Here's a patch that adds the necessary _PyVerify_fd checking for 3.4. It won't apply to 2.7 (too many changes between 2.7 and 3.4), and applies to 3.5 but does nothing because of the new Invalid Parameter Handler introduced into 3.5.

It doesn't fix the problem completely: there is then a new crash in sysmodule.c/sys_write().

Unfortunately I didn't manage to write a test that replicates this whole issue and fails if Python crashes.