# 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.runtime import platform
from twisted.test.test_tcp import ProperlyCloseFilesMixin

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


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)



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

    def connectionMade(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, 512)
    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
        C{reactor.connectSSL}.
    @type clientCtxFactory: L{ssl.DefaultOpenSSLContextFactory}

    @ivar serverCtxFactory: a generated context factory to be used in
        C{reactor.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{SSL.TLSv1_METHOD}.
        """
        isClient = False

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



class StolenTCPTestCase(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{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{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.
        try:
            import twisted.protocols.tls
        except ImportError:
            # 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 TLSTestCase(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.failUnless(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 SpammyTLSTestCase(TLSTestCase):
    """
    Test TLS features with bytes sitting in the out buffer.
    """
    fillBuffer = True



class BufferingTestCase(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()


    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)

        reactor.connectSSL('127.0.0.1', port.getHost().port, client, cCTX)

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



class ConnectionLostTestCase(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()
        clientConnector = 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.
        """
        class CloseAfterHandshake(protocol.Protocol):
            gotData = False

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

            def connectionMade(self):
                self.transport.write(b"a")

            def dataReceived(self, data):
                # If we got data, handshake is over:
                self.gotData = True
                self.transport.loseConnection()

            def connectionLost(self, reason):
                if not self.gotData:
                    reason = RuntimeError("We never received the data!")
                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
        clientConnector = 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
        clientConnector = 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.failIf(sSuccess)
        self.failIf(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.assertTrue(self.context._options & 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.assertTrue(self.context._options & 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 [StolenTCPTestCase, TLSTestCase, SpammyTLSTestCase,
                  BufferingTestCase, ConnectionLostTestCase,
                  DefaultOpenSSLContextFactoryTests,
                  ClientContextFactoryTests]:
        tCase.skip = "Reactor does not support SSL, cannot run SSL tests"

