# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Tests for twisted SSL support.
"""
from __future__ import division, absolute_import

from twisted.python.filepath import FilePath
from twisted.trial import unittest
from twisted.internet import protocol, reactor, interfaces, defer
from twisted.internet.error import ConnectionDone
from twisted.protocols import basic
from twisted.python.reflect import requireModule
from twisted.python.runtime import platform
from twisted.test.test_tcp import ProperlyCloseFilesMixin
from twisted.test.proto_helpers import waitUntilAllDisconnected

import os, errno

try:
    from OpenSSL import SSL, crypto
    from twisted.internet import ssl
    from twisted.test.ssl_helpers import ClientTLSContext, certPath
except ImportError:
    def _noSSL():
        # ugh, make pyflakes happy.
        global SSL
        global ssl
        SSL = ssl = None
    _noSSL()

try:
    from twisted.protocols import tls as newTLS
except ImportError:
    # Assuming SSL exists, we're using old version in reactor (i.e. non-protocol)
    newTLS = None

from zope.interface import implementer

class UnintelligentProtocol(basic.LineReceiver):
    """
    @ivar deferred: a deferred that will fire at connection lost.
    @type deferred: L{defer.Deferred}

    @cvar pretext: text sent before TLS is set up.
    @type pretext: C{bytes}

    @cvar posttext: text sent after TLS is set up.
    @type posttext: C{bytes}
    """
    pretext = [
        b"first line",
        b"last thing before tls starts",
        b"STARTTLS"]

    posttext = [
        b"first thing after tls started",
        b"last thing ever"]

    def __init__(self):
        self.deferred = defer.Deferred()


    def connectionMade(self):
        for l in self.pretext:
            self.sendLine(l)


    def lineReceived(self, line):
        if line == b"READY":
            self.transport.startTLS(ClientTLSContext(), self.factory.client)
            for l in self.posttext:
                self.sendLine(l)
            self.transport.loseConnection()


    def connectionLost(self, reason):
        self.deferred.callback(None)



class LineCollector(basic.LineReceiver):
    """
    @ivar deferred: a deferred that will fire at connection lost.
    @type deferred: L{defer.Deferred}

    @ivar doTLS: whether the protocol is initiate TLS or not.
    @type doTLS: C{bool}

    @ivar fillBuffer: if set to True, it will send lots of data once
        C{STARTTLS} is received.
    @type fillBuffer: C{bool}
    """

    def __init__(self, doTLS, fillBuffer=False):
        self.doTLS = doTLS
        self.fillBuffer = fillBuffer
        self.deferred = defer.Deferred()


    def connectionMade(self):
        self.factory.rawdata = b''
        self.factory.lines = []


    def lineReceived(self, line):
        self.factory.lines.append(line)
        if line == b'STARTTLS':
            if self.fillBuffer:
                for x in range(500):
                    self.sendLine(b'X' * 1000)
            self.sendLine(b'READY')
            if self.doTLS:
                ctx = ServerTLSContext(
                    privateKeyFileName=certPath,
                    certificateFileName=certPath,
                )
                self.transport.startTLS(ctx, self.factory.server)
            else:
                self.setRawMode()


    def rawDataReceived(self, data):
        self.factory.rawdata += data
        self.transport.loseConnection()


    def connectionLost(self, reason):
        self.deferred.callback(None)



class SingleLineServerProtocol(protocol.Protocol):
    """
    A protocol that sends a single line of data at C{connectionMade}.
    """

    def connectionMade(self):
        self.transport.write(b"+OK <some crap>\r\n")
        self.transport.getPeerCertificate()



class RecordingClientProtocol(protocol.Protocol):
    """
    @ivar deferred: a deferred that will fire with first received content.
    @type deferred: L{defer.Deferred}
    """

    def __init__(self):
        self.deferred = defer.Deferred()


    def connectionMade(self):
        self.transport.getPeerCertificate()


    def dataReceived(self, data):
        self.deferred.callback(data)



@implementer(interfaces.IHandshakeListener)
class ImmediatelyDisconnectingProtocol(protocol.Protocol):
    """
    A protocol that disconnect immediately on connection. It fires the
    C{connectionDisconnected} deferred of its factory on connetion lost.
    """

    def handshakeCompleted(self):
        self.transport.loseConnection()


    def connectionLost(self, reason):
        self.factory.connectionDisconnected.callback(None)



def generateCertificateObjects(organization, organizationalUnit):
    """
    Create a certificate for given C{organization} and C{organizationalUnit}.

    @return: a tuple of (key, request, certificate) objects.
    """
    pkey = crypto.PKey()
    pkey.generate_key(crypto.TYPE_RSA, 1024)
    req = crypto.X509Req()
    subject = req.get_subject()
    subject.O = organization
    subject.OU = organizationalUnit
    req.set_pubkey(pkey)
    req.sign(pkey, "md5")

    # Here comes the actual certificate
    cert = crypto.X509()
    cert.set_serial_number(1)
    cert.gmtime_adj_notBefore(0)
    cert.gmtime_adj_notAfter(60) # Testing certificates need not be long lived
    cert.set_issuer(req.get_subject())
    cert.set_subject(req.get_subject())
    cert.set_pubkey(req.get_pubkey())
    cert.sign(pkey, "md5")

    return pkey, req, cert



def generateCertificateFiles(basename, organization, organizationalUnit):
    """
    Create certificate files key, req and cert prefixed by C{basename} for
    given C{organization} and C{organizationalUnit}.
    """
    pkey, req, cert = generateCertificateObjects(organization, organizationalUnit)

    for ext, obj, dumpFunc in [
        ('key', pkey, crypto.dump_privatekey),
        ('req', req, crypto.dump_certificate_request),
        ('cert', cert, crypto.dump_certificate)]:
        fName = os.extsep.join((basename, ext)).encode("utf-8")
        FilePath(fName).setContent(dumpFunc(crypto.FILETYPE_PEM, obj))



class ContextGeneratingMixin:
    """
    Offer methods to create L{ssl.DefaultOpenSSLContextFactory} for both client
    and server.

    @ivar clientBase: prefix of client certificate files.
    @type clientBase: C{str}

    @ivar serverBase: prefix of server certificate files.
    @type serverBase: C{str}

    @ivar clientCtxFactory: a generated context factory to be used in
        L{IReactorSSL.connectSSL}.
    @type clientCtxFactory: L{ssl.DefaultOpenSSLContextFactory}

    @ivar serverCtxFactory: a generated context factory to be used in
        L{IReactorSSL.listenSSL}.
    @type serverCtxFactory: L{ssl.DefaultOpenSSLContextFactory}
    """

    def makeContextFactory(self, org, orgUnit, *args, **kwArgs):
        base = self.mktemp()
        generateCertificateFiles(base, org, orgUnit)
        serverCtxFactory = ssl.DefaultOpenSSLContextFactory(
            os.extsep.join((base, 'key')),
            os.extsep.join((base, 'cert')),
            *args, **kwArgs)

        return base, serverCtxFactory


    def setupServerAndClient(self, clientArgs, clientKwArgs, serverArgs,
                             serverKwArgs):
        self.clientBase, self.clientCtxFactory = self.makeContextFactory(
            *clientArgs, **clientKwArgs)
        self.serverBase, self.serverCtxFactory = self.makeContextFactory(
            *serverArgs, **serverKwArgs)



if SSL is not None:
    class ServerTLSContext(ssl.DefaultOpenSSLContextFactory):
        """
        A context factory with a default method set to
        L{OpenSSL.SSL.TLSv1_METHOD}.
        """
        isClient = False

        def __init__(self, *args, **kw):
            kw['sslmethod'] = SSL.TLSv1_METHOD
            ssl.DefaultOpenSSLContextFactory.__init__(self, *args, **kw)



class StolenTCPTests(ProperlyCloseFilesMixin, unittest.TestCase):
    """
    For SSL transports, test many of the same things which are tested for
    TCP transports.
    """

    def createServer(self, address, portNumber, factory):
        """
        Create an SSL server with a certificate using L{IReactorSSL.listenSSL}.
        """
        cert = ssl.PrivateCertificate.loadPEM(FilePath(certPath).getContent())
        contextFactory = cert.options()
        return reactor.listenSSL(
            portNumber, factory, contextFactory, interface=address)


    def connectClient(self, address, portNumber, clientCreator):
        """
        Create an SSL client using L{IReactorSSL.connectSSL}.
        """
        contextFactory = ssl.CertificateOptions()
        return clientCreator.connectSSL(address, portNumber, contextFactory)


    def getHandleExceptionType(self):
        """
        Return L{OpenSSL.SSL.Error} as the expected error type which will be
        raised by a write to the L{OpenSSL.SSL.Connection} object after it has
        been closed.
        """
        return SSL.Error


    def getHandleErrorCode(self):
        """
        Return the argument L{OpenSSL.SSL.Error} will be constructed with for
        this case. This is basically just a random OpenSSL implementation
        detail. It would be better if this test worked in a way which did not
        require this.
        """
        # Windows 2000 SP 4 and Windows XP SP 2 give back WSAENOTSOCK for
        # SSL.Connection.write for some reason.  The twisted.protocols.tls
        # implementation of IReactorSSL doesn't suffer from this imprecation,
        # though, since it is isolated from the Windows I/O layer (I suppose?).

        # If test_properlyCloseFiles waited for the SSL handshake to complete
        # and performed an orderly shutdown, then this would probably be a
        # little less weird: writing to a shutdown SSL connection has a more
        # well-defined failure mode (or at least it should).

        # So figure out if twisted.protocols.tls is in use.  If it can be
        # imported, it should be.
        if requireModule('twisted.protocols.tls') is None:
            # It isn't available, so we expect WSAENOTSOCK if we're on Windows.
            if platform.getType() == 'win32':
                return errno.WSAENOTSOCK

        # Otherwise, we expect an error about how we tried to write to a
        # shutdown connection.  This is terribly implementation-specific.
        return [('SSL routines', 'SSL_write', 'protocol is shutdown')]



class TLSTests(unittest.TestCase):
    """
    Tests for startTLS support.

    @ivar fillBuffer: forwarded to L{LineCollector.fillBuffer}
    @type fillBuffer: C{bool}
    """
    fillBuffer = False

    clientProto = None
    serverProto = None


    def tearDown(self):
        if self.clientProto.transport is not None:
            self.clientProto.transport.loseConnection()
        if self.serverProto.transport is not None:
            self.serverProto.transport.loseConnection()


    def _runTest(self, clientProto, serverProto, clientIsServer=False):
        """
        Helper method to run TLS tests.

        @param clientProto: protocol instance attached to the client
            connection.
        @param serverProto: protocol instance attached to the server
            connection.
        @param clientIsServer: flag indicated if client should initiate
            startTLS instead of server.

        @return: a L{defer.Deferred} that will fire when both connections are
            lost.
        """
        self.clientProto = clientProto
        cf = self.clientFactory = protocol.ClientFactory()
        cf.protocol = lambda: clientProto
        if clientIsServer:
            cf.server = False
        else:
            cf.client = True

        self.serverProto = serverProto
        sf = self.serverFactory = protocol.ServerFactory()
        sf.protocol = lambda: serverProto
        if clientIsServer:
            sf.client = False
        else:
            sf.server = True

        port = reactor.listenTCP(0, sf, interface="127.0.0.1")
        self.addCleanup(port.stopListening)

        reactor.connectTCP('127.0.0.1', port.getHost().port, cf)

        return defer.gatherResults([clientProto.deferred, serverProto.deferred])


    def test_TLS(self):
        """
        Test for server and client startTLS: client should received data both
        before and after the startTLS.
        """
        def check(ignore):
            self.assertEqual(
                self.serverFactory.lines,
                UnintelligentProtocol.pretext + UnintelligentProtocol.posttext
            )
        d = self._runTest(UnintelligentProtocol(),
                          LineCollector(True, self.fillBuffer))
        return d.addCallback(check)


    def test_unTLS(self):
        """
        Test for server startTLS not followed by a startTLS in client: the data
        received after server startTLS should be received as raw.
        """
        def check(ignored):
            self.assertEqual(
                self.serverFactory.lines,
                UnintelligentProtocol.pretext
            )
            self.assertTrue(self.serverFactory.rawdata,
                            "No encrypted bytes received")
        d = self._runTest(UnintelligentProtocol(),
                          LineCollector(False, self.fillBuffer))
        return d.addCallback(check)


    def test_backwardsTLS(self):
        """
        Test startTLS first initiated by client.
        """
        def check(ignored):
            self.assertEqual(
                self.clientFactory.lines,
                UnintelligentProtocol.pretext + UnintelligentProtocol.posttext
            )
        d = self._runTest(LineCollector(True, self.fillBuffer),
                          UnintelligentProtocol(), True)
        return d.addCallback(check)



class SpammyTLSTests(TLSTests):
    """
    Test TLS features with bytes sitting in the out buffer.
    """
    fillBuffer = True



class BufferingTests(unittest.TestCase):
    serverProto = None
    clientProto = None


    def tearDown(self):
        if self.serverProto.transport is not None:
            self.serverProto.transport.loseConnection()
        if self.clientProto.transport is not None:
            self.clientProto.transport.loseConnection()

        return waitUntilAllDisconnected(
            reactor, [self.serverProto, self.clientProto])


    def test_openSSLBuffering(self):
        serverProto = self.serverProto = SingleLineServerProtocol()
        clientProto = self.clientProto = RecordingClientProtocol()

        server = protocol.ServerFactory()
        client = self.client = protocol.ClientFactory()

        server.protocol = lambda: serverProto
        client.protocol = lambda: clientProto

        sCTX = ssl.DefaultOpenSSLContextFactory(certPath, certPath)
        cCTX = ssl.ClientContextFactory()

        port = reactor.listenSSL(0, server, sCTX, interface='127.0.0.1')
        self.addCleanup(port.stopListening)

        clientConnector = reactor.connectSSL('127.0.0.1', port.getHost().port,
                                             client, cCTX)
        self.addCleanup(clientConnector.disconnect)

        return clientProto.deferred.addCallback(
            self.assertEqual, b"+OK <some crap>\r\n")



class ConnectionLostTests(unittest.TestCase, ContextGeneratingMixin):
    """
    SSL connection closing tests.
    """

    def testImmediateDisconnect(self):
        org = "twisted.test.test_ssl"
        self.setupServerAndClient(
            (org, org + ", client"), {},
            (org, org + ", server"), {})

        # Set up a server, connect to it with a client, which should work since our verifiers
        # allow anything, then disconnect.
        serverProtocolFactory = protocol.ServerFactory()
        serverProtocolFactory.protocol = protocol.Protocol
        self.serverPort = serverPort = reactor.listenSSL(0,
            serverProtocolFactory, self.serverCtxFactory)

        clientProtocolFactory = protocol.ClientFactory()
        clientProtocolFactory.protocol = ImmediatelyDisconnectingProtocol
        clientProtocolFactory.connectionDisconnected = defer.Deferred()
        reactor.connectSSL('127.0.0.1',
            serverPort.getHost().port, clientProtocolFactory, self.clientCtxFactory)

        return clientProtocolFactory.connectionDisconnected.addCallback(
            lambda ignoredResult: self.serverPort.stopListening())


    def test_bothSidesLoseConnection(self):
        """
        Both sides of SSL connection close connection; the connections should
        close cleanly, and only after the underlying TCP connection has
        disconnected.
        """
        @implementer(interfaces.IHandshakeListener)
        class CloseAfterHandshake(protocol.Protocol):
            gotData = False

            def __init__(self):
                self.done = defer.Deferred()

            def handshakeCompleted(self):
                self.transport.loseConnection()

            def connectionLost(self, reason):
                self.done.errback(reason)
                del self.done

        org = "twisted.test.test_ssl"
        self.setupServerAndClient(
            (org, org + ", client"), {},
            (org, org + ", server"), {})

        serverProtocol = CloseAfterHandshake()
        serverProtocolFactory = protocol.ServerFactory()
        serverProtocolFactory.protocol = lambda: serverProtocol
        serverPort = reactor.listenSSL(0,
            serverProtocolFactory, self.serverCtxFactory)
        self.addCleanup(serverPort.stopListening)

        clientProtocol = CloseAfterHandshake()
        clientProtocolFactory = protocol.ClientFactory()
        clientProtocolFactory.protocol = lambda: clientProtocol
        reactor.connectSSL('127.0.0.1',
            serverPort.getHost().port, clientProtocolFactory, self.clientCtxFactory)

        def checkResult(failure):
            failure.trap(ConnectionDone)
        return defer.gatherResults(
            [clientProtocol.done.addErrback(checkResult),
             serverProtocol.done.addErrback(checkResult)])

    if newTLS is None:
        test_bothSidesLoseConnection.skip = "Old SSL code doesn't always close cleanly."


    def testFailedVerify(self):
        org = "twisted.test.test_ssl"
        self.setupServerAndClient(
            (org, org + ", client"), {},
            (org, org + ", server"), {})

        def verify(*a):
            return False
        self.clientCtxFactory.getContext().set_verify(SSL.VERIFY_PEER, verify)

        serverConnLost = defer.Deferred()
        serverProtocol = protocol.Protocol()
        serverProtocol.connectionLost = serverConnLost.callback
        serverProtocolFactory = protocol.ServerFactory()
        serverProtocolFactory.protocol = lambda: serverProtocol
        self.serverPort = serverPort = reactor.listenSSL(0,
            serverProtocolFactory, self.serverCtxFactory)

        clientConnLost = defer.Deferred()
        clientProtocol = protocol.Protocol()
        clientProtocol.connectionLost = clientConnLost.callback
        clientProtocolFactory = protocol.ClientFactory()
        clientProtocolFactory.protocol = lambda: clientProtocol
        reactor.connectSSL('127.0.0.1',
            serverPort.getHost().port, clientProtocolFactory, self.clientCtxFactory)

        dl = defer.DeferredList([serverConnLost, clientConnLost], consumeErrors=True)
        return dl.addCallback(self._cbLostConns)


    def _cbLostConns(self, results):
        (sSuccess, sResult), (cSuccess, cResult) = results

        self.assertFalse(sSuccess)
        self.assertFalse(cSuccess)

        acceptableErrors = [SSL.Error]

        # Rather than getting a verification failure on Windows, we are getting
        # a connection failure.  Without something like sslverify proxying
        # in-between we can't fix up the platform's errors, so let's just
        # specifically say it is only OK in this one case to keep the tests
        # passing.  Normally we'd like to be as strict as possible here, so
        # we're not going to allow this to report errors incorrectly on any
        # other platforms.

        if platform.isWindows():
            from twisted.internet.error import ConnectionLost
            acceptableErrors.append(ConnectionLost)

        sResult.trap(*acceptableErrors)
        cResult.trap(*acceptableErrors)

        return self.serverPort.stopListening()



class FakeContext:
    """
    L{OpenSSL.SSL.Context} double which can more easily be inspected.
    """
    def __init__(self, method):
        self._method = method
        self._options = 0


    def set_options(self, options):
        self._options |= options


    def use_certificate_file(self, fileName):
        pass


    def use_privatekey_file(self, fileName):
        pass



class DefaultOpenSSLContextFactoryTests(unittest.TestCase):
    """
    Tests for L{ssl.DefaultOpenSSLContextFactory}.
    """
    def setUp(self):
        # pyOpenSSL Context objects aren't introspectable enough.  Pass in
        # an alternate context factory so we can inspect what is done to it.
        self.contextFactory = ssl.DefaultOpenSSLContextFactory(
            certPath, certPath, _contextFactory=FakeContext)
        self.context = self.contextFactory.getContext()


    def test_method(self):
        """
        L{ssl.DefaultOpenSSLContextFactory.getContext} returns an SSL context
        which can use SSLv3 or TLSv1 but not SSLv2.
        """
        # SSLv23_METHOD allows SSLv2, SSLv3, or TLSv1
        self.assertEqual(self.context._method, SSL.SSLv23_METHOD)

        # And OP_NO_SSLv2 disables the SSLv2 support.
        self.assertEqual(self.context._options & SSL.OP_NO_SSLv2,
                         SSL.OP_NO_SSLv2)

        # Make sure SSLv3 and TLSv1 aren't disabled though.
        self.assertFalse(self.context._options & SSL.OP_NO_SSLv3)
        self.assertFalse(self.context._options & SSL.OP_NO_TLSv1)


    def test_missingCertificateFile(self):
        """
        Instantiating L{ssl.DefaultOpenSSLContextFactory} with a certificate
        filename which does not identify an existing file results in the
        initializer raising L{OpenSSL.SSL.Error}.
        """
        self.assertRaises(
            SSL.Error,
            ssl.DefaultOpenSSLContextFactory, certPath, self.mktemp())


    def test_missingPrivateKeyFile(self):
        """
        Instantiating L{ssl.DefaultOpenSSLContextFactory} with a private key
        filename which does not identify an existing file results in the
        initializer raising L{OpenSSL.SSL.Error}.
        """
        self.assertRaises(
            SSL.Error,
            ssl.DefaultOpenSSLContextFactory, self.mktemp(), certPath)



class ClientContextFactoryTests(unittest.TestCase):
    """
    Tests for L{ssl.ClientContextFactory}.
    """
    def setUp(self):
        self.contextFactory = ssl.ClientContextFactory()
        self.contextFactory._contextFactory = FakeContext
        self.context = self.contextFactory.getContext()


    def test_method(self):
        """
        L{ssl.ClientContextFactory.getContext} returns a context which can use
        SSLv3 or TLSv1 but not SSLv2.
        """
        self.assertEqual(self.context._method, SSL.SSLv23_METHOD)
        self.assertEqual(self.context._options & SSL.OP_NO_SSLv2,
                         SSL.OP_NO_SSLv2)
        self.assertFalse(self.context._options & SSL.OP_NO_SSLv3)
        self.assertFalse(self.context._options & SSL.OP_NO_TLSv1)



if interfaces.IReactorSSL(reactor, None) is None:
    for tCase in [StolenTCPTests, TLSTests, SpammyTLSTests,
                  BufferingTests, ConnectionLostTests,
                  DefaultOpenSSLContextFactoryTests,
                  ClientContextFactoryTests]:
        tCase.skip = "Reactor does not support SSL, cannot run SSL tests"
