Implement ALPN in tlslite.

third_party/tlslite/patches/alpn.patch

+diff --git a/third_party/tlslite/tlslite/constants.py b/third_party/tlslite/tlslite/constants.py
+index 715def9..e9743e4 100644
+--- a/third_party/tlslite/tlslite/constants.py
++++ b/third_party/tlslite/tlslite/constants.py
+@@ -54,6 +54,7 @@ class ExtensionType:    # RFC 6066 / 4366
+     status_request = 5  # RFC 6066 / 4366
+     srp = 12            # RFC 5054  
+     cert_type = 9       # RFC 6091
++    alpn = 16           # RFC 7301
+     signed_cert_timestamps = 18  # RFC 6962
+     extended_master_secret = 23  # RFC 7627
+     token_binding = 24           # draft-ietf-tokbind-negotiation
+diff --git a/third_party/tlslite/tlslite/messages.py b/third_party/tlslite/tlslite/messages.py
+index 5762ac6..3d684d4 100644
+--- a/third_party/tlslite/tlslite/messages.py
++++ b/third_party/tlslite/tlslite/messages.py
+@@ -99,6 +99,27 @@ class HandshakeMsg(object):
+         headerWriter.add(len(w.bytes), 3)
+         return headerWriter.bytes + w.bytes
+ 
++    def parse_next_protos(self, b):
++        protos = []
++        while True:
++            if len(b) == 0:
++                break
++            l = b[0]
++            b = b[1:]
++            if len(b) < l:
++                raise BadNextProtos(len(b))
++            protos.append(b[:l])
++            b = b[l:]
++        return protos
++
++    def next_protos_encoded(self, protocol_list):
++        b = bytearray()
++        for e in protocol_list:
++            if len(e) > 255 or len(e) == 0:
++                raise BadNextProtos(len(e))
++            b += bytearray( [len(e)] ) + bytearray(e)
++        return b
++
+ class ClientHello(HandshakeMsg):
+     def __init__(self, ssl2=False):
+         HandshakeMsg.__init__(self, HandshakeType.client_hello)
+@@ -111,6 +132,7 @@ class ClientHello(HandshakeMsg):
+         self.compression_methods = []   # a list of 8-bit values
+         self.srp_username = None        # a string
+         self.tack = False
++        self.alpn_protos_advertised = None
+         self.supports_npn = False
+         self.server_name = bytearray(0)
+         self.channel_id = False
+@@ -120,8 +142,8 @@ class ClientHello(HandshakeMsg):
+         self.status_request = False
+ 
+     def create(self, version, random, session_id, cipher_suites,
+-               certificate_types=None, srpUsername=None,
+-               tack=False, supports_npn=False, serverName=None):
++               certificate_types=None, srpUsername=None, tack=False,
++               alpn_protos_advertised=None, supports_npn=False, serverName=None):
+         self.client_version = version
+         self.random = random
+         self.session_id = session_id
+@@ -131,6 +153,7 @@ class ClientHello(HandshakeMsg):
+         if srpUsername:
+             self.srp_username = bytearray(srpUsername, "utf-8")
+         self.tack = tack
++        self.alpn_protos_advertised = alpn_protos_advertised
+         self.supports_npn = supports_npn
+         if serverName:
+             self.server_name = bytearray(serverName, "utf-8")
+@@ -171,6 +194,11 @@ class ClientHello(HandshakeMsg):
+                         self.certificate_types = p.getVarList(1, 1)
+                     elif extType == ExtensionType.tack:
+                         self.tack = True
++                    elif extType == ExtensionType.alpn:
++                        structLength = p.get(2)
++                        if (structLength + 2 != extLength):
++                            raise SyntaxError()
++                        self.alpn_protos_advertised = self.parse_next_protos(p.getFixBytes(structLength))
+                     elif extType == ExtensionType.supports_npn:
+                         self.supports_npn = True
+                     elif extType == ExtensionType.server_name:
+@@ -243,6 +271,12 @@ class ClientHello(HandshakeMsg):
+             w2.add(ExtensionType.srp, 2)
+             w2.add(len(self.srp_username)+1, 2)
+             w2.addVarSeq(self.srp_username, 1, 1)
++        if self.alpn_protos_advertised is not None:
++            encoded_alpn_protos_advertised = self.next_protos_encoded(self.alpn_protos_advertised)
++            w2.add(ExtensionType.alpn, 2)
++            w2.add(len(encoded_alpn_protos_advertised) + 2, 2)
++            w2.add(len(encoded_alpn_protos_advertised), 2)
++            w2.addFixSeq(encoded_alpn_protos_advertised, 1)
+         if self.supports_npn:
+             w2.add(ExtensionType.supports_npn, 2)
+             w2.add(0, 2)
+@@ -267,6 +301,13 @@ class BadNextProtos(Exception):
+     def __str__(self):
+         return 'Cannot encode a list of next protocols because it contains an element with invalid length %d. Element lengths must be 0 < x < 256' % self.length
+ 
++class InvalidAlpnResponse(Exception):
++    def __init__(self, l):
++        self.length = l
++
++    def __str__(self):
++        return 'ALPN server response protocol list has invalid length %d.  It must be of length one.' % self.length
++
+ class ServerHello(HandshakeMsg):
+     def __init__(self):
+         HandshakeMsg.__init__(self, HandshakeType.server_hello)
+@@ -277,6 +318,7 @@ class ServerHello(HandshakeMsg):
+         self.certificate_type = CertificateType.x509
+         self.compression_method = 0
+         self.tackExt = None
++        self.alpn_proto_selected = None
+         self.next_protos_advertised = None
+         self.next_protos = None
+         self.channel_id = False
+@@ -286,7 +328,8 @@ class ServerHello(HandshakeMsg):
+         self.status_request = False
+ 
+     def create(self, version, random, session_id, cipher_suite,
+-               certificate_type, tackExt, next_protos_advertised):
++               certificate_type, tackExt, alpn_proto_selected,
++               next_protos_advertised):
+         self.server_version = version
+         self.random = random
+         self.session_id = session_id
+@@ -294,6 +337,7 @@ class ServerHello(HandshakeMsg):
+         self.certificate_type = certificate_type
+         self.compression_method = 0
+         self.tackExt = tackExt
++        self.alpn_proto_selected = alpn_proto_selected
+         self.next_protos_advertised = next_protos_advertised
+         return self
+ 
+@@ -316,35 +360,22 @@ class ServerHello(HandshakeMsg):
+                     self.certificate_type = p.get(1)
+                 elif extType == ExtensionType.tack and tackpyLoaded:
+                     self.tackExt = TackExtension(p.getFixBytes(extLength))
++                elif extType == ExtensionType.alpn:
++                    structLength = p.get(2)
++                    if (structLength + 2 != extLength):
++                        raise SyntaxError()
++                    alpn_protos = self.parse_next_protos(p.getFixBytes(structLength))
++                    if (alpn_protos.len() != 1):
++                        raise InvalidAlpnResponse(alpn_protos.len());
++                    self.alpn_proto_selected = alpn_protos[0]
+                 elif extType == ExtensionType.supports_npn:
+-                    self.next_protos = self.__parse_next_protos(p.getFixBytes(extLength))
++                    self.next_protos = self.parse_next_protos(p.getFixBytes(extLength))
+                 else:
+                     p.getFixBytes(extLength)
+                 soFar += 4 + extLength
+         p.stopLengthCheck()
+         return self
+ 
+-    def __parse_next_protos(self, b):
+-        protos = []
+-        while True:
+-            if len(b) == 0:
+-                break
+-            l = b[0]
+-            b = b[1:]
+-            if len(b) < l:
+-                raise BadNextProtos(len(b))
+-            protos.append(b[:l])
+-            b = b[l:]
+-        return protos
+-
+-    def __next_protos_encoded(self):
+-        b = bytearray()
+-        for e in self.next_protos_advertised:
+-            if len(e) > 255 or len(e) == 0:
+-                raise BadNextProtos(len(e))
+-            b += bytearray( [len(e)] ) + bytearray(e)
+-        return b
+-
+     def write(self):
+         w = Writer()
+         w.add(self.server_version[0], 1)
+@@ -365,8 +396,16 @@ class ServerHello(HandshakeMsg):
+             w2.add(ExtensionType.tack, 2)
+             w2.add(len(b), 2)
+             w2.bytes += b
+-        if self.next_protos_advertised is not None:
+-            encoded_next_protos_advertised = self.__next_protos_encoded()
++        if self.alpn_proto_selected is not None:
++            alpn_protos_single_element_list = [self.alpn_proto_selected]
++            encoded_alpn_protos_advertised = self.next_protos_encoded(alpn_protos_single_element_list)
++            w2.add(ExtensionType.alpn, 2)
++            w2.add(len(encoded_alpn_protos_advertised) + 2, 2)
++            w2.add(len(encoded_alpn_protos_advertised), 2)
++            w2.addFixSeq(encoded_alpn_protos_advertised, 1)
++        # Do not use NPN if ALPN is used.
++        elif self.next_protos_advertised is not None:
++            encoded_next_protos_advertised = self.next_protos_encoded(self.next_protos_advertised)
+             w2.add(ExtensionType.supports_npn, 2)
+             w2.add(len(encoded_next_protos_advertised), 2)
+             w2.addFixSeq(encoded_next_protos_advertised, 1)
+diff --git a/third_party/tlslite/tlslite/tlsconnection.py b/third_party/tlslite/tlslite/tlsconnection.py
+index 41aab85..1dc39e1 100644
+--- a/third_party/tlslite/tlslite/tlsconnection.py
++++ b/third_party/tlslite/tlslite/tlsconnection.py
+@@ -337,8 +337,8 @@ class TLSConnection(TLSRecordLayer):
+ 
+     def handshakeClientCert(self, certChain=None, privateKey=None,
+                             session=None, settings=None, checker=None,
+-                            nextProtos=None, reqTack=True, serverName="",
+-                            async=False):
++                            alpnProtos=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
+@@ -383,6 +383,11 @@ class TLSConnection(TLSRecordLayer):
+         @param checker: A Checker instance.  This instance will be
+         invoked to examine the other party's authentication
+         credentials, if the handshake completes succesfully.
++
++        @type alpnProtos: list of strings.
++        @param alpnProtos: A list of upper layer protocols ordered by
++        preference, to advertise in the Application-Layer Protocol Negotiation
++        Extension (RFC 7301).
+         
+         @type nextProtos: list of strings.
+         @param nextProtos: A list of upper layer protocols ordered by
+@@ -417,7 +422,8 @@ class TLSConnection(TLSRecordLayer):
+         handshaker = self._handshakeClientAsync(certParams=(certChain,
+                         privateKey), session=session, settings=settings,
+                         checker=checker, serverName=serverName, 
+-                        nextProtos=nextProtos, reqTack=reqTack)
++                        alpnProtos=alpnProtos, 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
+@@ -433,7 +439,8 @@ class TLSConnection(TLSRecordLayer):
+ 
+     def _handshakeClientAsync(self, srpParams=(), certParams=(), anonParams=(),
+                              session=None, settings=None, checker=None,
+-                             nextProtos=None, serverName="", reqTack=True):
++                             alpnProtos=None, nextProtos=None, serverName="",
++                             reqTack=True):
+ 
+         handshaker = self._handshakeClientAsyncHelper(srpParams=srpParams,
+                 certParams=certParams,
+@@ -441,6 +448,7 @@ class TLSConnection(TLSRecordLayer):
+                 session=session,
+                 settings=settings,
+                 serverName=serverName,
++                alpnProtos=alpnProtos,
+                 nextProtos=nextProtos,
+                 reqTack=reqTack)
+         for result in self._handshakeWrapperAsync(handshaker, checker):
+@@ -448,7 +456,8 @@ class TLSConnection(TLSRecordLayer):
+ 
+ 
+     def _handshakeClientAsyncHelper(self, srpParams, certParams, anonParams,
+-                               session, settings, serverName, nextProtos, reqTack):
++                               session, settings, serverName, alpnProtos,
++                               nextProtos, reqTack):
+         
+         self._handshakeStart(client=True)
+ 
+@@ -485,6 +494,9 @@ class TLSConnection(TLSRecordLayer):
+                 reqTack = False
+             if not settings or not settings.useExperimentalTackExtension:
+                 reqTack = False
++        if alpnProtos is not None:
++            if len(alpnProtos) == 0:
++                raise ValueError("Caller passed no alpnProtos")
+         if nextProtos is not None:
+             if len(nextProtos) == 0:
+                 raise ValueError("Caller passed no nextProtos")
+@@ -530,8 +542,8 @@ class TLSConnection(TLSRecordLayer):
+         # Send the ClientHello.
+         for result in self._clientSendClientHello(settings, session, 
+                                         srpUsername, srpParams, certParams,
+-                                        anonParams, serverName, nextProtos,
+-                                        reqTack):
++                                        anonParams, serverName, alpnProtos,
++                                        nextProtos, reqTack):
+             if result in (0,1): yield result
+             else: break
+         clientHello = result
+@@ -543,9 +555,11 @@ class TLSConnection(TLSRecordLayer):
+         serverHello = result
+         cipherSuite = serverHello.cipher_suite
+         
+-        # Choose a matching Next Protocol from server list against ours
+-        # (string or None)
+-        nextProto = self._clientSelectNextProto(nextProtos, serverHello)
++        #Ignore NPN if server response has ALPN.
++        if (serverHello.alpn_proto_selected):
++          nextProto = None
++        else:
++          nextProto = self._clientSelectNextProto(nextProtos, serverHello)
+ 
+         #If the server elected to resume the session, it is handled here.
+         for result in self._clientResume(session, serverHello, 
+@@ -621,7 +635,7 @@ class TLSConnection(TLSRecordLayer):
+ 
+     def _clientSendClientHello(self, settings, session, srpUsername,
+                                 srpParams, certParams, anonParams, 
+-                                serverName, nextProtos, reqTack):
++                                serverName, alpnProtos, nextProtos, reqTack):
+         #Initialize acceptable ciphersuites
+         cipherSuites = [CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV]
+         if srpParams:
+@@ -651,7 +665,7 @@ class TLSConnection(TLSRecordLayer):
+                                    session.sessionID, cipherSuites,
+                                    certificateTypes, 
+                                    session.srpUsername,
+-                                   reqTack, nextProtos is not None,
++                                   reqTack, alpnProtos, nextProtos is not None,
+                                    session.serverName)
+ 
+         #Or send ClientHello (without)
+@@ -661,7 +675,7 @@ class TLSConnection(TLSRecordLayer):
+                                bytearray(0), cipherSuites,
+                                certificateTypes, 
+                                srpUsername,
+-                               reqTack, nextProtos is not None, 
++                               reqTack, alpnProtos, nextProtos is not None,
+                                serverName)
+         for result in self._sendMsg(clientHello):
+             yield result
+@@ -714,6 +728,11 @@ class TLSConnection(TLSRecordLayer):
+                     AlertDescription.illegal_parameter,
+                     "Server responded with unrequested Tack Extension"):
+                     yield result
++        if serverHello.alpn_proto_selected and not clientHello.alpn_protos_advertised:
++            for result in self._sendError(\
++                AlertDescription.illegal_parameter,
++                "Server responded with unrequested ALPN Extension"):
++                yield result
+         if serverHello.next_protos and not clientHello.supports_npn:
+             for result in self._sendError(\
+                 AlertDescription.illegal_parameter,
+@@ -1102,7 +1121,7 @@ class TLSConnection(TLSRecordLayer):
+                         sessionCache=None, settings=None, checker=None,
+                         reqCAs = None, reqCertTypes = None,
+                         tacks=None, activationFlags=0,
+-                        nextProtos=None, anon=False,
++                        alpnProtos=None, nextProtos=None, anon=False,
+                         signedCertTimestamps=None,
+                         fallbackSCSV=False, ocspResponse=None):
+         """Perform a handshake in the role of server.
+@@ -1172,6 +1191,11 @@ class TLSConnection(TLSRecordLayer):
+         @param reqCertTypes: A list of certificate_type values to be sent
+         along with a certificate request. This does not affect verification.
+ 
++        @type alpnProtos: list of strings.
++        @param alpnProtos: A list of upper layer protocols with zero or one
++        elements.  If not empty, its single element is the protocol negotiated
++        via the Application-Layer Protocol Negotiation Extension (RFC 7301).
++
+         @type nextProtos: list of strings.
+         @param nextProtos: A list of upper layer protocols to expose to the
+         clients through the Next-Protocol Negotiation Extension, 
+@@ -1208,7 +1232,7 @@ class TLSConnection(TLSRecordLayer):
+                 certChain, privateKey, reqCert, sessionCache, settings,
+                 checker, reqCAs, reqCertTypes,
+                 tacks=tacks, activationFlags=activationFlags, 
+-                nextProtos=nextProtos, anon=anon,
++                alpnProtos=alpnProtos, nextProtos=nextProtos, anon=anon,
+                 signedCertTimestamps=signedCertTimestamps,
+                 fallbackSCSV=fallbackSCSV, ocspResponse=ocspResponse):
+             pass
+@@ -1218,7 +1242,7 @@ class TLSConnection(TLSRecordLayer):
+                              certChain=None, privateKey=None, reqCert=False,
+                              sessionCache=None, settings=None, checker=None,
+                              reqCAs=None, reqCertTypes=None,
+-                             tacks=None, activationFlags=0,
++                             tacks=None, activationFlags=0, alpnProtos=None,
+                              nextProtos=None, anon=False,
+                              signedCertTimestamps=None,
+                              fallbackSCSV=False,
+@@ -1240,7 +1264,7 @@ class TLSConnection(TLSRecordLayer):
+             privateKey=privateKey, reqCert=reqCert,
+             sessionCache=sessionCache, settings=settings, 
+             reqCAs=reqCAs, reqCertTypes=reqCertTypes,
+-            tacks=tacks, activationFlags=activationFlags, 
++            tacks=tacks, activationFlags=activationFlags, alpnProtos=alpnProtos,
+             nextProtos=nextProtos, anon=anon,
+             signedCertTimestamps=signedCertTimestamps,
+             fallbackSCSV=fallbackSCSV,
+@@ -1257,7 +1281,7 @@ class TLSConnection(TLSRecordLayer):
+                              certChain, privateKey, reqCert, sessionCache,
+                              settings, reqCAs, reqCertTypes,
+                              tacks, activationFlags, 
+-                             nextProtos, anon,
++                             alpnProtos, nextProtos, anon,
+                              signedCertTimestamps, fallbackSCSV,
+                              ocspResponse):
+ 
+@@ -1314,7 +1338,16 @@ class TLSConnection(TLSRecordLayer):
+             sessionID = getRandomBytes(32)
+         else:
+             sessionID = bytearray(0)
+-        
++
++        alpn_proto_selected = None
++        if clientHello.alpn_protos_advertised is not None:
++            if alpnProtos is not None:
++                for proto in alpnProtos:
++                    if proto in clientHello.alpn_protos_advertised:
++                        alpn_proto_selected = proto
++                        nextProtos = None
++                        break;
++
+         if not clientHello.supports_npn:
+             nextProtos = None
+ 
+@@ -1330,7 +1363,7 @@ class TLSConnection(TLSRecordLayer):
+         serverHello = ServerHello()
+         serverHello.create(self.version, getRandomBytes(32), sessionID, \
+                             cipherSuite, CertificateType.x509, tackExt,
+-                            nextProtos)
++                            alpn_proto_selected, nextProtos)
+         serverHello.channel_id = \
+             clientHello.channel_id and settings.enableChannelID
+         serverHello.extended_master_secret = \
+@@ -1397,7 +1430,7 @@ class TLSConnection(TLSRecordLayer):
+         for result in self._serverFinished(premasterSecret, 
+                                 clientHello.random, serverHello.random,
+                                 cipherSuite, settings.cipherImplementations,
+-                                nextProtos, serverHello.channel_id,
++                                alpnProtos, nextProtos, serverHello.channel_id,
+                                 serverHello.extended_master_secret):
+                 if result in (0,1): yield result
+                 else: break
+@@ -1540,7 +1573,7 @@ class TLSConnection(TLSRecordLayer):
+                 serverHello = ServerHello()
+                 serverHello.create(self.version, getRandomBytes(32),
+                                    session.sessionID, session.cipherSuite,
+-                                   CertificateType.x509, None, None)
++                                   CertificateType.x509, None, None, None)
+                 serverHello.extended_master_secret = \
+                     clientHello.extended_master_secret and \
+                     settings.enableExtendedMasterSecret
+@@ -1854,8 +1887,8 @@ class TLSConnection(TLSRecordLayer):
+ 
+ 
+     def _serverFinished(self,  premasterSecret, clientRandom, serverRandom,
+-                        cipherSuite, cipherImplementations, nextProtos,
+-                        doingChannelID, useExtendedMasterSecret):
++                        cipherSuite, cipherImplementations, alpnProtos,
++                        nextProtos, doingChannelID, useExtendedMasterSecret):
+         masterSecret = calcMasterSecret(self.version, premasterSecret,
+                                       clientRandom, serverRandom,
+                                       self._ems_handshake_hash,