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[3.8] bpo-43577: Fix deadlock with SSLContext._msg_callback and sni_callback (GH-24957) #24959

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Merged
miss-islington merged 1 commit into from
Mar 21, 2021
Merged

[3.8] bpo-43577: Fix deadlock with SSLContext._msg_callback and sni_callback (GH-24957) #24959

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22 changes: 22 additions & 0 deletions Lib/test/test_ssl.py
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Original file line number Diff line number Diff line change
Expand Up @@ -4730,6 +4730,28 @@ def msg_cb(conn, direction, version, content_type, msg_type, data):
msg
)

def test_msg_callback_deadlock_bpo43577(self):
client_context, server_context, hostname = testing_context()
server_context2 = testing_context()[1]

def msg_cb(conn, direction, version, content_type, msg_type, data):
pass

def sni_cb(sock, servername, ctx):
sock.context = server_context2

server_context._msg_callback = msg_cb
server_context.sni_callback = sni_cb

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))
with client_context.wrap_socket(socket.socket(),
server_hostname=hostname) as s:
s.connect((HOST, server.port))


def test_main(verbose=False):
if support.verbose:
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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2021-03-21-10-13-17.bpo-43577.m7JnAV.rst
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@@ -0,0 +1 @@
Fix deadlock when using :class:`ssl.SSLContext` debug callback with :meth:`ssl.SSLContext.sni_callback`.
5 changes: 5 additions & 0 deletions Modules/_ssl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2205,6 +2205,11 @@ static int PySSL_set_context(PySSLSocket *self, PyObject *value,
Py_INCREF(value);
Py_SETREF(self->ctx, (PySSLContext *)value);
SSL_set_SSL_CTX(self->ssl, self->ctx->ctx);
/* Set SSL* internal msg_callback to state of new context's state */
SSL_set_msg_callback(
self->ssl,
self->ctx->msg_cb ? _PySSL_msg_callback : NULL
);
#endif
} else {
PyErr_SetString(PyExc_TypeError, "The value must be a SSLContext");
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1 change: 1 addition & 0 deletions Modules/_ssl/debughelpers.c
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Expand Up @@ -23,6 +23,7 @@ _PySSL_msg_callback(int write_p, int version, int content_type,
ssl_obj = (PySSLSocket *)SSL_get_app_data(ssl);
assert(PySSLSocket_Check(ssl_obj));
if (ssl_obj->ctx->msg_cb == NULL) {
PyGILState_Release(threadstate);
return;
}

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