Here is a patch to fix the issue: recompute the timeout.

It's unclear to me if we should reset the timeout after each successful read/write, or if the timeout is "global" (total duration of the ssl method). I asked the question on the python-dev mailing list.
https://mail.python.org/pipermail/python-dev/2015-April/139001.html

My patch uses a global timeout (never reset the timeout), whereas socket.sendall() resets the timeout at each send() success.