GARBAGE"
session = Session()._createSharedKey(identifier, sharedKey)
#Initialize locals
serverCertChain = None
cipherSuite = 0
certificateType = CertificateType.x509
premasterSecret = None
#Get client nonce
clientRandom = getRandomBytes(32)
#Initialize acceptable ciphersuites
cipherSuites = []
if srpParams:
cipherSuites += CipherSuite.getSrpRsaSuites(settings.cipherNames)
cipherSuites += CipherSuite.getSrpSuites(settings.cipherNames)
elif certParams:
cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames)
elif unknownParams:
if srpCallback:
cipherSuites += \
CipherSuite.getSrpRsaSuites(settings.cipherNames)
cipherSuites += \
CipherSuite.getSrpSuites(settings.cipherNames)
cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames)
elif sharedKeyParams:
cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames)
else:
cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames)
#Initialize acceptable certificate types
certificateTypes = settings._getCertificateTypes()
#Tentatively set the version to the client's minimum version.
#We'll use this for the ClientHello, and if an error occurs
#parsing the Server Hello, we'll use this version for the response
self.version = settings.maxVersion
#Either send ClientHello (with a resumable session)...
if session:
#If it's a resumable (i.e. not a shared-key session), then its
#ciphersuite must be one of the acceptable ciphersuites
if (not sharedKeyParams) and \
session.cipherSuite not in cipherSuites:
raise ValueError("Session's cipher suite not consistent "\
"with parameters")
else:
clientHello = ClientHello()
clientHello.create(settings.maxVersion, clientRandom,
session.sessionID, cipherSuites,
certificateTypes, session.srpUsername)
#Or send ClientHello (without)
else:
clientHello = ClientHello()
clientHello.create(settings.maxVersion, clientRandom,
createByteArraySequence([]), cipherSuites,
certificateTypes, srpUsername)
for result in self._sendMsg(clientHello):
yield result
#Get ServerHello (or missing_srp_username)
for result in self._getMsg((ContentType.handshake,
ContentType.alert),
HandshakeType.server_hello):
if result in (0,1):
yield result
else:
break
msg = result
if isinstance(msg, ServerHello):
serverHello = msg
elif isinstance(msg, Alert):
alert = msg
#If it's not a missing_srp_username, re-raise
if alert.description != AlertDescription.missing_srp_username:
print "TLSConnection._handshakeClientAsyncHelper: _shutdown: Alert (%s, %s)" % (repr(alert.level), repr(alert.description))
self._shutdown(False)
raise TLSRemoteAlert(alert)
#If we're not in SRP callback mode, we won't have offered SRP
#without a username, so we shouldn't get this alert
if not srpCallback:
for result in self._sendError(\
AlertDescription.unexpected_message):
yield result
srpParams = srpCallback()
#If the callback returns None, cancel the handshake
if srpParams == None:
for result in self._sendError(AlertDescription.user_canceled):
yield result
#Recursively perform handshake
for result in self._handshakeClientAsyncHelper(srpParams,
None, None, None, None, settings, True):
yield result
return
#Get the server version. Do this before anything else, so any
#error alerts will use the server's version
self.version = serverHello.server_version
#Future responses from server must use this version
self._versionCheck = True
#Check ServerHello
if serverHello.server_version < settings.minVersion:
for result in self._sendError(\
AlertDescription.protocol_version,
"Too old version: %s" % str(serverHello.server_version)):
yield result
if serverHello.server_version > settings.maxVersion:
for result in self._sendError(\
AlertDescription.protocol_version,
"Too new version: %s" % str(serverHello.server_version)):
yield result
if serverHello.cipher_suite not in cipherSuites:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server responded with incorrect ciphersuite"):
yield result
if serverHello.certificate_type not in certificateTypes:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server responded with incorrect certificate type"):
yield result
if serverHello.compression_method != 0:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server responded with incorrect compression method"):
yield result
#Get the server nonce
serverRandom = serverHello.random
#If the server agrees to resume
if session and session.sessionID and \
serverHello.session_id == session.sessionID:
#If a shared-key, we're flexible about suites; otherwise the
#server-chosen suite has to match the session's suite
if sharedKeyParams:
session.cipherSuite = serverHello.cipher_suite
elif serverHello.cipher_suite != session.cipherSuite:
for result in self._sendError(\
AlertDescription.illegal_parameter,\
"Server's ciphersuite doesn't match session"):
yield result
#Set the session for this connection
self.session = session
#Calculate pending connection states
self._calcPendingStates(clientRandom, serverRandom,
settings.cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._getFinished():
yield result
for result in self._sendFinished():
yield result
#Mark the connection as open
self._handshakeDone(resumed=True)
#If server DOES NOT agree to resume
else:
if sharedKeyParams:
for result in self._sendError(\
AlertDescription.user_canceled,
"Was expecting a shared-key resumption"):
yield result
#We've already validated these
cipherSuite = serverHello.cipher_suite
certificateType = serverHello.certificate_type
#If the server chose an SRP suite...
if cipherSuite in CipherSuite.srpSuites:
#Get ServerKeyExchange, ServerHelloDone
for result in self._getMsg(ContentType.handshake,
HandshakeType.server_key_exchange, cipherSuite):
if result in (0,1):
yield result
else:
break
serverKeyExchange = result
for result in self._getMsg(ContentType.handshake,
HandshakeType.server_hello_done):
if result in (0,1):
yield result
else:
break
serverHelloDone = result
#If the server chose an SRP+RSA suite...
elif cipherSuite in CipherSuite.srpRsaSuites:
#Get Certificate, ServerKeyExchange, ServerHelloDone
for result in self._getMsg(ContentType.handshake,
HandshakeType.certificate, certificateType):
if result in (0,1):
yield result
else:
break
serverCertificate = result
for result in self._getMsg(ContentType.handshake,
HandshakeType.server_key_exchange, cipherSuite):
if result in (0,1):
yield result
else:
break
serverKeyExchange = result
for result in self._getMsg(ContentType.handshake,
HandshakeType.server_hello_done):
if result in (0,1):
yield result
else:
break
serverHelloDone = result
#If the server chose an RSA suite...
elif cipherSuite in CipherSuite.rsaSuites:
#Get Certificate[, CertificateRequest], ServerHelloDone
for result in self._getMsg(ContentType.handshake,
HandshakeType.certificate, certificateType):
if result in (0,1):
yield result
else:
break
serverCertificate = result
for result in self._getMsg(ContentType.handshake,
(HandshakeType.server_hello_done,
HandshakeType.certificate_request)):
if result in (0,1):
yield result
else:
break
msg = result
certificateRequest = None
if isinstance(msg, CertificateRequest):
certificateRequest = msg
for result in self._getMsg(ContentType.handshake,
HandshakeType.server_hello_done):
if result in (0,1):
yield result
else:
break
serverHelloDone = result
elif isinstance(msg, ServerHelloDone):
serverHelloDone = msg
else:
raise AssertionError()
#Calculate SRP premaster secret, if server chose an SRP or
#SRP+RSA suite
if cipherSuite in CipherSuite.srpSuites + \
CipherSuite.srpRsaSuites:
#Get and check the server's group parameters and B value
N = serverKeyExchange.srp_N
g = serverKeyExchange.srp_g
s = serverKeyExchange.srp_s
B = serverKeyExchange.srp_B
if (g,N) not in goodGroupParameters:
for result in self._sendError(\
AlertDescription.untrusted_srp_parameters,
"Unknown group parameters"):
yield result
if numBits(N) < settings.minKeySize:
for result in self._sendError(\
AlertDescription.untrusted_srp_parameters,
"N value is too small: %d" % numBits(N)):
yield result
if numBits(N) > settings.maxKeySize:
for result in self._sendError(\
AlertDescription.untrusted_srp_parameters,
"N value is too large: %d" % numBits(N)):
yield result
if B % N == 0:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Suspicious B value"):
yield result
#Check the server's signature, if server chose an
#SRP+RSA suite
if cipherSuite in CipherSuite.srpRsaSuites:
#Hash ServerKeyExchange/ServerSRPParams
hashBytes = serverKeyExchange.hash(clientRandom,
serverRandom)
#Extract signature bytes from ServerKeyExchange
sigBytes = serverKeyExchange.signature
if len(sigBytes) == 0:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server sent an SRP ServerKeyExchange "\
"message without a signature"):
yield result
#Get server's public key from the Certificate message
for result in self._getKeyFromChain(serverCertificate,
settings):
if result in (0,1):
yield result
else:
break
publicKey, serverCertChain = result
#Verify signature
if not publicKey.verify(sigBytes, hashBytes):
for result in self._sendError(\
AlertDescription.decrypt_error,
"Signature failed to verify"):
yield result
#Calculate client's ephemeral DH values (a, A)
a = bytesToNumber(getRandomBytes(32))
A = powMod(g, a, N)
#Calculate client's static DH values (x, v)
x = makeX(bytesToString(s), srpUsername, password)
v = powMod(g, x, N)
#Calculate u
u = makeU(N, A, B)
#Calculate premaster secret
k = makeK(N, g)
S = powMod((B - (k*v)) % N, a+(u*x), N)
if self.fault == Fault.badA:
A = N
S = 0
premasterSecret = numberToBytes(S)
#Send ClientKeyExchange
for result in self._sendMsg(\
ClientKeyExchange(cipherSuite).createSRP(A)):
yield result
#Calculate RSA premaster secret, if server chose an RSA suite
elif cipherSuite in CipherSuite.rsaSuites:
#Handle the presence of a CertificateRequest
if certificateRequest:
if unknownParams and certCallback:
certParamsNew = certCallback()
if certParamsNew:
clientCertChain, privateKey = certParamsNew
#Get server's public key from the Certificate message
for result in self._getKeyFromChain(serverCertificate,
settings):
if result in (0,1):
yield result
else:
break
publicKey, serverCertChain = result
#Calculate premaster secret
premasterSecret = getRandomBytes(48)
premasterSecret[0] = settings.maxVersion[0]
premasterSecret[1] = settings.maxVersion[1]
if self.fault == Fault.badPremasterPadding:
premasterSecret[0] = 5
if self.fault == Fault.shortPremasterSecret:
premasterSecret = premasterSecret[:-1]
#Encrypt premaster secret to server's public key
encryptedPreMasterSecret = publicKey.encrypt(premasterSecret)
#If client authentication was requested, send Certificate
#message, either with certificates or empty
if certificateRequest:
clientCertificate = Certificate(certificateType)
if clientCertChain:
#Check to make sure we have the same type of
#certificates the server requested
wrongType = False
if certificateType == CertificateType.x509:
if not isinstance(clientCertChain, X509CertChain):
wrongType = True
elif certificateType == CertificateType.cryptoID:
if not isinstance(clientCertChain,
cryptoIDlib.CertChain.CertChain):
wrongType = True
if wrongType:
for result in self._sendError(\
AlertDescription.handshake_failure,
"Client certificate is of wrong type"):
yield result
clientCertificate.create(clientCertChain)
for result in self._sendMsg(clientCertificate):
yield result
else:
#The server didn't request client auth, so we
#zeroize these so the clientCertChain won't be
#stored in the session.
privateKey = None
clientCertChain = None
#Send ClientKeyExchange
clientKeyExchange = ClientKeyExchange(cipherSuite,
self.version)
clientKeyExchange.createRSA(encryptedPreMasterSecret)
for result in self._sendMsg(clientKeyExchange):
yield result
#If client authentication was requested and we have a
#private key, send CertificateVerify
if certificateRequest and privateKey:
if self.version == (3,0):
#Create a temporary session object, just for the
#purpose of creating the CertificateVerify
session = Session()
session._calcMasterSecret(self.version,
premasterSecret,
clientRandom,
serverRandom)
verifyBytes = self._calcSSLHandshakeHash(\
session.masterSecret, "")
elif self.version in ((3,1), (3,2)):
verifyBytes = stringToBytes(\
self._handshake_md5.digest() + \
self._handshake_sha.digest())
if self.fault == Fault.badVerifyMessage:
verifyBytes[0] = ((verifyBytes[0]+1) % 256)
signedBytes = privateKey.sign(verifyBytes)
certificateVerify = CertificateVerify()
certificateVerify.create(signedBytes)
for result in self._sendMsg(certificateVerify):
yield result
#Create the session object
self.session = Session()
self.session._calcMasterSecret(self.version, premasterSecret,
clientRandom, serverRandom)
self.session.sessionID = serverHello.session_id
self.session.cipherSuite = cipherSuite
self.session.srpUsername = srpUsername
self.session.clientCertChain = clientCertChain
self.session.serverCertChain = serverCertChain
#Calculate pending connection states
self._calcPendingStates(clientRandom, serverRandom,
settings.cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._sendFinished():
yield result
for result in self._getFinished():
yield result
#Mark the connection as open
self.session._setResumable(True)
self._handshakeDone(resumed=False)
def handshakeServer(self, sharedKeyDB=None, verifierDB=None,
certChain=None, privateKey=None, reqCert=False,
sessionCache=None, settings=None, checker=None):
"""Perform a handshake in the role of server.
This function performs an SSL or TLS handshake. Depending on
the arguments and the behavior of the client, this function can
perform a shared-key, SRP, or certificate-based handshake. It
can also perform a combined SRP and server-certificate
handshake.
Like any handshake function, this can be called on a closed
TLS connection, or on a TLS connection that is already open.
If called on an open connection it performs a re-handshake.
This function does not send a Hello Request message before
performing the handshake, so if re-handshaking is required,
the server must signal the client to begin the re-handshake
through some other means.
If the function completes without raising an exception, the
TLS connection will be open and available for data transfer.
If an exception is raised, the connection will have been
automatically closed (if it was ever open).
@type sharedKeyDB: L{tlslite.SharedKeyDB.SharedKeyDB}
@param sharedKeyDB: A database of shared symmetric keys
associated with usernames. If the client performs a
shared-key handshake, the session's sharedKeyUsername
attribute will be set.
@type verifierDB: L{tlslite.VerifierDB.VerifierDB}
@param verifierDB: A database of SRP password verifiers
associated with usernames. If the client performs an SRP
handshake, the session's srpUsername attribute will be set.
@type certChain: L{tlslite.X509CertChain.X509CertChain} or
L{cryptoIDlib.CertChain.CertChain}
@param certChain: The certificate chain to be used if the
client requests server certificate authentication.
@type privateKey: L{tlslite.utils.RSAKey.RSAKey}
@param privateKey: The private key to be used if the client
requests server certificate authentication.
@type reqCert: bool
@param reqCert: Whether to request client certificate
authentication. This only applies if the client chooses server
certificate authentication; if the client chooses SRP or
shared-key authentication, this will be ignored. If the client
performs a client certificate authentication, the sessions's
clientCertChain attribute will be set.
@type sessionCache: L{tlslite.SessionCache.SessionCache}
@param sessionCache: An in-memory cache of resumable sessions.
The client can resume sessions from this cache. Alternatively,
if the client performs a full handshake, a new session will be
added to the cache.
@type settings: L{tlslite.HandshakeSettings.HandshakeSettings}
@param settings: Various settings which can be used to control
the ciphersuites and SSL/TLS version chosen by the server.
@type checker: L{tlslite.Checker.Checker}
@param checker: A Checker instance. This instance will be
invoked to examine the other party's authentication
credentials, if the handshake completes succesfully.
@raise socket.error: If a socket error occurs.
@raise tlslite.errors.TLSAbruptCloseError: If the socket is closed
without a preceding alert.
@raise tlslite.errors.TLSAlert: If a TLS alert is signalled.
@raise tlslite.errors.TLSAuthenticationError: If the checker
doesn't like the other party's authentication credentials.
"""
for result in self.handshakeServerAsync(sharedKeyDB, verifierDB,
certChain, privateKey, reqCert, sessionCache, settings,
checker):
pass
def handshakeServerAsync(self, sharedKeyDB=None, verifierDB=None,
certChain=None, privateKey=None, reqCert=False,
sessionCache=None, settings=None, checker=None):
"""Start a server handshake operation on the TLS connection.
This function returns a generator which behaves similarly to
handshakeServer(). Successive invocations of the generator
will return 0 if it is waiting to read from the socket, 1 if it is
waiting to write to the socket, or it will raise StopIteration
if the handshake operation is complete.
@rtype: iterable
@return: A generator; see above for details.
"""
handshaker = self._handshakeServerAsyncHelper(\
sharedKeyDB=sharedKeyDB,
verifierDB=verifierDB, certChain=certChain,
privateKey=privateKey, reqCert=reqCert,
sessionCache=sessionCache, settings=settings)
for result in self._handshakeWrapperAsync(handshaker, checker):
yield result
def _handshakeServerAsyncHelper(self, sharedKeyDB, verifierDB,
certChain, privateKey, reqCert, sessionCache,
settings):
self._handshakeStart(client=False)
if (not sharedKeyDB) and (not verifierDB) and (not certChain):
raise ValueError("Caller passed no authentication credentials")
if certChain and not privateKey:
raise ValueError("Caller passed a certChain but no privateKey")
if privateKey and not certChain:
raise ValueError("Caller passed a privateKey but no certChain")
if not settings:
settings = HandshakeSettings()
settings = settings._filter()
#Initialize acceptable cipher suites
cipherSuites = []
if verifierDB:
if certChain:
cipherSuites += \
CipherSuite.getSrpRsaSuites(settings.cipherNames)
cipherSuites += CipherSuite.getSrpSuites(settings.cipherNames)
if sharedKeyDB or certChain:
cipherSuites += CipherSuite.getRsaSuites(settings.cipherNames)
#Initialize acceptable certificate type
certificateType = None
if certChain:
try:
import cryptoIDlib.CertChain
if isinstance(certChain, cryptoIDlib.CertChain.CertChain):
certificateType = CertificateType.cryptoID
except ImportError:
pass
if isinstance(certChain, X509CertChain):
certificateType = CertificateType.x509
if certificateType == None:
raise ValueError("Unrecognized certificate type")
#Initialize locals
clientCertChain = None
serverCertChain = None #We may set certChain to this later
postFinishedError = None
#Tentatively set version to most-desirable version, so if an error
#occurs parsing the ClientHello, this is what we'll use for the
#error alert
self.version = settings.maxVersion
#Get ClientHello
for result in self._getMsg(ContentType.handshake,
HandshakeType.client_hello):
if result in (0,1):
yield result
else:
break
clientHello = result
#If client's version is too low, reject it
if clientHello.client_version < settings.minVersion:
self.version = settings.minVersion
for result in self._sendError(\
AlertDescription.protocol_version,
"Too old version: %s" % str(clientHello.client_version)):
yield result
#If client's version is too high, propose my highest version
elif clientHello.client_version > settings.maxVersion:
self.version = settings.maxVersion
else:
#Set the version to the client's version
self.version = clientHello.client_version
#Get the client nonce; create server nonce
clientRandom = clientHello.random
serverRandom = getRandomBytes(32)
#Calculate the first cipher suite intersection.
#This is the 'privileged' ciphersuite. We'll use it if we're
#doing a shared-key resumption or a new negotiation. In fact,
#the only time we won't use it is if we're resuming a non-sharedkey
#session, in which case we use the ciphersuite from the session.
#
#Given the current ciphersuite ordering, this means we prefer SRP
#over non-SRP.
print "handshake: cipherSuites=", repr(cipherSuites)
print "handshake: clientHello.cipher_suites=", repr(clientHello.cipher_suites)
for cipherSuite in cipherSuites:
if cipherSuite in clientHello.cipher_suites:
break
else:
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
#If resumption was requested...
if clientHello.session_id and (sharedKeyDB or sessionCache):
session = None
#Check in the sharedKeys container
if sharedKeyDB and len(clientHello.session_id)==16:
try:
#Trim off zero padding, if any
for x in range(16):
if clientHello.session_id[x]==0:
break
self.allegedSharedKeyUsername = bytesToString(\
clientHello.session_id[:x])
session = sharedKeyDB[self.allegedSharedKeyUsername]
if not session.sharedKey:
raise AssertionError()
#use privileged ciphersuite
session.cipherSuite = cipherSuite
except KeyError:
pass
#Then check in the session cache
if sessionCache and not session:
try:
session = sessionCache[bytesToString(\
clientHello.session_id)]
if session.sharedKey:
raise AssertionError()
if not session.resumable:
raise AssertionError()
#Check for consistency with ClientHello
if session.cipherSuite not in cipherSuites:
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
if session.cipherSuite not in clientHello.cipher_suites:
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
if clientHello.srp_username:
if clientHello.srp_username != session.srpUsername:
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
except KeyError:
pass
#If a session is found..
if session:
#Set the session
self.session = session
#Send ServerHello
serverHello = ServerHello()
serverHello.create(self.version, serverRandom,
session.sessionID, session.cipherSuite,
certificateType)
for result in self._sendMsg(serverHello):
yield result
#From here on, the client's messages must have the right version
self._versionCheck = True
#Calculate pending connection states
self._calcPendingStates(clientRandom, serverRandom,
settings.cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._sendFinished():
yield result
for result in self._getFinished():
yield result
#Mark the connection as open
self._handshakeDone(resumed=True)
return
#If not a resumption...
#TRICKY: we might have chosen an RSA suite that was only deemed
#acceptable because of the shared-key resumption. If the shared-
#key resumption failed, because the identifier wasn't recognized,
#we might fall through to here, where we have an RSA suite
#chosen, but no certificate.
if cipherSuite in CipherSuite.rsaSuites and not certChain:
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
#If an RSA suite is chosen, check for certificate type intersection
#(We do this check down here because if the mismatch occurs but the
# client is using a shared-key session, it's okay)
if cipherSuite in CipherSuite.rsaSuites + \
CipherSuite.srpRsaSuites:
if certificateType not in clientHello.certificate_types:
for result in self._sendError(\
AlertDescription.handshake_failure,
"the client doesn't support my certificate type"):
yield result
#Move certChain -> serverCertChain, now that we're using it
serverCertChain = certChain
#Create sessionID
if sessionCache:
sessionID = getRandomBytes(32)
else:
sessionID = createByteArraySequence([])
#If we've selected an SRP suite, exchange keys and calculate
#premaster secret:
if cipherSuite in CipherSuite.srpSuites + CipherSuite.srpRsaSuites:
#If there's no SRP username...
if not clientHello.srp_username:
#Ask the client to re-send ClientHello with one
for result in self._sendMsg(Alert().create(\
AlertDescription.missing_srp_username,
AlertLevel.warning)):
yield result
#Get ClientHello
for result in self._getMsg(ContentType.handshake,
HandshakeType.client_hello):
if result in (0,1):
yield result
else:
break
clientHello = result
#Check ClientHello
#If client's version is too low, reject it (COPIED CODE; BAD!)
if clientHello.client_version < settings.minVersion:
self.version = settings.minVersion
for result in self._sendError(\
AlertDescription.protocol_version,
"Too old version: %s" % str(clientHello.client_version)):
yield result
#If client's version is too high, propose my highest version
elif clientHello.client_version > settings.maxVersion:
self.version = settings.maxVersion
else:
#Set the version to the client's version
self.version = clientHello.client_version
#Recalculate the privileged cipher suite, making sure to
#pick an SRP suite
cipherSuites = [c for c in cipherSuites if c in \
CipherSuite.srpSuites + \
CipherSuite.srpRsaSuites]
for cipherSuite in cipherSuites:
if cipherSuite in clientHello.cipher_suites:
break
else:
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
#Get the client nonce; create server nonce
clientRandom = clientHello.random
serverRandom = getRandomBytes(32)
#The username better be there, this time
if not clientHello.srp_username:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Client resent a hello, but without the SRP"\
" username"):
yield result
#Get username
self.allegedSrpUsername = clientHello.srp_username
#Get parameters from username
try:
entry = verifierDB[self.allegedSrpUsername]
except KeyError:
for result in self._sendError(\
AlertDescription.unknown_srp_username):
yield result
(N, g, s, v) = entry
#Calculate server's ephemeral DH values (b, B)
b = bytesToNumber(getRandomBytes(32))
k = makeK(N, g)
B = (powMod(g, b, N) + (k*v)) % N
#Create ServerKeyExchange, signing it if necessary
serverKeyExchange = ServerKeyExchange(cipherSuite)
serverKeyExchange.createSRP(N, g, stringToBytes(s), B)
if cipherSuite in CipherSuite.srpRsaSuites:
hashBytes = serverKeyExchange.hash(clientRandom,
serverRandom)
serverKeyExchange.signature = privateKey.sign(hashBytes)
#Send ServerHello[, Certificate], ServerKeyExchange,
#ServerHelloDone
msgs = []
serverHello = ServerHello()
serverHello.create(self.version, serverRandom, sessionID,
cipherSuite, certificateType)
msgs.append(serverHello)
if cipherSuite in CipherSuite.srpRsaSuites:
certificateMsg = Certificate(certificateType)
certificateMsg.create(serverCertChain)
msgs.append(certificateMsg)
msgs.append(serverKeyExchange)
msgs.append(ServerHelloDone())
for result in self._sendMsgs(msgs):
yield result
#From here on, the client's messages must have the right version
self._versionCheck = True
#Get and check ClientKeyExchange
for result in self._getMsg(ContentType.handshake,
HandshakeType.client_key_exchange,
cipherSuite):
if result in (0,1):
yield result
else:
break
clientKeyExchange = result
A = clientKeyExchange.srp_A
if A % N == 0:
postFinishedError = (AlertDescription.illegal_parameter,
"Suspicious A value")
#Calculate u
u = makeU(N, A, B)
#Calculate premaster secret
S = powMod((A * powMod(v,u,N)) % N, b, N)
premasterSecret = numberToBytes(S)
#If we've selected an RSA suite, exchange keys and calculate
#premaster secret:
elif cipherSuite in CipherSuite.rsaSuites:
#Send ServerHello, Certificate[, CertificateRequest],
#ServerHelloDone
msgs = []
msgs.append(ServerHello().create(self.version, serverRandom,
sessionID, cipherSuite, certificateType))
msgs.append(Certificate(certificateType).create(serverCertChain))
if reqCert:
msgs.append(CertificateRequest())
msgs.append(ServerHelloDone())
for result in self._sendMsgs(msgs):
yield result
#From here on, the client's messages must have the right version
self._versionCheck = True
#Get [Certificate,] (if was requested)
if reqCert:
if self.version == (3,0):
for result in self._getMsg((ContentType.handshake,
ContentType.alert),
HandshakeType.certificate,
certificateType):
if result in (0,1):
yield result
else:
break
msg = result
if isinstance(msg, Alert):
#If it's not a no_certificate alert, re-raise
alert = msg
if alert.description != \
AlertDescription.no_certificate:
print "TLSConnection._handshakeClientAsyncHelper: _shutdown: Alert (%s, %s)" % (repr(alert.level), repr(alert.description))
self._shutdown(False)
raise TLSRemoteAlert(alert)
elif isinstance(msg, Certificate):
clientCertificate = msg
if clientCertificate.certChain and \
clientCertificate.certChain.getNumCerts()!=0:
clientCertChain = clientCertificate.certChain
else:
raise AssertionError()
elif self.version in ((3,1), (3,2)):
for result in self._getMsg(ContentType.handshake,
HandshakeType.certificate,
certificateType):
if result in (0,1):
yield result
else:
break
clientCertificate = result
if clientCertificate.certChain and \
clientCertificate.certChain.getNumCerts()!=0:
clientCertChain = clientCertificate.certChain
else:
raise AssertionError()
#Get ClientKeyExchange
for result in self._getMsg(ContentType.handshake,
HandshakeType.client_key_exchange,
cipherSuite):
if result in (0,1):
yield result
else:
break
clientKeyExchange = result
#Decrypt ClientKeyExchange
premasterSecret = privateKey.decrypt(\
clientKeyExchange.encryptedPreMasterSecret)
randomPreMasterSecret = getRandomBytes(48)
versionCheck = (premasterSecret[0], premasterSecret[1])
if not premasterSecret:
premasterSecret = randomPreMasterSecret
elif len(premasterSecret)!=48:
premasterSecret = randomPreMasterSecret
elif versionCheck != clientHello.client_version:
if versionCheck != self.version: #Tolerate buggy IE clients
premasterSecret = randomPreMasterSecret
#Get and check CertificateVerify, if relevant
if clientCertChain:
if self.version == (3,0):
#Create a temporary session object, just for the purpose
#of checking the CertificateVerify
session = Session()
session._calcMasterSecret(self.version, premasterSecret,
clientRandom, serverRandom)
verifyBytes = self._calcSSLHandshakeHash(\
session.masterSecret, "")
elif self.version in ((3,1), (3,2)):
verifyBytes = stringToBytes(self._handshake_md5.digest() +\
self._handshake_sha.digest())
for result in self._getMsg(ContentType.handshake,
HandshakeType.certificate_verify):
if result in (0,1):
yield result
else:
break
certificateVerify = result
publicKey = clientCertChain.getEndEntityPublicKey()
if len(publicKey) < settings.minKeySize:
postFinishedError = (AlertDescription.handshake_failure,
"Client's public key too small: %d" % len(publicKey))
if len(publicKey) > settings.maxKeySize:
postFinishedError = (AlertDescription.handshake_failure,
"Client's public key too large: %d" % len(publicKey))
if not publicKey.verify(certificateVerify.signature,
verifyBytes):
postFinishedError = (AlertDescription.decrypt_error,
"Signature failed to verify")
#Create the session object
self.session = Session()
self.session._calcMasterSecret(self.version, premasterSecret,
clientRandom, serverRandom)
self.session.sessionID = sessionID
self.session.cipherSuite = cipherSuite
self.session.srpUsername = self.allegedSrpUsername
self.session.clientCertChain = clientCertChain
self.session.serverCertChain = serverCertChain
#Calculate pending connection states
self._calcPendingStates(clientRandom, serverRandom,
settings.cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._getFinished():
yield result
#If we were holding a post-finished error until receiving the client
#finished message, send it now. We delay the call until this point
#because calling sendError() throws an exception, and our caller might
#shut down the socket upon receiving the exception. If he did, and the
#client was still sending its ChangeCipherSpec or Finished messages, it
#would cause a socket error on the client side. This is a lot of
#consideration to show to misbehaving clients, but this would also
#cause problems with fault-testing.
if postFinishedError:
for result in self._sendError(*postFinishedError):
yield result
for result in self._sendFinished():
yield result
#Add the session object to the session cache
if sessionCache and sessionID:
sessionCache[bytesToString(sessionID)] = self.session
#Mark the connection as open
self.session._setResumable(True)
self._handshakeDone(resumed=False)
def _handshakeWrapperAsync(self, handshaker, checker):
if not self.fault:
try:
for result in handshaker:
yield result
if checker:
try:
checker(self)
except TLSAuthenticationError:
alert = Alert().create(AlertDescription.close_notify,
AlertLevel.fatal)
for result in self._sendMsg(alert):
yield result
raise
except:
print "TLSConnection._handshakeWrapperAsync: _shutdown: Exception (!fault path)"
import traceback
traceback.print_exc()
self._shutdown(False)
raise
else:
try:
for result in handshaker:
yield result
if checker:
try:
checker(self)
except TLSAuthenticationError:
alert = Alert().create(AlertDescription.close_notify,
AlertLevel.fatal)
for result in self._sendMsg(alert):
yield result
raise
except socket.error, e:
raise TLSFaultError("socket error!")
except TLSAbruptCloseError, e:
raise TLSFaultError("abrupt close error!")
except TLSAlert, alert:
if alert.description not in Fault.faultAlerts[self.fault]:
raise TLSFaultError(str(alert))
else:
pass
except:
print "TLSConnection._handshakeWrapperAsync: _shutdown: Exception (fault path)"
import traceback
traceback.print_exc()
self._shutdown(False)
raise
else:
raise TLSFaultError("No error!")
def _getKeyFromChain(self, certificate, settings):
#Get and check cert chain from the Certificate message
certChain = certificate.certChain
if not certChain or certChain.getNumCerts() == 0:
for result in self._sendError(AlertDescription.illegal_parameter,
"Other party sent a Certificate message without "\
"certificates"):
yield result
#Get and check public key from the cert chain
publicKey = certChain.getEndEntityPublicKey()
if len(publicKey) < settings.minKeySize:
for result in self._sendError(AlertDescription.handshake_failure,
"Other party's public key too small: %d" % len(publicKey)):
yield result
if len(publicKey) > settings.maxKeySize:
for result in self._sendError(AlertDescription.handshake_failure,
"Other party's public key too large: %d" % len(publicKey)):
yield result
yield publicKey, certChain
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