diff options
| -rw-r--r-- | Doc/library/ssl.rst | 30 | ||||
| -rw-r--r-- | Lib/ssl.py | 2 | ||||
| -rw-r--r-- | Lib/test/ssl_servers.py | 4 | ||||
| -rw-r--r-- | Lib/test/test_ssl.py | 29 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Modules/_ssl.c | 35 | ||||
| -rw-r--r-- | Python/fileutils.c | 6 |
7 files changed, 103 insertions, 6 deletions
diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst index 9b3306c..0525e89 100644 --- a/Doc/library/ssl.rst +++ b/Doc/library/ssl.rst @@ -428,9 +428,17 @@ Constants .. versionadded:: 3.3 +.. data:: OP_SINGLE_DH_USE + + Prevents re-use of the same DH key for distinct SSL sessions. This + improves forward secrecy but requires more computational resources. + This option only applies to server sockets. + + .. versionadded:: 3.3 + .. data:: OP_SINGLE_ECDH_USE - Prevents re-use of the same ECDH key for several SSL sessions. This + Prevents re-use of the same ECDH key for distinct SSL sessions. This improves forward secrecy but requires more computational resources. This option only applies to server sockets. @@ -707,12 +715,24 @@ to speed up repeated connections from the same clients. when connected, the :meth:`SSLSocket.cipher` method of SSL sockets will give the currently selected cipher. +.. method:: SSLContext.load_dh_params(dhfile) + + Load the key generation parameters for Diffie-Helman (DH) key exchange. + Using DH key exchange improves forward secrecy at the expense of + computational resources (both on the server and on the client). + The *dhfile* parameter should be the path to a file containing DH + parameters in PEM format. + + This setting doesn't apply to client sockets. You can also use the + :data:`OP_SINGLE_DH_USE` option to further improve security. + + .. versionadded:: 3.3 + .. method:: SSLContext.set_ecdh_curve(curve_name) - Set the curve name for Elliptic Curve-based Diffie-Hellman (abbreviated - ECDH) key exchange. Using Diffie-Hellman key exchange improves forward - secrecy at the expense of computational resources (both on the server and - on the client). The *curve_name* parameter should be a string describing + Set the curve name for Elliptic Curve-based Diffie-Hellman (ECDH) key + exchange. ECDH is significantly faster than regular DH while arguably + as secure. The *curve_name* parameter should be a string describing a well-known elliptic curve, for example ``prime256v1`` for a widely supported curve. @@ -68,7 +68,7 @@ from _ssl import ( from _ssl import CERT_NONE, CERT_OPTIONAL, CERT_REQUIRED from _ssl import ( OP_ALL, OP_NO_SSLv2, OP_NO_SSLv3, OP_NO_TLSv1, - OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_ECDH_USE, + OP_CIPHER_SERVER_PREFERENCE, OP_SINGLE_DH_USE, OP_SINGLE_ECDH_USE, ) try: from _ssl import OP_NO_COMPRESSION diff --git a/Lib/test/ssl_servers.py b/Lib/test/ssl_servers.py index becbfab..8686153 100644 --- a/Lib/test/ssl_servers.py +++ b/Lib/test/ssl_servers.py @@ -180,6 +180,8 @@ if __name__ == "__main__": parser.add_argument('--curve-name', dest='curve_name', type=str, action='store', help='curve name for EC-based Diffie-Hellman') + parser.add_argument('--dh', dest='dh_file', type=str, action='store', + help='PEM file containing DH parameters') args = parser.parse_args() support.verbose = args.verbose @@ -192,6 +194,8 @@ if __name__ == "__main__": context.load_cert_chain(CERTFILE) if args.curve_name: context.set_ecdh_curve(args.curve_name) + if args.dh_file: + context.load_dh_params(args.dh_file) server = HTTPSServer(("", args.port), handler_class, context) if args.verbose: diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py index d549799..a4bcdd0 100644 --- a/Lib/test/test_ssl.py +++ b/Lib/test/test_ssl.py @@ -56,6 +56,8 @@ WRONGCERT = data_file("XXXnonexisting.pem") BADKEY = data_file("badkey.pem") NOKIACERT = data_file("nokia.pem") +DHFILE = data_file("dh512.pem") +BYTES_DHFILE = os.fsencode(DHFILE) def handle_error(prefix): exc_format = ' '.join(traceback.format_exception(*sys.exc_info())) @@ -99,6 +101,7 @@ class BasicSocketTests(unittest.TestCase): ssl.CERT_OPTIONAL ssl.CERT_REQUIRED ssl.OP_CIPHER_SERVER_PREFERENCE + ssl.OP_SINGLE_DH_USE ssl.OP_SINGLE_ECDH_USE if ssl.OPENSSL_VERSION_INFO >= (1, 0): ssl.OP_NO_COMPRESSION @@ -538,6 +541,19 @@ class ContextTests(unittest.TestCase): # Issue #10989: crash if the second argument type is invalid self.assertRaises(TypeError, ctx.load_verify_locations, None, True) + def test_load_dh_params(self): + ctx = ssl.SSLContext(ssl.PROTOCOL_TLSv1) + ctx.load_dh_params(DHFILE) + if os.name != 'nt': + ctx.load_dh_params(BYTES_DHFILE) + self.assertRaises(TypeError, ctx.load_dh_params) + self.assertRaises(TypeError, ctx.load_dh_params, None) + with self.assertRaises(FileNotFoundError) as cm: + ctx.load_dh_params(WRONGCERT) + self.assertEqual(cm.exception.errno, errno.ENOENT) + with self.assertRaisesRegex(ssl.SSLError, "PEM routines"): + ctx.load_dh_params(CERTFILE) + @skip_if_broken_ubuntu_ssl def test_session_stats(self): for proto in PROTOCOLS: @@ -1802,6 +1818,19 @@ else: chatty=True, connectionchatty=True) self.assertIs(stats['compression'], None) + def test_dh_params(self): + # Check we can get a connection with ephemeral Diffie-Hellman + context = ssl.SSLContext(ssl.PROTOCOL_TLSv1) + context.load_cert_chain(CERTFILE) + context.load_dh_params(DHFILE) + context.set_ciphers("kEDH") + stats = server_params_test(context, context, + chatty=True, connectionchatty=True) + cipher = stats["cipher"][0] + parts = cipher.split("-") + if "ADH" not in parts and "EDH" not in parts and "DHE" not in parts: + self.fail("Non-DH cipher: " + cipher[0]) + def test_main(verbose=False): if support.verbose: @@ -419,6 +419,9 @@ Core and Builtins Library ------- +- Issue #13626: Add support for SSL Diffie-Hellman key exchange, through the + SSLContext.load_dh_params() method and the ssl.OP_SINGLE_DH_USE option. + - Issue #11006: Don't issue low level warning in subprocess when pipe2() fails. - Issue #13620: Support for Chrome browser in webbrowser.py Patch contributed diff --git a/Modules/_ssl.c b/Modules/_ssl.c index 02fe5f3..3e5ecfd 100644 --- a/Modules/_ssl.c +++ b/Modules/_ssl.c @@ -1922,6 +1922,38 @@ load_verify_locations(PySSLContext *self, PyObject *args, PyObject *kwds) } static PyObject * +load_dh_params(PySSLContext *self, PyObject *filepath) +{ + FILE *f; + DH *dh; + + f = _Py_fopen(filepath, "rb"); + if (f == NULL) { + if (!PyErr_Occurred()) + PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, filepath); + return NULL; + } + errno = 0; + PySSL_BEGIN_ALLOW_THREADS + dh = PEM_read_DHparams(f, NULL, NULL, NULL); + PySSL_END_ALLOW_THREADS + if (dh == NULL) { + if (errno != 0) { + ERR_clear_error(); + PyErr_SetFromErrnoWithFilenameObject(PyExc_OSError, filepath); + } + else { + _setSSLError(NULL, 0, __FILE__, __LINE__); + } + return NULL; + } + if (SSL_CTX_set_tmp_dh(self->ctx, dh) == 0) + _setSSLError(NULL, 0, __FILE__, __LINE__); + DH_free(dh); + Py_RETURN_NONE; +} + +static PyObject * context_wrap_socket(PySSLContext *self, PyObject *args, PyObject *kwds) { char *kwlist[] = {"sock", "server_side", "server_hostname", NULL}; @@ -2050,6 +2082,8 @@ static struct PyMethodDef context_methods[] = { METH_VARARGS, NULL}, {"load_cert_chain", (PyCFunction) load_cert_chain, METH_VARARGS | METH_KEYWORDS, NULL}, + {"load_dh_params", (PyCFunction) load_dh_params, + METH_O, NULL}, {"load_verify_locations", (PyCFunction) load_verify_locations, METH_VARARGS | METH_KEYWORDS, NULL}, {"session_stats", (PyCFunction) session_stats, @@ -2505,6 +2539,7 @@ PyInit__ssl(void) PyModule_AddIntConstant(m, "OP_NO_TLSv1", SSL_OP_NO_TLSv1); 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_SINGLE_ECDH_USE", SSL_OP_SINGLE_ECDH_USE); #ifdef SSL_OP_NO_COMPRESSION PyModule_AddIntConstant(m, "OP_NO_COMPRESSION", diff --git a/Python/fileutils.c b/Python/fileutils.c index 1e71431..8993c8c 100644 --- a/Python/fileutils.c +++ b/Python/fileutils.c @@ -310,6 +310,12 @@ _Py_fopen(PyObject *path, const char *mode) wchar_t wmode[10]; int usize; + if (!PyUnicode_Check(path)) { + PyErr_Format(PyExc_TypeError, + "str file path expected under Windows, got %R", + Py_TYPE(path)); + return NULL; + } wpath = PyUnicode_AsUnicode(path); if (wpath == NULL) return NULL; |