"""

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:

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.