Lib/test/test_ssl.py

# Test the support for SSL and sockets

import sys
import unittest
from test import test_support
import asyncore
import socket
import select
import time
import gc
import os
import errno
import pprint
import urllib, urlparse
import traceback
import weakref
import functools
import platform

from BaseHTTPServer import HTTPServer
from SimpleHTTPServer import SimpleHTTPRequestHandler

# Optionally test SSL support, if we have it in the tested platform
skip_expected = False
try:
    import ssl
except ImportError:
    skip_expected = True

HOST = test_support.HOST
CERTFILE = None
SVN_PYTHON_ORG_ROOT_CERT = None

def handle_error(prefix):
    exc_format = ' '.join(traceback.format_exception(*sys.exc_info()))
    if test_support.verbose:
        sys.stdout.write(prefix + exc_format)


class BasicTests(unittest.TestCase):

    def test_sslwrap_simple(self):
        # A crude test for the legacy API
        try:
            ssl.sslwrap_simple(socket.socket(socket.AF_INET))
        except IOError, e:
            if e.errno == 32: # broken pipe when ssl_sock.do_handshake(), this test doesn't care about that
                pass
            else:
                raise
        try:
            ssl.sslwrap_simple(socket.socket(socket.AF_INET)._sock)
        except IOError, e:
            if e.errno == 32: # broken pipe when ssl_sock.do_handshake(), this test doesn't care about that
                pass
            else:
                raise

# Issue #9415: Ubuntu hijacks their OpenSSL and forcefully disables SSLv2
def skip_if_broken_ubuntu_ssl(func):
    # We need to access the lower-level wrapper in order to create an
    # implicit SSL context without trying to connect or listen.
    import _ssl
    @functools.wraps(func)
    def f(*args, **kwargs):
        try:
            s = socket.socket(socket.AF_INET)
            _ssl.sslwrap(s._sock, 0, None, None,
                         ssl.CERT_NONE, ssl.PROTOCOL_SSLv2, None, None)
        except ssl.SSLError as e:
            if (ssl.OPENSSL_VERSION_INFO == (0, 9, 8, 15, 15) and
                platform.linux_distribution() == ('debian', 'squeeze/sid', '')
                and 'Invalid SSL protocol variant specified' in str(e)):
                raise unittest.SkipTest("Patched Ubuntu OpenSSL breaks behaviour")
        return func(*args, **kwargs)
    return f


class BasicSocketTests(unittest.TestCase):

    def test_constants(self):
        ssl.PROTOCOL_SSLv2
        ssl.PROTOCOL_SSLv23
        ssl.PROTOCOL_SSLv3
        ssl.PROTOCOL_TLSv1
        ssl.CERT_NONE
        ssl.CERT_OPTIONAL
        ssl.CERT_REQUIRED

    def test_random(self):
        v = ssl.RAND_status()
        if test_support.verbose:
            sys.stdout.write("\n RAND_status is %d (%s)\n"
                             % (v, (v and "sufficient randomness") or
                                "insufficient randomness"))
        try:
            ssl.RAND_egd(1)
        except TypeError:
            pass
        else:
            print "didn't raise TypeError"
        ssl.RAND_add("this is a random string", 75.0)

    def test_parse_cert(self):
        # note that this uses an 'unofficial' function in _ssl.c,
        # provided solely for this test, to exercise the certificate
        # parsing code
        p = ssl._ssl._test_decode_cert(CERTFILE, False)
        if test_support.verbose:
            sys.stdout.write("\n" + pprint.pformat(p) + "\n")

    def test_DER_to_PEM(self):
        with open(SVN_PYTHON_ORG_ROOT_CERT, 'r') as f:
            pem = f.read()
        d1 = ssl.PEM_cert_to_DER_cert(pem)
        p2 = ssl.DER_cert_to_PEM_cert(d1)
        d2 = ssl.PEM_cert_to_DER_cert(p2)
        self.assertEqual(d1, d2)
        if not p2.startswith(ssl.PEM_HEADER + '\n'):
            self.fail("DER-to-PEM didn't include correct header:\n%r\n" % p2)
        if not p2.endswith('\n' + ssl.PEM_FOOTER + '\n'):
            self.fail("DER-to-PEM didn't include correct footer:\n%r\n" % p2)

    def test_openssl_version(self):
        n = ssl.OPENSSL_VERSION_NUMBER
        t = ssl.OPENSSL_VERSION_INFO
        s = ssl.OPENSSL_VERSION
        self.assertIsInstance(n, (int, long))
        self.assertIsInstance(t, tuple)
        self.assertIsInstance(s, str)
        # Some sanity checks follow
        # >= 0.9
        self.assertGreaterEqual(n, 0x900000)
        # < 2.0
        self.assertLess(n, 0x20000000)
        major, minor, fix, patch, status = t
        self.assertGreaterEqual(major, 0)
        self.assertLess(major, 2)
        self.assertGreaterEqual(minor, 0)
        self.assertLess(minor, 256)
        self.assertGreaterEqual(fix, 0)
        self.assertLess(fix, 256)
        self.assertGreaterEqual(patch, 0)
        self.assertLessEqual(patch, 26)
        self.assertGreaterEqual(status, 0)
        self.assertLessEqual(status, 15)
        # Version string as returned by OpenSSL, the format might change
        self.assertTrue(s.startswith("OpenSSL {:d}.{:d}.{:d}".format(major, minor, fix)),
                        (s, t))

    def test_ciphers(self):
        if not test_support.is_resource_enabled('network'):
            return
        remote = ("svn.python.org", 443)
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_NONE, ciphers="ALL")
        s.connect(remote)
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_NONE, ciphers="DEFAULT")
        s.connect(remote)
        # Error checking occurs when connecting, because the SSL context
        # isn't created before.
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_NONE, ciphers="^$:,;?*'dorothyx")
        with self.assertRaisesRegexp(ssl.SSLError, "No cipher can be selected"):
            s.connect(remote)

    @test_support.cpython_only
    def test_refcycle(self):
        # Issue #7943: an SSL object doesn't create reference cycles with
        # itself.
        s = socket.socket(socket.AF_INET)
        ss = ssl.wrap_socket(s)
        wr = weakref.ref(ss)
        del ss
        self.assertEqual(wr(), None)


class NetworkedTests(unittest.TestCase):

    def test_connect(self):
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_NONE)
        s.connect(("svn.python.org", 443))
        c = s.getpeercert()
        if c:
            self.fail("Peer cert %s shouldn't be here!")
        s.close()

        # this should fail because we have no verification certs
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_REQUIRED)
        try:
            s.connect(("svn.python.org", 443))
        except ssl.SSLError:
            pass
        finally:
            s.close()

        # this should succeed because we specify the root cert
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_REQUIRED,
                            ca_certs=SVN_PYTHON_ORG_ROOT_CERT)
        try:
            s.connect(("svn.python.org", 443))
        finally:
            s.close()

    @unittest.skipIf(os.name == "nt", "Can't use a socket as a file under Windows")
    def test_makefile_close(self):
        # Issue #5238: creating a file-like object with makefile() shouldn't
        # delay closing the underlying "real socket" (here tested with its
        # file descriptor, hence skipping the test under Windows).
        ss = ssl.wrap_socket(socket.socket(socket.AF_INET))
        ss.connect(("svn.python.org", 443))
        fd = ss.fileno()
        f = ss.makefile()
        f.close()
        # The fd is still open
        os.read(fd, 0)
        # Closing the SSL socket should close the fd too
        ss.close()
        gc.collect()
        with self.assertRaises(OSError) as e:
            os.read(fd, 0)
        self.assertEqual(e.exception.errno, errno.EBADF)

    def test_non_blocking_handshake(self):
        s = socket.socket(socket.AF_INET)
        s.connect(("svn.python.org", 443))
        s.setblocking(False)
        s = ssl.wrap_socket(s,
                            cert_reqs=ssl.CERT_NONE,
                            do_handshake_on_connect=False)
        count = 0
        while True:
            try:
                count += 1
                s.do_handshake()
                break
            except ssl.SSLError, err:
                if err.args[0] == ssl.SSL_ERROR_WANT_READ:
                    select.select([s], [], [])
                elif err.args[0] == ssl.SSL_ERROR_WANT_WRITE:
                    select.select([], [s], [])
                else:
                    raise
        s.close()
        if test_support.verbose:
            sys.stdout.write("\nNeeded %d calls to do_handshake() to establish session.\n" % count)

    def test_get_server_certificate(self):
        pem = ssl.get_server_certificate(("svn.python.org", 443))
        if not pem:
            self.fail("No server certificate on svn.python.org:443!")

        try:
            pem = ssl.get_server_certificate(("svn.python.org", 443), ca_certs=CERTFILE)
        except ssl.SSLError:
            #should fail
            pass
        else:
            self.fail("Got server certificate %s for svn.python.org!" % pem)

        pem = ssl.get_server_certificate(("svn.python.org", 443), ca_certs=SVN_PYTHON_ORG_ROOT_CERT)
        if not pem:
            self.fail("No server certificate on svn.python.org:443!")
        if test_support.verbose:
            sys.stdout.write("\nVerified certificate for svn.python.org:443 is\n%s\n" % pem)

    def test_algorithms(self):
        # Issue #8484: all algorithms should be available when verifying a
        # certificate.
        # SHA256 was added in OpenSSL 0.9.8
        if ssl.OPENSSL_VERSION_INFO < (0, 9, 8, 0, 15):
            self.skipTest("SHA256 not available on %r" % ssl.OPENSSL_VERSION)
        # NOTE: https://sha256.tbs-internet.com is another possible test host
        remote = ("sha2.hboeck.de", 443)
        sha256_cert = os.path.join(os.path.dirname(__file__), "sha256.pem")
        s = ssl.wrap_socket(socket.socket(socket.AF_INET),
                            cert_reqs=ssl.CERT_REQUIRED,
                            ca_certs=sha256_cert,)
        with test_support.transient_internet():
            try:
                s.connect(remote)
                if test_support.verbose:
                    sys.stdout.write("\nCipher with %r is %r\n" %
                                     (remote, s.cipher()))
                    sys.stdout.write("Certificate is:\n%s\n" %
                                     pprint.pformat(s.getpeercert()))
            finally:
                s.close()


try:
    import threading
except ImportError:
    _have_threads = False
else:
    _have_threads = True

    class ThreadedEchoServer(threading.Thread):

        class ConnectionHandler(threading.Thread):

            """A mildly complicated class, because we want it to work both
            with and without the SSL wrapper around the socket connection, so
            that we can test the STARTTLS functionality."""

            def __init__(self, server, connsock):
                self.server = server
                self.running = False
                self.sock = connsock
                self.sock.setblocking(1)
                self.sslconn = None
                threading.Thread.__init__(self)
                self.daemon = True

            def show_conn_details(self):
                if self.server.certreqs == ssl.CERT_REQUIRED:
                    cert = self.sslconn.getpeercert()
                    if test_support.verbose and self.server.chatty:
                        sys.stdout.write(" client cert is " + pprint.pformat(cert) + "\n")
                    cert_binary = self.sslconn.getpeercert(True)
                    if test_support.verbose and self.server.chatty:
                        sys.stdout.write(" cert binary is " + str(len(cert_binary)) + " bytes\n")
                cipher = self.sslconn.cipher()
                if test_support.verbose and self.server.chatty:
                    sys.stdout.write(" server: connection cipher is now " + str(cipher) + "\n")

            def wrap_conn(self):
                try:
                    self.sslconn = ssl.wrap_socket(self.sock, server_side=True,
                                                   certfile=self.server.certificate,
                                                   ssl_version=self.server.protocol,
                                                   ca_certs=self.server.cacerts,
                                                   cert_reqs=self.server.certreqs,
                                                   ciphers=self.server.ciphers)
                except ssl.SSLError:
                    # XXX Various errors can have happened here, for example
                    # a mismatching protocol version, an invalid certificate,
                    # or a low-level bug. This should be made more discriminating.
                    if self.server.chatty:
                        handle_error("\n server:  bad connection attempt from " +
                                     str(self.sock.getpeername()) + ":\n")
                    self.close()
                    self.running = False
                    self.server.stop()
                    return False
                else:
                    return True

            def read(self):
                if self.sslconn:
                    return self.sslconn.read()
                else:
                    return self.sock.recv(1024)

            def write(self, bytes):
                if self.sslconn:
                    return self.sslconn.write(bytes)
                else:
                    return self.sock.send(bytes)

            def close(self):
                if self.sslconn:
                    self.sslconn.close()
                else:
                    self.sock._sock.close()

            def run(self):
                self.running = True
                if not self.server.starttls_server:
                    if isinstance(self.sock, ssl.SSLSocket):
                        self.sslconn = self.sock
                    elif not self.wrap_conn():
                        return
                    self.show_conn_details()
                while self.running:
                    try:
                        msg = self.read()
                        if not msg:
                            # eof, so quit this handler
                            self.running = False
                            self.close()
                        elif msg.strip() == 'over':
                            if test_support.verbose and self.server.connectionchatty:
                                sys.stdout.write(" server: client closed connection\n")
                            self.close()
                            return
                        elif self.server.starttls_server and msg.strip() == 'STARTTLS':
                            if test_support.verbose and self.server.connectionchatty:
                                sys.stdout.write(" server: read STARTTLS from client, sending OK...\n")
                            self.write("OK\n")
                            if not self.wrap_conn():
                                return
                        elif self.server.starttls_server and self.sslconn and msg.strip() == 'ENDTLS':
                            if test_support.verbose and self.server.connectionchatty:
                                sys.stdout.write(" server: read ENDTLS from client, sending OK...\n")
                            self.write("OK\n")
                            self.sslconn.unwrap()
                            self.sslconn = None
                            if test_support.verbose and self.server.connectionchatty:
                                sys.stdout.write(" server: connection is now unencrypted...\n")
                        else:
                            if (test_support.verbose and
                                self.server.connectionchatty):
                                ctype = (self.sslconn and "encrypted") or "unencrypted"
                                sys.stdout.write(" server: read %s (%s), sending back %s (%s)...\n"
                                                 % (repr(msg), ctype, repr(msg.lower()), ctype))
                            self.write(msg.lower())
                    except ssl.SSLError:
                        if self.server.chatty:
                            handle_error("Test server failure:\n")
                        self.close()
                        self.running = False
                        # normally, we'd just stop here, but for the test
                        # harness, we want to stop the server
                        self.server.stop()

        def __init__(self, certificate, ssl_version=None,
                     certreqs=None, cacerts=None,
                     chatty=True, connectionchatty=False, starttls_server=False,
                     wrap_accepting_socket=False, ciphers=None):

            if ssl_version is None:
                ssl_version = ssl.PROTOCOL_TLSv1
            if certreqs is None:
                certreqs = ssl.CERT_NONE
            self.certificate = certificate
            self.protocol = ssl_version
            self.certreqs = certreqs
            self.cacerts = cacerts
            self.ciphers = ciphers
            self.chatty = chatty
            self.connectionchatty = connectionchatty
            self.starttls_server = starttls_server
            self.sock = socket.socket()
            self.flag = None
            if wrap_accepting_socket:
                self.sock = ssl.wrap_socket(self.sock, server_side=True,
                                            certfile=self.certificate,
                                            cert_reqs = self.certreqs,
                                            ca_certs = self.cacerts,
                                            ssl_version = self.protocol,
                                            ciphers = self.ciphers)
                if test_support.verbose and self.chatty:
                    sys.stdout.write(' server:  wrapped server socket as %s\n' % str(self.sock))
            self.port = test_support.bind_port(self.sock)
            self.active = False
            threading.Thread.__init__(self)
            self.daemon = True

        def start(self, flag=None):
            self.flag = flag
            threading.Thread.start(self)

        def run(self):
            self.sock.settimeout(0.05)
            self.sock.listen(5)
            self.active = True
            if self.flag:
                # signal an event
                self.flag.set()
            while self.active:
                try:
                    newconn, connaddr = self.sock.accept()
                    if test_support.verbose and self.chatty:
                        sys.stdout.write(' server:  new connection from '
                                         + str(connaddr) + '\n')
                    handler = self.ConnectionHandler(self, newconn)
                    handler.start()
                except socket.timeout:
                    pass
                except KeyboardInterrupt:
                    self.stop()
            self.sock.close()

        def stop(self):
            self.active = False

    class AsyncoreEchoServer(threading.Thread):

        class EchoServer(asyncore.dispatcher):

            class ConnectionHandler(asyncore.dispatcher_with_send):

                def __init__(self, conn, certfile):
                    asyncore.dispatcher_with_send.__init__(self, conn)
                    self.socket = ssl.wrap_socket(conn, server_side=True,
                                                  certfile=certfile,
                                                  do_handshake_on_connect=False)
                    self._ssl_accepting = True

                def readable(self):
                    if isinstance(self.socket, ssl.SSLSocket):
                        while self.socket.pending() > 0:
                            self.handle_read_event()
                    return True

                def _do_ssl_handshake(self):
                    try:
                        self.socket.do_handshake()
                    except ssl.SSLError, err:
                        if err.args[0] in (ssl.SSL_ERROR_WANT_READ,
                                           ssl.SSL_ERROR_WANT_WRITE):
                            return
                        elif err.args[0] == ssl.SSL_ERROR_EOF:
                            return self.handle_close()
                        raise
                    except socket.error, err:
                        if err.args[0] == errno.ECONNABORTED:
                            return self.handle_close()
                    else:
                        self._ssl_accepting = False

                def handle_read(self):
                    if self._ssl_accepting:
                        self._do_ssl_handshake()
                    else:
                        data = self.recv(1024)
                        if data and data.strip() != 'over':
                            self.send(data.lower())

                def handle_close(self):
                    self.close()
                    if test_support.verbose:
                        sys.stdout.write(" server:  closed connection %s\n" % self.socket)

                def handle_error(self):
                    raise

            def __init__(self, certfile):
                self.certfile = certfile
                asyncore.dispatcher.__init__(self)
                self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
                self.port = test_support.bind_port(self.socket)
                self.listen(5)

            def handle_accept(self):
                sock_obj, addr = self.accept()
                if test_support.verbose:
                    sys.stdout.write(" server:  new connection from %s:%s\n" %addr)
                self.ConnectionHandler(sock_obj, self.certfile)

            def handle_error(self):
                raise

        def __init__(self, certfile):
            self.flag = None
            self.active = False
            self.server = self.EchoServer(certfile)
            self.port = self.server.port
            threading.Thread.__init__(self)
            self.daemon = True

        def __str__(self):
            return "<%s %s>" % (self.__class__.__name__, self.server)

        def start(self, flag=None):
            self.flag = flag
            threading.Thread.start(self)

        def run(self):
            self.active = True
            if self.flag:
                self.flag.set()
            while self.active:
                asyncore.loop(0.05)

        def stop(self):
            self.active = False
            self.server.close()

    class SocketServerHTTPSServer(threading.Thread):

        class HTTPSServer(HTTPServer):

            def __init__(self, server_address, RequestHandlerClass, certfile):
                HTTPServer.__init__(self, server_address, RequestHandlerClass)
                # we assume the certfile contains both private key and certificate
                self.certfile = certfile
                self.allow_reuse_address = True

            def __str__(self):
                return ('<%s %s:%s>' %
                        (self.__class__.__name__,
                         self.server_name,
                         self.server_port))

            def get_request(self):
                # override this to wrap socket with SSL
                sock, addr = self.socket.accept()
                sslconn = ssl.wrap_socket(sock, server_side=True,
                                          certfile=self.certfile)
                return sslconn, addr

        class RootedHTTPRequestHandler(SimpleHTTPRequestHandler):
            # need to override translate_path to get a known root,
            # instead of using os.curdir, since the test could be
            # run from anywhere

            server_version = "TestHTTPS/1.0"

            root = None

            def translate_path(self, path):
                """Translate a /-separated PATH to the local filename syntax.

                Components that mean special things to the local file system
                (e.g. drive or directory names) are ignored.  (XXX They should
                probably be diagnosed.)

                """
                # abandon query parameters
                path = urlparse.urlparse(path)[2]
                path = os.path.normpath(urllib.unquote(path))
                words = path.split('/')
                words = filter(None, words)
                path = self.root
                for word in words:
                    drive, word = os.path.splitdrive(word)
                    head, word = os.path.split(word)
                    if word in self.root: continue
                    path = os.path.join(path, word)
                return path

            def log_message(self, format, *args):

                # we override this to suppress logging unless "verbose"

                if test_support.verbose:
                    sys.stdout.write(" server (%s:%d %s):\n   [%s] %s\n" %
                                     (self.server.server_address,
                                      self.server.server_port,
                                      self.request.cipher(),
                                      self.log_date_time_string(),
                                      format%args))


        def __init__(self, certfile):
            self.flag = None
            self.RootedHTTPRequestHandler.root = os.path.split(CERTFILE)[0]
            self.server = self.HTTPSServer(
                (HOST, 0), self.RootedHTTPRequestHandler, certfile)
            self.port = self.server.server_port
            threading.Thread.__init__(self)
            self.daemon = True

        def __str__(self):
            return "<%s %s>" % (self.__class__.__name__, self.server)

        def start(self, flag=None):
            self.flag = flag
            threading.Thread.start(self)

        def run(self):
            if self.flag:
                self.flag.set()
            self.server.serve_forever(0.05)

        def stop(self):
            self.server.shutdown()


    def bad_cert_test(certfile):
        """
        Launch a server with CERT_REQUIRED, and check that trying to
        connect to it with the given client certificate fails.
        """
        server = ThreadedEchoServer(CERTFILE,
                                    certreqs=ssl.CERT_REQUIRED,
                                    cacerts=CERTFILE, chatty=False)
        flag = threading.Event()
        server.start(flag)
        # wait for it to start
        flag.wait()
        # try to connect
        try:
            try:
                s = ssl.wrap_socket(socket.socket(),
                                    certfile=certfile,
                                    ssl_version=ssl.PROTOCOL_TLSv1)
                s.connect((HOST, server.port))
            except ssl.SSLError, x:
                if test_support.verbose:
                    sys.stdout.write("\nSSLError is %s\n" % x[1])
            except socket.error, x:
                if test_support.verbose:
                    sys.stdout.write("\nsocket.error is %s\n" % x[1])
            else:
                raise AssertionError("Use of invalid cert should have failed!")
        finally:
            server.stop()
            server.join()

    def server_params_test(certfile, protocol, certreqs, cacertsfile,
                           client_certfile, client_protocol=None, indata="FOO\n",
                           ciphers=None, chatty=True, connectionchatty=False,
                           wrap_accepting_socket=False):
        """
        Launch a server, connect a client to it and try various reads
        and writes.
        """
        server = ThreadedEchoServer(certfile,
                                    certreqs=certreqs,
                                    ssl_version=protocol,
                                    cacerts=cacertsfile,
                                    ciphers=ciphers,
                                    chatty=chatty,
                                    connectionchatty=connectionchatty,
                                    wrap_accepting_socket=wrap_accepting_socket)
        flag = threading.Event()
        server.start(flag)
        # wait for it to start
        flag.wait()
        # try to connect
        if client_protocol is None:
            client_protocol = protocol
        try:
            s = ssl.wrap_socket(socket.socket(),
                                certfile=client_certfile,
                                ca_certs=cacertsfile,
                                ciphers=ciphers,
                                cert_reqs=certreqs,
                                ssl_version=client_protocol)
            s.connect((HOST, server.port))
            for arg in [indata, bytearray(indata), memoryview(indata)]:
                if connectionchatty:
                    if test_support.verbose:
                        sys.stdout.write(
                            " client:  sending %s...\n" % (repr(arg)))
                s.write(arg)
                outdata = s.read()
                if connectionchatty:
                    if test_support.verbose:
                        sys.stdout.write(" client:  read %s\n" % repr(outdata))
                if outdata != indata.lower():
                    raise AssertionError(
                        "bad data <<%s>> (%d) received; expected <<%s>> (%d)\n"
                        % (outdata[:min(len(outdata),20)], len(outdata),
                           indata[:min(len(indata),20)].lower(), len(indata)))
            s.write("over\n")
            if connectionchatty:
                if test_support.verbose:
                    sys.stdout.write(" client:  closing connection.\n")
            s.close()
        finally:
            server.stop()
            server.join()

    def try_protocol_combo(server_protocol,
                           client_protocol,
                           expect_success,
                           certsreqs=None):
        if certsreqs is None:
            certsreqs = ssl.CERT_NONE
        certtype = {
            ssl.CERT_NONE: "CERT_NONE",
            ssl.CERT_OPTIONAL: "CERT_OPTIONAL",
            ssl.CERT_REQUIRED: "CERT_REQUIRED",
        }[certsreqs]
        if test_support.verbose:
            formatstr = (expect_success and " %s->%s %s\n") or " {%s->%s} %s\n"
            sys.stdout.write(formatstr %
                             (ssl.get_protocol_name(client_protocol),
                              ssl.get_protocol_name(server_protocol),
                              certtype))
        try:
            # NOTE: we must enable "ALL" ciphers, otherwise an SSLv23 client
            # will send an SSLv3 hello (rather than SSLv2) starting from
            # OpenSSL 1.0.0 (see issue #8322).
            server_params_test(CERTFILE, server_protocol, certsreqs,
                               CERTFILE, CERTFILE, client_protocol,
                               ciphers="ALL", chatty=False)
        # Protocol mismatch can result in either an SSLError, or a
        # "Connection reset by peer" error.
        except ssl.SSLError:
            if expect_success:
                raise
        except socket.error as e:
            if expect_success or e.errno != errno.ECONNRESET:
                raise
        else:
            if not expect_success:
                raise AssertionError(
                    "Client protocol %s succeeded with server protocol %s!"
                    % (ssl.get_protocol_name(client_protocol),
                       ssl.get_protocol_name(server_protocol)))


    class ThreadedTests(unittest.TestCase):

        def test_rude_shutdown(self):
            """A brutal shutdown of an SSL server should raise an IOError
            in the client when attempting handshake.
            """
            listener_ready = threading.Event()
            listener_gone = threading.Event()

            s = socket.socket()
            port = test_support.bind_port(s, HOST)

            # `listener` runs in a thread.  It sits in an accept() until
            # the main thread connects.  Then it rudely closes the socket,
            # and sets Event `listener_gone` to let the main thread know
            # the socket is gone.
            def listener():
                s.listen(5)
                listener_ready.set()
                s.accept()
                s.close()
                listener_gone.set()

            def connector():
                listener_ready.wait()
                c = socket.socket()
                c.connect((HOST, port))
                listener_gone.wait()
                try:
                    ssl_sock = ssl.wrap_socket(c)
                except IOError:
                    pass
                else:
                    self.fail('connecting to closed SSL socket should have failed')

            t = threading.Thread(target=listener)
            t.start()
            try:
                connector()
            finally:
                t.join()

        @skip_if_broken_ubuntu_ssl
        def test_echo(self):
            """Basic test of an SSL client connecting to a server"""
            if test_support.verbose:
                sys.stdout.write("\n")
            server_params_test(CERTFILE, ssl.PROTOCOL_TLSv1, ssl.CERT_NONE,
                               CERTFILE, CERTFILE, ssl.PROTOCOL_TLSv1,
                               chatty=True, connectionchatty=True)

        def test_getpeercert(self):
            if test_support.verbose:
                sys.stdout.write("\n")
            s2 = socket.socket()
            server = ThreadedEchoServer(CERTFILE,
                                        certreqs=ssl.CERT_NONE,
                                        ssl_version=ssl.PROTOCOL_SSLv23,
                                        cacerts=CERTFILE,
                                        chatty=False)
            flag = threading.Event()
            server.start(flag)
            # wait for it to start
            flag.wait()
            # try to connect
            try:
                s = ssl.wrap_socket(socket.socket(),
                                    certfile=CERTFILE,
                                    ca_certs=CERTFILE,
                                    cert_reqs=ssl.CERT_REQUIRED,
                                    ssl_version=ssl.PROTOCOL_SSLv23)
                s.connect((HOST, server.port))
                cert = s.getpeercert()
                self.assertTrue(cert, "Can't get peer certificate.")
                cipher = s.cipher()
                if test_support.verbose:
                    sys.stdout.write(pprint.pformat(cert) + '\n')
                    sys.stdout.write("Connection cipher is " + str(cipher) + '.\n')
                if 'subject' not in cert:
                    self.fail("No subject field in certificate: %s." %
                              pprint.pformat(cert))
                if ((('organizationName', 'Python Software Foundation'),)
                    not in cert['subject']):
                    self.fail(
                        "Missing or invalid 'organizationName' field in certificate subject; "
                        "should be 'Python Software Foundation'.")
                s.close()
            finally:
                server.stop()
                server.join()

        def test_empty_cert(self):
            """Connecting with an empty cert file"""
            bad_cert_test(os.path.join(os.path.dirname(__file__) or os.curdir,
                                      "nullcert.pem"))
        def test_malformed_cert(self):
            """Connecting with a badly formatted certificate (syntax error)"""
            bad_cert_test(os.path.join(os.path.dirname(__file__) or os.curdir,
                                       "badcert.pem"))
        def test_nonexisting_cert(self):
            """Connecting with a non-existing cert file"""
            bad_cert_test(os.path.join(os.path.dirname(__file__) or os.curdir,
                                       "wrongcert.pem"))
        def test_malformed_key(self):
            """Connecting with a badly formatted key (syntax error)"""
            bad_cert_test(os.path.join(os.path.dirname(__file__) or os.curdir,
                                       "badkey.pem"))

        @skip_if_broken_ubuntu_ssl
        def test_protocol_sslv2(self):
            """Connecting to an SSLv2 server with various client options"""
            if test_support.verbose:
                sys.stdout.write("\n")
            try_protocol_combo(ssl.PROTOCOL_SSLv2, ssl.PROTOCOL_SSLv2, True)
            try_protocol_combo(ssl.PROTOCOL_SSLv2, ssl.PROTOCOL_SSLv2, True, ssl.CERT_OPTIONAL)
            try_protocol_combo(ssl.PROTOCOL_SSLv2, ssl.PROTOCOL_SSLv2, True, ssl.CERT_REQUIRED)
            try_protocol_combo(ssl.PROTOCOL_SSLv2, ssl.PROTOCOL_SSLv23, True)
            try_protocol_combo(ssl.PROTOCOL_SSLv2, ssl.PROTOCOL_SSLv3, False)
            try_protocol_combo(ssl.PROTOCOL_SSLv2, ssl.PROTOCOL_TLSv1, False)

        @skip_if_broken_ubuntu_ssl
        def test_protocol_sslv23(self):
            """Connecting to an SSLv23 server with various client options"""
            if test_support.verbose:
                sys.stdout.write("\n")
            try:
                try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv2, True)
            except (ssl.SSLError, socket.error), x:
                # this fails on some older versions of OpenSSL (0.9.7l, for instance)
                if test_support.verbose:
                    sys.stdout.write(
                        " SSL2 client to SSL23 server test unexpectedly failed:\n %s\n"
                        % str(x))
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv3, True)
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv23, True)
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_TLSv1, True)

            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv3, True, ssl.CERT_OPTIONAL)
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv23, True, ssl.CERT_OPTIONAL)
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_TLSv1, True, ssl.CERT_OPTIONAL)

            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv3, True, ssl.CERT_REQUIRED)
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_SSLv23, True, ssl.CERT_REQUIRED)
            try_protocol_combo(ssl.PROTOCOL_SSLv23, ssl.PROTOCOL_TLSv1, True, ssl.CERT_REQUIRED)

        @skip_if_broken_ubuntu_ssl
        def test_protocol_sslv3(self):
            """Connecting to an SSLv3 server with various client options"""
            if test_support.verbose:
                sys.stdout.write("\n")
            try_protocol_combo(ssl.PROTOCOL_SSLv3, ssl.PROTOCOL_SSLv3, True)
            try_protocol_combo(ssl.PROTOCOL_SSLv3, ssl.PROTOCOL_SSLv3, True, ssl.CERT_OPTIONAL)
            try_protocol_combo(ssl.PROTOCOL_SSLv3, ssl.PROTOCOL_SSLv3, True, ssl.CERT_REQUIRED)
            try_protocol_combo(ssl.PROTOCOL_SSLv3, ssl.PROTOCOL_SSLv2, False)
            try_protocol_combo(ssl.PROTOCOL_SSLv3, ssl.PROTOCOL_SSLv23, False)
            try_protocol_combo(ssl.PROTOCOL_SSLv3, ssl.PROTOCOL_TLSv1, False)

        @skip_if_broken_ubuntu_ssl
        def test_protocol_tlsv1(self):
            """Connecting to a TLSv1 server with various client options"""
            if test_support.verbose:
                sys.stdout.write("\n")
            try_protocol_combo(ssl.PROTOCOL_TLSv1, ssl.PROTOCOL_TLSv1, True)
            try_protocol_combo(ssl.PROTOCOL_TLSv1, ssl.PROTOCOL_TLSv1, True, ssl.CERT_OPTIONAL)
            try_protocol_combo(ssl.PROTOCOL_TLSv1, ssl.PROTOCOL_TLSv1, True, ssl.CERT_REQUIRED)
            try_protocol_combo(ssl.PROTOCOL_TLSv1, ssl.PROTOCOL_SSLv2, False)
            try_protocol_combo(ssl.PROTOCOL_TLSv1, ssl.PROTOCOL_SSLv3, False)
            try_protocol_combo(ssl.PROTOCOL_TLSv1, ssl.PROTOCOL_SSLv23, False)

        def test_starttls(self):
            """Switching from clear text to encrypted and back again."""
            msgs = ("msg 1", "MSG 2", "STARTTLS", "MSG 3", "msg 4", "ENDTLS", "msg 5", "msg 6")

            server = ThreadedEchoServer(CERTFILE,
                                        ssl_version=ssl.PROTOCOL_TLSv1,
                                        starttls_server=True,
                                        chatty=True,
                                        connectionchatty=True)
            flag = threading.Event()
            server.start(flag)
            # wait for it to start
            flag.wait()
            # try to connect
            wrapped = False
            try:
                s = socket.socket()
                s.setblocking(1)
                s.connect((HOST, server.port))
                if test_support.verbose:
                    sys.stdout.write("\n")
                for indata in msgs:
                    if test_support.verbose:
                        sys.stdout.write(
                            " client:  sending %s...\n" % repr(indata))
                    if wrapped:
                        conn.write(indata)
                        outdata = conn.read()
                    else:
                        s.send(indata)
                        outdata = s.recv(1024)
                    if (indata == "STARTTLS" and
                        outdata.strip().lower().startswith("ok")):
                        # STARTTLS ok, switch to secure mode
                        if test_support.verbose:
                            sys.stdout.write(
                                " client:  read %s from server, starting TLS...\n"
                                % repr(outdata))
                        conn = ssl.wrap_socket(s, ssl_version=ssl.PROTOCOL_TLSv1)
                        wrapped = True
                    elif (indata == "ENDTLS" and
                        outdata.strip().lower().startswith("ok")):
                        # ENDTLS ok, switch back to clear text
                        if test_support.verbose:
                            sys.stdout.write(
                                " client:  read %s from server, ending TLS...\n"
                                % repr(outdata))
                        s = conn.unwrap()
                        wrapped = False
                    else:
                        if test_support.verbose:
                            sys.stdout.write(
                                " client:  read %s from server\n" % repr(outdata))
                if test_support.verbose:
                    sys.stdout.write(" client:  closing connection.\n")
                if wrapped:
                    conn.write("over\n")
                else:
                    s.send("over\n")
                s.close()
            finally:
                server.stop()
                server.join()

        def test_socketserver(self):
            """Using a SocketServer to create and manage SSL connections."""
            server = SocketServerHTTPSServer(CERTFILE)
            flag = threading.Event()
            server.start(flag)
            # wait for it to start
            flag.wait()
            # try to connect
            try:
                if test_support.verbose:
                    sys.stdout.write('\n')
                with open(CERTFILE, 'rb') as f:
                    d1 = f.read()
                d2 = ''
                # now fetch the same data from the HTTPS server
                url = 'https://127.0.0.1:%d/%s' % (
                    server.port, os.path.split(CERTFILE)[1])
                with test_support.check_py3k_warnings():
                    f = urllib.urlopen(url)
                dlen = f.info().getheader("content-length")
                if dlen and (int(dlen) > 0):
                    d2 = f.read(int(dlen))
                    if test_support.verbose:
                        sys.stdout.write(
                            " client: read %d bytes from remote server '%s'\n"
                            % (len(d2), server))
                f.close()
                self.assertEqual(d1, d2)
            finally:
                server.stop()
                server.join()

        def test_wrapped_accept(self):
            """Check the accept() method on SSL sockets."""
            if test_support.verbose:
                sys.stdout.write("\n")
            server_params_test(CERTFILE, ssl.PROTOCOL_SSLv23, ssl.CERT_REQUIRED,
                               CERTFILE, CERTFILE, ssl.PROTOCOL_SSLv23,
                               chatty=True, connectionchatty=True,
                               wrap_accepting_socket=True)

        def test_asyncore_server(self):
            """Check the example asyncore integration."""
            indata = "TEST MESSAGE of mixed case\n"

            if test_support.verbose:
                sys.stdout.write("\n")
            server = AsyncoreEchoServer(CERTFILE)
            flag = threading.Event()
            server.start(flag)
            # wait for it to start
            flag.wait()
            # try to connect
            try:
                s = ssl.wrap_socket(socket.socket())
                s.connect(('127.0.0.1', server.port))
                if test_support.verbose:
                    sys.stdout.write(
                        " client:  sending %s...\n" % (repr(indata)))
                s.write(indata)
                outdata = s.read()
                if test_support.verbose:
                    sys.stdout.write(" client:  read %s\n" % repr(outdata))
                if outdata != indata.lower():
                    self.fail(
                        "bad data <<%s>> (%d) received; expected <<%s>> (%d)\n"
                        % (outdata[:min(len(outdata),20)], len(outdata),
                           indata[:min(len(indata),20)].lower(), len(indata)))
                s.write("over\n")
                if test_support.verbose:
                    sys.stdout.write(" client:  closing connection.\n")
                s.close()
            finally:
                server.stop()
                # wait for server thread to end
                server.join()

        def test_recv_send(self):
            """Test recv(), send() and friends."""
            if test_support.verbose:
                sys.stdout.write("\n")

            server = ThreadedEchoServer(CERTFILE,
                                        certreqs=ssl.CERT_NONE,
                                        ssl_version=ssl.PROTOCOL_TLSv1,
                                        cacerts=CERTFILE,
                                        chatty=True,
                                        connectionchatty=False)
            flag = threading.Event()
            server.start(flag)
            # wait for it to start
            flag.wait()
            # try to connect
            s = ssl.wrap_socket(socket.socket(),
                                server_side=False,
                                certfile=CERTFILE,
                                ca_certs=CERTFILE,
                                cert_reqs=ssl.CERT_NONE,
                                ssl_version=ssl.PROTOCOL_TLSv1)
            s.connect((HOST, server.port))
            try:
                # helper methods for standardising recv* method signatures
                def _recv_into():
                    b = bytearray("\0"*100)
                    count = s.recv_into(b)
                    return b[:count]

                def _recvfrom_into():
                    b = bytearray("\0"*100)
                    count, addr = s.recvfrom_into(b)
                    return b[:count]

                # (name, method, whether to expect success, *args)
                send_methods = [
                    ('send', s.send, True, []),
                    ('sendto', s.sendto, False, ["some.address"]),
                    ('sendall', s.sendall, True, []),
                ]
                recv_methods = [
                    ('recv', s.recv, True, []),
                    ('recvfrom', s.recvfrom, False, ["some.address"]),
                    ('recv_into', _recv_into, True, []),
                    ('recvfrom_into', _recvfrom_into, False, []),
                ]
                data_prefix = u"PREFIX_"

                for meth_name, send_meth, expect_success, args in send_methods:
                    indata = data_prefix + meth_name
                    try:
                        send_meth(indata.encode('ASCII', 'strict'), *args)
                        outdata = s.read()
                        outdata = outdata.decode('ASCII', 'strict')
                        if outdata != indata.lower():
                            self.fail(
                                "While sending with <<%s>> bad data "
                                "<<%r>> (%d) received; "
                                "expected <<%r>> (%d)\n" % (
                                    meth_name, outdata[:20], len(outdata),
                                    indata[:20], len(indata)
                                )
                            )
                    except ValueError as e:
                        if expect_success:
                            self.fail(
                                "Failed to send with method <<%s>>; "
                                "expected to succeed.\n" % (meth_name,)
                            )
                        if not str(e).startswith(meth_name):
                            self.fail(
                                "Method <<%s>> failed with unexpected "
                                "exception message: %s\n" % (
                                    meth_name, e
                                )
                            )

                for meth_name, recv_meth, expect_success, args in recv_methods:
                    indata = data_prefix + meth_name
                    try:
                        s.send(indata.encode('ASCII', 'strict'))
                        outdata = recv_meth(*args)
                        outdata = outdata.decode('ASCII', 'strict')
                        if outdata != indata.lower():
                            self.fail(
                                "While receiving with <<%s>> bad data "
                                "<<%r>> (%d) received; "
                                "expected <<%r>> (%d)\n" % (
                                    meth_name, outdata[:20], len(outdata),
                                    indata[:20], len(indata)
                                )
                            )
                    except ValueError as e:
                        if expect_success:
                            self.fail(
                                "Failed to receive with method <<%s>>; "
                                "expected to succeed.\n" % (meth_name,)
                            )
                        if not str(e).startswith(meth_name):
                            self.fail(
                                "Method <<%s>> failed with unexpected "
                                "exception message: %s\n" % (
                                    meth_name, e
                                )
                            )
                        # consume data
                        s.read()

                s.write("over\n".encode("ASCII", "strict"))
                s.close()
            finally:
                server.stop()
                server.join()

        def test_handshake_timeout(self):
            # Issue #5103: SSL handshake must respect the socket timeout
            server = socket.socket(socket.AF_INET)
            host = "127.0.0.1"
            port = test_support.bind_port(server)
            started = threading.Event()
            finish = False

            def serve():
                server.listen(5)
                started.set()
                conns = []
                while not finish:
                    r, w, e = select.select([server], [], [], 0.1)
                    if server in r:
                        # Let the socket hang around rather than having
                        # it closed by garbage collection.
                        conns.append(server.accept()[0])

            t = threading.Thread(target=serve)
            t.start()
            started.wait()

            try:
                try:
                    c = socket.socket(socket.AF_INET)
                    c.settimeout(0.2)
                    c.connect((host, port))
                    # Will attempt handshake and time out
                    self.assertRaisesRegexp(ssl.SSLError, "timed out",
                                            ssl.wrap_socket, c)
                finally:
                    c.close()
                try:
                    c = socket.socket(socket.AF_INET)
                    c.settimeout(0.2)
                    c = ssl.wrap_socket(c)
                    # Will attempt handshake and time out
                    self.assertRaisesRegexp(ssl.SSLError, "timed out",
                                            c.connect, (host, port))
                finally:
                    c.close()
            finally:
                finish = True
                t.join()
                server.close()


def test_main(verbose=False):
    if skip_expected:
        raise unittest.SkipTest("No SSL support")

    global CERTFILE, SVN_PYTHON_ORG_ROOT_CERT
    CERTFILE = os.path.join(os.path.dirname(__file__) or os.curdir,
                            "keycert.pem")
    SVN_PYTHON_ORG_ROOT_CERT = os.path.join(
        os.path.dirname(__file__) or os.curdir,
        "https_svn_python_org_root.pem")

    if (not os.path.exists(CERTFILE) or
        not os.path.exists(SVN_PYTHON_ORG_ROOT_CERT)):
        raise test_support.TestFailed("Can't read certificate files!")

    tests = [BasicTests]

    if test_support.is_resource_enabled('network'):
        tests.append(NetworkedTests)

    if _have_threads:
        thread_info = test_support.threading_setup()
        if thread_info and test_support.is_resource_enabled('network'):
            tests.append(ThreadedTests)

    try:
        test_support.run_unittest(*tests)
    finally:
        if _have_threads:
            test_support.threading_cleanup(*thread_info)

if __name__ == "__main__":
    test_main()