Issue #19500: Add client-side SSL session resumption to the ssl module.

Doc/library/ssl.rst

@@ -776,6 +776,10 @@ Constants
 
    :class:`enum.IntFlag` collection of OP_* constants.
 
+.. data:: OP_NO_TICKET
+
+   Prevent client side from requesting a session ticket.
+
    .. versionadded:: 3.6
 
 .. data:: HAS_ALPN
@@ -1176,6 +1180,19 @@ SSL sockets also have the following additional methods and attributes:
 
    .. versionadded:: 3.2
 
+.. attribute:: SSLSocket.session
+
+   The :class:`SSLSession` for this SSL connection. The session is available
+   for client and server side sockets after the TLS handshake has been
+   performed. For client sockets the session can be set before
+   :meth:`~SSLSocket.do_handshake` has been called to reuse a session.
+
+   .. versionadded:: 3.6
+
+.. attribute:: SSLSocket.session_reused
+
+   .. versionadded:: 3.6
+
 
 SSL Contexts
 ------------
@@ -1509,7 +1526,7 @@ to speed up repeated connections from the same clients.
 
 .. method:: SSLContext.wrap_socket(sock, server_side=False, \
       do_handshake_on_connect=True, suppress_ragged_eofs=True, \
-      server_hostname=None)
+      server_hostname=None, session=None)
 
    Wrap an existing Python socket *sock* and return an :class:`SSLSocket`
    object.  *sock* must be a :data:`~socket.SOCK_STREAM` socket; other socket
@@ -1526,19 +1543,27 @@ to speed up repeated connections from the same clients.
    quite similarly to HTTP virtual hosts. Specifying *server_hostname* will
    raise a :exc:`ValueError` if *server_side* is true.
 
+   *session*, see :attr:`~SSLSocket.session`.
+
    .. versionchanged:: 3.5
       Always allow a server_hostname to be passed, even if OpenSSL does not
       have SNI.
 
+   .. versionchanged:: 3.6
+      *session* argument was added.
+
 .. method:: SSLContext.wrap_bio(incoming, outgoing, server_side=False, \
-                                server_hostname=None)
+                                server_hostname=None, session=None)
 
    Create a new :class:`SSLObject` instance by wrapping the BIO objects
    *incoming* and *outgoing*. The SSL routines will read input data from the
    incoming BIO and write data to the outgoing BIO.
 
-   The *server_side* and *server_hostname* parameters have the same meaning as
+   The *server_side*, *server_hostname* and *session* parameters have the
-   in :meth:`SSLContext.wrap_socket`.
+   same meaning as in :meth:`SSLContext.wrap_socket`.
+
+   .. versionchanged:: 3.6
+      *session* argument was added.
 
 .. method:: SSLContext.session_stats()
 
@@ -2045,6 +2070,8 @@ provided.
    - :attr:`~SSLSocket.context`
    - :attr:`~SSLSocket.server_side`
    - :attr:`~SSLSocket.server_hostname`
+   - :attr:`~SSLSocket.session`
+   - :attr:`~SSLSocket.session_reused`
    - :meth:`~SSLSocket.read`
    - :meth:`~SSLSocket.write`
    - :meth:`~SSLSocket.getpeercert`
@@ -2126,6 +2153,22 @@ purpose.  It wraps an OpenSSL memory BIO (Basic IO) object:
       become true after all data currently in the buffer has been read.
 
 
+SSL session
+-----------
+
+.. versionadded:: 3.6
+
+.. class:: SSLSession
+
+   Session object used by :attr:`~SSLSocket.session`.
+
+   .. attribute:: id
+   .. attribute:: time
+   .. attribute:: timeout
+   .. attribute:: ticket_lifetime_hint
+   .. attribute:: has_ticket
+
+
 .. _ssl-security:
 
 Security considerations

Lib/ssl.py

@@ -99,7 +99,7 @@ from enum import Enum as _Enum, IntEnum as _IntEnum, IntFlag as _IntFlag
 import _ssl             # if we can't import it, let the error propagate
 
 from _ssl import OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_INFO, OPENSSL_VERSION
-from _ssl import _SSLContext, MemoryBIO
+from _ssl import _SSLContext, MemoryBIO, SSLSession
 from _ssl import (
     SSLError, SSLZeroReturnError, SSLWantReadError, SSLWantWriteError,
     SSLSyscallError, SSLEOFError,
@@ -391,18 +391,18 @@ class SSLContext(_SSLContext):
     def wrap_socket(self, sock, server_side=False,
                     do_handshake_on_connect=True,
                     suppress_ragged_eofs=True,
-                    server_hostname=None):
+                    server_hostname=None, session=None):
         return SSLSocket(sock=sock, server_side=server_side,
                          do_handshake_on_connect=do_handshake_on_connect,
                          suppress_ragged_eofs=suppress_ragged_eofs,
                          server_hostname=server_hostname,
-                         _context=self)
+                         _context=self, _session=session)
 
     def wrap_bio(self, incoming, outgoing, server_side=False,
-                 server_hostname=None):
+                 server_hostname=None, session=None):
         sslobj = self._wrap_bio(incoming, outgoing, server_side=server_side,
                                 server_hostname=server_hostname)
-        return SSLObject(sslobj)
+        return SSLObject(sslobj, session=session)
 
     def set_npn_protocols(self, npn_protocols):
         protos = bytearray()
@@ -572,10 +572,12 @@ class SSLObject:
      * The ``do_handshake_on_connect`` and ``suppress_ragged_eofs`` machinery.
     """
 
-    def __init__(self, sslobj, owner=None):
+    def __init__(self, sslobj, owner=None, session=None):
         self._sslobj = sslobj
         # Note: _sslobj takes a weak reference to owner
         self._sslobj.owner = owner or self
+        if session is not None:
+            self._sslobj.session = session
 
     @property
     def context(self):
@@ -586,6 +588,20 @@ class SSLObject:
     def context(self, ctx):
         self._sslobj.context = ctx
 
+    @property
+    def session(self):
+        """The SSLSession for client socket."""
+        return self._sslobj.session
+
+    @session.setter
+    def session(self, session):
+        self._sslobj.session = session
+
+    @property
+    def session_reused(self):
+        """Was the client session reused during handshake"""
+        return self._sslobj.session_reused
+
     @property
     def server_side(self):
         """Whether this is a server-side socket."""
@@ -703,7 +719,7 @@ class SSLSocket(socket):
                  family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None,
                  suppress_ragged_eofs=True, npn_protocols=None, ciphers=None,
                  server_hostname=None,
-                 _context=None):
+                 _context=None, _session=None):
 
         if _context:
             self._context = _context
@@ -735,11 +751,16 @@ class SSLSocket(socket):
         # mixed in.
         if sock.getsockopt(SOL_SOCKET, SO_TYPE) != SOCK_STREAM:
             raise NotImplementedError("only stream sockets are supported")
-        if server_side and server_hostname:
+        if server_side:
-            raise ValueError("server_hostname can only be specified "
+            if server_hostname:
-                             "in client mode")
+                raise ValueError("server_hostname can only be specified "
+                                 "in client mode")
+            if _session is not None:
+                raise ValueError("session can only be specified in "
+                                 "client mode")
         if self._context.check_hostname and not server_hostname:
             raise ValueError("check_hostname requires server_hostname")
+        self._session = _session
         self.server_side = server_side
         self.server_hostname = server_hostname
         self.do_handshake_on_connect = do_handshake_on_connect
@@ -775,7 +796,8 @@ class SSLSocket(socket):
             try:
                 sslobj = self._context._wrap_socket(self, server_side,
                                                     server_hostname)
-                self._sslobj = SSLObject(sslobj, owner=self)
+                self._sslobj = SSLObject(sslobj, owner=self,
+                                         session=self._session)
                 if do_handshake_on_connect:
                     timeout = self.gettimeout()
                     if timeout == 0.0:
@@ -796,6 +818,24 @@ class SSLSocket(socket):
         self._context = ctx
         self._sslobj.context = ctx
 
+    @property
+    def session(self):
+        """The SSLSession for client socket."""
+        if self._sslobj is not None:
+            return self._sslobj.session
+
+    @session.setter
+    def session(self, session):
+        self._session = session
+        if self._sslobj is not None:
+            self._sslobj.session = session
+
+    @property
+    def session_reused(self):
+        """Was the client session reused during handshake"""
+        if self._sslobj is not None:
+            return self._sslobj.session_reused
+
     def dup(self):
         raise NotImplemented("Can't dup() %s instances" %
                              self.__class__.__name__)
@@ -1028,7 +1068,8 @@ class SSLSocket(socket):
         if self._connected:
             raise ValueError("attempt to connect already-connected SSLSocket!")
         sslobj = self.context._wrap_socket(self, False, self.server_hostname)
-        self._sslobj = SSLObject(sslobj, owner=self)
+        self._sslobj = SSLObject(sslobj, owner=self,
+                                 session=self._session)
         try:
             if connect_ex:
                 rc = socket.connect_ex(self, addr)

Lib/test/test_ssl.py

@@ -2163,7 +2163,8 @@ if _have_threads:
             self.server.close()
 
     def server_params_test(client_context, server_context, indata=b"FOO\n",
-                           chatty=True, connectionchatty=False, sni_name=None):
+                           chatty=True, connectionchatty=False, sni_name=None,
+                           session=None):
         """
         Launch a server, connect a client to it and try various reads
         and writes.
@@ -2174,7 +2175,7 @@ if _have_threads:
                                     connectionchatty=False)
         with server:
             with client_context.wrap_socket(socket.socket(),
-                    server_hostname=sni_name) as s:
+                    server_hostname=sni_name, session=session) as s:
                 s.connect((HOST, server.port))
                 for arg in [indata, bytearray(indata), memoryview(indata)]:
                     if connectionchatty:
@@ -2202,6 +2203,8 @@ if _have_threads:
                     'client_alpn_protocol': s.selected_alpn_protocol(),
                     'client_npn_protocol': s.selected_npn_protocol(),
                     'version': s.version(),
+                    'session_reused': s.session_reused,
+                    'session': s.session,
                 })
                 s.close()
             stats['server_alpn_protocols'] = server.selected_alpn_protocols
@@ -3412,6 +3415,111 @@ if _have_threads:
                         s.sendfile(file)
                         self.assertEqual(s.recv(1024), TEST_DATA)
 
+        def test_session(self):
+            server_context = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
+            server_context.load_cert_chain(SIGNED_CERTFILE)
+            client_context = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
+            client_context.verify_mode = ssl.CERT_REQUIRED
+            client_context.load_verify_locations(SIGNING_CA)
+
+            # first conncetion without session
+            stats = server_params_test(client_context, server_context)
+            session = stats['session']
+            self.assertTrue(session.id)
+            self.assertGreater(session.time, 0)
+            self.assertGreater(session.timeout, 0)
+            self.assertTrue(session.has_ticket)
+            if ssl.OPENSSL_VERSION_INFO > (1, 0, 1):
+                self.assertGreater(session.ticket_lifetime_hint, 0)
+            self.assertFalse(stats['session_reused'])
+            sess_stat = server_context.session_stats()
+            self.assertEqual(sess_stat['accept'], 1)
+            self.assertEqual(sess_stat['hits'], 0)
+
+            # reuse session
+            stats = server_params_test(client_context, server_context, session=session)
+            sess_stat = server_context.session_stats()
+            self.assertEqual(sess_stat['accept'], 2)
+            self.assertEqual(sess_stat['hits'], 1)
+            self.assertTrue(stats['session_reused'])
+            session2 = stats['session']
+            self.assertEqual(session2.id, session.id)
+            self.assertEqual(session2, session)
+            self.assertIsNot(session2, session)
+            self.assertGreaterEqual(session2.time, session.time)
+            self.assertGreaterEqual(session2.timeout, session.timeout)
+
+            # another one without session
+            stats = server_params_test(client_context, server_context)
+            self.assertFalse(stats['session_reused'])
+            session3 = stats['session']
+            self.assertNotEqual(session3.id, session.id)
+            self.assertNotEqual(session3, session)
+            sess_stat = server_context.session_stats()
+            self.assertEqual(sess_stat['accept'], 3)
+            self.assertEqual(sess_stat['hits'], 1)
+
+            # reuse session again
+            stats = server_params_test(client_context, server_context, session=session)
+            self.assertTrue(stats['session_reused'])
+            session4 = stats['session']
+            self.assertEqual(session4.id, session.id)
+            self.assertEqual(session4, session)
+            self.assertGreaterEqual(session4.time, session.time)
+            self.assertGreaterEqual(session4.timeout, session.timeout)
+            sess_stat = server_context.session_stats()
+            self.assertEqual(sess_stat['accept'], 4)
+            self.assertEqual(sess_stat['hits'], 2)
+
+        def test_session_handling(self):
+            context = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+            context.verify_mode = ssl.CERT_REQUIRED
+            context.load_verify_locations(CERTFILE)
+            context.load_cert_chain(CERTFILE)
+
+            context2 = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+            context2.verify_mode = ssl.CERT_REQUIRED
+            context2.load_verify_locations(CERTFILE)
+            context2.load_cert_chain(CERTFILE)
+
+            server = ThreadedEchoServer(context=context, chatty=False)
+            with server:
+                with context.wrap_socket(socket.socket()) as s:
+                    # session is None before handshake
+                    self.assertEqual(s.session, None)
+                    self.assertEqual(s.session_reused, None)
+                    s.connect((HOST, server.port))
+                    session = s.session
+                    self.assertTrue(session)
+                    with self.assertRaises(TypeError) as e:
+                        s.session = object
+                    self.assertEqual(str(e.exception), 'Value is not a SSLSession.')
+
+                with context.wrap_socket(socket.socket()) as s:
+                    s.connect((HOST, server.port))
+                    # cannot set session after handshake
+                    with self.assertRaises(ValueError) as e:
+                        s.session = session
+                    self.assertEqual(str(e.exception),
+                                     'Cannot set session after handshake.')
+
+                with context.wrap_socket(socket.socket()) as s:
+                    # can set session before handshake and before the
+                    # connection was established
+                    s.session = session
+                    s.connect((HOST, server.port))
+                    self.assertEqual(s.session.id, session.id)
+                    self.assertEqual(s.session, session)
+                    self.assertEqual(s.session_reused, True)
+
+                with context2.wrap_socket(socket.socket()) as s:
+                    # cannot re-use session with a different SSLContext
+                    with self.assertRaises(ValueError) as e:
+                        s.session = session
+                        s.connect((HOST, server.port))
+                    self.assertEqual(str(e.exception),
+                                     'Session refers to a different SSLContext.')
+
 
 def test_main(verbose=False):
     if support.verbose:

Misc/NEWS

@@ -138,6 +138,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #19500: Add client-side SSL session resumption to the ssl module.
+
 - Issue #28022: Deprecate ssl-related arguments in favor of SSLContext. The
   deprecation include manual creation of SSLSocket and certfile/keyfile
   (or similar) in ftplib, httplib, imaplib, smtplib, poplib and urllib.

Modules/_ssl.c

@@ -187,6 +187,19 @@ static X509_VERIFY_PARAM *X509_STORE_get0_param(X509_STORE *store)
 {
     return store->param;
 }
+
+static int
+SSL_SESSION_has_ticket(const SSL_SESSION *s)
+{
+    return (s->tlsext_ticklen > 0) ? 1 : 0;
+}
+
+static unsigned long
+SSL_SESSION_get_ticket_lifetime_hint(const SSL_SESSION *s)
+{
+    return s->tlsext_tick_lifetime_hint;
+}
+
 #endif /* OpenSSL < 1.1.0 or LibreSSL */
 
 
@@ -293,25 +306,35 @@ typedef struct {
     int eof_written;
 } PySSLMemoryBIO;
 
+typedef struct {
+    PyObject_HEAD
+    SSL_SESSION *session;
+    PySSLContext *ctx;
+} PySSLSession;
+
 static PyTypeObject PySSLContext_Type;
 static PyTypeObject PySSLSocket_Type;
 static PyTypeObject PySSLMemoryBIO_Type;
+static PyTypeObject PySSLSession_Type;
 
 /*[clinic input]
 module _ssl
 class _ssl._SSLContext "PySSLContext *" "&PySSLContext_Type"
 class _ssl._SSLSocket "PySSLSocket *" "&PySSLSocket_Type"
 class _ssl.MemoryBIO "PySSLMemoryBIO *" "&PySSLMemoryBIO_Type"
+class _ssl.SSLSession "PySSLSession *" "&PySSLSession_Type"
 [clinic start generated code]*/
-/*[clinic end generated code: output=da39a3ee5e6b4b0d input=7bf7cb832638e2e1]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=bdc67fafeeaa8109]*/
 
 #include "clinic/_ssl.c.h"
 
 static int PySSL_select(PySocketSockObject *s, int writing, _PyTime_t timeout);
 
+
 #define PySSLContext_Check(v)   (Py_TYPE(v) == &PySSLContext_Type)
 #define PySSLSocket_Check(v)    (Py_TYPE(v) == &PySSLSocket_Type)
 #define PySSLMemoryBIO_Check(v)    (Py_TYPE(v) == &PySSLMemoryBIO_Type)
+#define PySSLSession_Check(v)   (Py_TYPE(v) == &PySSLSession_Type)
 
 typedef enum {
     SOCKET_IS_NONBLOCKING,
@@ -2325,6 +2348,152 @@ _ssl__SSLSocket_tls_unique_cb_impl(PySSLSocket *self)
     return retval;
 }
 
+#ifdef OPENSSL_VERSION_1_1
+
+static SSL_SESSION*
+_ssl_session_dup(SSL_SESSION *session) {
+    SSL_SESSION *newsession = NULL;
+    int slen;
+    unsigned char *senc = NULL, *p;
+    const unsigned char *const_p;
+
+    if (session == NULL) {
+        PyErr_SetString(PyExc_ValueError, "Invalid session");
+        goto error;
+    }
+
+    /* get length */
+    slen = i2d_SSL_SESSION(session, NULL);
+    if (slen == 0 || slen > 0xFF00) {
+        PyErr_SetString(PyExc_ValueError, "i2d() failed.");
+        goto error;
+    }
+    if ((senc = PyMem_Malloc(slen)) == NULL) {
+        PyErr_NoMemory();
+        goto error;
+    }
+    p = senc;
+    if (!i2d_SSL_SESSION(session, &p)) {
+        PyErr_SetString(PyExc_ValueError, "i2d() failed.");
+        goto error;
+    }
+    const_p = senc;
+    newsession = d2i_SSL_SESSION(NULL, &const_p, slen);
+    if (session == NULL) {
+        goto error;
+    }
+    PyMem_Free(senc);
+    return newsession;
+  error:
+    if (senc != NULL) {
+        PyMem_Free(senc);
+    }
+    return NULL;
+}
+#endif
+
+static PyObject *
+PySSL_get_session(PySSLSocket *self, void *closure) {
+    /* get_session can return sessions from a server-side connection,
+     * it does not check for handshake done or client socket. */
+    PySSLSession *pysess;
+    SSL_SESSION *session;
+
+#ifdef OPENSSL_VERSION_1_1
+    /* duplicate session as workaround for session bug in OpenSSL 1.1.0,
+     * https://github.com/openssl/openssl/issues/1550 */
+    session = SSL_get0_session(self->ssl);  /* borrowed reference */
+    if (session == NULL) {
+        Py_RETURN_NONE;
+    }
+    if ((session = _ssl_session_dup(session)) == NULL) {
+        return NULL;
+    }
+#else
+    session = SSL_get1_session(self->ssl);
+    if (session == NULL) {
+        Py_RETURN_NONE;
+    }
+#endif
+
+    pysess = PyObject_New(PySSLSession, &PySSLSession_Type);
+    if (pysess == NULL) {
+        SSL_SESSION_free(session);
+        return NULL;
+    }
+
+    assert(self->ctx);
+    pysess->ctx = self->ctx;
+    Py_INCREF(pysess->ctx);
+    pysess->session = session;
+    return (PyObject *)pysess;
+}
+
+static int PySSL_set_session(PySSLSocket *self, PyObject *value,
+                             void *closure)
+                              {
+    PySSLSession *pysess;
+#ifdef OPENSSL_VERSION_1_1
+    SSL_SESSION *session;
+#endif
+    int result;
+
+    if (!PySSLSession_Check(value)) {
+        PyErr_SetString(PyExc_TypeError, "Value is not a SSLSession.");
+        return -1;
+    }
+    pysess = (PySSLSession *)value;
+
+    if (self->ctx->ctx != pysess->ctx->ctx) {
+        PyErr_SetString(PyExc_ValueError,
+                        "Session refers to a different SSLContext.");
+        return -1;
+    }
+    if (self->socket_type != PY_SSL_CLIENT) {
+        PyErr_SetString(PyExc_ValueError,
+                        "Cannot set session for server-side SSLSocket.");
+        return -1;
+    }
+    if (self->handshake_done) {
+        PyErr_SetString(PyExc_ValueError,
+                        "Cannot set session after handshake.");
+        return -1;
+    }
+#ifdef OPENSSL_VERSION_1_1
+    /* duplicate session */
+    if ((session = _ssl_session_dup(pysess->session)) == NULL) {
+        return -1;
+    }
+    result = SSL_set_session(self->ssl, session);
+    /* free duplicate, SSL_set_session() bumps ref count */
+    SSL_SESSION_free(session);
+#else
+    result = SSL_set_session(self->ssl, pysess->session);
+#endif
+    if (result == 0) {
+        _setSSLError(NULL, 0, __FILE__, __LINE__);
+        return -1;
+    }
+    return 0;
+}
+
+PyDoc_STRVAR(PySSL_set_session_doc,
+"_setter_session(session)\n\
+\
+Get / set SSLSession.");
+
+static PyObject *
+PySSL_get_session_reused(PySSLSocket *self, void *closure) {
+    if (SSL_session_reused(self->ssl)) {
+        Py_RETURN_TRUE;
+    } else {
+        Py_RETURN_FALSE;
+    }
+}
+
+PyDoc_STRVAR(PySSL_get_session_reused_doc,
+"Was the client session reused during handshake?");
+
 static PyGetSetDef ssl_getsetlist[] = {
     {"context", (getter) PySSL_get_context,
                 (setter) PySSL_set_context, PySSL_set_context_doc},
@@ -2334,6 +2503,10 @@ static PyGetSetDef ssl_getsetlist[] = {
                         PySSL_get_server_hostname_doc},
     {"owner", (getter) PySSL_get_owner, (setter) PySSL_set_owner,
               PySSL_get_owner_doc},
+    {"session", (getter) PySSL_get_session,
+                (setter) PySSL_set_session, PySSL_set_session_doc},
+    {"session_reused", (getter) PySSL_get_session_reused, NULL,
+              PySSL_get_session_reused_doc},
     {NULL},            /* sentinel */
 };
 
@@ -2618,7 +2791,7 @@ _ssl__SSLContext_get_ciphers_impl(PySSLContext *self)
 {
     SSL *ssl = NULL;
     STACK_OF(SSL_CIPHER) *sk = NULL;
-    SSL_CIPHER *cipher;
+    const SSL_CIPHER *cipher;
     int i=0;
     PyObject *result = NULL, *dct;
 
@@ -4086,6 +4259,193 @@ static PyTypeObject PySSLMemoryBIO_Type = {
 };
 
 
+/*
+ * SSL Session object
+ */
+
+static void
+PySSLSession_dealloc(PySSLSession *self)
+{
+    Py_XDECREF(self->ctx);
+    if (self->session != NULL) {
+        SSL_SESSION_free(self->session);
+    }
+    PyObject_Del(self);
+}
+
+static PyObject *
+PySSLSession_richcompare(PyObject *left, PyObject *right, int op)
+{
+    int result;
+
+    if (left == NULL || right == NULL) {
+        PyErr_BadInternalCall();
+        return NULL;
+    }
+
+    if (!PySSLSession_Check(left) || !PySSLSession_Check(right)) {
+        Py_RETURN_NOTIMPLEMENTED;
+    }
+
+    if (left == right) {
+        result = 0;
+    } else {
+        const unsigned char *left_id, *right_id;
+        unsigned int left_len, right_len;
+        left_id = SSL_SESSION_get_id(((PySSLSession *)left)->session,
+                                     &left_len);
+        right_id = SSL_SESSION_get_id(((PySSLSession *)right)->session,
+                                      &right_len);
+        if (left_len == right_len) {
+            result = memcmp(left_id, right_id, left_len);
+        } else {
+            result = 1;
+        }
+    }
+
+    switch (op) {
+      case Py_EQ:
+        if (result == 0) {
+            Py_RETURN_TRUE;
+        } else {
+            Py_RETURN_FALSE;
+        }
+        break;
+      case Py_NE:
+        if (result != 0) {
+            Py_RETURN_TRUE;
+        } else {
+            Py_RETURN_FALSE;
+        }
+        break;
+      case Py_LT:
+      case Py_LE:
+      case Py_GT:
+      case Py_GE:
+        Py_RETURN_NOTIMPLEMENTED;
+        break;
+      default:
+        PyErr_BadArgument();
+        return NULL;
+    }
+}
+
+static int
+PySSLSession_traverse(PySSLSession *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->ctx);
+    return 0;
+}
+
+static int
+PySSLSession_clear(PySSLSession *self)
+{
+    Py_CLEAR(self->ctx);
+    return 0;
+}
+
+
+static PyObject *
+PySSLSession_get_time(PySSLSession *self, void *closure) {
+    return PyLong_FromLong(SSL_SESSION_get_time(self->session));
+}
+
+PyDoc_STRVAR(PySSLSession_get_time_doc,
+"Session creation time (seconds since epoch).");
+
+
+static PyObject *
+PySSLSession_get_timeout(PySSLSession *self, void *closure) {
+    return PyLong_FromLong(SSL_SESSION_get_timeout(self->session));
+}
+
+PyDoc_STRVAR(PySSLSession_get_timeout_doc,
+"Session timeout (delta in seconds).");
+
+
+static PyObject *
+PySSLSession_get_ticket_lifetime_hint(PySSLSession *self, void *closure) {
+    unsigned long hint = SSL_SESSION_get_ticket_lifetime_hint(self->session);
+    return PyLong_FromUnsignedLong(hint);
+}
+
+PyDoc_STRVAR(PySSLSession_get_ticket_lifetime_hint_doc,
+"Ticket life time hint.");
+
+
+static PyObject *
+PySSLSession_get_session_id(PySSLSession *self, void *closure) {
+    const unsigned char *id;
+    unsigned int len;
+    id = SSL_SESSION_get_id(self->session, &len);
+    return PyBytes_FromStringAndSize((const char *)id, len);
+}
+
+PyDoc_STRVAR(PySSLSession_get_session_id_doc,
+"Session id");
+
+
+static PyObject *
+PySSLSession_get_has_ticket(PySSLSession *self, void *closure) {
+    if (SSL_SESSION_has_ticket(self->session)) {
+        Py_RETURN_TRUE;
+    } else {
+        Py_RETURN_FALSE;
+    }
+}
+
+PyDoc_STRVAR(PySSLSession_get_has_ticket_doc,
+"Does the session contain a ticket?");
+
+
+static PyGetSetDef PySSLSession_getsetlist[] = {
+    {"has_ticket", (getter) PySSLSession_get_has_ticket, NULL,
+              PySSLSession_get_has_ticket_doc},
+    {"id",   (getter) PySSLSession_get_session_id, NULL,
+              PySSLSession_get_session_id_doc},
+    {"ticket_lifetime_hint", (getter) PySSLSession_get_ticket_lifetime_hint,
+              NULL, PySSLSession_get_ticket_lifetime_hint_doc},
+    {"time", (getter) PySSLSession_get_time, NULL,
+              PySSLSession_get_time_doc},
+    {"timeout", (getter) PySSLSession_get_timeout, NULL,
+              PySSLSession_get_timeout_doc},
+    {NULL},            /* sentinel */
+};
+
+static PyTypeObject PySSLSession_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "_ssl.Session",                            /*tp_name*/
+    sizeof(PySSLSession),                      /*tp_basicsize*/
+    0,                                         /*tp_itemsize*/
+    (destructor)PySSLSession_dealloc,          /*tp_dealloc*/
+    0,                                         /*tp_print*/
+    0,                                         /*tp_getattr*/
+    0,                                         /*tp_setattr*/
+    0,                                         /*tp_reserved*/
+    0,                                         /*tp_repr*/
+    0,                                         /*tp_as_number*/
+    0,                                         /*tp_as_sequence*/
+    0,                                         /*tp_as_mapping*/
+    0,                                         /*tp_hash*/
+    0,                                         /*tp_call*/
+    0,                                         /*tp_str*/
+    0,                                         /*tp_getattro*/
+    0,                                         /*tp_setattro*/
+    0,                                         /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT,                        /*tp_flags*/
+    0,                                         /*tp_doc*/
+    (traverseproc)PySSLSession_traverse,       /*tp_traverse*/
+    (inquiry)PySSLSession_clear,               /*tp_clear*/
+    PySSLSession_richcompare,                  /*tp_richcompare*/
+    0,                                         /*tp_weaklistoffset*/
+    0,                                         /*tp_iter*/
+    0,                                         /*tp_iternext*/
+    0,                                         /*tp_methods*/
+    0,                                         /*tp_members*/
+    PySSLSession_getsetlist,                   /*tp_getset*/
+};
+
+
 /* helper routines for seeding the SSL PRNG */
 /*[clinic input]
 _ssl.RAND_add
@@ -4771,6 +5131,9 @@ PyInit__ssl(void)
         return NULL;
     if (PyType_Ready(&PySSLMemoryBIO_Type) < 0)
         return NULL;
+    if (PyType_Ready(&PySSLSession_Type) < 0)
+        return NULL;
+
 
     m = PyModule_Create(&_sslmodule);
     if (m == NULL)
@@ -4842,6 +5205,10 @@ PyInit__ssl(void)
     if (PyDict_SetItemString(d, "MemoryBIO",
                              (PyObject *)&PySSLMemoryBIO_Type) != 0)
         return NULL;
+    if (PyDict_SetItemString(d, "SSLSession",
+                             (PyObject *)&PySSLSession_Type) != 0)
+        return NULL;
+
     PyModule_AddIntConstant(m, "SSL_ERROR_ZERO_RETURN",
                             PY_SSL_ERROR_ZERO_RETURN);
     PyModule_AddIntConstant(m, "SSL_ERROR_WANT_READ",
@@ -4968,6 +5335,7 @@ PyInit__ssl(void)
     PyModule_AddIntConstant(m, "OP_CIPHER_SERVER_PREFERENCE",
                             SSL_OP_CIPHER_SERVER_PREFERENCE);
     PyModule_AddIntConstant(m, "OP_SINGLE_DH_USE", SSL_OP_SINGLE_DH_USE);
+    PyModule_AddIntConstant(m, "OP_NO_TICKET", SSL_OP_NO_TICKET);
 #ifdef SSL_OP_SINGLE_ECDH_USE
     PyModule_AddIntConstant(m, "OP_SINGLE_ECDH_USE", SSL_OP_SINGLE_ECDH_USE);
 #endif