[Python-checkins] [2.7] bpo-32947: Fixes for TLS 1.3 and OpenSSL 1.1.1 (GH-8761) (GH-11876)
Victor Stinner
webhook-mailer at python.org
Fri Feb 15 12:27:48 EST 2019
https://github.com/python/cpython/commit/2149a9ad7a9d39d7d680ec0fb602042c91057484
commit: 2149a9ad7a9d39d7d680ec0fb602042c91057484
branch: 2.7
author: stratakis <cstratak at redhat.com>
committer: Victor Stinner <vstinner at redhat.com>
date: 2019-02-15T18:27:44+01:00
summary:
[2.7] bpo-32947: Fixes for TLS 1.3 and OpenSSL 1.1.1 (GH-8761) (GH-11876)
Backport of TLS 1.3 related fixes from 3.7.
Misc fixes and workarounds for compatibility with OpenSSL 1.1.1 from git
master and TLS 1.3 support. With OpenSSL 1.1.1, Python negotiates TLS 1.3 by
default. Some test cases only apply to TLS 1.2.
OpenSSL 1.1.1 has added a new option OP_ENABLE_MIDDLEBOX_COMPAT for TLS
1.3. The feature is enabled by default for maximum compatibility with
broken middle boxes. Users should be able to disable the hack and CPython's test suite needs
it to verify default options
Signed-off-by: Christian Heimes <christian at python.org>
(cherry picked from commit 2a4ee8aa01d61b6a9c8e9c65c211e61bdb471826)
files:
A Misc/NEWS.d/next/Library/2018-08-14-08-57-01.bpo-32947.mqStVW.rst
M Doc/library/ssl.rst
M Lib/test/test_ssl.py
M Modules/_ssl.c
diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst
index 35c954815d75..8e9049238cc0 100644
--- a/Doc/library/ssl.rst
+++ b/Doc/library/ssl.rst
@@ -742,6 +742,15 @@ Constants
.. versionadded:: 2.7.9
+.. data:: OP_ENABLE_MIDDLEBOX_COMPAT
+
+ Send dummy Change Cipher Spec (CCS) messages in TLS 1.3 handshake to make
+ a TLS 1.3 connection look more like a TLS 1.2 connection.
+
+ This option is only available with OpenSSL 1.1.1 and later.
+
+ .. versionadded:: 2.7.16
+
.. data:: OP_NO_COMPRESSION
Disable compression on the SSL channel. This is useful if the application
diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
index 01e543241cfd..0eecc781d9e6 100644
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -82,6 +82,7 @@ def data_file(*name):
OP_SINGLE_DH_USE = getattr(ssl, "OP_SINGLE_DH_USE", 0)
OP_SINGLE_ECDH_USE = getattr(ssl, "OP_SINGLE_ECDH_USE", 0)
OP_CIPHER_SERVER_PREFERENCE = getattr(ssl, "OP_CIPHER_SERVER_PREFERENCE", 0)
+OP_ENABLE_MIDDLEBOX_COMPAT = getattr(ssl, "OP_ENABLE_MIDDLEBOX_COMPAT", 0)
def handle_error(prefix):
@@ -806,7 +807,8 @@ def test_options(self):
default = (ssl.OP_ALL | ssl.OP_NO_SSLv2 | ssl.OP_NO_SSLv3)
# SSLContext also enables these by default
default |= (OP_NO_COMPRESSION | OP_CIPHER_SERVER_PREFERENCE |
- OP_SINGLE_DH_USE | OP_SINGLE_ECDH_USE)
+ OP_SINGLE_DH_USE | OP_SINGLE_ECDH_USE |
+ OP_ENABLE_MIDDLEBOX_COMPAT)
self.assertEqual(default, ctx.options)
ctx.options |= ssl.OP_NO_TLSv1
self.assertEqual(default | ssl.OP_NO_TLSv1, ctx.options)
@@ -1697,23 +1699,43 @@ def wrap_conn(self):
self.sock, server_side=True)
self.server.selected_npn_protocols.append(self.sslconn.selected_npn_protocol())
self.server.selected_alpn_protocols.append(self.sslconn.selected_alpn_protocol())
- except socket.error as e:
- # We treat ConnectionResetError as though it were an
- # SSLError - OpenSSL on Ubuntu abruptly closes the
- # connection when asked to use an unsupported protocol.
- #
- # 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 not isinstance(e, ssl.SSLError) and e.errno != errno.ECONNRESET:
- raise
- self.server.conn_errors.append(e)
- if self.server.chatty:
- handle_error("\n server: bad connection attempt from " + repr(self.addr) + ":\n")
- self.running = False
- self.server.stop()
- self.close()
- return False
+ except (ssl.SSLError, socket.error, OSError) as e:
+ if e.errno in (errno.ECONNRESET, errno.EPIPE, errno.ESHUTDOWN):
+ # Mimick Python 3:
+ #
+ # except (ConnectionResetError, BrokenPipeError):
+ #
+ # We treat ConnectionResetError as though it were an
+ # SSLError - OpenSSL on Ubuntu abruptly closes the
+ # connection when asked to use an unsupported protocol.
+ #
+ # BrokenPipeError is raised in TLS 1.3 mode, when OpenSSL
+ # tries to send session tickets after handshake.
+ # https://github.com/openssl/openssl/issues/6342
+ self.server.conn_errors.append(str(e))
+ if self.server.chatty:
+ handle_error(
+ "\n server: bad connection attempt from "
+ + repr(self.addr) + ":\n")
+ self.running = False
+ self.close()
+ return False
+ else:
+ # OSError may occur with wrong protocols, e.g. both
+ # sides use PROTOCOL_TLS_SERVER.
+ #
+ # 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 not isinstance(e, ssl.SSLError) and e.errno != errno.ECONNRESET:
+ raise
+ self.server.conn_errors.append(e)
+ if self.server.chatty:
+ handle_error("\n server: bad connection attempt from " + repr(self.addr) + ":\n")
+ self.running = False
+ self.server.stop()
+ self.close()
+ return False
else:
if self.server.context.verify_mode == ssl.CERT_REQUIRED:
cert = self.sslconn.getpeercert()
@@ -2769,7 +2791,7 @@ def serve():
# Block on the accept and wait on the connection to close.
evt.set()
remote[0], peer[0] = server.accept()
- remote[0].recv(1)
+ remote[0].send(remote[0].recv(4))
t = threading.Thread(target=serve)
t.start()
@@ -2777,6 +2799,8 @@ def serve():
evt.wait()
client = context.wrap_socket(socket.socket())
client.connect((host, port))
+ client.send(b'data')
+ client.recv()
client_addr = client.getsockname()
client.close()
t.join()
diff --git a/Misc/NEWS.d/next/Library/2018-08-14-08-57-01.bpo-32947.mqStVW.rst b/Misc/NEWS.d/next/Library/2018-08-14-08-57-01.bpo-32947.mqStVW.rst
new file mode 100644
index 000000000000..28de360c3671
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-08-14-08-57-01.bpo-32947.mqStVW.rst
@@ -0,0 +1,2 @@
+Add OP_ENABLE_MIDDLEBOX_COMPAT and test workaround for TLSv1.3 for future
+compatibility with OpenSSL 1.1.1.
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 80078aa3cb05..93b635cc4ac9 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -4411,6 +4411,10 @@ init_ssl(void)
PyModule_AddIntConstant(m, "OP_NO_COMPRESSION",
SSL_OP_NO_COMPRESSION);
#endif
+#ifdef SSL_OP_ENABLE_MIDDLEBOX_COMPAT
+ PyModule_AddIntConstant(m, "OP_ENABLE_MIDDLEBOX_COMPAT",
+ SSL_OP_ENABLE_MIDDLEBOX_COMPAT);
+#endif
#if HAVE_SNI
r = Py_True;
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