From 5b45fb0a449543fab6e7b606e51b739cb316d3c4 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Sun, 30 Jun 2019 23:51:40 -0700 Subject: [3.7] bpo-37428: Don't set PHA verify flag on client side (GH-14421) (GH-14493) SSLContext.post_handshake_auth = True no longer sets SSL_VERIFY_POST_HANDSHAKE verify flag for client connections. Although the option is documented as ignored for clients, OpenSSL implicitly enables cert chain validation when the flag is set. Signed-off-by: Christian Heimes https://bugs.python.org/issue37428 (cherry picked from commit f0f5930ac88482ef896283db5be9b8d508d077db) Co-authored-by: Christian Heimes https://bugs.python.org/issue37428 --- Lib/test/test_ssl.py | 31 ++++++++++++++++ .../2019-06-27-13-27-02.bpo-37428._wcwUd.rst | 4 ++ Modules/_ssl.c | 43 +++++++++++++--------- 3 files changed, 61 insertions(+), 17 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2019-06-27-13-27-02.bpo-37428._wcwUd.rst diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py index 73b6bdf01e..86f790b4a2 100644 --- a/Lib/test/test_ssl.py +++ b/Lib/test/test_ssl.py @@ -4437,6 +4437,37 @@ class TestPostHandshakeAuth(unittest.TestCase): s.write(b'PHA') self.assertIn(b'WRONG_SSL_VERSION', s.recv(1024)) + def test_bpo37428_pha_cert_none(self): + # verify that post_handshake_auth does not implicitly enable cert + # validation. + hostname = SIGNED_CERTFILE_HOSTNAME + client_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) + client_context.post_handshake_auth = True + client_context.load_cert_chain(SIGNED_CERTFILE) + # no cert validation and CA on client side + client_context.check_hostname = False + client_context.verify_mode = ssl.CERT_NONE + + server_context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER) + server_context.load_cert_chain(SIGNED_CERTFILE) + server_context.load_verify_locations(SIGNING_CA) + server_context.post_handshake_auth = True + server_context.verify_mode = ssl.CERT_REQUIRED + + server = ThreadedEchoServer(context=server_context, chatty=False) + with server: + with client_context.wrap_socket(socket.socket(), + server_hostname=hostname) as s: + s.connect((HOST, server.port)) + s.write(b'HASCERT') + self.assertEqual(s.recv(1024), b'FALSE\n') + s.write(b'PHA') + self.assertEqual(s.recv(1024), b'OK\n') + s.write(b'HASCERT') + self.assertEqual(s.recv(1024), b'TRUE\n') + # server cert has not been validated + self.assertEqual(s.getpeercert(), {}) + def test_main(verbose=False): if support.verbose: diff --git a/Misc/NEWS.d/next/Library/2019-06-27-13-27-02.bpo-37428._wcwUd.rst b/Misc/NEWS.d/next/Library/2019-06-27-13-27-02.bpo-37428._wcwUd.rst new file mode 100644 index 0000000000..2cdce6b24d --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-06-27-13-27-02.bpo-37428._wcwUd.rst @@ -0,0 +1,4 @@ +SSLContext.post_handshake_auth = True no longer sets +SSL_VERIFY_POST_HANDSHAKE verify flag for client connections. Although the +option is documented as ignored for clients, OpenSSL implicitly enables cert +chain validation when the flag is set. diff --git a/Modules/_ssl.c b/Modules/_ssl.c index 30c91f5931..e8955eedfa 100644 --- a/Modules/_ssl.c +++ b/Modules/_ssl.c @@ -931,6 +931,26 @@ newPySSLSocket(PySSLContext *sslctx, PySocketSockObject *sock, SSL_set_mode(self->ssl, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER | SSL_MODE_AUTO_RETRY); +#ifdef TLS1_3_VERSION + if (sslctx->post_handshake_auth == 1) { + if (socket_type == PY_SSL_SERVER) { + /* bpo-37428: OpenSSL does not ignore SSL_VERIFY_POST_HANDSHAKE. + * Set SSL_VERIFY_POST_HANDSHAKE flag only for server sockets and + * only in combination with SSL_VERIFY_PEER flag. */ + int mode = SSL_get_verify_mode(self->ssl); + if (mode & SSL_VERIFY_PEER) { + int (*verify_cb)(int, X509_STORE_CTX *) = NULL; + verify_cb = SSL_get_verify_callback(self->ssl); + mode |= SSL_VERIFY_POST_HANDSHAKE; + SSL_set_verify(self->ssl, mode, verify_cb); + } + } else { + /* client socket */ + SSL_set_post_handshake_auth(self->ssl, 1); + } + } +#endif + if (server_hostname != NULL) { if (_ssl_configure_hostname(self, server_hostname) < 0) { Py_DECREF(self); @@ -2928,10 +2948,10 @@ _set_verify_mode(PySSLContext *self, enum py_ssl_cert_requirements n) "invalid value for verify_mode"); return -1; } -#ifdef TLS1_3_VERSION - if (self->post_handshake_auth) - mode |= SSL_VERIFY_POST_HANDSHAKE; -#endif + + /* bpo-37428: newPySSLSocket() sets SSL_VERIFY_POST_HANDSHAKE flag for + * server sockets and SSL_set_post_handshake_auth() for client. */ + /* keep current verify cb */ verify_cb = SSL_CTX_get_verify_callback(self->ctx); SSL_CTX_set_verify(self->ctx, mode, verify_cb); @@ -3628,8 +3648,6 @@ get_post_handshake_auth(PySSLContext *self, void *c) { #if TLS1_3_VERSION static int set_post_handshake_auth(PySSLContext *self, PyObject *arg, void *c) { - int (*verify_cb)(int, X509_STORE_CTX *) = NULL; - int mode = SSL_CTX_get_verify_mode(self->ctx); if (arg == NULL) { PyErr_SetString(PyExc_AttributeError, "cannot delete attribute"); return -1; @@ -3641,17 +3659,8 @@ set_post_handshake_auth(PySSLContext *self, PyObject *arg, void *c) { } self->post_handshake_auth = pha; - /* client-side socket setting, ignored by server-side */ - SSL_CTX_set_post_handshake_auth(self->ctx, pha); - - /* server-side socket setting, ignored by client-side */ - verify_cb = SSL_CTX_get_verify_callback(self->ctx); - if (pha) { - mode |= SSL_VERIFY_POST_HANDSHAKE; - } else { - mode ^= SSL_VERIFY_POST_HANDSHAKE; - } - SSL_CTX_set_verify(self->ctx, mode, verify_cb); + /* bpo-37428: newPySSLSocket() sets SSL_VERIFY_POST_HANDSHAKE flag for + * server sockets and SSL_set_post_handshake_auth() for client. */ return 0; } -- cgit v1.2.1