Chapter 06: lib.SSL_get_version segfaults on python3.6.6 darwin 16.7.0 about fopnp

[dellnoantechnp]

SSLSocket.version()

Return the actual SSL protocol version negotiated by the connection as a string, or None is no secure connection is established. As of this writing, possible return values include "SSLv2", "SSLv3", "TLSv1", "TLSv1.1" and "TLSv1.2". Recent OpenSSL versions may define more return values.

New in version 3.5.

---

    if sys.version_info >= (3, 5):
        protocol_version = ssl_sock.version()
    else:
        protocol_version = SSL_get_version(ssl_sock)

[brandon-rhodes]

Oh, neat! The next time I return to these fopnp examples to update them, I'll include this fix.

[brandon-rhodes]

Thanks for the report! I'm not sure how soon I'll get the chance to dig in and debug this, but the big question will be whether this depends on the operating system (Mac vs Linux) or whether the struct underlying Python 3.6 is different and my ctypes code — which hand-copies the shape of the C language struct as I read it out of the SSL .h file in the Python source code — needs to be updated and be different for different versions of Python.

If you're interested in debugging yourself, simply dig into the older .h files that define the SSL struct, looking for the same fields you can see me naming in my ctypes code. Chances are that the fields changed somewhere between earlier versions of Python 3 and the version Python 3.6 that you're using, and that my module needs an if statement to select a new list of fields if the Python version is recent enough. Feel free to comment here with further findings as you explore!