python3: ctypes double representation BoF (CVE-2021-3177)

sources:

• https://nvd.nist.gov/vuln/detail/CVE-2021-3177
• https://bugs.python.org/issue42938

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.

Affected aports with active support

• master: python3 3.8.7-r1
• 3.13-stable: python3 3.8.7-r0
• 3.12-stable: python3 3.8.5-r0
• 3.11-stable: python3 3.8.2-r1
• 3.10-stable: python3 3.7.7-r1