blob: dfac274b6e939f631db5099046c9b8f89838b60a [file] [log] [blame]
# Authors:
# Trevor Perrin
# Google - added reqCAs parameter
# Google (adapted by Sam Rushing and Marcelo Fernandez) - NPN support
# Dimitris Moraitis - Anon ciphersuites
# Martin von Loewis - python 3 port
# Yngve Pettersen (ported by Paul Sokolovsky) - TLS 1.2
#
# See the LICENSE file for legal information regarding use of this file.
"""
MAIN CLASS FOR TLS LITE (START HERE!).
"""
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
from .utils.tackwrapper import *
from .utils.rsakey import RSAKey
from .utils import p256
class KeyExchange(object):
def __init__(self, cipherSuite, clientHello, serverHello, privateKey):
"""
Initializes the KeyExchange. privateKey is the signing private key.
"""
self.cipherSuite = cipherSuite
self.clientHello = clientHello
self.serverHello = serverHello
self.privateKey = privateKey
def makeServerKeyExchange():
"""
Returns a ServerKeyExchange object for the server's initial leg in the
handshake. If the key exchange method does not send ServerKeyExchange
(e.g. RSA), it returns None.
"""
raise NotImplementedError()
def processClientKeyExchange(clientKeyExchange):
"""
Processes the client's ClientKeyExchange message and returns the
premaster secret. Raises TLSLocalAlert on error.
"""
raise NotImplementedError()
class RSAKeyExchange(KeyExchange):
def makeServerKeyExchange(self):
return None
def processClientKeyExchange(self, clientKeyExchange):
premasterSecret = self.privateKey.decrypt(\
clientKeyExchange.encryptedPreMasterSecret)
# On decryption failure randomize premaster secret to avoid
# Bleichenbacher's "million message" attack
randomPreMasterSecret = getRandomBytes(48)
if not premasterSecret:
premasterSecret = randomPreMasterSecret
elif len(premasterSecret)!=48:
premasterSecret = randomPreMasterSecret
else:
versionCheck = (premasterSecret[0], premasterSecret[1])
if versionCheck != self.clientHello.client_version:
#Tolerate buggy IE clients
if versionCheck != self.serverHello.server_version:
premasterSecret = randomPreMasterSecret
return premasterSecret
def _hexStringToNumber(s):
s = s.replace(" ", "").replace("\n", "")
if len(s) % 2 != 0:
raise ValueError("Length is not even")
return bytesToNumber(bytearray(s.decode("hex")))
class DHE_RSAKeyExchange(KeyExchange):
# 2048-bit MODP Group (RFC 3526, Section 3)
dh_p = _hexStringToNumber("""
FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1
29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD
EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245
E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED
EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D
C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F
83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D
670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B
E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9
DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510
15728E5A 8AACAA68 FFFFFFFF FFFFFFFF""")
dh_g = 2
# RFC 3526, Section 8.
strength = 160
def makeServerKeyExchange(self):
# Per RFC 3526, Section 1, the exponent should have double the entropy
# of the strength of the curve.
self.dh_Xs = bytesToNumber(getRandomBytes(self.strength * 2 / 8))
dh_Ys = powMod(self.dh_g, self.dh_Xs, self.dh_p)
version = self.serverHello.server_version
serverKeyExchange = ServerKeyExchange(self.cipherSuite, version)
serverKeyExchange.createDH(self.dh_p, self.dh_g, dh_Ys)
hashBytes = serverKeyExchange.hash(self.clientHello.random,
self.serverHello.random)
if version >= (3,3):
# TODO: Signature algorithm negotiation not supported.
hashBytes = RSAKey.addPKCS1SHA1Prefix(hashBytes)
serverKeyExchange.signature = self.privateKey.sign(hashBytes)
return serverKeyExchange
def processClientKeyExchange(self, clientKeyExchange):
dh_Yc = clientKeyExchange.dh_Yc
# First half of RFC 2631, Section 2.1.5. Validate the client's public
# key.
if not 2 <= dh_Yc <= self.dh_p - 1:
raise TLSLocalAlert(AlertDescription.illegal_parameter,
"Invalid dh_Yc value")
S = powMod(dh_Yc, self.dh_Xs, self.dh_p)
return numberToByteArray(S)
class ECDHE_RSAKeyExchange(KeyExchange):
def makeServerKeyExchange(self):
public, self.private = p256.generatePublicPrivate()
version = self.serverHello.server_version
serverKeyExchange = ServerKeyExchange(self.cipherSuite, version)
serverKeyExchange.createECDH(NamedCurve.secp256r1, bytearray(public))
hashBytes = serverKeyExchange.hash(self.clientHello.random,
self.serverHello.random)
if version >= (3,3):
# TODO: Signature algorithm negotiation not supported.
hashBytes = RSAKey.addPKCS1SHA1Prefix(hashBytes)
serverKeyExchange.signature = self.privateKey.sign(hashBytes)
return serverKeyExchange
def processClientKeyExchange(self, clientKeyExchange):
ecdh_Yc = clientKeyExchange.ecdh_Yc
return bytearray(p256.generateSharedValue(bytes(ecdh_Yc), self.private))
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}).
"""
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)
#*********************************************************
# Client Handshake Functions
#*********************************************************
def handshakeClientAnonymous(self, session=None, settings=None,
checker=None, serverName="",
async=False):
"""Perform an anonymous handshake in the role of client.
This function performs an SSL or TLS handshake using an
anonymous Diffie Hellman ciphersuite.
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 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 serverName: string
@param serverName: The ServerNameIndication TLS Extension.
@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(anonParams=(True),
session=session,
settings=settings,
checker=checker,
serverName=serverName)
if async:
return handshaker
for result in handshaker:
pass
def handshakeClientSRP(self, username, password, session=None,
settings=None, checker=None,
reqTack=True, serverName="",
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.
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 reqTack: bool
@param reqTack: Whether or not to send a "tack" TLS Extension,
requesting the server return a TackExtension if it has one.
@type serverName: string
@param serverName: The ServerNameIndication TLS Extension.
@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,
reqTack=reqTack, serverName=serverName)
# The handshaker is a Python Generator which executes the handshake.
# It allows the handshake to be run in a "piecewise", asynchronous
# fashion, returning 1 when it is waiting to able to write, 0 when
# it is waiting to read.
#
# If 'async' is True, the generator is returned to the caller,
# otherwise it is executed to completion here.
if async:
return handshaker
for result in handshaker:
pass
def handshakeClientCert(self, certChain=None, privateKey=None,
session=None, settings=None, checker=None,
nextProtos=None, reqTack=True, serverName="",
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 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.
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}
@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 nextProtos: list of strings.
@param nextProtos: A list of upper layer protocols ordered by
preference, to use in the Next-Protocol Negotiation Extension.
@type reqTack: bool
@param reqTack: Whether or not to send a "tack" TLS Extension,
requesting the server return a TackExtension if it has one.
@type serverName: string
@param serverName: The ServerNameIndication TLS Extension.
@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, serverName=serverName,
nextProtos=nextProtos, reqTack=reqTack)
# The handshaker is a Python Generator which executes the handshake.
# It allows the handshake to be run in a "piecewise", asynchronous
# fashion, returning 1 when it is waiting to able to write, 0 when
# it is waiting to read.
#
# If 'async' is True, the generator is returned to the caller,
# otherwise it is executed to completion here.
if async:
return handshaker
for result in handshaker:
pass
def _handshakeClientAsync(self, srpParams=(), certParams=(), anonParams=(),
session=None, settings=None, checker=None,
nextProtos=None, serverName="", reqTack=True):
handshaker = self._handshakeClientAsyncHelper(srpParams=srpParams,
certParams=certParams,
anonParams=anonParams,
session=session,
settings=settings,
serverName=serverName,
nextProtos=nextProtos,
reqTack=reqTack)
for result in self._handshakeWrapperAsync(handshaker, checker):
yield result
def _handshakeClientAsyncHelper(self, srpParams, certParams, anonParams,
session, settings, serverName, nextProtos, reqTack):
self._handshakeStart(client=True)
#Unpack parameters
srpUsername = None # srpParams[0]
password = None # srpParams[1]
clientCertChain = None # certParams[0]
privateKey = None # certParams[1]
# Allow only one of (srpParams, certParams, anonParams)
if srpParams:
assert(not certParams)
assert(not anonParams)
srpUsername, password = srpParams
if certParams:
assert(not srpParams)
assert(not anonParams)
clientCertChain, privateKey = certParams
if anonParams:
assert(not srpParams)
assert(not certParams)
#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 reqTack:
if not tackpyLoaded:
reqTack = False
if not settings or not settings.useExperimentalTackExtension:
reqTack = False
if nextProtos is not None:
if len(nextProtos) == 0:
raise ValueError("Caller passed no nextProtos")
# Validates the settings and filters out any unsupported ciphers
# or crypto libraries that were requested
if not settings:
settings = HandshakeSettings()
settings = settings._filter()
if clientCertChain:
if not isinstance(clientCertChain, X509CertChain):
raise ValueError("Unrecognized certificate type")
if "x509" not in settings.certificateTypes:
raise ValueError("Client certificate doesn't match "\
"Handshake Settings")
if session:
# session.valid() ensures session is resumable and has
# non-empty sessionID
if not session.valid():
session = None #ignore non-resumable sessions...
elif session.resumable:
if session.srpUsername != srpUsername:
raise ValueError("Session username doesn't match")
if session.serverName != serverName:
raise ValueError("Session servername 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"
#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
# OK Start sending messages!
# *****************************
# Send the ClientHello.
for result in self._clientSendClientHello(settings, session,
srpUsername, srpParams, certParams,
anonParams, serverName, nextProtos,
reqTack):
if result in (0,1): yield result
else: break
clientHello = result
#Get the ServerHello.
for result in self._clientGetServerHello(settings, clientHello):
if result in (0,1): yield result
else: break
serverHello = result
cipherSuite = serverHello.cipher_suite
# Choose a matching Next Protocol from server list against ours
# (string or None)
nextProto = self._clientSelectNextProto(nextProtos, serverHello)
#If the server elected to resume the session, it is handled here.
for result in self._clientResume(session, serverHello,
clientHello.random,
settings.cipherImplementations,
nextProto):
if result in (0,1): yield result
else: break
if result == "resumed_and_finished":
self._handshakeDone(resumed=True)
return
#If the server selected an SRP ciphersuite, the client finishes
#reading the post-ServerHello messages, then derives a
#premasterSecret and sends a corresponding ClientKeyExchange.
if cipherSuite in CipherSuite.srpAllSuites:
for result in self._clientSRPKeyExchange(\
settings, cipherSuite, serverHello.certificate_type,
srpUsername, password,
clientHello.random, serverHello.random,
serverHello.tackExt):
if result in (0,1): yield result
else: break
(premasterSecret, serverCertChain, tackExt) = result
#If the server selected an anonymous ciphersuite, the client
#finishes reading the post-ServerHello messages.
elif cipherSuite in CipherSuite.anonSuites:
for result in self._clientAnonKeyExchange(settings, cipherSuite,
clientHello.random, serverHello.random):
if result in (0,1): yield result
else: break
(premasterSecret, serverCertChain, tackExt) = result
#If the server selected a certificate-based RSA ciphersuite,
#the client finishes reading the post-ServerHello messages. If
#a CertificateRequest message was sent, the client responds with
#a Certificate message containing its certificate chain (if any),
#and also produces a CertificateVerify message that signs the
#ClientKeyExchange.
else:
for result in self._clientRSAKeyExchange(settings, cipherSuite,
clientCertChain, privateKey,
serverHello.certificate_type,
clientHello.random, serverHello.random,
serverHello.tackExt):
if result in (0,1): yield result
else: break
(premasterSecret, serverCertChain, clientCertChain,
tackExt) = result
#After having previously sent a ClientKeyExchange, the client now
#initiates an exchange of Finished messages.
for result in self._clientFinished(premasterSecret,
clientHello.random,
serverHello.random,
cipherSuite, settings.cipherImplementations,
nextProto):
if result in (0,1): yield result
else: break
masterSecret = result
# Create the session object which is used for resumptions
self.session = Session()
self.session.create(masterSecret, serverHello.session_id, cipherSuite,
srpUsername, clientCertChain, serverCertChain,
tackExt, serverHello.tackExt!=None, serverName)
self._handshakeDone(resumed=False)
def _clientSendClientHello(self, settings, session, srpUsername,
srpParams, certParams, anonParams,
serverName, nextProtos, reqTack):
#Initialize acceptable ciphersuites
cipherSuites = [CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
if srpParams:
cipherSuites += CipherSuite.getSrpAllSuites(settings)
elif certParams:
# TODO: Client DHE_RSA not supported.
# cipherSuites += CipherSuite.getDheCertSuites(settings)
cipherSuites += CipherSuite.getCertSuites(settings)
elif anonParams:
cipherSuites += CipherSuite.getAnonSuites(settings)
else:
assert(False)
#Initialize acceptable certificate types
certificateTypes = settings._getCertificateTypes()
#Either send ClientHello (with a resumable session)...
if session and session.sessionID:
#If it's resumable, then its
#ciphersuite must be one of the acceptable ciphersuites
if session.cipherSuite not in cipherSuites:
raise ValueError("Session's cipher suite not consistent "\
"with parameters")
else:
clientHello = ClientHello()
clientHello.create(settings.maxVersion, getRandomBytes(32),
session.sessionID, cipherSuites,
certificateTypes,
session.srpUsername,
reqTack, nextProtos is not None,
session.serverName)
#Or send ClientHello (without)
else:
clientHello = ClientHello()
clientHello.create(settings.maxVersion, getRandomBytes(32),
bytearray(0), cipherSuites,
certificateTypes,
srpUsername,
reqTack, nextProtos is not None,
serverName)
for result in self._sendMsg(clientHello):
yield result
yield clientHello
def _clientGetServerHello(self, settings, clientHello):
for result in self._getMsg(ContentType.handshake,
HandshakeType.server_hello):
if result in (0,1): yield result
else: break
serverHello = result
#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 clientHello.cipher_suites:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server responded with incorrect ciphersuite"):
yield result
if serverHello.certificate_type not in clientHello.certificate_types:
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
if serverHello.tackExt:
if not clientHello.tack:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server responded with unrequested Tack Extension"):
yield result
if serverHello.next_protos and not clientHello.supports_npn:
for result in self._sendError(\
AlertDescription.illegal_parameter,
"Server responded with unrequested NPN Extension"):
yield result
if not serverHello.tackExt.verifySignatures():
for result in self._sendError(\
AlertDescription.decrypt_error,
"TackExtension contains an invalid signature"):
yield result
yield serverHello
def _clientSelectNextProto(self, nextProtos, serverHello):
# nextProtos is None or non-empty list of strings
# serverHello.next_protos is None or possibly-empty list of strings
#
# !!! We assume the client may have specified nextProtos as a list of
# strings so we convert them to bytearrays (it's awkward to require
# the user to specify a list of bytearrays or "bytes", and in
# Python 2.6 bytes() is just an alias for str() anyways...
if nextProtos is not None and serverHello.next_protos is not None:
for p in nextProtos:
if bytearray(p) in serverHello.next_protos:
return bytearray(p)
else:
# If the client doesn't support any of server's protocols,
# or the server doesn't advertise any (next_protos == [])
# the client SHOULD select the first protocol it supports.
return bytearray(nextProtos[0])
return None
def _clientResume(self, session, serverHello, clientRandom,
cipherImplementations, nextProto):
#If the server agrees to resume
if session and session.sessionID and \
serverHello.session_id == session.sessionID:
if serverHello.cipher_suite != session.cipherSuite:
for result in self._sendError(\
AlertDescription.illegal_parameter,\
"Server's ciphersuite doesn't match session"):
yield result
#Calculate pending connection states
self._calcPendingStates(session.cipherSuite,
session.masterSecret,
clientRandom, serverHello.random,
cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._getFinished(session.masterSecret):
yield result
for result in self._sendFinished(session.masterSecret, nextProto):
yield result
#Set the session for this connection
self.session = session
yield "resumed_and_finished"
def _clientSRPKeyExchange(self, settings, cipherSuite, certificateType,
srpUsername, password,
clientRandom, serverRandom, tackExt):
#If the server chose an SRP+RSA suite...
if cipherSuite in CipherSuite.srpCertSuites:
#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
else:
serverCertificate = None
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
#Calculate SRP premaster secret
#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.insufficient_security,
"Unknown group parameters"):
yield result
if numBits(N) < settings.minKeySize:
for result in self._sendError(\
AlertDescription.insufficient_security,
"N value is too small: %d" % numBits(N)):
yield result
if numBits(N) > settings.maxKeySize:
for result in self._sendError(\
AlertDescription.insufficient_security,
"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
serverCertChain = None
if cipherSuite in CipherSuite.srpCertSuites:
#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
# Also validate the chain against the ServerHello's TACKext (if any)
# If none, and a TACK cert is present, return its TACKext
for result in self._clientGetKeyFromChain(serverCertificate,
settings, tackExt):
if result in (0,1): yield result
else: break
publicKey, serverCertChain, tackExt = 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(s, bytearray(srpUsername, "utf-8"),
bytearray(password, "utf-8"))
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 = numberToByteArray(S)
#Send ClientKeyExchange
for result in self._sendMsg(\
ClientKeyExchange(cipherSuite).createSRP(A)):
yield result
yield (premasterSecret, serverCertChain, tackExt)
def _clientRSAKeyExchange(self, settings, cipherSuite,
clientCertChain, privateKey,
certificateType,
clientRandom, serverRandom,
tackExt):
#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
# Get CertificateRequest or ServerHelloDone
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
# We got CertificateRequest, so this must be ServerHelloDone
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
# Get server's public key from the Certificate message
# Also validate the chain against the ServerHello's TACKext (if any)
# If none, and a TACK cert is present, return its TACKext
for result in self._clientGetKeyFromChain(serverCertificate,
settings, tackExt):
if result in (0,1): yield result
else: break
publicKey, serverCertChain, tackExt = 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
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:
signatureAlgorithm = None
if self.version == (3,0):
masterSecret = calcMasterSecret(self.version,
premasterSecret,
clientRandom,
serverRandom)
verifyBytes = self._calcSSLHandshakeHash(masterSecret, b"")
elif self.version in ((3,1), (3,2)):
verifyBytes = self._handshake_md5.digest() + \
self._handshake_sha.digest()
elif self.version == (3,3):
# TODO: Signature algorithm negotiation not supported.
signatureAlgorithm = (HashAlgorithm.sha1, SignatureAlgorithm.rsa)
verifyBytes = self._handshake_sha.digest()
verifyBytes = RSAKey.addPKCS1SHA1Prefix(verifyBytes)
if self.fault == Fault.badVerifyMessage:
verifyBytes[0] = ((verifyBytes[0]+1) % 256)
signedBytes = privateKey.sign(verifyBytes)
certificateVerify = CertificateVerify(self.version)
certificateVerify.create(signatureAlgorithm, signedBytes)
for result in self._sendMsg(certificateVerify):
yield result
yield (premasterSecret, serverCertChain, clientCertChain, tackExt)
def _clientAnonKeyExchange(self, settings, cipherSuite, clientRandom,
serverRandom):
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
#calculate Yc
dh_p = serverKeyExchange.dh_p
dh_g = serverKeyExchange.dh_g
dh_Xc = bytesToNumber(getRandomBytes(32))
dh_Ys = serverKeyExchange.dh_Ys
dh_Yc = powMod(dh_g, dh_Xc, dh_p)
#Send ClientKeyExchange
for result in self._sendMsg(\
ClientKeyExchange(cipherSuite, self.version).createDH(dh_Yc)):
yield result
#Calculate premaster secret
S = powMod(dh_Ys, dh_Xc, dh_p)
premasterSecret = numberToByteArray(S)
yield (premasterSecret, None, None)
def _clientFinished(self, premasterSecret, clientRandom, serverRandom,
cipherSuite, cipherImplementations, nextProto):
masterSecret = calcMasterSecret(self.version, premasterSecret,
clientRandom, serverRandom)
self._calcPendingStates(cipherSuite, masterSecret,
clientRandom, serverRandom,
cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._sendFinished(masterSecret, nextProto):
yield result
for result in self._getFinished(masterSecret, nextProto=nextProto):
yield result
yield masterSecret
def _clientGetKeyFromChain(self, certificate, settings, tackExt=None):
#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
# If there's no TLS Extension, look for a TACK cert
if tackpyLoaded:
if not tackExt:
tackExt = certChain.getTackExt()
# If there's a TACK (whether via TLS or TACK Cert), check that it
# matches the cert chain
if tackExt and tackExt.tacks:
for tack in tackExt.tacks:
if not certChain.checkTack(tack):
for result in self._sendError(
AlertDescription.illegal_parameter,
"Other party's TACK doesn't match their public key"):
yield result
yield publicKey, certChain, tackExt
#*********************************************************
# Server Handshake Functions
#*********************************************************
def handshakeServer(self, verifierDB=None,
certChain=None, privateKey=None, reqCert=False,
sessionCache=None, settings=None, checker=None,
reqCAs = None, reqCertTypes = None,
tacks=None, activationFlags=0,
nextProtos=None, anon=False,
signedCertTimestamps=None,
fallbackSCSV=False, ocspResponse=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 an 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 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}
@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
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.
@type reqCAs: list of L{bytearray} of unsigned bytes
@param reqCAs: A collection of DER-encoded DistinguishedNames that
will be sent along with a certificate request. This does not affect
verification.
@type reqCertTypes: list of int
@param reqCertTypes: A list of certificate_type values to be sent
along with a certificate request. This does not affect verification.
@type nextProtos: list of strings.
@param nextProtos: A list of upper layer protocols to expose to the
clients through the Next-Protocol Negotiation Extension,
if they support it.
@type signedCertTimestamps: str
@param signedCertTimestamps: A SignedCertificateTimestampList (as a
binary 8-bit string) that will be sent as a TLS extension whenever
the client announces support for the extension.
@type fallbackSCSV: bool
@param fallbackSCSV: if true, the server will implement
TLS_FALLBACK_SCSV and thus reject connections using less than the
server's maximum TLS version that include this cipher suite.
@type ocspResponse: str
@param ocspResponse: An OCSP response (as a binary 8-bit string) that
will be sent stapled in the handshake whenever the client announces
support for the status_request extension.
Note that the response is sent independent of the ClientHello
status_request extension contents, and is thus only meant for testing
environments. Real OCSP stapling is more complicated as it requires
choosing a suitable response based on the ClientHello status_request
extension contents.
@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(verifierDB,
certChain, privateKey, reqCert, sessionCache, settings,
checker, reqCAs, reqCertTypes,
tacks=tacks, activationFlags=activationFlags,
nextProtos=nextProtos, anon=anon,
signedCertTimestamps=signedCertTimestamps,
fallbackSCSV=fallbackSCSV, ocspResponse=ocspResponse):
pass
def handshakeServerAsync(self, verifierDB=None,
certChain=None, privateKey=None, reqCert=False,
sessionCache=None, settings=None, checker=None,
reqCAs=None, reqCertTypes=None,
tacks=None, activationFlags=0,
nextProtos=None, anon=False,
signedCertTimestamps=None,
fallbackSCSV=False,
ocspResponse=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(\
verifierDB=verifierDB, certChain=certChain,
privateKey=privateKey, reqCert=reqCert,
sessionCache=sessionCache, settings=settings,
reqCAs=reqCAs, reqCertTypes=reqCertTypes,
tacks=tacks, activationFlags=activationFlags,
nextProtos=nextProtos, anon=anon,
signedCertTimestamps=signedCertTimestamps,
fallbackSCSV=fallbackSCSV,
ocspResponse=ocspResponse)
for result in self._handshakeWrapperAsync(handshaker, checker):
yield result
if settings and settings.alertAfterHandshake:
for result in self._sendError(AlertDescription.internal_error,
"Spurious alert"):
yield result
def _handshakeServerAsyncHelper(self, verifierDB,
certChain, privateKey, reqCert, sessionCache,
settings, reqCAs, reqCertTypes,
tacks, activationFlags,
nextProtos, anon,
signedCertTimestamps, fallbackSCSV,
ocspResponse):
self._handshakeStart(client=False)
if (not verifierDB) and (not certChain) and not anon:
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 reqCAs and not reqCert:
raise ValueError("Caller passed reqCAs but not reqCert")
if reqCertTypes and not reqCert:
raise ValueError("Caller passed reqCertTypes but not reqCert")
if certChain and not isinstance(certChain, X509CertChain):
raise ValueError("Unrecognized certificate type")
if activationFlags and not tacks:
raise ValueError("Nonzero activationFlags requires tacks")
if tacks:
if not tackpyLoaded:
raise ValueError("tackpy is not loaded")
if not settings or not settings.useExperimentalTackExtension:
raise ValueError("useExperimentalTackExtension not enabled")
if signedCertTimestamps and not certChain:
raise ValueError("Caller passed signedCertTimestamps but no "
"certChain")
if not settings:
settings = HandshakeSettings()
settings = settings._filter()
# OK Start exchanging messages
# ******************************
# Handle ClientHello and resumption
for result in self._serverGetClientHello(settings, certChain,\
verifierDB, sessionCache,
anon, fallbackSCSV):
if result in (0,1): yield result
elif result == None:
self._handshakeDone(resumed=True)
return # Handshake was resumed, we're done
else: break
(clientHello, cipherSuite) = result
# Save the ClientHello for external code to query.
self.clientHello = clientHello
#If not a resumption...
# Create the ServerHello message
if sessionCache:
sessionID = getRandomBytes(32)
else:
sessionID = bytearray(0)
if not clientHello.supports_npn:
nextProtos = None
# If not doing a certificate-based suite, discard the TACK
if not cipherSuite in CipherSuite.certAllSuites:
tacks = None
# Prepare a TACK Extension if requested
if clientHello.tack:
tackExt = TackExtension.create(tacks, activationFlags)
else:
tackExt = None
serverHello = ServerHello()
serverHello.create(self.version, getRandomBytes(32), sessionID, \
cipherSuite, CertificateType.x509, tackExt,
nextProtos)
serverHello.channel_id = clientHello.channel_id
if clientHello.support_signed_cert_timestamps:
serverHello.signed_cert_timestamps = signedCertTimestamps
if clientHello.status_request:
serverHello.status_request = ocspResponse
# Perform the SRP key exchange
clientCertChain = None
if cipherSuite in CipherSuite.srpAllSuites:
for result in self._serverSRPKeyExchange(clientHello, serverHello,
verifierDB, cipherSuite,
privateKey, certChain):
if result in (0,1): yield result
else: break
premasterSecret = result
# Perform a certificate-based key exchange
elif cipherSuite in CipherSuite.certAllSuites:
if cipherSuite in CipherSuite.certSuites:
keyExchange = RSAKeyExchange(cipherSuite,
clientHello,
serverHello,
privateKey)
elif cipherSuite in CipherSuite.dheCertSuites:
keyExchange = DHE_RSAKeyExchange(cipherSuite,
clientHello,
serverHello,
privateKey)
elif cipherSuite in CipherSuite.ecdheCertSuites:
keyExchange = ECDHE_RSAKeyExchange(cipherSuite,
clientHello,
serverHello,
privateKey)
else:
assert(False)
for result in self._serverCertKeyExchange(clientHello, serverHello,
certChain, keyExchange,
reqCert, reqCAs, reqCertTypes, cipherSuite,
settings, ocspResponse):
if result in (0,1): yield result
else: break
(premasterSecret, clientCertChain) = result
# Perform anonymous Diffie Hellman key exchange
elif cipherSuite in CipherSuite.anonSuites:
for result in self._serverAnonKeyExchange(clientHello, serverHello,
cipherSuite, settings):
if result in (0,1): yield result
else: break
premasterSecret = result
else:
assert(False)
# Exchange Finished messages
for result in self._serverFinished(premasterSecret,
clientHello.random, serverHello.random,
cipherSuite, settings.cipherImplementations,
nextProtos, clientHello.channel_id):
if result in (0,1): yield result
else: break
masterSecret = result
#Create the session object
self.session = Session()
if cipherSuite in CipherSuite.certAllSuites:
serverCertChain = certChain
else:
serverCertChain = None
srpUsername = None
serverName = None
if clientHello.srp_username:
srpUsername = clientHello.srp_username.decode("utf-8")
if clientHello.server_name:
serverName = clientHello.server_name.decode("utf-8")
self.session.create(masterSecret, serverHello.session_id, cipherSuite,
srpUsername, clientCertChain, serverCertChain,
tackExt, serverHello.tackExt!=None, serverName)
#Add the session object to the session cache
if sessionCache and sessionID:
sessionCache[sessionID] = self.session
self._handshakeDone(resumed=False)
def _serverGetClientHello(self, settings, certChain, verifierDB,
sessionCache, anon, fallbackSCSV):
#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 simulating TLS intolerance, reject certain TLS versions.
elif (settings.tlsIntolerant is not None and
clientHello.client_version >= settings.tlsIntolerant):
if settings.tlsIntoleranceType == "alert":
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
elif settings.tlsIntoleranceType == "close":
self._abruptClose()
raise TLSUnsupportedError("Simulating version intolerance")
elif settings.tlsIntoleranceType == "reset":
self._abruptClose(reset=True)
raise TLSUnsupportedError("Simulating version intolerance")
else:
raise ValueError("Unknown intolerance type: '%s'" %
settings.tlsIntoleranceType)
#If client's version is too high, propose my highest version
elif clientHello.client_version > settings.maxVersion:
self.version = settings.maxVersion
#Detect if the client performed an inappropriate fallback.
elif fallbackSCSV and clientHello.client_version < settings.maxVersion:
self.version = clientHello.client_version
if CipherSuite.TLS_FALLBACK_SCSV in clientHello.cipher_suites:
for result in self._sendError(\
AlertDescription.inappropriate_fallback):
yield result
else:
#Set the version to the client's version
self.version = clientHello.client_version
#Initialize acceptable cipher suites
cipherSuites = []
if verifierDB:
if certChain:
cipherSuites += \
CipherSuite.getSrpCertSuites(settings, self.version)
cipherSuites += CipherSuite.getSrpSuites(settings, self.version)
elif certChain:
cipherSuites += CipherSuite.getEcdheCertSuites(settings, self.version)
cipherSuites += CipherSuite.getDheCertSuites(settings, self.version)
cipherSuites += CipherSuite.getCertSuites(settings, self.version)
elif anon:
cipherSuites += CipherSuite.getAnonSuites(settings, self.version)
else:
assert(False)
#If resumption was requested and we have a session cache...
if clientHello.session_id and sessionCache:
session = None
#Check in the session cache
if sessionCache and not session:
try:
session = sessionCache[clientHello.session_id]
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 not session.srpUsername or \
clientHello.srp_username != bytearray(session.srpUsername, "utf-8"):
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
if clientHello.server_name:
if not session.serverName or \
clientHello.server_name != bytearray(session.serverName, "utf-8"):
for result in self._sendError(\
AlertDescription.handshake_failure):
yield result
except KeyError:
pass
#If a session is found..
if session:
#Send ServerHello
serverHello = ServerHello()
serverHello.create(self.version, getRandomBytes(32),
session.sessionID, session.cipherSuite,
CertificateType.x509, None, None)
for result in self._sendMsg(serverHello):
yield result
#From here on, the client's messages must have right version
self._versionCheck = True
#Calculate pending connection states
self._calcPendingStates(session.cipherSuite,
session.masterSecret,
clientHello.random,
serverHello.random,
settings.cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._sendFinished(session.masterSecret):
yield result
for result in self._getFinished(session.masterSecret):
yield result
#Set the session
self.session = session
yield None # Handshake done!
#Calculate the first cipher suite intersection.
#This is the 'privileged' ciphersuite. We'll use it if we're
#doing a new negotiation. In fact,
#the only time we won't use it is if we're resuming a
#session, in which case we use the ciphersuite from the session.
#
#Given the current ciphersuite ordering, this means we prefer SRP
#over non-SRP.
for cipherSuite in cipherSuites:
if cipherSuite in clientHello.cipher_suites:
break
else:
for result in self._sendError(\
AlertDescription.handshake_failure,
"No mutual ciphersuite"):
yield result
if cipherSuite in CipherSuite.srpAllSuites and \
not clientHello.srp_username:
for result in self._sendError(\
AlertDescription.unknown_psk_identity,
"Client sent a hello, but without the SRP username"):
yield result
#If an RSA suite is chosen, check for certificate type intersection
if cipherSuite in CipherSuite.certAllSuites and CertificateType.x509 \
not in clientHello.certificate_types:
for result in self._sendError(\
AlertDescription.handshake_failure,
"the client doesn't support my certificate type"):
yield result
# If resumption was not requested, or
# we have no session cache, or
# the client's session_id was not found in cache:
yield (clientHello, cipherSuite)
def _serverSRPKeyExchange(self, clientHello, serverHello, verifierDB,
cipherSuite, privateKey, serverCertChain):
srpUsername = clientHello.srp_username.decode("utf-8")
self.allegedSrpUsername = srpUsername
#Get parameters from username
try:
entry = verifierDB[srpUsername]
except KeyError:
for result in self._sendError(\
AlertDescription.unknown_psk_identity):
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, self.version)
serverKeyExchange.createSRP(N, g, s, B)
if cipherSuite in CipherSuite.srpCertSuites:
hashBytes = serverKeyExchange.hash(clientHello.random,
serverHello.random)
serverKeyExchange.signature = privateKey.sign(hashBytes)
#Send ServerHello[, Certificate], ServerKeyExchange,
#ServerHelloDone
msgs = []
msgs.append(serverHello)
if cipherSuite in CipherSuite.srpCertSuites:
certificateMsg = Certificate(CertificateType.x509)
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:
for result in self._sendError(AlertDescription.illegal_parameter,
"Suspicious A value"):
yield result
assert(False) # Just to ensure we don't fall through somehow
#Calculate u
u = makeU(N, A, B)
#Calculate premaster secret
S = powMod((A * powMod(v,u,N)) % N, b, N)
premasterSecret = numberToByteArray(S)
yield premasterSecret
def _serverCertKeyExchange(self, clientHello, serverHello,
serverCertChain, keyExchange,
reqCert, reqCAs, reqCertTypes, cipherSuite,
settings, ocspResponse):
#Send ServerHello, Certificate[, ServerKeyExchange]
#[, CertificateRequest], ServerHelloDone
msgs = []
# If we verify a client cert chain, return it
clientCertChain = None
msgs.append(serverHello)
msgs.append(Certificate(CertificateType.x509).create(serverCertChain))
if serverHello.status_request:
msgs.append(CertificateStatus().create(ocspResponse))
serverKeyExchange = keyExchange.makeServerKeyExchange()
if serverKeyExchange is not None:
msgs.append(serverKeyExchange)
if reqCert:
reqCAs = reqCAs or []
#Apple's Secure Transport library rejects empty certificate_types,
#so default to rsa_sign.
reqCertTypes = reqCertTypes or [ClientCertificateType.rsa_sign]
#Only SHA-1 + RSA is supported.
sigAlgs = [(HashAlgorithm.sha1, SignatureAlgorithm.rsa)]
msgs.append(CertificateRequest(self.version).create(reqCertTypes,
reqCAs,
sigAlgs))
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.x509):
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:
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), (3,3)):
for result in self._getMsg(ContentType.handshake,
HandshakeType.certificate,
CertificateType.x509):
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
#Process ClientKeyExchange
try:
premasterSecret = \
keyExchange.processClientKeyExchange(clientKeyExchange)
except TLSLocalAlert, alert:
for result in self._sendError(alert.description, alert.message):
yield result
#Get and check CertificateVerify, if relevant
if clientCertChain:
if self.version == (3,0):
masterSecret = calcMasterSecret(self.version, premasterSecret,
clientHello.random, serverHello.random)
verifyBytes = self._calcSSLHandshakeHash(masterSecret, b"")
elif self.version in ((3,1), (3,2)):
verifyBytes = self._handshake_md5.digest() + \
self._handshake_sha.digest()
elif self.version == (3,3):
verifyBytes = self._handshake_sha.digest()
verifyBytes = RSAKey.addPKCS1SHA1Prefix(verifyBytes)
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:
for result in self._sendError(\
AlertDescription.handshake_failure,
"Client's public key too small: %d" % len(publicKey)):
yield result
if len(publicKey) > settings.maxKeySize:
for result in self._sendError(\
AlertDescription.handshake_failure,
"Client's public key too large: %d" % len(publicKey)):
yield result
if not publicKey.verify(certificateVerify.signature, verifyBytes):
for result in self._sendError(\
AlertDescription.decrypt_error,
"Signature failed to verify"):
yield result
yield (premasterSecret, clientCertChain)
def _serverAnonKeyExchange(self, clientHello, serverHello, cipherSuite,
settings):
# Calculate DH p, g, Xs, Ys
dh_p = getRandomSafePrime(32, False)
dh_g = getRandomNumber(2, dh_p)
dh_Xs = bytesToNumber(getRandomBytes(32))
dh_Ys = powMod(dh_g, dh_Xs, dh_p)
#Create ServerKeyExchange
serverKeyExchange = ServerKeyExchange(cipherSuite, self.version)
serverKeyExchange.createDH(dh_p, dh_g, dh_Ys)
#Send ServerHello[, Certificate], ServerKeyExchange,
#ServerHelloDone
msgs = []
msgs.append(serverHello)
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
dh_Yc = clientKeyExchange.dh_Yc
if dh_Yc % dh_p == 0:
for result in self._sendError(AlertDescription.illegal_parameter,
"Suspicious dh_Yc value"):
yield result
assert(False) # Just to ensure we don't fall through somehow
#Calculate premaster secre
S = powMod(dh_Yc,dh_Xs,dh_p)
premasterSecret = numberToByteArray(S)
yield premasterSecret
def _serverFinished(self, premasterSecret, clientRandom, serverRandom,
cipherSuite, cipherImplementations, nextProtos,
doingChannelID):
masterSecret = calcMasterSecret(self.version, premasterSecret,
clientRandom, serverRandom)
#Calculate pending connection states
self._calcPendingStates(cipherSuite, masterSecret,
clientRandom, serverRandom,
cipherImplementations)
#Exchange ChangeCipherSpec and Finished messages
for result in self._getFinished(masterSecret,
expect_next_protocol=nextProtos is not None,
expect_channel_id=doingChannelID):
yield result
for result in self._sendFinished(masterSecret):
yield result
yield masterSecret
#*********************************************************
# Shared Handshake Functions
#*********************************************************
def _sendFinished(self, masterSecret, nextProto=None):
#Send ChangeCipherSpec
for result in self._sendMsg(ChangeCipherSpec()):
yield result
#Switch to pending write state
self._changeWriteState()
if nextProto is not None:
nextProtoMsg = NextProtocol().create(nextProto)
for result in self._sendMsg(nextProtoMsg):
yield result
#Calculate verification data
verifyData = self._calcFinished(masterSecret, 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, masterSecret, expect_next_protocol=False, nextProto=None,
expect_channel_id=False):
#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()
#Server Finish - Are we waiting for a next protocol echo?
if expect_next_protocol:
for result in self._getMsg(ContentType.handshake, HandshakeType.next_protocol):
if result in (0,1):
yield result
if result is None:
for result in self._sendError(AlertDescription.unexpected_message,
"Didn't get NextProtocol message"):
yield result
self.next_proto = result.next_proto
else:
self.next_proto = None
#Client Finish - Only set the next_protocol selected in the connection
if nextProto:
self.next_proto = nextProto
#Server Finish - Are we waiting for a EncryptedExtensions?
if expect_channel_id:
for result in self._getMsg(ContentType.handshake, HandshakeType.encrypted_extensions):
if result in (0,1):
yield result
if result is None:
for result in self._sendError(AlertDescription.unexpected_message,
"Didn't get EncryptedExtensions message"):
yield result
encrypted_extensions = result
self.channel_id = result.channel_id_key
else:
self.channel_id = None
#Calculate verification data
verifyData = self._calcFinished(masterSecret, 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, masterSecret, send=True):
if self.version == (3,0):
if (self._client and send) or (not self._client and not send):
senderStr = b"\x43\x4C\x4E\x54"
else:
senderStr = b"\x53\x52\x56\x52"
verifyData = self._calcSSLHandshakeHash(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 = b"client finished"
else:
label = b"server finished"
handshakeHashes = self._handshake_md5.digest() + \
self._handshake_sha.digest()
verifyData = PRF(masterSecret, label, handshakeHashes, 12)
return verifyData
elif self.version == (3,3):
if (self._client and send) or (not self._client and not send):
label = b"client finished"
else:
label = b"server finished"
handshakeHashes = self._handshake_sha256.digest()
verifyData = PRF_1_2(masterSecret, label, handshakeHashes, 12)
return verifyData
else:
raise AssertionError()
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 GeneratorExit:
raise
except TLSAlert as alert:
if not self.fault:
raise
if alert.description not in Fault.faultAlerts[self.fault]:
raise TLSFaultError(str(alert))
else:
pass
except:
self._shutdown(False)
raise