bug#46631: Python CVE-2021-3177

[Leo Famulari]

Quoting from MITRE:

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Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in
_ctypes/callproc.c, which may lead to remote code execution in certain
Python applications that accept floating-point numbers as untrusted
input, as demonstrated by a 1e300 argument to c_double.from_param. This
occurs because sprintf is used unsafely. 
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https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3177

There is not yet an upstream release to fix the issue in the 3.8 series
that we distribute. I believe there are patches we can cherry-pick. Can
somebody find them?

I assume that Python is considered to be "graft-able". Can anyone
confirm?

The upstream bug report:
https://bugs.python.org/issue42938